Sex-Based Differences in Knee Morphology: A Comparative Analysis of Femoral Notch Width and Tibial Slope
Start Date
7-8-2026 11:45 AM
End Date
7-8-2026 12:00 PM
Location
ALT 206
Abstract
Anterior cruciate ligament (ACL) injuries occur more frequently in females than males, suggesting that anatomical differences in knee morphology may contribute to this disparity. Structural characteristics such as tibial slope and femoral notch width have been proposed as potential risk factors; however, findings regarding sex-based differences remain inconsistent. This study compared femoral notch width and tibial slope between males and females to evaluate their potential relationship to the increased incidence of ACL injuries in females.
Twenty magnetic resonance imaging (MRI) scans of knees (10 male, 10 female) were analyzed using 3D Slicer software. Anatomical landmarks, including the femoral condyles and ACL and posterior cruciate ligament (PCL) attachment sites, were used to measure femoral notch width, intercondylar width, medial tibial slope, and lateral tibial slope. The notch width index (NWI) was calculated from femoral notch width and intercondylar width. Independent two-sample t-tests compared male and female groups, and Cohen’s d was calculated to assess effect size.
Femoral notch width demonstrated the largest sex-based difference, with males exhibiting a wider notch than females (19.52 ± 3.36 mm vs. 16.68 ± 2.96 mm). Although this difference narrowly missed statistical significance (p = 0.06), it showed a large effect size (Cohen’s d = 0.90). No statistically significant sex differences were observed for lateral tibial slope, medial tibial slope, or NWI.
While femoral notch width showed the greatest sex-based difference, the absence of an NWI difference suggests that the narrower notch observed in females may reflect overall smaller knee size rather than a disproportionately narrower notch. Larger studies are needed to further clarify anatomical contributions to ACL injury risk.
Sex-Based Differences in Knee Morphology: A Comparative Analysis of Femoral Notch Width and Tibial Slope
ALT 206
Anterior cruciate ligament (ACL) injuries occur more frequently in females than males, suggesting that anatomical differences in knee morphology may contribute to this disparity. Structural characteristics such as tibial slope and femoral notch width have been proposed as potential risk factors; however, findings regarding sex-based differences remain inconsistent. This study compared femoral notch width and tibial slope between males and females to evaluate their potential relationship to the increased incidence of ACL injuries in females.
Twenty magnetic resonance imaging (MRI) scans of knees (10 male, 10 female) were analyzed using 3D Slicer software. Anatomical landmarks, including the femoral condyles and ACL and posterior cruciate ligament (PCL) attachment sites, were used to measure femoral notch width, intercondylar width, medial tibial slope, and lateral tibial slope. The notch width index (NWI) was calculated from femoral notch width and intercondylar width. Independent two-sample t-tests compared male and female groups, and Cohen’s d was calculated to assess effect size.
Femoral notch width demonstrated the largest sex-based difference, with males exhibiting a wider notch than females (19.52 ± 3.36 mm vs. 16.68 ± 2.96 mm). Although this difference narrowly missed statistical significance (p = 0.06), it showed a large effect size (Cohen’s d = 0.90). No statistically significant sex differences were observed for lateral tibial slope, medial tibial slope, or NWI.
While femoral notch width showed the greatest sex-based difference, the absence of an NWI difference suggests that the narrower notch observed in females may reflect overall smaller knee size rather than a disproportionately narrower notch. Larger studies are needed to further clarify anatomical contributions to ACL injury risk.
