Intercondylar Notch Stenosis of Knee Osteoarthritis and Relationship between Stenosis and Osteoarthritis Complicated with Anterior Cruciate Ligament Injury A Study in MRI

The aim of this study was to research whether the patients with knee osteoarthritis (OA) exist intercondylar notch stenosis and the relationship between stenosis and OA complicated with anterior cruciate ligament (ACL) injury from magnetic resonance imaging (MRI). A total of 79 cases of moderate-severe OA patients and 71 cases of healthy people were collected; among these OA patients, 38 were OA complicated with ACL injury and 41 were simple OA. The intercondylar notch was divided into A, U, and W types according to the notch shape in the axial sequence of MRI. Measurement of the notch width index (NWI) in the sequences of axial (NWI-1), coronal (NWI-2), and ACL attachment point at femoral (NWI-A) was done. The differences of NWI in different groups and different sequences were compared and the NWI cut-off values in different sequences were resolved by a receiver operating characteristic (ROC) curve which could be used as indicators for intercondylar notch narrowing were calculated. The proportion of type A in moderate-severe OA group was larger than healthy group, and similar to OA complicated with ACL injury and simple OA groups (P < 0.05). The NWI values of the moderate-severe OA group in three sequences were smaller than the healthy group, and similar to OA complicated with ACL injury and simple OA groups (P < 0.001). The cut-off values of ROC curve were NWI-1 < 0.266, NWI-2 < 0.247, and NWI-A < 0.253 in the moderate-severe OA group, and NWI-1 < 0.263, NWI-2 < 0.246, and NWI-A < 0.253 in the OA complicated with ACL injury group. The intercondylar notch of moderate-severe OA patients exist significant stenosis. Type A is one of the variables that predispose a notch to stenosis. Intercondylar notch stenosis and type A are risk factors for moderate-severe OA patients complicated with ACL injury.