Radiographic Knee Dimensions in Discoid Lateral Meniscus -Compared with Normal Control-

We reviewed the knee radiographs of 68 cases of arthroscopically-proven discoid lateral meniscus to evaluate usefulness of plain radiographs in diagnosing discoid lateral meniscus. The subject included 42 cases of complete type and 26 cases of incomplete type discoid lateral meniscus. Knee radiographs of 70 cases which had no pathology of the meniscus in knee arthroscopy were used as controls. We excluded patients who had a significant history of trauma and who were under 16 years of age or over 60 to avoid measuring radiographs of skeletally immature or degenerative knees. The absolute values and relative normalized values of specific knee dimensions such as a squared-off appearance of the lateral femoral condyle, widened femorotibial joint space, cupping of the lateral tibial plateau, obliquity of the lateral tibial plateau articular surface, high fibular head and hypoplasia of the Iateral intercondylar spine in discoid lateral meniscus and normal controls were compared. Among these dimensions, high fibular head and widened lateral tibiofemoral joint space showed statistically significant difference between the discoid lateral meniscus group and normal control group. We suggest that these findings could be useful in screening lateral discoid meniscus in plain radiographs.ope