Ankylosis of the temporomandibular joint is immobility or fusion of the joint.
(See also Overview of Temporomandibular Disorders.)
Ankylosis of the temporomandibular joint (TMJ) most often results from trauma or infection, but it may be congenital or due to a systemic disease such as rheumatoid arthritis. Chronic, painless limitation of mandibular motion occurs (typically less than 3 cm maximum mouth opening). When ankylosis leads to arrest of condylar growth, facial asymmetry is common (see Condylar Hyperplasia).
Intra-articular (true) ankylosis must be distinguished from extra-articular (false) ankylosis, which may be caused by enlargement of the coronoid process, depressed fracture of the zygomatic arch, or scarring resulting from surgery, irradiation, or infection. In most cases of true ankylosis, radiographs of the joint show loss of normal bony architecture.
Treatment may include a condylectomy if the ankylosis is intra-articular or an ostectomy of part of the ramus if the coronoid process and zygomatic arch are also affected (1, 2). Jaw-opening exercises must be continued after surgical correction to maintain mobility (3).
Forced opening of the jaws without surgery is usually ineffective because of fusion of the TMJ.
References
1. Khanna JN, Ramaswami R. Protocol for the management of ankylosis of the temporomandibular joint. Br J Oral Maxillofac Surg. 2019;57(10):1113-1118. doi:10.1016/j.bjoms.2019.10.298
2. Bi R, Jiang N, Yin Q, et al. A new clinical classification and treatment strategies for temporomandibular joint ankylosis. Int J Oral Maxillofac Surg. 2020;49(11):1449-1458. doi:10.1016/j.ijom.2020.02.020
3. Zhi K, Ren W, Zhou H, et al. Management of temporomandibular joint ankylosis: 11 years' clinical experience. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(5):687-692. doi:10.1016/j.tripleo.2009.06.041
