Dislocation of the temporomandibular joint

Causes of dislocation include:

¨ A direct punch or kick to the mandible

¨ Opening the mouth wide on yawning or eating

¨ Excessive laxity of the capsule and its ligaments, which allows excessive movement

¨ Intubation during general anaesthesia

 

Signs and Symptoms:

The patient with a bilateral dislocation presents with an anterior open bite with the mandible protruding forward and very limited opening. The patient often reports pain in the temporal fossae and there is difficulty in swallowing.

 

Management:

Dislocation may be treated with the patient awake, under sedation or under general anaesthesia. This often depends on the duration of the dislocation.

Muscle spasm around the joint can make reduction difficult, especially if considerable time has elapsed.

With the patient sitting or lying down the operator stands in front of or behind the patient. They place their thumbs (covered with gauze for protection) over molar teeth or on the retromolar region of the mandible on each side, whilst cupping the chin with the fingers of both hands. Exert a downward and backward pressure. This should slip the condyle head back over the eminence and into the glenoid fossa on each side.

Patients should be advised to avoid wide opening for 24 hours.

 

Chronic recurrent dislocations

Patients can often be taught to self-reduce if the problem is a lax joint.

In the long term, however, surgery in the form of enlarging the eminence by osteotomy, or grafting bone to stop the condyle slipping over it. A capsulorrhapy (tightening the capsule) can also be of help to such patients. See TMJ surgery.

 

Dislocation results when the condylar head is displaced out of the glenoid fossa, but still remains within the capsule. Dislocations are almost always anterior (beyond the articular eminence) and may be bilateral or unilateral.