Internal derangements and arthritis of the temporomandibular joint.

Internal derangements of the temporomandibular joint (TMJ) may be a significant factor in the etiology of painful dysfunction of the jaw and associated clinical symptoms. In a two-year prospective investigation, 170 TMJs in 85 patients were studied with plain tomography prior to arthrotomography. Arthritis was detected in 19 patients (22%), predominantly in the second to fourth decade of life, which correlated with internal derangements depicted by arthrotomography, operative findings, and histopathological examination of the condylar surface. The authors suggest that internal derangements related to meniscal dysfunction may be an important factor in the etiology of TMJ arthritis.