Posted in TMJ Disorders

Condylar Fractures

Introduction

The management of mandibular condylar injuries is one of the most controversial areas in the treatment of facial trauma. Fractures involving the mandibular condyle are the only facial bone fractures which involve a synovial joint. These injuries deserve special consideration apart from those of the rest of the mandible due to their anatomic differences, variations in clinical picture, unique management protocols and distinct healing potential.

Epidemiology

The incidence of fracture involving the mandibular condyle varies throughout the literature and is influenced by factors such as age, geographic location and socio-economic level of the study population. Serial studies by Kromer (1953) and Goldberg and Williams (1969) found that fractures of the condyles account for 15% to 30% of all mandibular fractures. Halazonetis (1968) and Ellis et al (1985) reported that condyle is the commonest site for mandibular fracture. Oikarinen and Malmstrom (1969), in a series of 600 mandibular fractures, found that 33.4% were in the subcondylar region. The incidence reported by certain other series are 27.7% (Elkholm, 1961), 25% (Schuchardt and Metz, 1966), 35.6% (Rowe and Killey, 1968), 32.4% (Tasanan et al, 1975), 37% (Larsen and Nielson, 1976), 47% (Van Hoof et al, 1977), 52.4% (Olson et al, 1982), 49% (Hill et al, 1984), 40% (Andersson et al, 1984), 29% (Ellis et al, 1985), 21% (Haug et al, 1990), 52.4% (Silvennoinen et al, 1992) etc.


Aetiology of condylar injuries

Facial injuries are most commonly associated with falls, motor vehicle accidents, sports-related trauma and interpersonal violence. Injury to the condyle may be caused by a variety of mechanisms, which also vary according to the characteristics of the group studied.

In adults, motor vehicle accidents account for the majority of condylar fractures, while interpersonal violence, work-related incidents, sporting accidents and falls play significant but lesser roles. In children, falls and bicycle accidents are the major causes, with motor vehicle accidents also contributing significantly. Different still are the elderly, in whom falls again constitute the primary aetiologic factor, followed by assaults and automobile accidents. Other less obvious causes of injury to the TMJ include orotracheal intubation, whiplash injury, childbirth and weight lifting.

Mechanism of condylar fractures

The condyle is a link in the direct continuity of the mandible from glenoid fossa of one side to the other. This has the effect that a fractured condyle can occur indirectly as a result of a blow to some other part of the mandible (contre-coup injury).

Factors that are considered important in determining the type of fracture and the degree of displacement are the nature, severity and direction of the traumatic force, the occlusion of the teeth and the position of mandible on impact, and anatomic considerations like the line of fracture and the influence of muscle pull, ligaments and the adjacent soft tissue.

The traumatic force

Studies of the relation between are the nature, severity and direction of the traumatic force on the resultant mandibular injury were made by Huelke (1961, 1962, 1964, 1968). Huelke and Harger (1969) found that greater than 75% of all experimentally produced fractures of the mandible were in primary areas tensile strain. Lindahl (1977) divided trauma causing condylar injury into three main groups.

  1. Kinetic energy imparted by a moving object through the tissues of a static individual. This commonly results from trauma sustained from a fist, during sporting activities, or in some industrial accidents.
  2. Kinetic energy derived from the movement of the individual and expended upon a static object example is fall during an epileptic fit or following a faint when the patient is unable to protect the face with an outstretched hand as in the case of the so called ‘parade-ground’ fracture.
  3. Kinetic energy which is summation of force derived from combination of 1 + 2 and generally produces a severe type of injury such as typically occurs in road traffic accident.

In addition to these forces, minor trauma (e.g. a yawn or pressure during dental treatment) may cause subluxation or even dislocation in those individuals who exhibit excessive laxity of the joint capsule.

In response to loading, the mandible is similar to an arch because it distributes the force of impact throughout its length. But it is not smooth curve of uniform bone, and contains discontinuities such as foramina, sharp bends, ridges and regions of reduced cross-sectional dimension like the subcondylar area. As a result, parts of the mandible develop greater force per unit area, and thus tensile strain is concentrated in these locations.

When a force is directed along the parasymphysis-body region of the mandible, compressive strain develops along the buccal aspect, and tensile strain along the lingual aspect. This produces a fracture that begins in the lingual surface and propagates towards the buccal surface. The mobile contralateral condyle moves in a direction away from the impact point until it is limited by the bony fossa and associated soft tissue. At this point, tension develops along the lateral aspect of the contralateral condylar neck, and a fracture develops. If greater force is applied to the parasymphysis-body region, the continued medial movement of the smaller ipsilateral mandibular segment will lead to bending and tension forces along the lateral aspect, and subsequent fracture of the ipsilateral condyle also.

Force applied directly in the symphysis region along an axial plane is distributed along the arch of the mandible. Because the condylar heads are free to rotate within the glenoid fossa to a certain degree, tension develops along the lateral aspect of the condylar neck and mandibular body regions, as well as along the lingual aspect of the symphysis. This leads to bilateral condylar fractures and a symphyseal fracture.

The connection between whiplash injury (cervical extension-flexion) and internal derangement of the TMJ was discussed by Roydhouse in 1973. This may be due to the stretching and tearing of the posterior and polar attachments of the disc in the cervical hyperextension phase. This typically happens in rear-end collisions when an unsupported head accelerates less quickly than the body with downward and forward displacements of the disc-condyle complex. Then, as the vehicle decelerates by braking or hitting other objects, there is a crushing impact of the already traumatised posterior attachment. Weinberg and Lapionte (1987) found TMJ internal derangement in 88% of their patients with whiplash injury. The importance of recognition of this connection and early therapeutic intervention were stressed by Manheimer et al in 1989.

Occlusion and mandibular position

Early observers felt that the presence of posterior dentition tended to reduce the incidence of condylar injury. The implication was that, as the mandible was forced superiorly and posteriorly, the dentition would meet and absorb some of the force, thereby diminishing the force received at the condyle. More recent findings show that all types of fractures occur irrespective of the dentition and occlusion. However, the presence of impacted third molars has been shown to markedly reduce the incidence of condylar fractures. The area of impacted tooth represents an area of inherent weakness, thus increasing the chance of fracture in that area and reducing the chance of condylar fractures.

The relative degree of mandibular opening at the time of impact plays an important role in the type of fracture that occurs. More recent investigations have shown that even the level of fracture varies with the degree of mouth opening. When the mouth is opened, the fracture tends to be more in the condylar neck or head region, whereas when it is closed, the fractures are in the subcondylar area.

Muscle pull

Once a fracture occurs, the associated soft tissues, particularly the muscles of mastication attached to the bony segments, determine the direction and degree of displacement or dislocation. Typically the fractured segments tend to override each other as a result of the powerful pull of the masseter, medial pterygoid and temporalis muscles. If the fracture line occurs below the attachment of the lateral pterygoid, which is most common, the medial, inferior and anterior pull of this muscle tends to displace the condylar head in that direction. This medial and anterior pull is directed towards the weakest area in the TMJ capsule, which is why antero-medial displacement and dislocation are the common patterns.


Classifications

Classically, fractures have been classified according to their location on the condyle or its neck, and the relation of the proximal segment to the glenoid fossa. Though the condylar fractures are generally classified as extracapsular, subcondylar and intracapsular, various authors have proposed many classifications down the years.

Wassmund (1934) described five types of condylar fractures.

Type I- fracture of the neck of the condyle with relatively slight displacement of the head. The angle between the head and the long axis of the ramus varies from 10 to 45 degrees. According to Wassmund, these fractures tend to reduce spontaneously.

Type II- fractures which produce an angle of 45 to 90 degrees, resulting in tearing of the medial portion of the capsule.

Type III- the fragments are not in contact, and the head is displaced mesially and forward owing to traction of the lateral pterygoid muscle. The fragments are generally confined to within the glenoid fossa. The capsule is torn, and the head is outside the capsule. Wassmund recommended an open reduction for this type of fractures.

Type IV- fractures where the condylar head articulates in an anterior position to the articular eminence.

Type V- vertical or oblique fractures through the head of the condyle. Wassmund suggested a bone graft to reconstitute the condylar head when considerable displacement of the fragments has occurred.

Other classifications of historical importance include those of Thoma (1958), Köhler (1951), Dingman and Natwig (1964), Rowe and Killey (1969), Reichenbach (1969) etc.

MacLennan (1952) evolved a clinical classification mainly based on the relationship of the fractured condyle to the remainder of the mandible.

Type I                        Non-displaced fracture

Type II                      Fracture deviation, where there is simple angulation of the condylar process to the major fragment. (e.g. greenstick fracture)

Type III                    Fracture displacement, where there is simple overlap of the condylar process and major mandibular fragments.

Type IV                      Fracture dislocation, where the head of the condyle is completely disrupted from the articular fossa.

Spiessl and Schroll (1972) suggested a simple classification listing the common sites and types of displacement.

  1. non-displaced fracture
  2. low-neck fracture with displacement, mostly with contact between fragments
  3. high-neck fracture with displacement, mostly without contact between fragments
  4. low-neck fracture with dislocation
  5. high-neck fracture with dislocation
  6. intracapsular fracture of condylar head

Lindahl in 1977 proposed a classification based on radiographic views in two planes at right angles to each other. He took into consideration three major aspects. They are the anatomic location of the fracture, relationship of condylar fragment to mandible and relationship of condylar head to the glenoid fossa.

  1. Anatomic location of the fracture
  2. Condylar head
  3. Condylar neck
  • Subcondylar
  1. Relationship of condylar fragment to mandible
  2. Nondisplaced
  3. Deviated
  • Displacement with medial or lateral overlap
  1. Displacement with anterior or posterior overlap
  2. No contact between fractured segments
  3. Relationship of condylar head to fossa
  4. Nondisplaced
  5. Displacement
  • Dislocation

Helmut Schüle in 1986 gave an exhaustive list of the types of injuries to the TMJ region

1.1.1      Contusion of the TMJ

  • Fractures of the condylar process without displacement of the fragments
    • Fractures of the condyle

Transcapitular.

Subcapitular.

  • Fractures of the condylar neck
  • Basal fracture of the condylar process.
  • Fractures of the condylar process with displacement of the fragments.

Displacement of the small fragments.

Ventrally.

Dorsally.

Medially.

Laterally.

Torsion of fragments

Displacement with contraction

Compression fracture of the condyle.

  • Sprains of the TMJ
  • Dislocation (subluxation) of the TMJ.

Dislocation of the condylar head (condyle).

Anteriorly.

Posteriorly

Cranially (central dislocation).

Medially

Laterally.

  • Fracture dislocations of the condylar process.

Dislocation of the condylar head (condyle).

Anteriorly

Medially

Laterally

Dorsally.

Injuries of the TMJ other than fractures

Although the most commonly documented result of trauma to the TMJ and condyles is fracture, other injuries occur as well, and must be considered in the differential diagnosis.

Contusion

Contusion of the TMJ refers to the consequences of blunt trauma to the joint region that is injurious but has not resulted in fracture or in tearing of the capsule.

Effusion and haemarthrosis

Like any other joint, the TMJ reacts to trauma with serous or haemorrhagic effusion. This often leads to distension of the joint capsule with varying amounts of discomfort. Frequently, deviation of the mandible away from the affected side occurs as a result of downward pressure on the condyle from the production of fluid within the joint. This produces facial asymmetry and malocclusion.

Rupture of minor blood vessels in the joint might cause a pooling of blood in the joint space. This condition, called haemarthrosis, presents with features similar to a simple effusion, but is more dangerous since it is thought to predispose to serious complications like infection or joint ankylosis.

Intracapsular soft tissue injury

Very often, a blunt trauma can lead to damage of the articular disk, articular cartilage or both. The joint typically responds with a serous effusion and/or muscle spasm. As the case may be, joint presents with a clinical deviation of the mandible and severe pain.

TMJ sprain

Sprain refers to strain of the ligaments and capsule of the joint with microscopic or macroscopic lacerations but without permanent change in the position of the condyle. Secondary phenomena are serous effusion or haemarthrosis. Sprains differ from dysfuncional arthropathy and habitual subluxation in that they are produced from by the action of a force which produces acute injury.

Subluxation

The term subluxation implies the displacement of the condylar head from the glenoid fossa, which the patient can reduce himself. This is usually the result of excessive laxity of the joint capsule coupled with varying degrees of continuous or intermittent trauma.

Dislocation

A dislocation is considered to be present if the condylar head is expelled from the glenoid fossa and remains fixed there. The condyle is often dislocated and fixed without laceration of the relatively flaccid capsule. The condition may be unilateral or bilateral. When this is associated with a fracture of the condyle, it is termed a ‘fracture-dislocation’. Dislocations can occur anteriorly, posteriorly, laterally and superiorly.

Anterior dislocation (Heslop, 1956)

Anterior dislocation occurs when the condyle moves anterior to the articular eminence. This is the most frequently seen condition, and it represents a pathologic forward extension of the normal translational movement of the condylar head. This may be caused by yawning, oral sex, phenothiazine use, and trauma. Traumatically induced anterior dislocations are usually bilateral, but it may occur unilaterally as well. Diagnosis is made by these features: an anterior open bite with inability to close the mouth, severe pain in the region anterior to the ear, absence of the condyle from the pre-auricular fossa with a pre-auricular depression, inability to move the mandible except slight opening, difficulty in speaking and a prognathic appearing lower jaw. An antero-lateral variant is described by Monis and Hutton (1957).

Posterior dislocation (Helmy, 1957)

This implies a coexistent fracture of the base of the skull or the anterior wall of the bony meatus.

Superior (Central) dislocation (Zechal, 1977)

Superior dislocation into the middle cranial fossa must be associated with a fracture of the glenoid fossa. The medial and lateral elevated margins of the fossa normally meet the articular surface of the condyle on impact, thus protecting the central weak area of the fossa and this injury is probably most often related to a small bounded condyle which fails to impinge on the margins.

Lateral dislocation (Allen and Young, 1969)

These authors describe two subgroups

Type I which is lateral subluxation

Type II a complete subluxation, where the condyle is forced laterally and then superiorly to enter the temporal fossa. An essential prerequisite for lateral displacement is a fracture of the body of mandible that occurs near the symphysis.

It should be emphasised that all the groups other than anterior dislocation are very rare.

 


Diagnosis of condylar injuries

Diagnosis is based on a suggestive history, determination of the direction of force, clinical signs and symptoms and radiographic visualisation of the joint and subcondylar region.

Clinical features

An overall evaluation of the patient with traumatic injury should precede evaluation of the maxillofacial region. Numerous symptoms point generally to traumatic damage in the joint region. They include pain, tenderness and swelling in the joint region, limitation of mouth opening and malocclusion. Supplementing these suggestive symptoms, different fracture types provide characteristic symptoms.

The deviation of mandibular path at rest or on attempts to open the mouth gives vital clues on the type of injury to the joint. A post-traumatic effusion or haemarthrosis may distract the joint surfaces, causing posterior open bite on the affected side with deviation of the mandibular midline to the opposite side. In unilateral dislocation without fracture, the mandibular midline is deviated to the contralateral side with inability to occlude being more pronounced on the affected side. Bilateral dislocation without fracture is likely to produce an appearance of prognathism with almost complete inability to occlude any teeth.

Three rare varieties of dislocations give characteristic findings

  1. Central dislocation through the glenoid fossa, without fracture of the condylar neck, produces deviation of the mandibular midline to the ipsilateral side, gagging of the ipsilateral posterior teeth, contralateral posterior open bite and absolute immobility which persists even under general anaesthesia.
  2. Lateral dislocation of the condylar head into the temporal fossa, where it would be palpable, is associated with a marked crossbite on the affected side. There will also be signs of associated fracture in some site in the anterior part of the mandible.
  3. Worthington in 1982 described a case of extreme antero-superior dislocation without fracture in which the condyle was displaced into the temporal fossa.

Apart from a suggestive history, the patient with fracture of mandibular condyle presents with these symptoms.

  1. Evidence of trauma, which may include facial contusions, abrasions, laceration of the chin and ecchymosis and/or haematoma in the TMJ region. These injuries should alert the clinician not only to possible fractures in the area of direct injury but also indirect injury to the ipsilateral as well as the contralateral TMJ.
  2. Bleeding from the external auditory canal, which may indicate fracture of anterior tympanic plate from a posteriorly displaced condyle.
  3. Visually noticeable or palpable swelling over the TMJ. This may be due to haematoma or oedema or may be secondary to a laterally displaced condylar head, which may be directly visible under the skin.
  4. Facial asymmetry as a result of soft tissue oedema or due to foreshortening of the ramus caused by overlap of proximal and distal fracture segments.
  5. Pain and tenderness to palpation of the affected joint. There may also be significant pain on attempted manipulation of the jaw by the patient or by the clinician.
  6. Crepitation over the affected joint secondary to friction of the irregular fracture ends sliding over one another during manipulation.
  7. Malocclusion, the type of which depends on the type of injury sustained. A unilateral condylar fracture usually results in ipsilateral premature contact of the posterior dentition on that side. This foreshortening may also result in contralateral posterior open bite due to the canting of the mandible. Bilateral condylar fractures may result in a marked anterior open bite and retrognathia. The medial pterygoid and masseter muscles exert a superior and posterior pull on the distal mandibular segment, causing it to telescope past the condylar segments. This telescoping results in premature contact of the posterior occlusion with rotation of the mandible around this point, and anterior open bite. Gagging of the posterior occlusion may also occasionally be seen because of the posteriorly positioned mandibular segment.
  8. Deviation of the mandibular midline may be seen both at rest and with attempted excursion of the mandible. At rest, this is because of the shortening of the ipsilateral ramus, causing the mandible to deviate towards the fracture side. In a unilateral fracture, with attempted opening of the mouth, the lateral pterygoid on the fracture side is unable to effect pull on the mandible, while the unaffected contralateral muscle functions normally. This inequality of function causes an exaggeration of the deviation towards the fractured side. Similar deviation is seen with protrusive movements. Attempts to move the mandible laterally away from the fractured side are met with great difficulty and discomfort because of the ineffective lateral pterygoid muscle. Bilateral condylar fractures may result in little deviation because both condyles are involved. As mentioned, an anterior open bite will be seen with retrognathia in addition to a severely limited range of motion.
  9. Muscle spasm (splinting) with associated pain and limited opening.
  10. Associated fractures (dento-alveolar / symphyseal / body of the mandible / angle / zygomatic complex regions)

Radiography

A variety of imaging methods is available to assist in accurate diagnosis and localisation of condylar injuries. The imaging techniques allow visualisation of the internal structures of the joint and the actual position of the fractured segments, and help in arriving at a proper treatment plan based on an accurate diagnosis. This usually requires at least two radiographs to be obtained, at right angles to each other.

Conventional radiography

The conventional radiographic techniques available to view the condylar region include

  1. Orthopantomogram (OPG)

The panoramic radiography gives the overall relationship of the proximal and distal fragments. The typical findings of condylar fractures visible on OPGs are a shortened condylar-ramus length, the presence of radiolucent fracture line or, in the case of overlapped segments, presence of a radio-opaque double density. A high OPG centred on the condyles in the mouth open position (if possible) would be of good help in visualisation of the condyle.

Chayra et al (1986) found that when compared to the standard mandibular series, the OPG has a higher accuracy in detecting all types of mandibular fractures. They site decreased cost, as well as lower radiation exposure, as advantages of the panoramic view. However, it requires the patient to be able to stand erect and immobile for an adequate period of time.

  1. Lateral oblique view of mandible

This is the radiographic view classically used for visualising the condylar region. This is still applicable if OPG facilities are not available; a view centred on the vertical ramus should be asked for. Displacements in the antero-posterior plane are well visualised in this radiograph.

  1. PA view of mandible

The postero-anterior (PA) or antero-posterior (AP) views have been traditionally used to view the subcondylar region and to detect lateral or medial displacements of the condylar head. This technique gives a good representation of the proximal and distal fragments in a medio-lateral plane. In most cases, the mastoid process overlaps the condylar region and the joint proper may not be adequately visualised.

  1. Reverse Towne’s view

The classical Towne’s (AP with 30° deviation) and the reverse Towne’s view (PA with 30° deviation) have been used to circumvent the overlapping of adjoining bony structures. These techniques show the condylar heads better than the conventional PA or AP, without superimposition on the image of the base of the skull.

The technique of modified Towne’s view, directing the X-ray beam superiorly an additional 5° may be used to further project the condyles below the mastoid process. The modified Towne’s view shows the degree of medial and lateral displacement of the fracture and allows for the visualisation of subtle deviation, such as seen in green-stick fractures that are not readily evident on panoramic view.

  1. Transcranial views for TMJ

These coned down views may be helpful in defining the relationship of the proximal condylar fragment to the glenoid fossa, and also in delineating the pattern of high (intracapsular) fractures. A lateral-oblique transcranial view is found to be the optimal technique for this purpose.

Tomography

Conventional tomography, either in coronal or sagittal planes could be made use of in cases where conventional radiographs have not been definitive or are not possible due to associated injuries. The advantage of this method is that it can be used without turning the face of the patient downward or other manipulations which may be difficult in an injured patient. It is often available at a lesser cost than CT scanning or MRI.

CT Scan

Computed tomography (CT) scans yield excellent bony detail of the facial skeleton in multiple views and, with adjustment of the contrast of the machine, give adequate soft tissue detail. It shows the relationship of the condyle to the fossa more precisely than conventional radiographs. It also better demonstrates fine bony alterations at the fracture site together with the direction of displacement of the fractured condyle in any plane. To a lesser extent, it can demonstrate changes in the position and function of the disc. Another advantage of CT scanning is the less dependence on patient co-operation, which is useful in severely injured or uncooperative patient.

The generally accepted indications for CT scanning are

  1. Significant displacement or dislocation, particularly if open reduction is contemplated.
  2. Suspected central dislocations of the condyle through the glenoid fossa, where it will also demonstrate the presence of any intra- or extracerebral haematoma
  3. Limited range of motion with a suspicion of mechanical obstruction caused by the position of the condylar segment
  4. Alteration of the surrounding osseous anatomy by other processes, such as previous internal derangement or TMJ surgery, to the point that a pre-treatment baseline is necessary
  5. Inability to position the multiple trauma patient for conventional radiographs.

The disadvantages of CT scans are the high cost, limited availability and radiation exposure.

Magnetic Resonance Imaging (MRI)

The MRI yields excellent soft tissue detail but lesser bony resolution compared to the CT scan. It may be used as an adjunctive study if significant soft tissue injury of the joint is suspected. It has the additional advantage of no ionising radiation exposure and the ability to obtain images in any desired plane of view by reconstructing the image data.

Harms et al (1985) used surface coil MR imaging in the diagnosis of internal derangement of TMJ. Modern techniques include MR fast scanning with T1 and T2 weighted imaging (Schellhas and Wilkes-1989) and dual-surface coil MR imaging of bilateral joints (Shellock and Pressman-1989). Schellas (1989) also used the MR to image the muscles of mastication. Accumulations of intra-articular fluid can be picked up by their signal intensity on GRASS (gradient-recalled acquisition in steady state) scans.

Arthrography

Arthography, by introducing a contrast medium into the upper and lower joint spaces, provide the best feasible method of visualising the position of the meniscus in internal derangement  (Wilke 1978). It is not a suitable method for use in acutely injured patient as it involves considerable subject co-operation during the examination. It can be combined with MRI as ‘two-compartment arthrography and MR’ (Schellhas et al 1988). Both methods can be used with a cinematic or videotape imaging to provide a dynamic scan in movement.


Management

The proper management of the fractured mandibular condyle is one of the most controversial topics in maxillofacial trauma. This controversy is reflected in a wide variety of opinions and proposed treatment modalities offered in the literature.

Goals of therapy

The objective of the surgeon treating condylar fractures is primarily directed towards functional rehabilitation. The generally accepted goals to be achieved in treatment are the following:

  1. Stable occlusion
  2. Restoration of inter-incisal opening
  • Full range of mandibular excursive movements
  1. Minimise deviation
  2. Relief from pain
  3. Avoid internal derangement of the TMJ
  • Avoid growth disturbance.

Conservative and functional management

This is a term used to cover all methods of treatment other than surgical intervention. Its objective is either to allow bony union to occur where there is no significant displacement of the condyle or in the case of fracture dislocation, to produce an acceptable functional pseudoarthrosis by re-education of the neuromuscular pathways. It appears that bony union occurs regardless of treatment if there is contact between proximal and distal fragments. These techniques are applicable therefore in all cases of unilateral or bilateral fracture other than in certain gross displacements in superior or lateral directions or certain other circumstances which will be detailed later.

The aims of conservative and functional treatment are to encourage active movement of the jaw as early as possible provided that the patient can bring his or her teeth into normal occlusion. Excessive pain or persistent malocclusion will require periods of intermaxillary fixation. Such a period of fixation should not exceed 10 days if there is a risk of ankylosis in circumstances, which has previously been outlined. In the case of children one must be aware of the remarkable remodelling capacity of the condyle which may persist in many subjects into teenage.

Dahlstrom et al in 1989 followed up 36 patients, 15 years after conservative treatment of condylar fractures. In 14 children there was o major growth disturbance observed and in most cases there were no signs of the earlier fracture and function of the masticatory system was good. In eight teenagers the anatomical and functional restitution of the TMJ was not as good as in the children, but hardly gave rise to objective symptoms. In 14 adults signs of dysfunction were frequently observed but not considered serious by the patients. The study involved careful analysis of the preceding fractures clinical examination including detailed measurement of mandibular mobility, estimation of biting force and radiographic analysis of the post treatment appearance of the articular fossa and the condylar head. Of the 14 adult patients assessed nine reported persisting discomfort although this was never rated as serious. Subjectively altered appearance was reported by three subjects and TMJ sounds were common in adult group. There was a significant reduction in the level of biting force.

Konstantinovic and Dimtrifevic (1992) compared 26 surgically and 54 conservatively treated unilateral condylar process fractures by standardised clinical examination and evaluation of computer stimulated graphic presentations of postero-anterior radiographs of the mandible. Surgical approach was through a submandibular incision with wire osteosynthesis. Using clinical parameter (maximal mouth opening, deviation, protrusion) no statistical differences between surgically and conservatively treated fractures were found. However the radiographic examinations showed a statistically better position of the surgically reduced condylar process fractures. At a minimum of 1 year after treatment the maximum mouth opening in both the groups has a mean of 3.9cm. A mean index calculated for deviation was 7.3% in both groups. In jaw protrusion also there was no significant difference. In conservatively treated group however there were no complications during the healing period, but in the surgically treated patients, four (15.4%) had infection of the wound and or transitory paresis of the marginal branches of the facial nerve.

Closed reduction

Placement of archbars or splints, immobilising the jaws for 2 to 4 weeks has been the mainstay of therapy for many decades.  Some authors have suggested that intermaxillary fixation (IMF) be used on all fractures as the initial insult leads to inflammation.

Lentrodt (1982) among other European authors believe that in displaced fractures of the neck of the condyle, the joint must be relieved of stress by opening the occlusion by 2 to 3 mm with an acrylic block in the distal molar region in the side of the fracture. They call this therapy ‘extension by means of a fulcrum’. The height of the fulcrum depends on the radiographically determined degree of ramus shortening. After 8 days, the fixation is removed and the patient is followed by functional movements with elastics applied in the anterior region.

According to the clinical data reported by MacGregor and Fordyce (1957), bony union appears to occur after condylar fractures regardless of whether intermaxillary fixation is employed or not. Similar observations have been made in experimental fractures in the rhesus monkey (Walkers-1960, Boyne-1967).

Open reduction

In surgical (open) reduction, the objective is to perform a repositioning of the fractured condyle as near to its anatomical location as possible. This is achieved by exposing the condylar fragment, reducing it to a normal relationship with the mandibular fragment and then fixing it in that position.

As the results of conservative treatment are good overall with a dysfunction rate of 15%, it is essential to decide which cases merit a surgical approach. Moreover surgical access in cases of fracture dislocations tends to be difficult with a real risk to branches of 7th cranial nerve and the maxillary artery.

Indications

Zide and Kent (1983) divided indications for open reduction of a condylar fracture into absolute and relative. The absolute indications are

  1. Displacement of the condyle into the middle cranial fossa
  2. Inability to achieve occlusion with a closed reduction
  3. Lateral fracture-dislocation of the condyle and
  4. Invasion of the joint space with a foreign body.

Relative indications for open reduction include

  1. Bilateral condylar fractures where establishing vertical facial height is important.
  2. Associated injuries that dictate early or immediate function
  3. Associated medical conditions that indicate an open reduction is preferable to maxillo-mandibular fixation and
  4. Conditions in which treatment has been delayed and early healing in a malaligned position has commenced.

Surgical approaches

The selection of surgical approach for open reduction depends on a variety of factors, which include the level at which the fracture has occurred, the degree of displacement or dislocation and the planned method of fixation.  Other factors are the quest for optimal access for visualisation and instrumentation, aesthetic factors like scarring, minimising injury to vital structures like nerves, blood vessels and ducts of salivary glands, surgeon’s convenience and patient preference.

The advantages of all extra-oral approaches are that a fracture is visualised and approached more directly than from an intra-oral approach. Each of the different approaches is designed to prevent or minimise injury to the branches of the facial nerve. The major disadvantages of all extra-oral approaches are visible scars and possible injury to the branches of the facial nerve.

It is claimed that the intraoral technique obviates the known complications of external open reduction such as the possibility of facial nerve injury, external scar, ischaemic compromise to the proximal segment and undoubted technical facilities. The main disadvantage of this approach is that exposure of the condylar segment is limited. Orientation and stabilisation of the fragment can at times be difficult. This is especially true if the fragment is medially displaced.

The options for access to fracture site of the condyles include

  1. Intra-oral approach
  2. Pre-auricular approach
  3. Retromandibular approach
  4. Submandibular approach

1.     Intra-oral approach

The intra-oral approach is indicated for minimally displaced low subcondylar or ramus fractures where the patient needs to have function. The technique of intra-oral approach to the fractured condyle was first described by Steinhauser in 1964 and was amplified by Niederdellmann (1986) and Jeter et al (1988). Lachner et al (1991) published the first results of a series of patients who had been surgically treated by intraoral open reduction of subcondylar fractures with semirigid fixation by use of miniplates.

This approach is very similar to that used in an intra-oral ramus osteotomy procedure. The mouth is propped open with a biteblock. Local anaesthetic with vasoconstrictor is injected into the medial and lateral regions of the mandibular ramus. An incision is made approximately halfway up the ascending ramus through the periosteum overlying the external oblique ridge. The lateral aspect of the ramus is exposed so that the entire surface of the ramus from the sigmoid notch to the angle region is exposed. When a condylar segment is medially displaced, the segment can be uprighted by sliding a periosteal elevator on the medial aspect of the ramus above the entrance of the inferior alveolar nerve. When the posterior elevator contacts the fragment, it can be used to push the fragment posterior and lateral. Fixation is accomplished through a combination of percutaneous incisions and lateral manipulation of plates and screws.

2.     Pre-auricular approach

The extra-oral pre-auricular approach with rigid fixation has been described by Koberg and Momma (1978), Petzel (1982) and Choung and Piper (1988). Al Kayat and Bramley in 1979 described a question mark shaped incision and elevation of a flap that includes in it both the main branches of the superficial temporal artery.

The preauricular incision gives a limited view of a fractured joint. The skin incision maybe made in a pre-auricular crease. The plane of dissection is immediately adjacent to the external auditory canal. As such the facial nerve injury is prevented by approaching from behind the major branches of facial nerve. Once the dissection reaches bony structures, the nerve branches are protected in the overlying soft tissue.

The incision begins at the anterior-superior base of the helix and is continued along the curvature inferiorly toward the crus helicis in the natural skin fold. Retracting the skin with digital pressure, the incision is carried over the crest of the tragus, following the outline. Dissection is carried on anteriorly along the cartilage just anterior to the perichondral plane to the level of the capsule. Superiorly, dissection is carried down to the temporalis fascia.  These two regions are then joined by blunt and sharp dissection through the confluence of fascia over the zygomatic arch. At this point, the joint capsule will be visible. Opening into the superior joint space is made by sharply incising over the superior glenoid tubercle and extending inferior through the capsule, and the condylar head is exposed. Placement of a towel clamp or a similar instrument to distract the distal segment is often necessary. A 0.62 threaded K-wire can be used to engage and control the proximal segment.

3.     Retromandibular approach

The retromandibular approach gives the best access to the fractures of the condylar neck with a single incision. It was first described by Hinds (1958, 1967, 1972). It provides excellent exposure of the ramus and the subcondylar region. Ellis and Zide (1995) believe that this approach allows access to the ramus by spreading between the buccal and mandibular branches of the facial nerve. This accounts for the low incidence of facial paralysis with this approach.

The incision is about 2.5 cm long and is made posterior and parallel to the posterior border of the ascending ramus from a point just below the lobe of the ear inferior to a point just above the angle of the mandible. The incision is vertical and is about 2 cm behind the posterior border of the mandible. The initial skin incision extends through the skin and subcutaneous tissues. Once down to the platysma, the dissection is bluntly directed forward toward the posterior border of the mandible. Zide and Ellis used sharp dissection of platysma while Van Sickels and Parks (1999) recommends blunt dissection. The dissection is below and behind the superficial lobe of the parotid. When the posterior border of mandible is reached, the tissues are bluntly spread, exposing the ramus. The pterygomasseteric sling is either sharply or bluntly dissected in a subperiosteal plane superiorly toward the fracture.

Rhytidectomy incision

The rhytidectomy incision has the advantages of a retromandibular incision and a good cosmesis. It was originally described as a ‘face-lift’ approach by Zide and Kent in 1983 to access the fractured condyle. It was described as a preauricular incision under the lobe of the ear that extended postauricularly on the posterior surface of the auricle.

In 1995, Ellis and Zide described this approach as a variant of the retromandibular approach with better cosmesis. The major disadvantage is the added time required to close the broad incision. The incision begins approximately 1.4 to 2 cm above the zygomatic arch. It can be just anterior to the pinna and continues under the lobe of the ear and approximately 3-mm onto the posterior surface of the auricle. It continues posteriorly toward the hairline for a few centimetres. The initial incision is carried through skin and subcutaneous tissue. A skin flap is elevated through this incision, using sharp and blunt dissection undermining to create a subcutaneous pocket that extends below the angle of the mandible and a few cms anterior to the posterior border of the mandible. From here, the dissection continues as described for the retromandibular approach.

4.     Submandibular approach

Access to the mandibular ramus, angle and posterior body is readily achieved with the submandibular approach, initially described by Risdon in 1933. It is seldom used alone for isolated condylar fractures. Visualisation of the superior aspects of the ramus is difficult with this approach. It is most useful for low subcondylar fractures and ramus fractures. Although the scar is hidden in a skin crease, cosmesis is not very good. This approach may be combined with a pre-auricular incision for better access to the entire ramus. Transient weakness of the 7th nerve is frequently seen with this approach, probably as a result of retraction.

The incision is 4 to 5 cm long in the skin crease line. The initial dissection is carried sharply through skin and subcutaneous tissue down to platysma. The subcutaneous tissues are widely undermined. Dissection is continued in layers, going through platysma and the deep cervical fascia. The pterygomasseteric sling is divided at the inferior border of the mandible. Subperiosteal dissection of the ramus is done to expose the fracture. Distraction of the distal segment is necessary to allow for space to align the proximal segment.

Methods of immobilisation of the condyle

Once the proximal segment is visualised and the fracture reduced, the fragments can be immobilised in a number of ways.

Simple Soft Tissue Repair without Fixation:

This was described by Silverman in 1925 and there is a report by Raveh et al (1989).       It is combined with a period of intermaxillary fixation of approximately 10 days in the latter report. There must be a significant risk of re-displacement due to the action of the lateral pterygoid muscle although the results of the latter authors would appear to be satisfactory with deviation of more than 4mm seen in only one case out of 29 postoperatively.

Transosseous wiring

Transosseous wiring is occasionally used in low subcondylar fractures, particularly those extending through the sigmoid notch. This is done through a submandibular incision. First the major fragment is wired so that this may be used for a downward traction to improve access to the condylar fragment. For passing wire through the smaller condylar fragment, a pull through wire may be used.

For higher level fractures preauricular incision is used. Thoma (1945) advocated a specific sequence for this method. The fragments are drilled obliquely from the external surface to the fracture surface. If there is lateral overlap of the condylar fragment, this is drilled first. An instrument such as a small bone elevator is used to reverse the overlap so that the lower segment becomes accessible to drilling. A pull-through wire is again needed for the second insertion. In cases of medial overlap, this sequence is reversed.

In fracture dislocation, transosseus wiring alone may be insufficient to resist the displacing action of the lateral pterygoid muscle. One of the following additional methods may be employed unless the method of detaching lateral pterygoid insertion described by Hendrick et al has been used. An alternative lassooing type technique has been described by Messer (1972) which is claimed to give more stability.

Bone pins

Archer (1975) described the insertion of pins into the condylar head and neck which were connected with an external bar and universal joints. Thoma (1945) had previously described a similar technique but placed the pins in the condylar neck and zygomatic bone. This would need to be combined with period of intermaxillary fixation.

Glenoid fossa-condyle suture

Wassmund (1935) described drilling a small hole through the lateral edge of the glenoid fossa and the related edge of the condylar articulating surface. A chromic catgut suture was looped through and tied. It may however resorb and loosen prematurely with unpredictable results as reported by Herfert (1961).

Kirschner Wire

A Kirschner wire may be drilled vertically through the main mandibular fragment from the angle, avoiding the inferior alveolar bundle, so that it enters the fracture, interface and can be further inserted into the condyle, which has previously been reduced (Lund-1972, Vero-1968). This technique has been modified by Brown and Obeid (1984) whereby Kirschner wire is inserted into the proximal condylar fragment and after this a groove is cut for its base in the main distal mandibular fragment. Two interosseus wires are then used to secure the basal part of the pin.

Intramedullary Screws

Petzel (1982) described use of an intramedullary screw transfixing the distal and proximal fragments. The screw was inserted through a submandibular approach. Kitayama (1989) described the use of similar type of screw via an intraoral approach. Specialised instruments like tapping drills, a variety of lengths of screws and specialised forceps are required for placing the screws.

Bone Plating

The use of small compact bone plates has tended to revolutionise practice in relation to stabilising the fracture proximal condylar fragment and should be regarded as the method of choice in view of its rigidity and relative ease of application. Robinson and Yoon (1960) mentioned two holed plates while Koberg and Momma (1978) advocate a four-hole plate, which has tended to become standard. An added advantage is that bone plates can be placed on a relatively small proximal fragment first, allowing for the creation of a handle to more effectively manipulate the fragment into an appropriate reduction. Currently available bone plating systems are equipped with instrumentation for percutaneous placement of screws, a provision which may be of use in cases where the incision do not allow for adequate access.

Three useful plating techniques are described.

  1. Extra-oral approach through the preauricular route
  2. Intraoral approach
  3. Osteotomy – extracorporeal reduction technique through a submandibular incision.

Extra-oral Approach through Preauricular Route and Plating:

The following has been described by Koberg and Momma (1978). Under general anaesthesia a preauricular Al-Kayat and Bramley incision is made. The incision is deepened carefully in layers with plane superficial to perichondrium of external auditory meatus. By careful blunt dissection the fractured surface of proximal fragment is located and identified.

Next step is gentle reduction into anatomical position of the proximal fragment. A helpful technique is by insertion of a bone pin into the neck and manipulating the proximal fragment into its correct position. Extensive stripping of soft tissue attachment should be avoided in order to reduce risk of ischaemic necrosis.

The jaws should be placed in intermaxillary fixation so that the proximal fragment can be manipulated into a correct relationship with the distal segment. Once this is attained a miniature four-hole plate of Wurzburg type is used to maintain the relationship. The incision closed in layer A miniature suction drain helps in reducing ecchymoses. It may be helpful in placing the patient in training elastics for 2-10 days.

Choung and Piper (1988) described reduction of the condyle in the manner indicated above together with concomitant repair of the discal injury. Once the condyle has been plated, the operating microscope is used to facilitate any necessary manipulations on the meniscus.

Intraoral Approach and Plating

The following account is based on the technique described by Lachner et al (1991). Early case selection confined itself to displaced low subcondylar neck fractures (extra capsular). The stages in the procedure were as follows.

Under general anaesthesia the subcondylar fractures were first managed by the following technique and subsequently other mandibular fractures were treated. Incision was put along the anterior border of ascending ramus and the masseter muscle was reflected laterally to the posterior border at a subperiosteal level. The sigmoid notch was identified so that Bauer type retractor could be positioned on it. The proximal segment was then carefully identified. If this proximal segment was displaced medially the mandible was distracted inferiorly with Mason type gag to position the proximal segment laterally.

A four-hole miniplate of Wurzburg type was then attached to the proximal segment with one or two screws. The periosteum of the proximal segment was elevated only to the degree necessary for plate placement so as to preserve as good as blood supply as possible. A percutaneous trocar was placed through a horizontal stab incision in the pre-auricular region (this should be done bluntly after initial skin incision so as to avoid damage to facial nerve branches) so that the correct angulation could be obtained for making the drill holes. Intermaxillary fixation was instituted. The plate was then attached to the distal segment with two further screws.

The incision was closed. Patients were training elastics between their fixation bars for 2-10 days.

Submandibular Approach for Osteotomy – Extracorporeal Reduction Technique:

Mikkonen et al (1989) described access to a fracture dislocation of the condylar head through a submandibular approach which was combined with a vertical subsigmoid osteotomy of the ramus to locate the proximal fragment. The minor osteotomised segment plus the condylar head were then reduced extracorporeally and firmly joined together before reimplantation in their correct anatomical position. This obviously required sectioning of the attachment of the lateral pterygoid muscle to the condylar head.

This technique which was originally described in conjunction with inter-osseous wiring has been modified as follows for use with bone plates by Schnetler and Juniper (1992). In their approach, a submandibular incision is made and the ascending ramus divided between the sigmoid notch and the angle of the mandible using a technique similar to that used in a vertical subsigmoid osteotomy. Bare miniplates are fitted and then removed prior to the completion of osteotomy cuts. After the fragment is removed the dislocated head of the condyle is readily visible and can be retrieved through the same incision. The fracture site at the condylar head can be reconstructed with ease away from the patient and semirigid fixation applied using a miniplate. The reconstructed osteotomised ramus and condylar head can now be reinserted through the wound and plated to the predetermined position. Downward traction on the mandible is usually required at this point and has been achieved with a circum-mandibular wire brought out through the submandibular incision. Post operatively early mobilisation of jaw is encouraged. The authors report three successful cases. They mentioned the risk of avascular necrosis but state that reports to date do not suggest that this has been a problem.


Specific Treatment of Condylar Fractures:

The following factors should be considered.

  1. The age of the patient whether under 10 years of age, 10-17 years of age, adults.
  2. Whether the fracture is intracapsular or extracapsular (low condylar neck or high condylar neck)
  3. Site, whether unilateral or bilateral
  4. Whether the occlusion is undisturbed or whether there is malocclusion.

Children under 10 years of age:

This group has been shown to be more likely to develop growth disturbance or limitation of movement than other groups. If malocclusion is present entirely as a result of condylar injury it should be disregarded because spontaneous correction will take place as the dentition develops. Displaced condylar neck fractures will undergo functional restitution in most cases. Unilateral and bilateral fractures are treated the same. Treatment should be entirely functional where possible. Indirect immobilisation by intermaxillary fixation is indicated for control of pain and should be released after 7-10 days. Where an intracapsular fracture has been diagnosed careful follow up and monitoring of growth is required and treatment with myofunctional appliances instituted if subsequent mandibular development is reduced.

Adolescents:   10-17 years of age

The same principles apply to this group with some modification. If malocclusion is present, the capacity for spontaneous correction is less than in younger group. Malocclusion is therefore an indication for intermaxillary fixation for 2-3 weeks. The dentition at this stage is suitable for application of simple eyelet wires.

Adults:

Unilateral Intracapsular Fractures:

The occlusion is usually undisturbed and the fracture should be treated conservatively without immobilisation of the mandible. Occasionally slight malocclusion is noted, particularly when there is associated effusion in the joint in which case simple intermaxillary fixation with eyelet wires should be applied for 2-3 weeks.

Unilateral condylar neck fractures:

If the fracture is undisplaced the occlusion will generally be undisturbed and no active treatment is necessary. A fracture dislocation will often induce significant malocclusion due to shortening of ramus height and premature contact of molar teeth on that side. A low condylar neck fracture is probably best treated by open reduction in these circumstances.

In the case of a high condylar neck fracture with extensive displacement and malocclusion, intermaxillary fixation is applied and maintained until stable bony union has occurred i.e. 3-4 weeks. In spite of maintaining occlusion by intermaxillary fixation relapse may take place when the fixation is removed. As that is usually slight it can be corrected by a combination of occlusal grinding and spontaneous adaptation.

Bilateral Intracapsular Fractures:

The occlusion is usually slightly damaged in these cases. The degree of displacement of the two condyles may not be the same and it is best to immobilise the mandible for the 3-4 weeks required for stable union. It used to be thought that this would predispose to chronic limitation of movement but post-reduction physiotherapy in the form of simple jaw exercises if effective in preventing this.

Bilateral condylar neck fractures:

These fractures present the major problem in treatment. There is usually considerable displacement of one side and/or the other. Even if displacement is not evident when first seen, the fractures are inherently unstable and functional treatment is contraindicated. Although the application of intermaximally fixation will establish occlusion, it will not reliably reduce the fracture on both sides. Operative reduction of atleast one of the fractures to restore ramus height is desirable. In the case of bilateral high condylar neck fractures, where operative reduction is likely to be difficult, intermaxillary fixation should be applied for up to 6 weeks. If strong arch bars or even cap splints are applied this will allow the use of intermittent intermaxillary elastics at night for several weeks after fixation is removed. This technique may encourage better functional remodelling.

Although ankylosis of the temporomandibular joint itself does not occur with condylar neck fractures, exuberant callus formation round grossly displaced fragments may cause extra articular interference with joint excursion. When a bilateral fracture of this nature is associated with a major mid facial fracture, operative reduction on both sides is desirable. It should be appreciated that this represents a considerable amount of operating time even in skilled hands. The situation may be temporarily saved by the use of extra-oral fixation utilising a box-frame or halo.


Post-operative care and follow-up

Whether the patient has had a closed or open reduction, post-operative physiotherapy is an integral part of treatment. There are a variety of protocols that can be used. In essence, the patient should be given progressive exercises to restore the rage of motion in all dimensions. These should be done while assuring a satisfactory occlusion.

Training elastics are frequently employed after surgery to maintain the occlusion. This usually means having two elastics present: one on the side of the fractures with a slight Class II (anterior) vector of pull and the other on the opposite side with a straight up and down vector of pull. Initially the patients should wear the elastics continuously. Within one week, they can be changed, allowing function during meals and oral hygiene. Within 2 weeks, elastics can be used at night. At 3 weeks the archbars and elastics can be removed. Diet should be restricted to soft foods for 8 weeks.


Complications

In considering any treatment, the potential for complications exists. These complications may be divided into those occurring early in the course of injury or treatment and those that occur later.

Early complications

Complications that occur concurrent with or early after treatment of condylar fractures include the following

Fracture of the tympanic plate and middle ear injury

A force transmitted through the mandible from the anterior to the posterior through the condyles will be transferred to the tympanic plate, and may cause its fracture. Owing to the close proximity of the plate and the external auditory canal, the primary symptom of this injury is bleeding from the ear. It may also cause a conductive hearing loss because of the close proximity to the middle ear. Patients with history of condylar fractures should undergo a careful otoscopic examination.

Fracture of the glenoid fossa

Fracture of the base of the skull might occur in the region of the relatively thin glenoid fossa and occasionally extends to the petrous portion of the temporal bone. It is thought that the unique scroll-like shape of the condylar head, with its large lateral pole, and the increased thickness of the lateral aspect of the fossa provide protection against penetration of the condylar head into the cranium. In certain cases, however, the condyle is more rounded in form, and this feature is thought to allow increased concentration of forces in the thin central portion of the glenoid fossa. This causes the fossa to fracture with possible penetration of the condyle into the middle cranial fossa.

Computed tomography scan is the best method of visualisation of condylar displacement into the middle cranial fossa. It can also detect concurrent intracranial haematomas.

Neurosurgical consultation is warranted to exclude cerebral damage, intracranial haemorrhage and cerebrospinal fluid leak. Reduction of the fracture and some period of immobilisation should be done. If required, a bone grafting of the glenoid fossa may be done.

Damage to cranial nerves

Basilar skull fracture might result in cerebral contusion. The spread of fracture through the petrous temporal bone can cause injury to the seventh and/or eighth cranial nerves, producing a neurosensory hearing deficit and facial paralysis. Damage to the nerves can also occur as a result of being stretched during the injury, lacerated or severed by the jagged edge of fractured bone ends, or iatrogenically damaged during surgical intervention. The facial nerve is again susceptible during condylar injury or during surgical treatment. Overriding of the condylar segment medially may cause injury to the inferior alveolar nerve as it enters the mandibular foramen at the lingula.

Vascular injury

Damage to the vascular structures can occur in a similar way. The internal maxillary artery is especially prone to injury as it travels just medial to the condyle. This might result in haematoma formation or development of a false aneurysm.

Late complications

The late complications of condylar injury commonly include the following.

Malocclusion

Malocclusion following condylar trauma may result from alterations in the condylar growth centre and/or malunion of the fracture segments. A properly timed and supervised program of training elastics and physiotherapy can avert significant malocclusion in a majority of cases. If the problem persists, the use of judicious occlusal equilibration, orthodontics or orthognathic surgery may be required. Before reconstruction of the occlusion to this new articulation, it is necessary to allow a period of 6-12 months for complete healing and any remodelling of the articular apparatus to occur. Most patients are amenable to conservative therapy and are able to compensate for a small degree of occlusal disharmony. In the edentulous patients, differences in the inter-occlusal relationship can be compensated for during the fabrication of new prostheses.

Growth alteration

Growth alterations as the result of condylar injury may occur as a result of two mechanisms: over/understimulation of the normal growth may result from direct injury to the condyle, or a restriction of normal growth may occur secondary to fibrosis or scarring of the surrounding tissues. Factors influencing the effect of condylar injury on growth include the age of the patient, the severity of the injury and the period of immobilisation.

Contrary to previous beliefs, it is now accepted that the growth deficit produced is not directly proportional to the age of the patient at the time of injury. This may be due to the fact that actively growing young individuals have the ability to regenerate the traumatised tissues to a good extent. The concept that condylar cartilage acts as a growth centre has been replaced by the ‘functional matrix’ theory, according to which the cartilage acts as a remodelling centre, which would influence future growth patterns.

If normal growth is disrupted, the affected ramus height is reduced while the unaffected side is allowed to grow normally. These inequality results significant facial asymmetry characterised by a shortened lower facial height, bowing of the inferior border and marked antegonial notching on the affected side, and an elongated inferior mandibular border and flattened facial contour on the contralateral side. As the patient attempts to establish a workable occlusion, many dental compensations occur, such as posterior crossbite on the affected side, a canting of the occlusal plane, tilting of dento-alveolar segments etc.

Temporomandibular joint dysfunction (Internal derangement)

As discussed by Goldman in 1991, a wide variety of injuries can result in the development of internal derangement of TMJ. There is a greater incidence of TMJ pain, deviation on opening and joint noise in patients with previous condylar fractures. The resultant internal derangement typically occurs in adults and is of two broad types. The first type occurs on the side of the fracture and is due to soft tissue injury within the joint. Open reduction with direct repair of the injured soft tissues has been advocated by some as a possible means of preventing this problem. The second type occurs contralateral to the condylar injury.  This derangement was described by Gerry (1965) as ‘condylar post-fracture syndrome’. Patients who develop a unilateral hinge type of joint after fracture can rapidly develop overfunction of the contralateral joint with hypermobility and, ultimately, anterior dislocation of the meniscus.

Ankylosis

Ankylosis of the TMJ is the most serious complication of condylar fracture. This is the development of significant or complete limitation of movement of temporomandibular joint by bone or fibrous tissue. Trauma is the leading cause of TMJ ankylosis (31% to 98% in various studies).

Laskin (1978) has carefully evaluated the factors that could contribute to the development of post-traumatic TMJ ankylosis.

Age of patient:

There is greater predisposition in younger than older patients and majority of reported cases have sustained such injuries before the age of 10 years (Topazian, 1964).

Site and type of fracture:

The intracapsular fracture is having high risk of ankylosis. This is especially so in children whereas pointed by Rowe (1969, 1982), the immature thinly covered and highly vascular condyle may tend to burst open, with resultant haemarthrosis containing multiple comminuted fragments of bone with a high osteogenic potential.

Laskin considered that the most important feature in fracture encouraging ankylosis is close contact between glenoid fossa and condylar stump and that this is more likely to occur with intracapsular fracture than with extracapsular fractures. Despite this only a relatively small number of cases of ankylosis occur in comparison with incidence of intracapsular fractures.

Duration of immobilisation:

Many authors point out the dangers of prolonged immobilisation but experimental work in primates (Markey-1980) has failed to produce ankylosis by this means after artificially produced condylar fractures. It is likely therefore that immobilisation is a contributory factor rather than a primary cause.

Damage to Meniscus:

Laskin has suggested that the position and the state of the meniscus may be the key factor in determining whether posttraumatic ankylosis will develop. Even when there is close relationship of the condylar stump to the glenoid fossa, the meniscus can act as a barrier to bony union, but if this is damaged or misplaced then ankylosis may occur as is demonstrated by experimental evidence from animal studies (Wheat et al, 1977).

In summary, the situations in which the risk of ankylosis is greatest comprise

  1. Close proximity of the fractured condylar neck to the glenoid fossa which is seen in:

Intracapsular fractures

Fracture dislocation with gross telescoping

Compound fractures particularly when coronoid and zygomatic areas are also involved.

  1. Patients under 10 years of age.

Clinically, the patients with TMJ ankylosis present with a greatly reduced inter-incisal distance and secondary facial deformities. The latter include significant mandibular retrusion, facial asymmetry in unilateral cases and occasionally, anterior open bite in bilateral cases.

Conclusion

Fractures of the mandibular condyle constitute a significant portion of mandibular fractures. A number of clinical signs and symptoms are characteristic of injury to the condylar apparatus. The use of plain radiographs in multiple view, or CT scans discloses most condylar fractures and displacements, if any. A number of classification systems are available to help in treatment planning and record keeping.

Non-surgical treatment is adequate for a majority of condylar fractures. A period of immobilisation followed by active functional therapy is indicated for most cases. Surgical management has specific indications, and can be accomplished through a wide variety of techniques. In general, complications are not common following condylar trauma. Important among the possible complications are ankylosis, growth disturbances and internal derangement.

References

  1. Principles of Oral & Maxillofacial Surgery. Peterson, Marciani and Indresano. Vol. I
  2. Oral and Maxillofacial Surgery. R. J. Fonseca Vol. III
  3. Killey’s fractures of the mandible
  4. Rowe and Williams Maxillofacial Injuries. Vol. II
  5. Oral & Maxillofacial Traumatology. Kruger and Schilli Vol. II
  6. Oral and Maxillofacial Trauma. Edited by R. J. Fonseca and R. V. Walker. Vol. I. 2nd
  7. Conservative treatment of unilateral condylar fractures in children: a long-term clinical and radiologic follow-up of 55 patients. Stobl et al. International Journal of Oral and Maxillofacial Surgery Vol. 28. 1999. Pages 95-98

 

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Posted in TMJ Disorders

TMJ Disease Management

Diseases of temporomandibular joint

Introduction

The temporomandibular joint is crucial to the everyday functioning of modern man. It is subject to all the diseases and disorders that can affect other joints, but vast majority of these problems can be dealt effectively with reversible nonsurgical methods. However, in small number of cases surgical procedure is indicated to eliminate the disease or deformity and to restore the function and anatomy. One should be aware of the basic biology of the joint, sound diagnostic knowledge and also on the efficacy of alternative treatments in managing these conditions

Classification

The disorders of temporomandibular joint can be classified into structural and functional disorders:

Structural disorders:

  1. Developmental
  2. Inflammation
  • Acute
  • Chronic
  1. Infection
  2. Degenerative
  3. Neoplasia
  4. Mobility disorders
  • Hypomobility / ankylosis
  • hypermobility
  1. Trauma

Functional disorders

Pain/ dysfunction syndrome

Congenital and growth abnormalities of the TMJ

The congenital defects and growth abnormalities of the temporomandibular joint occur less frequently than the common functional disorders of the temporomandibular joint seen in adults. The abnormalities may be unilateral or bilateral. The abnormalities seen are hypoplasia or hyperplasia of the condyle with associated facial asymmetry. The causes might be prenatal/ congenital or postnatal or acquired ones.

Hypoplasia

The causes for underdevelopment of the joint are

  1. Unilateral
  2. Prenatal growth disturbance
  • Confined to condyle
  • Widespread developmental failure e.g. Otomandibular dyostosis, hemifacial microsomia
  1. Postnatal growth disturbance
  • Trauma
  • Infection
  • Inflammation
  • Irradiation
  • Unknown causes
  1. Bilateral
  2. Prenatal growth disturbance
  • Hereditary e.g. Mandibulofacial abnormalities
  • Non-hereditary e.g. Pierre-Robin anomaly, fetal irradiation
  1. Postnatal growth disturbance
  • Endocrine defects
  • Osteodystrophy
  • Inflammation e.g. Juvenile rheumatism
  • Trauma
  • known causes

The most serious form of congenital abnormality occurs in otomandibular dyostosis. The defect is caused by rupture of the stapedial artery in the sixth week of pregnancy prior to the development of the carotid system. It has varied forms. In the severe form there is absence of the coronoid process and angle of the mandible. In less severe cases the condyle and ramus are hypoplastic.

Hemifacial microsomia is characterised by variable asymmetric defects involving the skeletal, soft tissues and neuromuscular component. The aetiology is unknown. Poswillo states that following bleeding from the developing stapedial artery results in the formation of hematoma in the area of the first and second branchial arches. The size of the hematoma determines the degree of involvement.

In cases of unilateral cases the features include

  1. Facial asymmetry with deviation of the chin to the affected side and deficient chin.
  2. There will be apparent deficiency of tissue on the normal side.
  3. There will be development of occlusal cant. This is more prominent in cases of hemifacial microsomia.

The skeletal deformity of the hemifacial deformity is classified based on the anatomy of the mandibular ramus and temporomandibular joint

Type I                    Skeletal deformity consisting of mini mandible and mini temporomandibular joint, with all structures normal in shape but small in size.

Type II                   Skeletal deformity consisting of abnormal shaped mandibular ramus with hypoplastic and medially displaced temporomandibular joint

Type II A              The degree of hypolplasia does not warrant replacement

Type II B               The hypoplasia is severe and requires reconstruction.

Type III                 There is complete absence of ramus and temporomandibular joint

In cases of bilateral cases there is facial defect of deficient chin. In Treacher Collins syndrome there is also hypoplasia of other structures of face.

Mangement

The management of hypoplasia of the condyle requires extensive evaluation of photographs, lateral cephalograms, posteroanterior cephalograms, models of face, stereolithic models etc. for outlining the deformity. The management is mainly surgical with reconstruction of the temporomandibular joint and orthognathic surgical procedures.

Hyperplasia

Condylar hyperplasia is a postnatal growth problem seen common in females. This is manifested as development of mandibular asymmetry during puberty.  This is due to an abnormal, hypermetabolic growth center in the affected condyle. There are two types of growth pattern in this disorder:

  1. Vertical: In this group the mandible grows vertically. These patients are characterised by vertical long ramus and body of the affected mandible. Intra-orally there is open bite on the affected side. There is no crossbite, or deviation of chin, or midline.
  2. Rotational: This group has resemblance with patients with hemifacial microsomia in clinical appearance. Ramus is of normal length but the mandibular body is convex and the chin points to the normal side. Intra-orally there is deviation of dental occlusion and crossbite on the normal side.

Diagnosis is by clinical evaluation and from radiography. Bone scans shows the presence of actively growing condyle. All these patients require evaluation of the deformity by means of lateral and posteroanterior cephalograms, photographs, models etc.

Management

The treatment depends on the diagnosis and whether the deformity is progressive or stable. Progressive deformity requires high condylectomy and the patient followed up with scans periodically.

In stable deformity, there is no need for joint surgery, unless there is mechanical interference. The facial asymmetry and malocclusion is corrected by means of orhtodontics and orthognathic surgical procedures.

Infections of the temporomandibular joint

Infections of the temporomandibular joint are not common. Prompt diagnosis and therapeutic intervention is required because joint distension is painful and permanent changes can occur.

Patients with joint infections usually exhibit a posterior open bite on the ipsilateral side as a result of increase in joint fluid. Patients will often maintain a posture to the contralateral side. The surface overlying the joint is usually warm and sometimes it is fluctuant.

Aetiology

The source of infection is spread of infection by hematogenous route. Joints with underlying arthritic disease tend to be more susceptible to distant infection. Spread of infection from dental infections of maxillary teeth and also by direct inoculation following traumatic injury is also possible.

The causative microorganisms include Nisseria gonorrhhoeae in sexually active adults and in children under 2 yrs it is usually due to Haemophilus influenzae. Other microorganisms isolated from TMJ joint infections include Staphylococci and ß haemolytic Streptococci.

Complications of infection of the temporomandibular joint infection include

  1. Fistula formation
  2. Fibrosis or bony ankylosis
  3. Temporal bone osteomyelitis
  4. Intracranial abscess formation.

Diagnosis

History and review of systems aids in the diagnosis of acute infectious arthritis of the TMJ. Aspiration of the joint should be considered to relieve the pain and for obtaining the material for identification of the microorganisms. Arthrocentesis is usually done under sedation or general anaesthesia. The aspiration is performed using 20-gauge needle or using a heavier gauge needle under strict aseptic conditions. The aspirate is examined for direct smear and cultured for both aerobic and anaerobic bacteria.

The synovial fluid of an inflamed joint contains more than 2000 WBC/mm3 (normal is < 200 WBC/mm3). Septic joints have WBC count greater than 50,000 per mm3. The cells are predominantly polymorphonuclear cells. The synovial fluid of the joints involved with gout, pseudogout and rheumatoid arthritis often contain greater than 100,000 WBC/mm3. The cells are predominantly mononuclear cells.  In cases of fungal or mycobacterial infection of the joint the synovial fluid contains less than 20,000 WBC/ mm3, which are predominantly mononuclear cells.

Management

This condition is managed by initiation of antibiotic therapy and followed by lavage of the joint. The best choice for initial empirical antibiotic therapy for an acute infectious TMJ arthritis is an agent that combines penicillin with a ß –lactamase inhibitor. Thus combination of ampicillin and sulbactum will cover infections from Staphylococcus, Streptococcus and Nisseria organisms. Other antibiotics that have been used for treating the septic arthritis include clindamycin 6oomg, cefotaximine, and tobramycin. The duration of treatment depends on the clinical course and the organisms isolated. Usually it requires antibiotic therapy for a period of 1 month with initial two weeks of parental antibiotics followed by oral antibiotics.

Following institution of antibiotic therapy lavage of the joint helps in removing the products of inflammation, reducing the bacterial count and relieving the joint distension. This would relieve patient’s symptoms and also may decrease the likelihood of spread of infection to temporal bone.

Following resolution of acute symptoms it is necessary to start on active physiotherapy for prevention of fibrous or bony ankylosis.

 


Internal derangement of the temporomandibular joint

Internal derangement of the temporomandibular joint is a localised mechanical fault in the joint, which interferes with its smooth function.

This is caused by the anteromedial displacement of the disk with associated posterosuperior displacement of the condyle in the closed jaw position and there is dysfunctional centric relation.

The existence of altered articular disk-fossa relations resulting in pain and abnormal function of the temporomandibular joint has been mentioned in the writings of Annandale since 1887. In 1814 Hey was the first to use the term “internal derangement” to describe a localised mechanical fault interfering with smooth articular function.  Other authors who have reported internal derangement in the literature include: Unlakeley (1929), Costen (1934), Burman and Senberg (1946), Bowman (1947), Ireland (1951), Kechn (1952), Christie (1953) and Silver and Simon (1956).  Despite this considerable amount of information, the dental profession for the most part choose to identify the musculature as the source of pain and dysfunction in TMJ problems.  Schwartz (1955) and later Laskin (1969) emphasised a psychological and muscular approach with very little emphasis on internal derangement or intracapsular pathology.  In the 1970s Farrar and McCarthy stimulated a renewed interest in internal derangement of the TMJ by correlating radiographs, range of motion measurements and patient history.  With the introduction of arthrogram, the validity of the concept of internal derangement became a reality. 

Internal derangement of the temporomandibular joint is progressive in nature and this can be demonstrated by changes seen in the range of movement, radiographs taken over a period of time and in other studies that are used to make a diagnosis.

The initiating factors can be classified into two groups.

  1. Sudden trauma
  2. Microtrauma over a period of time usually caused by missing posterior teeth, incisal interference, posterior deflective contacts or a deep curve of space.

This is a defect usually of gradual onset, which is caused by longstanding microtrauma (abnormal mandibular posture or excessive muscle activity). This leads to deranged functional adaptation of the articular disk resulting in stretching of the posterior ligament and stretching of the articular disk. Loosened disk will move to a medial position during activity. This produces pain and clicking of the joint during function.

Longstanding microtrauma

Stretching of posterior ligament

and loosening of articular disk

Intermittent clicking                                  Early stage feature

Continual clicking                            Intermediate

Clicking and locking                        late stage

Locking

Acute (↓ Opening, ↓ lateral excursion, ↑ deviation)

Chronic (↑ Opening, ↑ lateral excursion, ↓ deviation)

Degenerative joint disease

Signs and Symptoms:    The signs and symptoms of internal derangement are similar to those of temporomandibular patients in general.  They are headache in the retrobulbar and temporal area, earache, pain and tenderness, joint noise and limited range of motion.

Pain may be perceived by the patient as joint pain, head ache or symptoms relative of musculature. Pain will be dull aching, or sharp, gradually increasing and of long duration.

Clicking of the joint will be present in almost all patients. Joint clicks seen in internal derangement is called reciprocal clicking. In this as the condyle translates the disc remains lodged in front of the condyle until the opening click occur.  At this point, the condyle moves downwards and forward beneath the thickened posterior band of the disc, which moves backward and condylar translation proceeds normally now with the disc in a correct anatomic position.  During the closing motion the disc and condyle remain in their correct anatomic position until the condyle nears the terminus of its retrusive movement.  When the closing click occurs, the condyle is most often displaced posterio-superiorly and the disc becomes displaced anterio-medially with the posterior band slipping downward and forward.  Clinically the reciprocal click can be characterised as early, intermediate or late depending upon where the opening click occurs.  An early reciprocal click occurs at 10-29mm of opening and a late click at 40-50mm of opening.  A later grade reciprocal click usually progresses from an early grade reciprocal click as the posterior ligament is stretched and at this point the disc is probably beginning to be deformed.

The progressive variant of internal derangement is known as closed lock.  Most patients progress from intermittent locking or reciprocal clicking to the closed lock.  Some patients may be able to self reduce the lock.

Closed locks are classified into acute and chronic based on

  1. The length of time since occurrence
  2. The amount of condylar translation

            The degree of chronicity is proportional to the degree of condylar translation. 

            An acute closed lock has an average mandibular opening of 27mm with an average lateral excursion to the contralateral side of 4mm.  Deviation to the ipsilateral side is marked. 

            As the closed lock becomes more chronic, mandibular opening increases, excursion to the contralateral side increase and deviation decreases.  The joint may be basically, silent but by this time, the posterior ligament is stretched and the disk is generally deformed in a prolapsed anterior and medial position.  Following this perforations of the posterior ligament or disk can occur along with degenerative changes of both the condyle and fossa.

There is excellent clinical evidence that internal derangement is the precursor of degenerative joint disease since there is seldom radiographic evidence of degenerative joint disease without arthrographic or surgical evidence of internal derangement.

Diagnosis:

The diagnosis of internal derangement is based on the thorough history and clinical examination and diagnostic radiographs.  Arthrograms may be used where radiographs and correlated tomograms are not diagnostic.

While taking history the following information should be included.

  1. A description of the problem in the patient’s own words
  2. Location of symptoms – A typical TMJ patient complains of headache in the retro orbital and temporal areas.
  3. The length of time a patient has had symptoms and how often the symptoms occur.
  4. Whether any particular event preceded the symptoms – chewing or excessive jaw use or stressful events.
  5. Character of pain – Dull aching pain may be joint or muscle related whereas sharp lighting pain is indicative of neuralgia.
  6. The type of noises the patient perceives in the joints.
  7. Incidence of bruxism, migraine headaches and emotional stress.
  8. The type of treatment the patient has previously received and its effect.

Clinical Examination:

Clinical examination includes

–  Palpation of muscle

–  Occlusal analysis

Careful and objective range of motion of these the most important is the range of motion study.

Range of motion study:
Mandibular opening:

Normal mandibular opening is between 40 and 54mm.  Patients may have limited jaw opening because of temporomandibular joint pain, adhesions, fibrous and bony ankylosis and the closed lock variant of internal derangement.  Limitation may also be extracapsular.  A mandibular opening limited by an acute closed lock will have an opening of around 27mm.  If the opening is less than that, consideration must be given to superimposed pain, adhesions, fibrous or bony ankylosis or extracapsular problems.

Lateral excursions:

Measurement of lateral excursions is important in differentiating limited opening caused by intracapsular or extracapsular pathology.

A normal lateral excursion measured at one cm of opening is 9-13mm.  In a normal joint the ratio of maximum lateral excursion to maximum opening is around 1:4 (i.e. if the patient has a maximal opening of 40mm there should be 10mm of lateral excursions to both sides).

If the patient has a limited opening but normal lateral excursion then the limitation is extracapsular.  Limited opening and limited lateral excursions may indicate an intracapsular problem.

Deviation

A patient whose jaw deviates consistently to one side could have both a joint problem and a muscular problem.  Deviation is seen in internal derangement, unilateral loss of condylar height, posterior capsulitis, fibrous adhesions, ankylosis and true muscular or neurologic problems.

Joint noises:

Not all clicking within the joint is indicative of an internal derangement.  Reciprocal clicking should be graded for a specific diagnosis and treatment planning.

The following guidelines were drawn up by William and Farrar to grade reciprocal clicking.

        The opening click is graded on a scale of 1 to 5.  An opening click occurring at 1cm of opening would receive a grade of 1.  An opening click at 40mm would be graded 3.5 and so on.

        The closing click is graded by the degree of posterior condylar displacement that occurs coincident with the closing click. Instruct the patient to close into the intercuspal position and mark the teeth.  Then have the patient open past the opening click and close in a protruded position.   Next, instruct the patient to slide the jaw backward very slowly and gradually to cause the posterior teeth to fit together.  As the mandible extrudes, there will be a point at which it will hesitate.  This hesitation occurs because the posterior band of the disc is in its normal position before the closing click occurs.  Record this point forward of the original mark.  When the patient closes into the intercuspal position the closing click can be heard or observed.  The measurement between the two marks is the grade for the closing click.

        The grade of the reciprocal click is the average of the grades of the opening and closing clicks.  The higher the grade the more severe the problem.

There are other joint noises that are mistaken for reciprocal clicking.  One type occurs at the same point in the opening and closing, which is due to presence of a ridge in the disk or a deviation in the form of the condyle or fossa. Grinding and crepitus are indicative of late stage changes and are most often heard during translation. Grinding occurs as a result of irregular bony or disk surface or a perforation of the posterior ligament or articular disk.

Radiographs:

There is no perfect temporomandibular radiograph in the diagnosis of temporomandibular diseases.

Panaromic radiographs are excellent for screening, but not good for diagnosing internal derangement. This can demonstrate changes in condylar shape, image coronoid process and look for antegonial notching.

Transcranial radiographs is of some value in the diagnosis of internal derangement. As disk displacement occurs there is superior positioning of the condyle, which is seen in radiographs as lack of joint space.

Arthrography

The arthogram is the gold standard in the diagnosis of internal derangement.  This clearly demonstrates the phenomena of reciprocal clicking and locking in both acute and chronic.  Plain films may show a narrow joint space and some degree of arthritic change but the arthrogram will show the displacement.

Arthroscopy

This is helpful in diagnosing the presence and degree of disk displacement, which is seen as anteriorly positioned inflamed retrodiskal tissue with varying degrees of synovitis.

Mangement

After a thorough evaluation, management of internal derangement should begin with the nonsurgical phase.

The nonsurgical modalities include

  1. The soft diet
  2. Physical therapy by means of exercise, thermal agents, ultrasound and transcutaneous electric nerve stimulation.
  3. Muscle and trigger points injections.
  4. Occlusal modification and Splint therapy
  5. Stress reduction techniques by means of biofeedback.
  6. Medical therapy with agents such as analgesics, muscle relaxants, coticosteroids, anxiolytics, antihistamines and antidepressant medication can be used.
  7. Manual reduction of displaced disk.

Surgical treatment should be considered if dysfunction and pain is not corrected to the level of patient’s satisfaction. Surgical treatment is indicated if there is

  1. Severe pain resistant to conservative therapy.
  2. Considerable limitation of opening.
  3. Radiological evidence of disk, condyle or fossa damage.

The surgical procedures recommended are

  1. Disk repositioning and Diskoplasty
  2. Disk repositioning and arthroplasty (Eminectomy)
  3. Low or high Condylectomy
  4. Condylotomy and modified condylotomy
  5. Partial or total diskectomy/ menisectomy and replacement.

Reconstruction arthroplasty with repair or replacement of the damaged meniscus is the most accepted modality of treatment. The damaged disk can be repaired by means of plication procedure or by means of reconditioning the posterior band. If the disk is severely damaged it is better removed and replaced with materials such as silastic, metallic fossa, dermis, dura, temporalis fascia, temporalis muscle, choncal cartilage.


Degenerative diseases of temporomandibular joint

Degenerative disease of the TMJ is the most common organic disease of the joint and occurs when the capacity of the joint to adapt to insults of various types is exceeded.

These diseases include

  1. Osteoarthrosis
  2. Rheumatoid arthritis
  3. Ankylosing spondylitis
  4. Psoriatic arthritis
  5. Sarcoid arthritis
  6. Reiter’s syndrome
  7. Post traumatic arthritis
  8. Condylar resorption

The articular surface of the condyle is covered by a layer of fibrocartilage. A thin layer of cartilage cells is present between the articular surface and subchondral bone. This has the capacity to respond to physical forces (stress) by either progressive or regressive remodelling. Once the ability of the subarticular tissue to adapt to stress is exceeded, degenerative changes occur.

Toller in 1974 carried out histological studies and found four stages. These include

  1. Fibrillation
  2. Perforation
  3. Erosion
  4. Repair

Osteoarthrosis

Osteoarthorosis is a non-inflammatory degenerative disease affecting the articular surfaces, which is accompanied by remodelling of the underlying bone.

The clinical picture of ostoarthorosis is similar to those of other temporomandibular disorders. But the clinical course in the TMJ is outstandingly different from that occurring elsewhere. Toller (1973) named it as temporomandibular arthropathy.

Toller (1974) carried out an intensive survey and made the following observation.

  1. A primary symptom of the disease is pain on movement of the jaw. This is not confined to biting or attempted wide opening of the mouth but is frequently present at any part of the range of available movement.
  2. Pain becomes more prominent as the day progresses and is most noticeable when the patient is tried. This contrasts with those affected by the TMJ pain/dysfunction syndrome who more commonly experience pain and stiffness upon awakening.
  3. Tenderness is usually present when the TMJ is palpated, especially during movement. It is very much noticeable when palpation is directed against the back of the mandibular condyle with the mouth in open position.
  4. Limitation of condylar movement on the affected side is common and result in deviation of the jaw to the affected side together with a reduced jaw gap.
  5. There are characteristic sounds within the TMJ best described as grating, grinding or crunching noises. They are audible to the patient and are very noticeable on auscultation of the joint.  Clicking, which is heard in the TMJ dysfunction syndrome is a completely different sound.
  6. Radiographic changes on the surface of the mandibular condyle are present in all established conditions but may not be observed when the disease is of recent onset, only appearing at a later stage.

The majority of those who attend complaining of TMJ pain are found on examination to be suffering from TMJ pain/dysfunction syndrome.

Radiographic Observations

According to Toller (1969) the most suitable radiograph to show the structure of the bony surface of the condyle is achieved by using the transpharyngeal technique.  With this it is usually possible to obtain a finely defined image of the articular surface with minimal distortion of the condyle and with no overlying bony shadows.

The radiographic signs noted include subchondral bony sclerosis, loss of integrity of the articular bony end-plate often at the point of articular contact on the anterior or superior aspect of the condyle, a shallow excavation in the articular surface, erosive lesion, subarticular cysts and osteophytes.

In plain radiographs the degenerative changes of the articular surfaces where the degenerative changes occur are not visualised. The changes seen in radiographs might be physiologic adaptation to mechanical stress, so it is difficult to differentiate between osteoarthrosis and remodelling by radiographic examination alone.

Much information about the status of the can be obtained from a computed tomography scan or MRI scan.

Aetiology

Several factors contribute to the breakdown of joint surfaces. This condition occurs when the intensity of the stress exceeds the functional capacity of the joint or when the functional capacity of the joint is reduced and normal stress causes degenerative disease.

Excessive stress is caused by trauma or by chronic repetitive trauma. The functional capacity of the joint to adapt is reduced in systemic diseases like rheumatoid arthritis.

Histological Findings

Toller (1974) carried out histological studies upon specimens obtained at high condylectomy for those patients who required surgical intervention and identified four stages of the disease, which he classified as (1) Fibrillation (2) Perforation (3) Erosion  (4) Repair.

Management of Osteoarthrosis

The primary aims of treatment are

  1. Relief of pain
  2. To restore the normal range of motion
  3. To prevent progression of disease
  4. To induce regeneration of the affected condyle.

Treatment may be categorised into three types

(1) Supportive conservative measures

(2) The use of intra articular steroids

(3) Surgical intervention in refractory cases

Conservative Measures:

It may be used either singly or in combination.

Reassuring the patients

Explaining to the patient the nature of the disease and reassure the patient.  It should be emphasised that an arthrosis affects solitary joint and mechanical overloading plays a major role in the onset of the disease.

Correction of Occlusal Abnormalities

Most patients have an inadequate posterior occlusion and this can be corrected by elimination of abnormal or premature occlussal contacts and the fabrication of partial dentures.  Extraction of over erupted teeth or correction of their occlusion by complex restorative procedures may be necessary.  Marked  tilting of the teeth may be compensated by crowning or by incorporating occlusal onlays into a partial denture.

In the edentulous patient a surprisingly rapid reduction of pain may occur when an overclosure is corrected.  Bite raising appliances fitted over the natural dentition or a deliberate slightly excessive increase in vertical height in the edentulous may provide relief of especially severe pain.  Such as increase in vertical height in the edentulous may provide relief of especially severe pain.  Such an increase should be considered as a short term measure only since further occlusal damage or pain can occur beneath full dentures after only a few week’s function with an excessive vertical dimension.

Drugs:

Drugs prescribed should be confined to simple analgesic preparation.  Osteoarthrosis is not an inflamatory disease and so the non steroid anti-inflamatory drugs makes no significant contribution.

Physical Therapy

Massage over the affected joint in combination with counter irritant ointment is of considerable benefit to patients.  Local heat either as infrared therapy or use of warm flannel over the affected joint provides relief.

Patients should be advised not to use the affected joint excessively simply because these conservative measures have reduced the pain.  It should be emphasised that symptomatic relief only has been provided and that the natural course of events including further destruction followed by a reparative stage will still occur.  It is helpful to follow the progress of the disease by use of serial radiographic techniques.

Intra-Articular Steroids:

The use of intra-articular steroid first gained enthusiastic support but was later the subject of severe criticism following reports of gross destruction especially in experimental animals.  Henny (1954) reported the beneficial results following injections of hydrocortisone into the MJ.  Chandler and Wright (1958) and Salters etal (1967) reported destructive changes in treated joints which could be demonstrated on radiograph.  Poswillo (1970) and Toller (1977) found a favourable responds with the use of intra-articular steroid injections.

The success of intra-articular steroid injections is in the symptomatic relief of pain.  There is no correlation between symptoms and radiographic appearance.  The greatest improvements and the earliest return to function occur in those where obvious condylar changes are seen on radiograph at the time of injection.  An extension of the original lesion may be seen on serial follow up radiograph.  Approximately 12 months after treatment a radiologically new bony articular end plate is seen.  The condyle itself is reduced in size and has an abnormal shape but function well.

Evidence is accumulating to suggest that the steroid accelerates the destructive stages of the disease and then repair takes place at an earlier date.

Technique for Injection of the TMJ

A strict aseptic technique is essential. After palpating the head of the condyle, local anaesthetic solution is injected to produce auriculotemporal nerve block.  Injection of the solution commences just after skin penetration in the preauricular crease 1cm below the glenoid fossa.  The needle is advanced slightly upwards, Inwards, and forwards to contact the upper lateral aspect of the condyle after which it is withdrawn slightly and local anaesthetic deposited over the lateral aspect of the joint capsule.

1cc of an aqueous suspension containing 25mg of methyl prednisolone acetate is used for injecting.  It is most important to inject into the lower joint compartment since this place the steroid in contact with damaged condyle.  The patient’s mouth is opened not more than 1cm by placing a suitable prop between the teeth.  The needle is advanced through the previous skin puncture angled slightly downwards and 45o inwards and forwards to contact the posterosuperior surface of the condyle.  Gentle manipulation allows the needle to penetrate into the lower joint space and 0.5cc of the suspension is injected.  Lack of resistance confirms that the needle is in the joint space.  Where the upper space is also to be injected the needle is withdrawn to just below the skin and the patient’s mouth opened widely.  The needle is then passed upwards, inwards and forwards at approximately 45o until the roof of the glenoid fossa is contacted.  After slight withdrawal 0.5cc of solution is deposited.  The needle is withdrawn and a small plaster placed over the skin puncture for a few hours.  Some increase in pain and stiffness in the injected joint may be experienced for 2 or 3 days and the patient should be warned of this and analgesics prescribed.  Discomfort should then steadily diminish.

Surgical Treatment:

There remains a small but well defined group in whom either the symptoms are severe and uncontrollable from the start or in whom severe symptom persist 3-4 months after a steroid injection and where obvious radiological abnormalities are present.  These should be considered for surgery.  Where doubt exists as to whether the joint is responsible for the symptoms, an injection of local anaesthetic may aid diagnosis since pain will be abolished temporarily when true intra-articular disease exists whereas pain persists in those patients whose symptoms stem from a functional disorder.  The appropriate surgical procedures are high condylectomy or high condylar shaving, condylotomy, artroplasty, temporomandibular joint replacement.

Rheumatoid arthritis

This is an autoimmune disease primarily affecting the smaller peripheral joints. It is a debilitating condition with intermittent activity and progressive joint involvement.

The clinical features are intermittent pain, swelling and progressive limitation of joint motion. Characteristically the joints of the hand and feet are first affected. Rarely are the distal interphalangeal joints of the fingers affected in early stages. The disease progresses centrally. Involvement of the temporomandibular joint is usually bilateral. In acute stages there is swelling and tenderness. There is limitation of mandibular movement and it may eventually progress to ankylosis. Gross destruction of the condyle may reduce its vertical height, leading to anterior open bite. Juvenile rheumatoid arthritis or Still’s disease involvement of temporomandibular joint might result in ankylosis. This interferes with mandibular growth, resulting in “bird face” deformity.

This disease has features of anaemia, fever, malaise and anorexia. There is a positive result for rheumatoid factor tests. There is also a raised erythrocyte sedimentation rate and in acute stages there is presence of C reactive protein.

The histopathologic features are similar to those found in other joints. This is characterised by inflammation of the synovial tissues with an intense infiltration of lymphocytes and plasma cells. There is exudation into the joint cavity of leukocytes and lysosomal enzymes. The granulomatous synovial tissue (pannus) grows over the joint surface into the subchondral bone and into adjacent tendons and ligaments. This destroys the joint and when it ceases, scar tissue forms and limits motion. This might progress to ankylosis.

The radiologic features are non-specific and may be observed as in other joint diseases. These include flattening, sclerosis, erosion, osteophyte formation, reduction of joint space and reduced mobility.

Management is based on the severity and stage of the condition. In the acute stages, physiotherapy and anti-inflammatory agents are helpful. Intraarticular steroids may be helpful in persistent cases. In chronic destructive cases, surgery may be indicated for the release of ankylosis, restoration of occlusion or both.

Gout

This is a metabolic disease in which the joint tissues become inflamed as a result of deposition of crystals of sodium urate due to excess uric acid.

The joint area is reddened, warm, swollen, tender and movement is painful. There is raised ESR and uric acid level.

Radiographically, punched out bony erosions are seen, like the other degenerative diseases.

Ankylosing spondilitis

This is a chronic inflammatory disease of unknown aetiology and this is associated with histocompatibility antigen HLA B27. This mainly affects the spinal articulations, sacroiliac joint and paravertebral soft tissues.

Here there is prominent ligamentous calcification and ossification, with a tendency for bony ankylosis. TMJ is involved in 4 to 32% of cases. The temporomandibular symptoms were mild and restriction in mandibular motion is the main clinical feature.

Radiologic feature is characteristic and includes blurring of subchondral bone margins, subchondral sclerosis, bony erosions, progressive narrowing of the joint space and developing ankylosis.

The main goal in management is the maintenance of functional posture, in association with suppression of pain by means of anti-inflammatory medication. Intraarticular steroids are useful in reducing the symptoms and dysfunction.

Psoriatic arthritis

This is an autoimmune disease manifested by scaly pruritic skin lesions, distinctive nail lesions and susceptibility to secondary infections. It is characterised by erosive, asymmetric polyarthritis and negative results from rheumatoid factor tests. It mainly affects the distal interphalangeal joints.

The temporomandibular involvement is asssociated with features of pain, joint tenderness, limitation of motion and swelling.

Radiographs show features similar to rheumatoid arthritis.

Management of psoriatic arthritis is based on anti-inflammatory medications, physical therapy, steroid therapy and immunotherapy with methotrexate for severe, refractory cases.

Sarcoid arthritis

This is a systemic, granulomatous disease of undetermined cause and pathogenesis. Mediastinal and peripheral lymph nodes, lungs, liver, spleen, skin, eyes, phalangeal bones and parotid gland are most often involved.

Sarcoid arthritis may be seen as an acute, transient, migratory polyarthritis at the onset of disease and most frequently involves the joints of long bones and phalanges. In advanced chronic cases, the peripheral joints are involved.

Diagnosis is established from clinical features and a positive Kveim test result.

Reiter’s syndrome

It is a triad of Uretheritis, conjunctivitis and arthritis associated with antigen HLA B27. Features include fever, oral and genital mucous membrane lesions, cutaneous keratosis and iritis. Joints of spine and sacroiliac region are commonly involved. The clinical signs of TMJ involvement are limitation in motion and pain. Radiography shows evidence of erosion.

Management is mainly by anti-inflammatory medications.


Hypomobility and hypermobility of the temporomandibular joint

Motility disorders of the temporomandibular joint emanating from either too little or too much movement of the condyle occur much less frequently than internal derangement, arthrtidies and other diseases of the synovial joints. Mobility disorders present stern challenges in the diagnosis and treatment.

Hypomobility resulting from ankylosis is an extremely disabling affliction, causing problems in mastication, digestion, speech and oral hygiene. Ankylosis occurring in childhood may grossly affect mandibular growth and result in gross facial deformity. Hypomobility occurring from either intraarticular bony or fibrous ankylosis is called true ankylosis, while those arising from extraarticular causes are called false ankylosis.

Hypermobility disorders result from hypertranslation of the mandibular condyle anterior and superior to the articular eminence. These disorders are composed of hypertranslation, subluxation and dislocation.

 Hypomobility disorders.

The treatment of hypomobility disorders is a clinical challenge. These disorders can be classified into the following as trismus and ankylosis.

Trismus is caused by stiffness of the masticatory muscles.

Kazanjian in 1938 classified the ankylosis into true and false.

–   False ankylosis / Pseudoankylosis results from pathology outside the joint, resulting in mandibular hypomobility.

  • True ankylosis is caused by fibrous or bony fusion of intraarticular joint structures.

The more severe form of hypomobility result from true bony ankylosis of the condyle to the glenoid fossa.

Aetiology of hypomobility disorders.

The cause of hypomobility is varied arising as a result of

  1. Trismus
  2. Odontogenic – myofascial pain, malocclusion.
  3. Infection – masticator space.
  4. Trauma – fracture of the mandible, muscle contusion.
  5. Tumours – nasopharyngeal tumours, tumours that invade jaw muscles.
  6. Psychological – Hysterical trismus.
  7. Pharmacological – Phenothiazines
  8. Neurologic – Tetanus.
  9. Pseudoankylosis
  10. Depressed zygomatic arch fracture
  11. Fracture dislocation of the condyle.
  12. Adhesions of the coronoid process
  13. Hypertrophy of the coronoid process
  14. Fibrosis of the temporalis muscle
  15. Scar contracture following thermal injury
  16. Tumor of the condyle and coronoid process.
  17. True ankylosis
  18. Trauma
  19. Intracapsular fracture (children).
  20. Medial displaced condylar fracture
  • Obstretic trauma
  1. Intracapsular fibrosis
  2. Infection
  3. Otitis media.
  4. Suppurative arthritis.
  5. Inflammation
  6. Rheumatoid arthritis/
  7. Still’s disease.
  • Ankylosing spondilitis.
  1. Marie-StÛmpell disease.
  2. Psoriatic arthritis.
  3. Surgical
  4. Postoperative complication of TMJ surgery & Orthognathic surgery.
Trismus

The most frequent cause of hypomobility is muscular trismus. Trismus is derived from the Greek term meaning “grinding together” and may be myogenic, neurogenic or psychogenic origin.

Trismus is thought to be a protective reflex that minimises jaw movement to prevent the spread of bacteria, tumour cells, or further trauma to already injured tissue. Trismus id mediated through arthrokinetic reflex from propioceptive nerve endings in the periodontium, the muscle spindles and mechano-receptors situated in the joint capsule through the brainstem to the muscles of mastication.

The causes of trismus include: odontogenic sources like myofacscial pain, malocclusion etc.; infection around the masticator facial spaces; trauma with fracture of mandible; tumour invading the jaw muscles and contiguous structures; extrapyramidal reactions secondary to drugs such as the phenothiazines; and psychogenic and neurogenic sources such as hysterical trismus, tetanus toxins or brain tumours.

The management of trismus is directed at the causative factors.

False ankylosis

Hypomobility as a result of extraarticular causes of obstruction are called pseudoankylosis. There is confusing mention in the literature about false ankylosis and trismus. Miller et al in 1975 classified false ankylosis into six groups as:

Myogenic

Neurogenic

Psychogenic

Bone impingement

Fibrous adhesions

Tumors

The factors frequently cited as the cause for the extraarticular obstruction are

  1. The depressed fracture of the zygomatic arch, which impinges on the coronoid process result obstruction of free movement of the mandible.
  2. Fracture dislocation of the condyle limits mobility, either as a result of direct trauma to the soft tissues and joint structures or because the head of the condyle obstructs movement of the mandible.
  3. Changes in and around the coronoid process – either hypertrophy or fibrosis causes hypomobility.
  4. Fibrosis of temporalis muscle results in hypomobility. This is seen in temporal shunt procedures carried out for the correction of hydrocephalus.
  5. Other causes are fibrosis of the elevator muscles of mandible as a result of burns or radiation therapy and dystrophic calcification in myositis ossificans.

The management of these cases of false ankylosis is directed towards eliminating the causative factors.

True ankylosis

The intraarticular cause for ankylosis may range from fibrous, fibro-osseous, osseous to osteocartilagenous. The aetiology and pathogenesis are

  1. The most frequent cause for bony ankylosis is trauma to the joint. In the child the most likely mechanism of ankylosis is following a blow to the chin or following obstetric trauma. Rich anastamosis of capillaries penetrate the articular layer of condylar cartilage and found lying just under the thin cortex in the young individuals. The condylar neck is broader in the children. There is crushing injury to the articular surfaces following trivial injury. Trauma causes extravasation of blood resulting in haemarthrosis or intraarticular comminuted fracture with fragmentation and haemarthrosis. Subsequent ossification of this fibroosseous mass ultimately results in ankylosis. Obstetric trauma is also an etiologic factor in the development of ankylosis. In the adult ankylosis results either from a medial displaced fracture of condyle and bony fusion of the neck of condyle to the zygomatic arch or from fibrous ankylosis.
  2. Intraarticular infection is the second leading cause for true ankylosis. Before the use of antibiotics, the incidence of ankylosis resulting from infection exceeded that caused by trauma. Infection to the temporomandibular joint can produce prolonged limitation of motion, disturbance and destruction of articular surfaces and alteration of normal physiological process of temporomandibular joint. Destruction of articular surfaces along with limitation of motion will lead to ankylosis.
  3. Ankylosis as a result of inflammatory arthritidies occurs in less than 7 % of cases. Rheumatoid arthritis, Still’s disease (juvenile rheumatoid arthritis), Marie- StÛmpell disease, psoriatic arthritis and osteoarthritis comprise this group of disease.
  4. Fibrous and bony ankylosis can occur following TMJ arthroplasty and mandibular orhognathic procedures. Adhesions can form between the disk and the articular eminence following disk repair procedures. Bony ankylosis can occur after diskectomy procedures without proper postoperative physiotherapy or after multiple surgical procedures on TMJ.
  5. Rarely, ankylosis may result from neoplasia- either a tumor of the condyle, a metastatic lesion, or chondromatosis of the TMJ.

Diagnosis of ankylosis

The ankylosis of the temporomandibular joint has distinct clinical and radiological features.

Clinical examination

The findings depend on the time of onset, severity, duration and whether the ankylosis is unilateral or bilateral. The features seen in the ankylosis occurring at an early age before the completion of the growth of mandible are.

  1. Restriction of mandibular motion. In severe cases the mouth opening will be less than 5 mm. In false and fibrous ankylosis there will be varying degree of jaw motion, usually less than 15-mm. Unilateral ankylosis will produce deviation of the mandible to the ankylosed side on opening. This is due to the hypermobility of the condyle on the normal side and an absence of translation on the ankylosed side.
  2. Mandibular deficiency if the ankylosis has produced severe damage to the joint at an early age. There will be decreased ramal height, micrognathia and bird face appearance in cases of bilateral ankylosis. There is prominent antigonial notch due to pull of the muscles attached to the mandible. The facial deformity of the ankylosis is the combined result of loss of epiphyseal growth and absence of stimulation from the functional matrix.
  3. Facial asymmetry if the ankylosis is unilateral and occurs at an early age. There will be micrognathia with chin deviated to ankylosed side and apparent deficiency of the body of the mandible region on the normal side. This is due to normal growth of the mandible on the normal side when compared to the ankylosed side. These cases will have associated feature of canting of occlusion.
  4. Besides these there will be varying degree of malocclusion, caries tooth, poor oral hygiene, halitosis and hypertrophic suprahyoid musculature.

In case of adults the history is usually of limited jaw opening and altered mandibular function developing over a period of time. Facial morphological characteristics are normal because the alterations started after completion of growth.

When ankylosis is suspected it should be confirmed radiologically.

Radiological examination

Plain film radiographs is of little value. They help in visualising joint morphologic characteristics as narrowing of the joint in inflammatory joint disease

Arthrography may be occasionally useful in demonstrating fibrous ankylosis but it is contraindicated in bony ankylosis.

MRI imaging is of little value in the diagnosis of TMJ ankylosis.

The panoramic radiographic view is adequate for initial screening.

TMJ tomography taken in coronal and sagittal sections gives more information. They are helpful in localising and quantifying the bony ankylosis. Tomographic sections through the entire joint provide information about condyle and fossa morphologic conditions, joint space integrity and location of osseous union. They may also reveal large extraarticular mass of bone attached to the zygomatic arch laterally and to the base of the skull medially.

If ankylosis is suspected but not confirmed by tomography, then computed tomography (CT) imaging is helpful because of its greater delineation of osseous details and its ability to show spicules of bone that bridge the joint space. This is the best for visualising the medial extension of the ankylotic mass.

The more recent advance in imaging is the three dimensional CT scans with reconstruction of the joint, which can accurately reproduce the pathologic features on the medial and posterior aspects. This helps in better perception of the joint in all views. This information is important for precise surgical treatment planning because adequate resection is necessary to reduce the incidence of recurrence and postoperative failure.

Based on CT findings Sashi Aggarwal, Manorama Berry et al 1990 classified bony ankylosis of TMJ into two types

Type I        Medially angulated condyle with deformed articular fossa and a mild to moderate amount of new bone formation. Condyle could be identified – flattened irregular sclerosed or partially resorbed. The articular fossa has corresponding irregular, shallow or deep and usually sclerosed, the sclerosis extending to the adjacent areas of the temporal bone. Mild to moderate new bone formation which extends from the neck of the condyle or lateral superior aspect of the ramus to the squamous temporal bone and or zygomatic arch, frequently encroaching on the lateral aspect of the articular fossa.                                            Aetiology specific – trauma associated.

Type II      Joint architecture completely disrupted with no recognisable condyle or articular fossa. There are large masses of new bone, funnel shaped, extending from the thickened ramus to the grossly sclerosed and irregular base of the skull.                                                          Squealae of both trauma & non trauma cases.

Management

The management of this condition is by surgical means. This is by gap arthroplasty after resection of the ankylotic mass or inferiorly to the ankylotic mass. The main disadvantage with gap arthroplasty is reoccurrence of the ankylosis. To prevent reankylosis interpositonal arthroplasty with various materials have been used.

The objectives of treatment for ankylosis are

  1. To improve joint movement and function, which requires meticulous and radical removal of the ankylosed bone or creation of pseudo joint.
  2. To prevent recurrence of the ankylosis. This is by means of active postoperative physiotherapy, interpostional substances to prevent reankylosis, using radiation postoperatively to prevent reankylosis.
  3. To restore occlusion.
  4. To correct and restore the secondary facial deformity.

The actual surgical treatment varies, depending on several factors:

  1. The extent and type of ankylosis.
  2. The age of the patient at onset
  3. The age of the patient at the time of surgery.
  4. Whether the ankylosis is unilateral or bilateral.

The clinical and radiographic examinations will usually provide enough information to accurately determine the nature and extent of ankylosis. A surgical plan has to be developed, determining the location and extent of bone resection and the type of reconstruction that will be employed.

Raveh et al 1989 classifies temporomandibular ankylosis based on the extent of involvement of the articular fossa, median structures and skull base as

Class I             Ankylotic bone tissue limited to the condylar process and articular fossa.

Class II           The bone extends out of the fossa involving the medial aspect of the skull base up to the carotid- jugular vessel.

Class III          Extension and penetration into the middle cranial fossa.

Class IV          Combination of class II and III.

The authors advocates radical exposure and extensive resection of the ankylotic mass to avoid recurrence, particularly if the bony ankylosis extends beyond the fossa up to jugular-carotid vessels. If penetration into the middle cranial fossa is evident, removal of the ankylotic tissue may cause dural tear and result in CSF leak. This requires duraplasty by adapting the temporal fascia with glue and the resulting defect in the roof of the articular fossa is bridged with a thick layer of lyophilised cartilage. The authors advocate the use of interpositional substances as the lyophilised costochondral cartilage and aloplastic materials such as silastic.

Sawhney in 1986 described four types of ankylosis of the TMJ joint and discussed the selection of appropriate surgical treatment.

Type I              Condylar head is flattened or deformed in close approximation to the upper joint space. Dense fibrous adhesion is present within. Restricted motion is due to fibrosis in and around the joint.

Type II            Flattened condyle in close approximation to the glenoid fossa, bony fusion of the outer (lateral) aspect of the articular surface either anteriorly or posteriorly and limited to a small area.

Type III           Ankylosis usually results from a medially displaced fracture dislocation of the condyle with bone bridging the ramus of the mandible to the zygomatic arch. The atrophic condylar head is either free or fused to the medial aspect of the superior portion of the ramus.

Type IV           A wider bony block bridges the mandibular ramus and zygomatic arch, extending and obliterating the upper joint space and completely replacing the architecture of the joint.

The surgical procedures advocated by Sawhney et al are:

Type I and II ankylosis are amenable to lysis of either the fibrous or bony ankylosis. Recountouring of the condyle can be done with high condylar shave. When the disk is found, it is mobilised and sutured over the condylar stump. If the disk is not amenable, then dermis or temporalis fascia is suitable substitute.

Type III and IV ankylosis usually requires sufficient removal of bone to create a gap between the ramus and the superior joint structures. It is recommended to place an interpostional substance to reduce the incidence of recurrence of ankylosis and to minimise the loss of the posterior vertical dimension of the ramus.

Nitzan et al in 1998 advocated the preservation of the condylar stump and the disk in case type III ankylosis. He advocated the contouring of the remnant of the condyle would fulfil for the mandibular growth and function. There is no need for interpositional substance in these type of cases.

Kaban et al in 1990 laid down a protocol for management of temporomandibular joint ankylosis. These include

  1. Aggressive resection of the ankylotic segment with special attention for the medial aspect to ensure total resection.
  2. Ipsilateral coronoidectomy along with dissection and stripping of the temporalis, masseter and medial pterygoid to be done. This results in loss of one third of the ramus height.
  3. Contralateral coronoidectomy to be performed when the interincisal mouth opening was less than 35mm. This could be done through the intraoral approach.
  4. Lining the joint with temporalis or cartilage. If an intact disk is present it could be used to line the joint. In other cases, TMJ to be lined with temporalis fascia flap rotated over the arch pedicled inferiorly to the deep temporal vessels.
  5. Reconstruction of the ramus with a 6-cm long costochondral graft with 5mm thick costal cartilage contoured to the shape of the condyle.
  6. Rigid fixation of the graft and
  7. Early mobilisation and aggressive physical therapy.

With this protocol the authors advocate that there is minimised chance for reankylosis with adequate restoration of function.

Salins in 2000 gave a new perspective in the management of the ankylosis by performing an osteotomy inferior to the ankylotic mass(subankylotic approach) and producing a pseudoarthrosis. The author advocates use of temporalis muscle flap and interpostional substance of 7 to 8 mm thick to prevent reankylosis. Three major problems exist when conventional approach of resecting the ankylotic mass is carried out.

  1. The volume and extent of the ankylotic bony mass in relation to the cranial base is highly variable and so radical excision may prove to be a considerable risk.
  2. The scar tissue that surrounds the ankylotic mass often impedes mandibular movement even when the bony mass has been excised. Hence the management of reankylosis is difficult as the scar tissue increases with each successive surgical intervention.
  3. Radical removal of bone leaves large opposing surfaces of healing bone, which is likely to be bridged by dense scar tissue. The scar tissue thus formed can result in restriction of mandibular movements and give rise to reankylosis.

This technique differ form conventional technique in the following aspect

  1. The ankylotic mass is not resected / manipulated.
  2. Bone is not removed to create a gap as in the case of gap arthroplasty.
  3. A functional pseudoarthrosis is created between normal bone surfaces.

The advantages of this technique include

  1. A pseudoarthrosis is encouraged to form in normal bone below the base of the ankylotic mass.
  2. Since thin ridges of normal bone border the gap created with this technique, scar tissue formed is minimal and an effective interposition arthroplasty is made possible.
  3. There is no bone sacrifice to create a gap, therefore no reduction in ramal length.

Whatever the technique used in the release of ankylosis, the postoperative physiotherapy is vital in acquiring a normal jaw function and preventing re-ankylosis. Physiotherapy should be started at the earliest, possibly on the first postoperative day. Physiotherapy consists of active and passive jaw motion exercises.

The heterotropic ossification can be prevented by medical therapy and radiotherapy. The medial therapy is by means of antiresorptive agents like biphosphonates (sodium etidronate, pamidronate and allendronate). Radiation of up to 5oooGcy has been advocated to prevent osteoblasts from depositing osteoid.

Surgical treatment in children

Children who develop ankylosis before 5 yrs of age are more susceptible to deformities of the face as a result of interference from the ankylosis. The objectives for surgical treatment of ankylosis in children includes

  1. To improve mandibular function
  2. To maintain normal mandibular growth and development of the face.

The surgical option is same as in the management of the ankylosis in the adult, except in severe cases accompanied by growth disturbances where the destroyed condyle is to be reconstructed with grafts capable of growth. This is achieved by costochondral rib graft, which has growth potential that can restore facial skeletal harmony and also allows for improved function.

The surgical procedure requires both preauricular and submandibular approach. It involves lysis of ankylosis / creation of a gap and insertion of costochondral graft. In cases of unilateral ankylosis with facial asymmetry it might require a ramus osteotomy on the contralateral side to correct the deformity. This requires prior evaluation of the deformity by means of posteroanterior cephalograms, photographs and models to quantify the degree of facial skeletal deformity (asymmetry, vertical dysplasia & retrognathia).

Hypermobility disorders.

Hypermobility disorders mean excessive mobility, when applied to temporomandibular joint it means hypertranslation. In 1832, Sir Astley Cooper proposed the principles for diagnosis and treatment of dislocation of the lower jaw. He introduced the terms complete dislocation (luxation) and imperfect dislocation (subluxation).

Hypermobility can be divided into three interrelated clinical entities:

Hypertranslation / hypermobility

Subluxation and

Dislocation

Hypertranslation refers to the excessive anterior movement of the condyle during opening. Normally the condyle translates to the inferior aspect of the articular eminence on full opening. It may be predisposing factor to subluxation, dislocation or internal derangement. Treatment is seldom required for hypertranslation.

Subluxation is defined as the displacement of the condyle out of glenoid fossa and anterosuperior to the articular eminence, which can be reduced by the patient (self-reduced). Patient might usually complaint of temporary inability to close the jaw completely. Subluxation can occur along with internal derangement, here it occurs when the condyle translates over the posterior surface of the disk and comes to rest anterior to it. Treatment is not indicated in the absence of pain.

Dislocation is similar displacement of the condyle, which cannot be self-reduced. Dislocation might be acute or may be recurrent or habitual. The highest incidence of recurrent dislocation is among females.

Causes

The dislocation is caused by

  1. Dysfunction of TMJ
  2. Abnormal Glenoid fossa
  3. Abnormal Condylar head
  4. Relaxation of ligaments
  5. Relaxation of capsule
  6. Dysfunction of muscles of mastication

Acute dislocation is caused by

  1. Trauma
  2. Sudden movement as in singing or yawning or as a result of excessive downward pressure during extraction of teeth.

Factors precipitating dislocation can be grouped into extrinsic and intrinsic factors

Intrinsic factors:

Overextension injury

Yawning

Vomiting

Wide biting

Seizure disorders

Extrinsic factors:

Trauma

Blow to the chin when mouth is wide open

Manipulation of the jaw during

  • Intubation
  • Endoscopy
  • Tooth extractions

Miscellaneous causes

Internal derrangement

Occlusal discrepencies

Factors modifying dislocation:

Connective tissue diseases

Ehlers-Danlos syndrome

Marfan syndrome

Psychogenic

Habitual dislocation

Parkinson’s disease

Tardive orofacial dyskenesia

Drug induced

Phenothiazines.

 

The laxity of the ligaments and joint capsule predisposes the joint to dislocate. Looseness of the capsule and ligaments can result from inadequate healing from injury, as well as from long standing degenerative joint diseases. Occlusal abnormality and loss of vertical dimension can contribute to laxity.

Spontaneous dislocation is due to a break in the timing of muscular action in the first phase of closing. Dislocation can occur when the protractors fail to relax at the appropriate time and the elevators contract to dislocate the mandible in to the infra temporal fossa.

Once the condyle is out of fossa, anterior to the eminence, there will be excessive stretching of masseter.  This will cause involuntary reflex contraction of masseter. There is also a reflex initiated by proprioreceptors in the TMJ, ligaments and lateral pterygoid muscle. These contractions produce excessive dislocation of the condyle and form a vicious cycle.

Signs and symptoms of acute and chronic dislocation are the same and include

1.Inability to close the mouth.

  1. Preauricular depression of the skin
  2. Prominence of the condylar head anterior to the articular eminence.
  3. Elongated face.
  4. Excessive salivation
  5. Tense, spasmodic muscles of mastication and
  6. Severe pain of the TMJ.

Acute dislocation will produce damage to the disk, ligament and capsule. There is an inflammatory oedema characterised by swelling, tenderness and increased temperature.

In chronic dislocation pain will be minimum and there won’t be any swelling.

Radiologic examination is essential to rule out associated condylar fracture prior to reduction.

Management

Treatment of mandibular dislocation depends on time elapsed between occurrence and treatment. The longer elapsed period indicates a difficult reduction. In acute cases immediate reduction should be done and most often it will be adequate. In chronic and longstanding cases other forms of surgical treatment are to be considered.

Manual reduction will be complicated with difficulties because of

  1. Anxiety, apprehension of the patient
  2. Severe spasm of masseter.

Therefore before attempting reduction the following measures are to be taken

  1. Reassure the patient.
  2. Asking the patient to open the mouth
  3. Mild sedatives like Diazepam
  4. Tranquillisers
  5. Massage over the coronoid and masseter
  6. Injection of local anaesthetic to the joint, for disruption of reflex contraction reflex.
Manual reduction

This is done by standing in front of the patient. Patient is firmly seated and head supported. Thumbs wrapped with gauze and placed over the occlusal surface of mandibular molar teeth or alveolar ridge. The lower aspect of chin is grasped with fingers. Patient is encouraged to relax and open in the direction of dislocation. The condyle is depressed by pressing down in the mandibular molar region and simultaneously elevation of the anterior region with fingers will rotate the condyle over the articular eminence into the fossa.

After a successful reduction, immobilisation with follow up care is necessary for the soft tissue of the joint to heal. In chronic cases jaw immobilisation will not be helpful because the damaged ligaments will be highly laxed and by repeated dislocation this may not be relieved. In these cases jaw exercises to improve muscle tension are to be advocated.

Reduction of dislocation of several days duration are complicated by severe muscle spasm. Injecting local anaesthetic into the joint can facilitate reduction by blocking the sensory reflex mechanism of the joint, which reduces the spasm of muscles. Alternatively diazepam 10mg may be given 1-hour prior to sedate and reduce the muscle spasm before reduction.

The difficulty encountered with treating mandibular dislocation increases with the duration of dislocation. In long standing cases the dislocated condyle would have undergone fibrous adhesions to the disk and articular eminence. The jaw muscles would also have undergone fibrotic changes. These prevent nonsurgical methods of reduction. In such cases the modalities of management include:

  1. Manual reduction under general anaesthesia and muscle relaxant.
  2. Using functional appliance
  3. Using class III elastics.
  4. Surgical methods
  5. Open technique. Here wires are hooked around the sigmoid notch and the condyle is distracted inferiorly and condyle is repositioned into the fossa.
  6. In case of fibrotic temporalis coronoidectomy aids in repositioning of the condyle.
  7. Condylectomy
  8. Eminectomy
  9. Sagittal split osteotomy.
Management of chronic recurrent dislocation

Management of cases with chronic persistent dislocation is troublesome. These are ideally managed by surgical methods. Before initiating surgical intervention, all reversible etiologic causes should be investigated and possible psychological factors evaluated. Many procedures have been devised to manage this problem

Surgical procedures for correction recurrent dislocation can be divided into three types:

  1. Those that removing the blocking factor in the path of the condyles
  2. Those that limit the range of motion
  3. Those that alter muscle balance.

Blocking factors are removed by procedures such as eminectomy, diskectomy, condylectomy and high condylar shave.

Motion limitation can be achieved by directly restraining the condyle or by tightening of the joint capsule and ligaments or by creating mechanical barrier to the dislocation of condyle. The procedures include tethering of the mandible to another stable structure, capsular plication, arthroscopic sclerosis of the oblique protuberance and procedures that create an obstruction in the path of condylar translation by augmenting the eminence or repositioning of the disk is done.

Muscle balancing is accomplished by reducing the influence of the lateral pterygoid muscle. Procedures include lateral pterygoid myotomy, myotomy combined with diskectomy or arthroplasty and condylotomy.

All these surgical procedures create a scar around the TMJ which limits the motion of the condyle.

 


Chondromalacia

Chondromalacia means softening of the articular cartilage. TMJ chondromalacia is caused by stress-related microtrauma of chronic masticatory muscle hyperactivity (bruxism) overloading of the joint’s articular cartilage. This condition is more common in women.

The pathogenesis is following chronic microtrauma results in release of collagenases, which causes splitting of proteoglycans and softening of cartilage.

Stress Bruxism

Chronic microtrauma

Compression and shearing

Chondrocyte damage – Cathepsin release and other collagenases

Splitting of proteoglycan chain and water loss

Loss of cartilage resilience – Water reabsorption

Chondromalacia

Grade I        Softening of articular cartilage – Collagenases causes degradation of proteoglycans in fibrocartilage.

Grade II       Rupture of deep fibrils attached to the subchondral bone – Loss of proteoglycans & Ability to withstand compressive & shearing forces.

Grade III      Rupture of parallel articular fibres of fibrocartilage producing fibrillated and frayed cartilage strands and resulting in increased frictional surface.

Grade IV      Degeneration of fibrocartilage with exposure of subchondral bone.

The treatment of chondromalacia is not clinically necessary until grade III or grade IV is reached. Treatment is necessary when obvious fibrillation is present. The treatment consists of motorised shaving of the fibrillation. In grade IV chondromalacia abrasion arthroplasty can be done with motorised arthroscopic unit.

Chondromatosis

Synovial chondromatosi is a benign monoarticular lesion that most frequently affects the larger articular joints. Involvement of temporomandibular joint is very rare. It is of unknown etiology. Trauma has been implicated as an etiological factor.

Synovial chondromatosis is characterised by the development of metaplastic, highly cellular cartilagenous foci in the synovial membrane. It is belived to be cartilagenous metaplasia with primitive skeletogenic mesenchymal tissue remanants in it.

It has been classified by Milgram et al in 1977 into three developmental stages.

  • Metaplasia is found in the synovial membrane without presence of detached particles.
  • Metaplasia is found in the synovial membrane with the presence of detached particles in the joint that are nourished by diffusion of synovial fluid..
  • Only detached particles are found in the joint.

Synovial chondromatosis has been described in primary and secondary form. Secondary form chondromatosis is associated with degenerative, inflammatory or non-inflammatory diseases. Primary form is aggressive and may erode bone.

Radiographic feature is presence of loose bodies in the joint space. Calcification or ossification of these loose bodies are required to demonstrate it by radiographs. CT and MRI can detect these masses.

The treatment of synovial chondromatosis of the temporomandibular joint is surgical exploration of the joint or arthroscopical removal of the mass together with the loose bodies and the affected synovium. Condylectomy and meniscectomy is indicated in case of extensive damage to them.

Neoplasms

Tumours affecting the temporomandibular joint area are exceedingly rare. The tissues from which neoplasm may arise include the synovium, bone, cartilage and associated musculature.

The benign tumours include osteomas, chondromas, synovial chondromatosis and other tumours. The features include deforming swelling associated with pain. Synovial chondromatosis is metaplasia of the synovial membrane, which is characterised by the formation of cartilage particles in the synovial membrane. These migrate into the joint compartments. Treatment of benign tumours includes condylar head resection with or without reconstruction. For synovial chondromatosis the treatment is by surgical removal of the freely mobile particles in the joint space.

The malignant tumours reported in temporomandibular joint include chondrosarcoma, synovial fibrosarcoma, osteosarcoma and malignant fibrous histiocytoma and other metastatic tumours. Primary malignancies of the Temporomandibular joint require aggressive therapy to prevent intracranial extension. Radiation therapy can be used for palliation in disseminated disease to control pain.

 


Conclusion

The temporomandibular joint is crucial to the everyday functioning of modern man.  It is subject to all the diseases and disorders that can affect other joints, but the vast majority of these problems can be dealt effectively by non-surgical methods.  However, in a small number of patients surgery is indicated to eliminate disease or deformity and to restore function and anatomy.  Before such decision can be made the clinician needs to be aware of the basic biology of the joint, the diagnosis must be secure and the efficacy of alternative treatments assessed.

 

 


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  16. Evaluation of the patient with facial pain. Myron R Tucker. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 1873 – 1904. Lippincott – Raven Publishers.
  17. Non surgical management of Temporomandibular disorders. Steven B Syrop. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 1905 – 1932. Lippincott – Raven Publishers.
  18. Surgery for internal derangements of the temporomandibular joint. Leslie B Heffez. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 1997. 1933 – 1968. Lippincott – Raven Publishers.
  19. Surgical management of the degenerative temporomandibular disease. David A Keith. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 1969 – 1988. Lippincott – Raven Publishers.
  20. Management of Hypomobility and Hypermobility of the temporomandibular joint. Kenneth S Rotskoff. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 1997. 1989 – 2014. Lippincott – Raven Publishers.
  21. Arthroscopy of the mandibular joint. Howard A Israel. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 2015 – 2042. Lippincott – Raven Publishers.
  22. Management of the failed surgical patient. Steven M Roser, A Thomas Indresano, Bruce Sanders, Ralph Merrill, Ralph D Buoncristiani. Principles of Oral & Maxillofacial surgery. Vol. III. Larry J Peterson, A Thomas Indresano, Robert D Marciani, Steven M Roser. 2043 – 2051. Lippincott – Raven Publishers.
  23. Surgical management of temporomandibular joint ankylosis type II by retaining the displaced condyle and disc. Dorrit W Nitzan, Jacob Bar Ziv & Arie Shteyer. J. Oral Maxillofac Surg. 1998: 56: 1133 — 1138.
  24. Temporomandibular Disorders. Robert A Bays & Peter D Quinn. Oral & Maxillofacial surgery. Vol. IV. Raymond J Fonseca. 2001. W B Saunders Company.
  25. New perceptives in the management of cranio-mandibular ankylosis. Paul C Salins. Int J. Oral Maxillofac Surg. 2000: 29: 337 – 340.
  26. Dislocation of the temporomandibular joint. Christoper W Shorey & John H Campbell. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000: 89: 662 – 668.

 

 

 

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Posted in TMJ Disorders

Subluxation and Dislocation of TMJ

INTRODUCTION

Hypertranslation, Subluxation, and Dislocation

Normally the condyle, translates to the inferior aspect of the articular eminence on full opening. Hypermobility means “Excessive mobility” when applied to the TMJ it refers to a condition of “Hypertranslation”. Hypermobility can be divided into three interrelated clinical entities.

  • Hypertranslation refers to the excessive anterior movement of the condyle during opening.
  • The term subluxation is defined as a self reducing partial dislocation of the tmj during which the condyle passes anterior to the articular eminence.
  • The term dislocation can be defined as long lasting inability to close the mouth due to the complete translation of the condyle anterior to the articular eminence.

Movements:

  • The mandible may depressed (opening of mouth) or elevated (closure of mouth). Protruded / Retracted.
  • A considerable amount of restorations occurs. Three activates involve gliding, spin and angulation.

In the position of rest the teeth of the mandible and maxilla are not in contact but slightly separated on closure of the jaws. The teeth come into opposition in the occlusal position.

  • Depression of jaw (opening of mouth):

Is accomplished by, lateral pterygoid resistance in the rotation of the head of mandible/condyle digastric, geniohyoid, mylohyoid round a horizontal axis under the articular disc (lower compartment) and the disc (upper compartment) and finally some rotation and gliding of the head (lower compartment) so that the head articulates with most anterior part of the articular disc.

  • Elevation of jaw (Closure of mouth):

Is by reverse movements, temporalis, masseter, helical pterygoid of both sides gliding backward followed by rotations of the head (lower compartment) and finally gliding of the disc (upper compartment) due to relaxation of the lateral pterygoid muscle.

  • Protrusion (Protraction): is a movement where lower teeth protrude forwards beyond upper teeth (upper compartment) (lateral and medial pterygoid, muscle).
  • Retrction: mol is drawn backwards to the position of rest (upper compartment) temporalis muscle posterior fissure.


SUBLUXATION:

Definition:

  • An incomplete dislocation of the condyle with maximum opening the condyle translates anterior to the articular eminence and is able to return to the fossa after either self manipulation or spontaneous voluntary retention.
  • Subluxation may coexist with internal derangement.
  • It usually report a momentarily / short duration of open dislocation with the jaw ‘sticking’ / temporarily inability to close the jaw completely.
  • Is on incomplete joint dislocation / partial evaporation of articular surfaces.

C/F:

  • Subluxation is noted by the mandible sticking / catching open for a short period before it reduces itself into the fossae.
  • When internal derangement is associated with hypermobility multiple clicks can be detected which represents the condyle snapping over the posterior and anterior edges of the disk.
  • “Click” occurs only on wide opening and not on protrusive or lateral movement / excursions.

Treatment:

  • Limit mouth opening.
  • Exercise not strengthen the elevator muscle.
  • Inj of sclerosing solution to reduce the laxity of the capsule.

Etiology of subluxation / dislocation of TMJ:

Causes:

  1. Intrinsic trauma.

Over intention injury.

Yawning, vomiting.

Wide biting, seizure disorder.

  1. Extrinsic trauma:
  2. Trauma

Flexion, extension injury to the mandible.

Intubation with general anesthesic.

Endoscopy.

Dental extractions.

Forceful hyperextensions.

  1. Connective tissue disorders:

Hypermobility syndrome.

Shler’c Dantos syndrome.

Morfan syndrome.

 

  1. Miscellaneous causes:

Internal derangement.

Dis synchesmous muscle function.

Contralateral intraarticular obstruction.

Host vertical dimensions.

Occlusal discrepancies.

Horizontal dislocation.

Tradive orofacial dyskensica.

  1. Drug induced

Phenothiezinos

Predisposing factors to hypermobility (subluxation dislocations)

  • Previous capsule and ligament injury.
  • Laxity of ligaments (TMJ)
  • Degenerative joint disease.
  • Systynechenous muscle function.
  • Morphologic conditions of the condyle and eminence.
  • Subluxation/ dislocation are most frequently caused by the combination of TMJ overextensions and dyssynchromes muscle function.
  • Joint over extension may be caused by yawning wide jaw opening / vomiting.
  • Dysynchromes muscle contraction results from an alteration of the normal contraction sequelae of the protractor and elevator muscles of the mandible.
  • The condyle protractors fail to release of the condyle reaches its most anteroinferior position in relation to the articular eminence on opening and the elevators. Simultaneously contracts to dislocate the mandible into the extratemporal fossae.
  • Dislocation may also be a con———- of internal derangement.
  • He disk lower to rest between the eminence and posterosuperior surface of the condyle and blocks the return of the condyle to the glenoid fossa.

Mandibular Dislocations:

“Occurs when the condyle moves into a position anterior to the articular eminence (open lock) from which it cannot be voluntarily reduced or repositioned into the glenoid fossa”.

  • Dislocation is also called luxation of the TMJ.
  • Dislocation of mandible is one of the earliest afflictions of the jaws to be described in the literature.
  • Hippocrates is the 5th century described the dislocation and its treatment.
  • Mandible dislocation is uncommon compared to other joint dislocations.
  • Its incidence is 3%.
  • It is uncommon in the extremes of age and there is a higher incidence in females.
  • Dislocation most commonly occur in an anterior direction in relationship to the articular eminence.
  • Superior, posterior and direct medial dislocations rquires lateral dislocations are associated with fracture of the mandible and are rare.
  • Anterior dislocation / subluxations of the condyle may be either unilateral / bilateral.
  • They can be 1) Acute, 2) Chronic.
  1. Acute dislocation:
  • Acute dislocation is common.
  • Can be brought about by a blow on the chin while mouth is open.
  • Injudicious use of mouth gag during G.A. excessive pressure during dental extractions excessive yawning vomiting laughing loudly opening mouth to wide for sating.


  1. Chronic dislocations types:
  2. Long standing.
  3. Recurrent
  4. Recurrent dislocation:

Dislocation which takes place repeatedly and which lost for short/long internals.

  1. Long standing dislocation:

A dislocation that remains locked anteriorly for several days to years is in old.

  1. Habitual dislocation:

This term chronic dislocation is appropriately used in those cases where the patient is able to dislocate and reduce at will this condition is often referred or habitual.

  • Habitual dislocation is usually associated with psychological factor.
  • Chronic dislocation may be an expression of a centrally mediated motor disturbance.

Clinical examinations:

Patient present with hypertranslation without external derangement or dislocation may have c/o capsule and joint soreness.

  • temporofrontal headache.
  • A sensation of fullness in the TMJ.
  1. Dislocation C/F:
  • In acute dislocation one should carefully assertain the causative event, onset and duration of the dislocation.
  • Acute dislocation is easy to recognize clinically.
  • The patient presents with acute pain in the affected joint end associated muscles of mastication.
  • Dislocation can be unilateral / bilateral.
  1. Unilateral dislocation:

Difficulty in mastication and swallowing, speaking profuse d        rooling of saliva in the early stage.

A deviation of chin toward contralateral side (unaffected side) lateral crossbite, a open bite on unaffected side.

Mouth is partly open and deviation of the midline towards unaffected side.

Palpation of the preauricular area reveals a hollow space anterior to the tregus with the condyle palpable anterior to the articular eminence.

The coronoid process is palpable posterior and inferior to the molar bone.

The capsule structures are tender, quite painful to palpation.

Bilateral acute dislocation:

  • Associated with pain.
  • Inability to close the mouth.
  • Tense masticatory muscles.
  • Difficulty in speech, excessive salivation protruding chin.
  • The mandible is postured forward and movements are restricted gagging of the molar teeth / posterior teeth with the presence of anterior open bite.
  • Difficulty in swallowing and drooling of saliva.
  • Patient will C/O pain in the temporal region
  • Palpation of the preauricular area reveales a hollow space anterior to the tragus with the condyle palpable anterior to the articular eminence.
  • The coronoid process is palpable posterior and inferior to the molar bone.
  • The patient is unable to close the mouth/ move the mandible from side to side.

Radiological Evaluation:

  • Absence of the condyle from the glenoid fossae it is often displaced to a position anterosuperior to the anterior articular eminence on both open and closed mouth views.
  • Radiographic evaluation is indicated for preoperative evaluation of the morphologic characteristics architecture of the eminence.
  • Surgeon importance is pneumatization of the articular eminence.
  • In chronic recurrent dislocation radiographic are useful to assess the longterm remodeling changes that have occurred in the condyle and articular eminence before determining the feasibility of surgical reduction.

Treatment:

  • the initial acute, long standing and the chronic recurring dislocations of the mandible require different treatments. The acute dislocation needs immediate treatment attention for relief of pain and anxiety to minimize damage to the joint structure.
  • Reduction and immobilization for 4 weeks will slow damaged ligaments, capsule, disk to heal.
  • The chronic care and the treatment consists of exercise to gain better muscular control and restraint of opening.

Management by surgery may be indicated for long standing and chronic dislocations but rarely for an initial acute dislocations.

  • The major problem to overcome in all dislocations is muscle contraction.

Treatment:

There are various approaches to treatment of acute/chronic dislocations of TMJ.

  1. Non surgical treatment.
  2. Surgical treatment.
    1. Non-surgical treatment:
    2. Digital manipulation:
    3. a) Manipulation after infiltration of local anesthesia into glenoid fossa. First advocated by Johnson 1958. After dislocation the muscles of mastication are in a state of spasm relaxation of these muscle being required before reduction.

Local anesthetic effect:

  • To overcome muscle spasm produced by soft tissue damage associated with dislocation.
  • To abolish the muscle spasm produced by raflener during the actual reduction of the dislocation. LA to block the sensory site of local reflexes.

Ex: Pain/ muscle stretch reflexes.

  1. b) Manipulation muscles G.A. with the muscle relaxants.
  2. c) Manipulation under either oral / IV sedation (with/without LA).
  3. d) Slow traction under GA using arch bars digital manipulation firls.

Stimulation of the gag reflex by touching a mouth mirror to the soft palate may inhibit elevator muscle activity. Thus increasing the articular disc space.

2) Physical therapy (Recurrent dislocation):

  • The use of isometric exercises to improve opening and closing pattern.
  • Patient with chronic subluxation and dislocation have a habit of initial translation during the opening phase.
  • Synchronized isometric contraction exercise of masticatory opening muscles and their antagonists should be performed on a regular basis. This results in improvement by strengthening the muscles and there by improving joint stability.
  • Exercise trains the suprahyoid muscles to stabilize the mandible and reduce forward movement of the condyle in the early opening phase.

3) Symptomatic treatment:

Patients with subluxation and dislocation suffer arthealgia and reyalgia.

Analgesic and NSAID drugs used.

Muscle relaxants and transquilizers are useful. An important of etenoid ex: methyl prednisolone.

(Long acting corticosteroid avoided leads to CT atrophy and weakening of collagenous tissue therefore increasing joint luxity.

4) Occlusal Treatment:

Occlusal disturbances like: curpol interferences and xlon occlusion due to missing teeth with loss of vertical support should be corrected to prevent the instability of the joint.


5) Other ultrasound:

Has been shown to promote in vitro collagen synthesis by human fibroblasts therefore this may be help in stabilizing the point in conjunction with isometric exercise.

Techniques of manual reduction:

Manual repositioning of the condyles is best performed with the patient seated upright in a chair with the back supported and in front of the standing clinician.

The clinician’s thumbs are wrapped in gauge and positioned over the second molars bilaterally.

The index fingers are placed securely under the inferior border on both sides of the mandible just anterior to the antegonial notches.

The patient is asked to relax or much as possible to allow the mandible to move anteriorly.

The posterior aspect of the mandible is depressed inferiorly while the chin is elevated anteriorly to depress the condyles. The mandible is manipulated to allow the condyles to move posteriorly and reposition themselves in the fossa.

In bilateral dislocation relaxation of the condyles can occur simultaneously.

Often reduction of one side results in the reduction of the other side.

  1. Reduction of a dislocation of several days duration of those that are complicated by severe muscle spasms can be facilitated by an injection of local anesthetics into the glenoid fossa.

The anesthetic agent blocks the sensory reflex mechanism of the joint. Thus reducing the muscle spasm produced by the dislocation and preventing the reflex spasm imitated by the manipulation procedure.

  1. Diazepam (valium) 10mg given orally / 1hr before / I.V. immediately before manipulation may help to facilitate manual reduction.
  2. More severe cases require reduction with the patient under GA and administration of muscle relaxant to permit reduction.
  3. Jaw immobilization with I.M.F. is usually necessary and also helpful in patient who experiences excessive pain.

Yurino’s method places the patient is a supine position without a pillow.

The patient is encouraged to relax completely while the operator stands near the patient’s head and holds the body of the mandible from the opposite side.

The patient is asked to open and close the mouth and the operator moves the mandible up and down in phase with the patients opening and closing movements.

The operator then locates the dislocated condyle with his thumb and simultaneously with the patients closing motion pushes it completely downward while moving the body of the mandible upward by this procedure the condyle moves over the articular eminence and ships into the fossa. In case of bilateral dislocation one side is reduced first.

Chemical capsulorraphy:

The injection of sclerosing agents into the supporting ligaments into the joint.

Objective: is to produce fibrosis and tightening of the capsular ligaments thus limiting motion of the mandible and preventing subluxation and dislocations.

Ex:    Sodium prylliate emulsion in oil.

Sodium morrhurate

Sodium tetraderyl sulfate

Alcohol, homogenous blood.

Disadvantages: Inability to predict the amount of limitation that will be produced.

It can be too little / too much

Complication of 7th nerve damage.

0.5ml solution, about 2 to 3 injections.

The injections were spaced 1 to 2 weeks apart the average t/t time was 1 month maxilla and mandible fixation avoid excessive opening.

Intermaxillary fixation (I.M.F.)

Limiting the oral opening by giving elastics total immobilization of the jaw for the period of 3 to 4 weeks gives rest to the joint.

Keep the patient on bioccid / soft diet.

The factor recosting reduction of a dislocation

  1. Normal tone in the muscles of mastication.
  2. Spasm in the muscles of mastication –
  1. Produced by a result of an abnormal position of the mandible and resultant soft tissue injury.
  2. Induced by attempts to reduce the dislocations.
    1. Displacement and wedging of the meniscus.
    2. Fibrous adhesions.
    3. Filling of the articular tissue with dense fibrous tissue.
    4. Surgical Treatment:

– The disorders of the TMJ non-surgical method will control the symptoms of the majority of patients.

It is prudent then to ensure that the patient has undergone adequate conservative treatment before recommending surgery.

It is also important that muscular and psychological factors are managed appropriately. If psychological disturbance may control indicative to the surgery.

The indications for surgery include a disassing recurrent dislocation and long standing dislocation not responsive to closed manipulations and other non surgical treatment.

Acute dislocation and habitual dislocation with significant psychologic influence are rarely indications for surgery.

A number of different surgical methods have been described:

There are three broad categories of procedures which are designed to limit:

  1. Procedures to limit translation.
  2. Anchoring procedures:
    • Capsular placation.
    • Flaps secured to the capsule.
    • Autogenous and alloplastic slings between the condyle and zygomatic process.
    • Securing the disk to the capsule and tragus cartilage anchoring the coronoid process to the zygoma.
  1. To eliminate blocking factors in the condylar path of closure / both.
  2. Diskectomy.
  3. Eminectomy.
  4. Combined procedures to eliminate blocking and limiting translation.
  5. Lateral pterygoid myostomy with diskectomy.
  6. Condylotomy.
  7. Condylectomy – high condylectomy.

Procedures to limit translation:

Anchoring procedures reduce or eliminate the anterior or trantational motion of the condyle.

  1. a) Capsulorrhapy: Consists of shortening the capsule by removing a section and suturing it to make it tight.

“Rahn” used a 1x6mm de epidermized skin flap from the occipital region based on clinical periosteum trimmed and secured to the capsule to augment a capsullorrapy.

“Neiden” modified Rahn is procedure by using a temporal fascia flap is a some manner.

Morris sutured the capsule to the zygomatic process of the temporal bone to reduce laxity.

  1. b) Disk placation: can be either a complete / partial procedure.

In complete disk placation a full wedge of retrodiskal tissue is removed and the disk is repositioned by suturing the remaining retrodiskal tissue directly to the posterior ligament. The partial placation a small pH shaped wedge of tissue is removed to facilitate repositioning.

  1. c) Autogenous/alloplastic slings between the condyle and zygomatic process.

“Gordon” used fascia lata transplants secured through a vertical hole in the zygomatic process wear its base and another horizontal hole in the condyle anteriorly to the inhibit anterior movement of the condyle.

“Mertrill” modified this technique by utilizing wide Dorson sutures.

  1. d) Lateral pterygoid myotomy:
  • Rationale of this procedure is to reduce/eliminate the muscular force thought to be responsible for pulling the mandible into the dislocated position.
  • Condylar translation is reduced convexity.
  • Roman first described this procedure for recurrent dislocation.
  • Myotomy eliminates the action of the superior belly of the lateral pterygoid mucle.
  • The upper half of the lower belly is severed at its infection to the condyle.
  • “Laskin” reported that the lateral pterygoid muscle was detached and a short of silicone rubber was secured over the pterygoid fossa of the condyle to prevent reattachment.

Blocking procedures:

Blocking / arthrocresis procedures to interface with translation are designed to create an obstacle to the condyle in its opening path.

  • Soft tissue, 2) bony procedures.

The better increase the height of the articular eminence by osteotomies, bone grafts and metal implants.

  • Soft tissue:

“Konketzuy” method

surgically creates a closed lock by the disk.

This procedure produces fixation of the disk in an anterior position (closed lock) the posterior ligament of the disk in released and the anterior attachment is preserved.

The disk is pulled anteriorly and inferiorly and is anchored vertically infront of the condyle by suturing it to the lateral pterygoid muscle inferiorly and to the capsule laterally.

  • Bony:

Foged and others say that there is a loss of flattening of the articular eminence is patients with recurrent and habitual dislocation and they advocated the rebuilding of the eminence to create a block to condylar motion.

“Mayer”, resulted a 1.5µm segment of the zygomatic arch and grafted it into a furrow he created in the articular eminence.

“Lindemann”

Muscle on oblique osteotomy to increase the height of the articular tubercle bone of the tubercle and eminence was tilted inferiorly and anteriorly.


Eossere and Cautery:

Advocated the zygomatic arch is cut vertically infront of the joint and lowered.

Resistance to forward glide of the condyle is provided by a bony abutment placed directly anterior to the condyle and firmly attached to the zygomatic bone posteriorly.

Advantages: It nearly doubles the height of the articular tubercle.

“Morgen” restoring a flattened eminence when associated with subluxation and dislocation by using an eminence chrome cobalt prosthesis to create a blocking effect.

In repeated dislocation there is abnormal laxity of supporting ligaments and host the articular eminence. Create new eminence and block with a rib graft.

Eliminating blocking factors in the condylar path:

  • To eliminate obstacles in the condylar path that may either trigger/ a dislocation / mechanically prevent reduction of the condyle into the glenoid fossa.
  • A torn / displaced disk caught behind the condyle or a prominent articular eminence, may also or an obstacle to closure contributing to the condyle becoming stuck momentarily in subluxation prolonged dislocations. Two procedures are there:
  1. b. Diskectomy.
  2. Diskectomy / meniskectomy:

In the removal of the central avascular portion of the disk and the area of perforation through the posterior ligament.

Most difficult portion of the disk to remove in its medial subunion.

Menisectomy with replacement:

Autogenous, allogenic and olloplastic materials have all been need to replace the disk after menisectomy.

Autogenous – desuis, auricular cartilage, temporalis fascia/ temporalis muscle/ infections.

Allogenic – fascia, dura, and cartilage.

Dermal graft can be harvested free hand in the lateral thigh/abdomen.

An elliptical incision is made to exercise the full thickness graft with both epidermis/ dermis intact.

The graft molecule about 3 to 4mm. a 15 blade is used to remove the epidermal layer because graft tends to contract during harvesting and handling the piece of tissue exercised should be larger than the actual dimensions of the meniscal defect.

The skin graft is repositioned and sutured at the periphery.


Eminectomy:

  • Is an operation currently used to correct recurrent dislocation.
  • Relatively uncomplicated procedure.
  • There is no study that supports the concept that the eminence blocks condylar reduction. Intact the eminence in patients with chronic subluxation and dislocation is flat.
  • Exn of skull reveals that the eminence is actually quite flat anteriorly while the posterior slope may be steep.
  • Acute spasm of elevator muscle keeps the condyle in the locked open position.
  • First report by Myshong in 1951.
  • Rationale – is to allow the condylar head to move forward and backward free of obstruction by the excision of the articular eminence instead of attempting to restrict the forward movement of the condylar head.

Indications:

  1. Recurrent episodes of dislocations.
  2. Chronic hypermobility associated with severe pain.
  3. Irreversible TMJ pain associated with clicking / grafting.
  4. Internal derangement.

Disadvantages:

  • Eminectomy exposes marrow and levalar a longbased area surface hemorrhage and enucleated friction between the articular surfaces and can lead to adhesions and limitations.
  • Intracranial exposure of temporal lobe.

Procedure:

  • Eminectomy is performed through the usual surgical approach to the TMJ without suturing the joint.
  • After the zygomatic arch is identified a horizontal incision is made in the periosteum over the arch and is reflected inferiorly to expose the eminence.
  • The osteotome directed inferiorly and medially in a surgically created groove and is tapped lightly to fracture the lateral tubercle and eminence.
  • Frequent mistake is to remove only lateral tubercle and it may recurrence.
  • Using a pneumatic bone file the medial aspect of the eminence is reduced and lateral area smoothened from contouring is done with a diamond hand file.
  • Preoperative homologous taken to rule out pneumatization of the eminence.
  • (T and MRI shows extension of the cancellous bone in the eminence so have to be taken to prevent intracranial exposure of the temporal lobe.
  • The eminence must be recontoured as far medially as possible to ensure that adequate bone is removed.
  • The foramen spinosum is located at the mesial aspect of the articular eminence. Injury to middle meningeal artery hemorrhage after eminectomy.
  • Combined procedures to eliminate blocking and limit translation:
  1. Lateral pterygoid myotomy with diskectomy.
  2. Lateral pterygoid myotomy with diskectomy:
    • First described by Roman.
    • Restricts anterior gliding movement of the condyle and eliminates obstruction caused by the disk.
    • Surgical procedure for recurrent dislocation.
  3. Condylotomy:
    • First described by Ward in 1952.

Indication:

  1. painful joints with internal derangements.
  2. I/O approach to treat recurrent dislocation.

Advantages:

Entirely extra articular unilateral condylotomy is often sufficient for bilateral dislocation.

Condylotomy is an osteotomy through the condylar neck which is performed through an intraoral and intraoral apparatus.

Both procedures release the condyle and allow it to displace anteriorly and sag inferiorly.

The procedure reduce the strength of the lateral pterygoid muscle by shortening it while allowing it to remain functional.

Condylotomy is to reduce lateral pterygoid muscle pull to reduce conflicts of the condyle with the disk and eminence due to its inferior displacement.

Performed with “Gigli saw”.

The procedure was designed to induce displaced fracture through the condylar neck so that the condyle would be repositioned inferiorly and anteriorly.

This allows the condylar head to seat under the displaced meniscus and unload the posterior attachment.

An intraoral subsigmoid. Vertical osteotomy is performed and the patient is maintained in I.M.F. with notches for a 2 to 4 weeks period.

Condylectomy:

  • Is a procedure in which the entire condyle is resected.
  • Is a surgical approach to treat-ankylosis.
  • Prepare the joint for a total alloplastic prosthesis costochondral graft.
  1. A complete condylectomy.
  2. High condylectomy.
  3. Complete condylectomy:

Disadvantages:

Of producing facial and occlusal deformity.

Lateral pterygoid muscle is sacrified allowing only rotational movement without translation.

The ramus is shortened producing in open bite deformity and retrusion of the mandible.

The blocking effect of the condyle on the disk/ eminence is removed in this procedure.

It can be considered a procedure that both restricts forward motion and removes blocking factors.

This operation is a host lost resort when other operations have failed/ in long standing dislocations.

Procedure:

Is performed through the standard indural approach used to identify the neck of condyle of the level of the sigmoid notch below the most inferior lateral capsular attachment. The condyle is sectioned with 1mm. pressure bur is used to make up at the level of the sigmoid notch. The cut is made completely through the lateral anterior and posterior surfaces but the lost section of medial cortical bone is preserved a T-bar osteotome is gently tapped and traveled to complete the condyles cut. While protection is provided the inferior maxillary artery which lies medial to the condylar neck.

High condylectomy:

  • 7to 8mm of the entire condylar head is removed.
  • Is a more conservative operation with preservation of most of the lateral pterygoid muscle.
  • Low significant decrease in vertical height of the ramu.
  • It is preferred over condylectomy and it will also eliminate conflicts with the disk and eminence.
  • Scar formation and partial loss of lateral pterygoid muscle will limit movement.
  • Condylectomy for ankylosis and protects joint placement and with chomoral grils grafting.
  • In which osteotomy cut in at the base of the coronoid to prevent post surgical ankylosis.
  • In case of ankylosis sectioning the condyle at a level below the ankylosis (at sigmoid notch) is advised before attempting to separate the ankylosis bone at the superior glenoid fossa margin.


Conclusion:

  • The treatment of hypermobility disorders painful hypertranslation subluxation dislocation should be approached in a careful and conservative manner.
  • The surgeon should employ the simplest and most effective method with the least morbidity for a specific patient.
  • It is also important that muscular and psychologic factors are managed appropriately.

REFERENCES

  1. Principles of Oral and Maxillofacial surgery – vol. 3, Peterson.
  2. Surgery of the TMJ – David A. Keith.
  3. Color atlas of TMJ surgery – Peter D. Quinn.
  4. Oral and Maxillofacial surgery TMJ disorders – R.J. Fonseca.
  5. Anatomy for surgeons head and neck – Vol. I – W.H. Hollinshead.
  6. Text book of oral and maxillofacial surgery – Kruger.
  7. The role of local anesthesia in the reduction of longstanding dislocation of the TMJ. BJOMS, 1980; 18: 81-85.
  8. Articular eminectomy for recurrent dislocation. BJOMS, 1987; 25: 237-243.
  9. A new approach to the reduction of acute dislocation of the TMJ. A report of three cases, BJOMS 1987; 25: 244-49.
  10. Shortening of the temporalis tendon for hypermobility of the TMJ. J. Oral Surg. Vol. 76, July 1978.
  11. Miniplate eminoplasty: A new surgical treatment for TMJ dislocation. JOCMF Surg. 1993, 21: 176-178.
  12. TMJ disorders diagnosis and treatment – Kaplan and Arsael.