This article reports on the results of a study of the arthroscopic findings in the joint surfaces of osteoarthritic temporomandibular joints (TMJs).
Arthroscopy was performed in the upper joint compartment of 40 TMJs in 40 patients. Thirty-one TMJs that were diagnosed with osteoarthritis (OA) constituted the OA group. On the basis of the presence of symptoms related to disc displacement and perforation, OA subgroups were defined. Nine TMJs that were not involved with OA constituted the control group. During the examination, various arthroscopic variables were recorded. Differences between groups and between subgroups were tested statistically.
In the OA group, several arthroscopic variables were found significantly more frequently than in the control group. These included retrodiscal tissue redundancy, adhesions, and heightened attachment to the posterior wall of the glenoid fossa; articular disc displacement and limited mobility; and cartilage degeneration in the articular eminence. Moreover, in the OA group, disc displacement was found significantly more frequently in the period after 6 months than during the first 6 months of clinical signs and symptoms. Anterodiscal hypervascularity was found significantly more frequently during the first year than after the first year, as well as more during the first 2 years than after the first 2 years of clinical signs and symptoms, whereas a lowered attachment on the anterior slope of the articular eminence was found significantly more often after 2 years than during the first 2 years of clinical signs and symptoms.
The findings in this study suggest that OA of the TMJ may initially result in synovial tissue hypervascularity, creeping synovitis, and redundancy, and subsequently in adhesion formation and a reduction of the posterior and anterior recess. Because of cartilage fibrillation on the articular eminence, and the subsequently reduced surface smoothness, the articular disc may become displaced. Eventually, disc mobility is limited, and adhesions and a reduced posterior and anterior recess prevail.