Changes to the Intercondylar Ligaments of the Knee in Different Stages of Osteoarthritis-A Retrospective Cross-Sectional Study.

The intercondylar notch (IN) houses the central ligaments of the knee joint, namely the anterior and posterior cruciate ligaments (ACL and PCL) as well as the anterior and posterior meniscofemoral ligaments (aMFL and pMFL). As not only the available intercondylar space directly influences the encased ligaments, but also the ligaments themselves may influence each other, the purpose of this study was to evaluate the influence of osteoarthritis on central ligament morphology. Imaging data from the osteoarthritis initiative was used to assess 415 randomly selected patients, equally distributed across five groups based on osteoarthritis severity using the Kellgren and Lawrence classification. MRI scans were used to measure ligament structures in the coronal, axial and sagittal planes. The ACL was evaluated and classified into healthy, pathologic and ruptured. The relationship between osteoarthritis severity and the shape of the IN (A-shape, inverse-U-shape and Ω-shape) was analyzed in relation to ligament morphometrics and ACL condition. The morphology of the ligaments is directly influenced by the development of osteoarthritis. In particular, the Ω-shape, which is associated with severe-grade osteoarthritis, is a risk factor for the development of ACL rupture ( < 0.001). But also, the condition of the ACL influenced the morphometrics of the posterior ligaments, and the PCL as well as the MFLs influenced each other. Statistically significant morphological changes to the encased ligaments in the intercondylar space in osteoarthritis were reported. In particular, the ACL shows a higher risk for pathological changes during ongoing joint degeneration due to osteoarthritis. The other evaluated ligaments-MFLs and PCL-are influenced by the condition of the osseous structures and the shape of the IN as well as by the condition and continuity of the ACL.