Research On The Appearances And Dimensions Of Adult Knee Radiographs In Discoid Lateral Meniscus

Purpose: To establish the radiologic features of discoid lateral meniscus by special dimensions and analysis of the knee radiographs of discoid lateral meniscus, comparing with normal controls.Materials and Methods: The knee radiographs of 89 cases of discoid lateral meniscus which proven by the arthroscopy, including 69 cases of complete type and 20 cases of incomplete type discoid lateral meniscus were measured. Knee radiographs of 80 cases of normal meniscus proven by arthroscopy were used as controls. We excluded patients who had significant trauma history, significant degenerative knees, skeletally immature and malformation. Values and characteristics were all observed before operation. All patients and controls underwent a standardized knee radiograph that was a non-weight bearing anterior-posterior. The relative normalized values of specific knee dimensions, such as width of medial and lateral joint space, height of medial and lateral intercondyloid spine, height of fibular head, cupping of the lateral tibial plateau, square appearance of the lateral femoral condyle, shrink of the lateral femoral condyle, notching of the lateral femoral condyle, acute or irregular lateral border of tibial plateau, acute medial intercondyloid spine, hardening medial tibial plateau, were compared between the discoid lateral meniscus and the controls.Results: Among these dimensions, widened lateral joint space, hypoplasia of the lateral intercondyloid spine and shrink of the lateral femoral condyle show statistical signification differences between the discoid lateral meniscus group and the control group. The incidence of acute or irregular lateral border of tibial plateau is higher in discoid lateral meniscus. The square appearance of the lateral femoral condyle, high fibular head,cupping of the lateral tibial plateau, acute medial intercondyloid spine, hardening medial tibial plateau and notching of the lateral femoral condyle show no statistical differences.Conclusions: Although the features mentioned above are not immediate, fromour research we conclude that the plain radiography is useful in screening discoid lateral meniscus.