Analysis of the risk factors for anterior cruciate ligament injury: an investigation of structural tendencies

Objective: The aim of this study was to determine the most important anatomical risk factors for injury of the anterior cruciate ligament (ACL) of the knee. Materials and methods: After study approval by our institutional ethics committee, 3 radiologists reinterpreted the preoperative magnetic resonance (MR) images of 86 patients who had undergone surgery for ACL rupture. The measurements were compared with those for a control group comprising 109 patients with intact ACL who had undergone MR examinations for other reasons, such as meniscal injuries or Baker cyst ruptures. Interobserver differences were calculated after measurement of the notch width (NW), NW index (NWI), medial condyle width (MCW), lateral condyle width (LCW), MCW/LCW ratios, alpha (alpha) angle, NW angle, quadriceps angle (Q angle), posterior medial tibial slope (MTS), posterior lateral tibial slope, coronal tibial slope, and depth of medial tibial plateau for each group. The relationships between these parameters and ACL injury were studied by performing logistic regression and receiver operating characteristic curve analyses in comparison with those in the control group. Results: We found that there were significant differences in the anatomical parameters of the NW, MCW, NWI,alpha angle, and MTS between the ACL injured and noninjured groups (p < 0.05). There were also significant differences in the bicondylar width, alpha angle, Q angle, and MTS between the patients with ACL rupture because of noncontact injuries and the control group (p < 0.05). The NWI and MTS had the highest predicted relative risk for both the male and female groups. Conclusion: We found that the NW, NWI, and MTS were the most important parameters in risk assessment of ACL injuries.