We report a case of temporomandibular joint （TMJ） ankylosis suspected to be caused by psoriatic arthritis and treated by condylectomy. The patient was a 63-year-old woman. She was referred to our department by a university oral surgery department because of trismus. Her medical history revealed the onset of psoriasis at the age of 14 years. She experienced pain on mouth opening in the right TMJ, and the interincisal distance was 12 mm. Panoramic radiography and computed tomography revealed narrowing of the right TMJ cavity. Blood tests indicated a mildly increased C-reactive protein level, negativity for rheumatoid factor, and presence of human leukocyte antigens A2 and B46. On the basis of a clinical diagnosis of TMJ ankylosis caused by psoriatic arthritis, condylectomy was performed with the patient under general anesthesia. During surgery, the mandibular condyle was found to adhere to the temporal bone in the right TMJ region. The lower portion of the mandibular condyle adhesions was resected, and the temporal and masseter muscles were detached bilaterally. This resulted in an intraoperative interincisal distance of 40 mm. After surgery, the patient performed the recommended mouth-opening exercise training. However, 1 year after surgery, the interincisal distance had decreased to 22 mm because of an exacerbation of systemic symptoms of psoriasis.
