Diagnostic accuracy of the ultrathin arthroscope for temporomandibular joint osteoarthrosis: comparison of arthroscopic and histologic findings in a sheep model.

The diagnostic accuracy of the ultrathin arthroscope was evaluated by examination of the superior joint space of the left temporomandibular joint in 20 sheep. At the time of induction of osteoarthrosis all joints were found to be normal. Six months later the arthroscopic examination was repeated and the results compared with the histologic examination. Similar findings were seen in 11 joints (55%), with arthroscopic overdiagnosis in two (10%) and underdiagnosis in seven (35%). Eight of 16 (50%) disc perforations were found. It was concluded that underdiagnosis occurred because the whole joint space cannot be examined arthroscopically and fibrillated tissue masks bone exposure.