Anatomical variants of the medial synovial fold of the posterior cruciate ligament: Morphological Classification Based on Magnetic Resonance Imaging of the Knee

Abstract Purpose The aim of this study was to evaluate the necessity of reporting the medial synovial fold of the posterior cruciate ligament on magnetic resonance imaging of the knee joint and the relationship of its frequency with side and sex. Methods All magnetic resonance imaging of the knee joint were retrospectively reviewed independently by two musculoskeletal radiologists. The medial synovial fold of the posterior cruciate ligament was divided into 3 types according to the imaginary line drawn between the lateral border of the medial femoral condyle and the medial tibial intercondylar tubercle. Results The distribution of the frequency of medial synovial fold in all patients according to type was type A (30.1%), type B (55.4%) and type C (14.5%). Intra- and inter-observer agreement was high. Between sex, medial synovial fold types were statistically significantly higher in men. Conclusion Medial synovial folds of the posterior cruciate ligament can be seen on various types of magnetic resonance imaging of the knee joint and may need to be mentioned in reports, especially in patients undergoing knee surgery for various reasons.