“Ankylosis” is the term used to describe fusion and subsequent rigidity of the joints, which can occur in several different parts of the body, including the ankle, elbow, knee, shoulder, finger, or jawbone.
The joint responsible for opening and closing of the mouth is called Temporomandibular Joint (TMJ). They are two joints on the 2 sides of the face, in front of the ears, that work synchronously to open and close the mouth. Fusion of one or the 2 joints to the bone is the reason for Locked jaw or TMJ ankylosis.
What is the Cause of Locked Jaw?
1. Ear infection is a major cause of locked jaw in children. The ear is directly behind the joints. Prolonged pus producing infection of the ear usually spread to the joint anteriorly, leading to fibrosis and rigidity of the joint.
2. Trauma to the chin following a fall is another major cause of locked jaw. An impact on the chin transmits to the 2 joints. If such occurrence is not followed by active jaw exercise, the joint will heal in that position leading to a locked jaw.
3. Noma (Cancrum oris) is another cause of TMJ ankylosis. This is a disease that starts from the gum in malnourished children, and spreads to the face, leading to fibrosis and extra articular fusion.
4. Malunited facial bone fracture is another cause of locked jaw. This occurs when a poorly treated or untreated facial bone fractures heal wrongly and lead to inability to open mouth.
5. Other uncommon causesinclude genetics, birth injury, rheumatoid arthritis and condylar hyperplasia.
How does Locked jaw cause facial deformity?
Fusion of the joint on either side of the face leads to cessation of growth of the lower jaw bone (Mandible). This leads to disproportionate growth of the face. But in case of affectation of the 2 joints together, the lower jaw fails to grow and the face presents with classical ‘bird face‘ deformity which is typically a face without the chin. Inability to open the mouth makes feeding and talking difficult while the oral hygiene is very poor and may be smelly (See Method of feeding in a locked jaw patient). Patient is psychologically imbalance.
What is the Treatment of Locked Jaw?
The treatment is basically surgical correction plus jaw exercise. No medication or any other method brings about opening of the mouth. The jaw exercise following surgery must be active and may last up to 6 months after operation, to prevent recurrence.
Can we Prevent Locked Jaw?
Prevention of the disease and the attendant harrowing psychological trauma is possible with the understanding of the disease process. Ear infection must be treated well in children. Whenever there in an injury to the face, early consultation with expert maxillofacial surgeons will prevent such a long term complication.
Locked jaw is a major cause of facial deformity and inestimable social dislocation. Special attention should be paid to ear infection and facial injuries especially in children. Locked jaw is better prevented than a child witness the harrowing experience of social stigma and abnormalities of speech and feeding. At Cleft and Facial Deformity Foundation, we have carried out numerous free successful surgical operations for the correction of this facial anomaly on the indigent patients and we are prepared to do more subject to availability of funds.