Temporomandibular joint osteoarthrosis and temporomandibular joint hypermobility

For studying the relationship between condylar hypermobility of the temporomandibular joint (TMJ) and osteoarthrosis (OA), 13 patients with bilateral condylar hypermobility were evaluated clinically and radiographically, 30 years after non-surgical treatment. The evaluation included range of motion, joint and muscle tenderness to palpation, joint sounds and masticatory function. Radiographs of the TMJs were evaluated for the absence or presence of degenerative changes. The hypermobile group (HG) was compared with a control group (CG) (n = 13). The CG was evaluated in the same way as the HG. Statistics included t-tests (to compare ranges of motion in the HG over time and to compare ranges of motion in HG and CG), non-parametric tests (to compare tenderness of muscles and joints, joint sounds, masticatory function and radiographic changes over time in the HG). The tests were also used to compare the same variables between the HG and CG group. The groups' only difference was the presence of radiographic signs of OA. In the HG the number of joints with radiographic degenerative changes increased significantly over time and was significantly higher than the CG. Clinically and functionally, the HG and CG did not differ. Therefore, it is concluded that TMJ hypermobility is a subsidiary factor in the development of TMJ OA.