We developed a new thin rod-lens arthroscope (DRK scope-21) to achieve highly reliable arthroscopy of the temporomandibular joint (TMJ) under local anesthesia in an outpatient setting. In this study, the accuracy of this arthroscope for diagnosis of osteoarthritis (OA) was experimentally evaluated in 21 rabbit knee joints: 17 with OA and 4 without OA.
The diagnostic accuracy of this arthroscope for OA based on stereomicroscopic findings was verified by histopathological examination and was compared with the accuracy of MRI and soft X-ray examination. The diagnostic sensitivity of the arthroscope was 100%, the specificity was 80.0%, and the accuracy was 95.2%. These values were higher than those of MRI (sensitivity, 50.0 %; specificity, 40.0 %; accuracy, 52.4%) or soft X-ray examination (sensitivity, 43.8%; specificity, 40.0 %; accuracy, 47.6%).
In addition, the arthroscopic diagnosis of the severity of OA was compared with the stereomicroscopic diagnosis, considered the optimal standard. The severity of OA was classified into the following 3 stages: normal, fibrillation, and exposure of subchondral bone. The rate of agreement between arthroscopic diagnosis and stereomicroscopic diagnosis was 90.5%(19/21 joints). In the remaining 9.5%(2/21 joints), there was overdiagnosis by arthroscopy.
In conclusion, the present findings show that the DRK scope-21 is highly accurate for diagnosis of OA, with a very low risk of failing to detect OA.
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