Measurement of Knee Morphometrics Using MRI: A Comparative Study between ACL-Injured and Non-Injured Knees

PURPOSE The purpose of this study is to find out the differences of distal femur morphology between the anterior cruciate ligament (ACL)-injured and the non-ACL injured on an magnetic resonance imaging (MRI), and the difference of bone structure by gender. MATERIALS AND METHODS MRI Measurements of notch width (NW), bicondylar width (BCW), medial condyle width (MCW), lateral condyle width (LCW), medial-to-lateral condyle ratio (M:L ratio), and notch entrance width (NE) were taken from 120 subjects with ACL injury and the other 106 subjects without ACL injury, by three independent observers, at two different times. The measured values from MRI figures between the ACL-injured and the non-ACL-injured were compared and analyzed, with consideration of the differences by gender. Both intra and inter-observer reliability were calculated. RESULTS There were significant differences of NW, BCW, MCW, LCW and NE by gender (p<0.001). While NW and MCW in male group were different (p<0.001), NW, MCW, M:L ratio and NW index (NWI) in female group were significantly different (p<0.001) in the bone morphology between the ACL-injured and non-ACL-injured. The intra- and inter-observer reliability was satisfying. CONCLUSIONS If necessary to take an MRI, female patients with small NWI and NW injury should be carefully treated because of possibility of ACL injuries.