Temporomandibular joint (TMJ) ankylosis most commonly results from trauma or infection that leads to fibrosis and bony fusion within the joint space. Post-injury hematoma or septic arthritis triggers an inflammatory response causing fibro-osseous proliferation, thereby restricting mandibular movement. Early recognition and adequate surgical intervention such as gap arthroplasty or interpositional arthroplasty are critical to restore function and prevent recurrence. Congenital causes, rheumatoid arthritis, and neoplasms are far less frequent etiologies.

Reference: Oral and Maxillofacial Surgery, Raymond J. Fonseca, 3rd Edition.