Magnetic Resonance Imaging Analysis of The Relationship Between Intercondylar Notch Angle and Anterior Cruciate Ligament Injury

Abstract Background The most damaged ligament resulted from knee joint injury is the anterior cruciate ligament (ACL), representing 50% of all knee injuries, However, the etiology of ACL tears is not com-pletely clear. Some studies showed morphological predispositions such as narrow intercondylar notch dimensions, Identifying anatomical factors that may predispose to ACL injuries could help to control the extrinsic risk factors to reduce the risk of injury. Aim of the Work to identify the associations between intercondylar notch angle and ACL injury and thus clarify its role in ACL injury. In this study, the angle formed by the femoral axis and Blumensaat line was defined as the intercondylar notch angle (INA). Our study was done retrospectively and included 30 case with acute ACL injury and 30 controls with intact ACL. Patients and Methods This study is a case control Study, the study was conducted at Ain Shams University Hospitals at Radiology department and the main source of data for this study was the retrospectively conducted scans and clinical history of the patients referred to the MRI section of the department of Radiology, Ain Shams University Hospitals. Results The INA (intercondylar notch angle) measurement was significantly different between the two groups (t = -5.530, p < 0.001). The case group had a higher mean INA (40.23±3.61) than the control group (34.93±3.81). The cutoff point was >38 with a sensitivity of 66.67%, specificity of 90%, positive predictive value (PPV) of 87%, and negative predictive value (NPV) of 73%. The INWI (intercondylar notch width index) measurement was significantly different between the two groups (t = 3.218, p = 0.002). The case group had a lower mean INWI (0.29±0.02) than the control group (0.31±0.02). The cutoff point was ≤0.314 with a sensitivity of 86.67%, specificity of 46.67%, PPV of 61.9%, and NPV of 77.8%. The INW (intercondylar notch width) measurement was not significantly different between the two groups (t = 1.747, p = 0.086) and The TCW (total condylar width) measurement was not significantly different between the two groups (t = -1.313, p = 0.195) Conclusion A narrow intercondylar notch (intercondylar notch index) < 0,31 and a large INA > 38 are risk factors in predicting the likelihood for ACL injury. The INA might be the factor with the strongest prediction for ACL injury.