A review of 56 cases of chronic closed lock treated with temporomandibular joint arthroscopy.

PURPOSE: The aims of this prospective clinical study were to look at the features that constitute chronic closed lock of the temporomandibular joint (TMJ) and to assess the effectiveness of TMJ arthroscopic lavage and lysis in the management of this condition. PATIENTS AND MATERIALS: Sixty joints in 56 patients who presented with mandibular hypomobility suggestive of chronic closed lock were prospectively examined and treated with TMJ arthroscopic lavage and lysis during a 3-year period from 1996 to 1999. RESULTS: Eighty-seven percent (49 of 56) of patients were found to have chronic closed lock of the TMJ. The most common intra-articular findings were fibrillation (76%) and synovitis (54%). TMJ arthroscopic lavage and lysis were found to be effective in the management of chronic closed lock in 84% (47 of 56) of patients, with an average 66% reduction in pain levels and a mean improvement of 9.8 mm in interincisal mouth opening up to 6 weeks after the procedure. CONCLUSIONS: Chronic mandibular hypomobility is a clinical sign that is often but not always caused by chronic closed lock of the TMJ. The intra-articular findings of this study suggest that cartilage degradation and synovial inflammation are important components of chronic closed lock of the TMJ that respond well to arthroscopic lavage. Patients with mandibular hypomobility not caused by closed lock of the TMJ (ie, myofascial pain and dysfunction, osteoarthrosis, and others) are less likely to derive benefit from arthroscopic lavage and lysis, so other treatment methods should be considered.