The relationship of the notch width index of the femur to the incidence of anterior cruciate ligament tears

It has been proposed that a narrow intercondylar notch may increase the risk of anterior cruciate ligament (ACL) injury but the data are conflicting. We performed this cross-sectional study to investigate the significance of Notch width index for ACL tears. Materials and Methods: All adult patients with knee problems, who were referred to the Department of Orthopaedics Amrita Institute of Medical Sciences, Kochi and underwent MRI knee, from August 2016 to August 2018, were included in this study. Axial and longitudinal MRI was performed using 1.5 Tesla or 3 Tesla MRI with the patient's knee in an extended position. In all patients, the femoral notch Index was measured. Patient were divided into 2 groups depending on their NWI (<0.2 or >0.2) Because of the effect of osteoarthritis in decreasing the intercondylar notch index, cases with obvious osteoarthritis were not included in the study. To test the statistical significance of the difference in Femoral Notch Width Index with respect to gender Student’s t test was used. To test the statistical significance of difference in percentage’s with respect to ACL tear (yes or no) and Femoral Notch Width Index(<0.2 or >0.2) Chi-square test was used. Results: 300 patients were enrolled in the study. The age range was 20-50 years. We found that group 1 (<0.2 NWI) has higher percentage of ACL tear as compared to group 2 (>0.2 NWI). We also found that male’s have a higher NWI as compared to females (p value <0.001). Conclusion: ACL tear was found to be higher among the patients with NWI < 0.2 as compared to patients with NWI >0.2 which is statistically significant.