Lower extremity malalignments and anterior cruciate ligament injury history.

To identify if lower extremity malalignments were associated with increased propensity of a history of anterior cruciate ligament (ACL) ruptures in males and females using a case control design. Twenty subjects (10 males, 10 females) had a history of ACL injury and twenty (10 males, 10 females) had no history of ACL injury. Subjects were assessed for navicular drop, quadriceps angle, pelvic tilt, hip internal and external rotation range of motion, and true and apparent leg length discrepancies. Statistical analysis was performed to identify differences in these measures in regard to injury history and gender, and to identify if any of these measures were predictive of ACL injury history. Increased navicular drop and anterior pelvic tilt were found to be statistically significant predictors of ACL injury history regardless of gender. Limbs that had previously suffered ACL ruptures were found to have increased navicular drop and anterior pelvic tilt compared to uninjured limbs. Based on the results of this retrospective study, the lower extremity malalignments examined do not appear to predispose females to tearing their ACLs more than males. Key PointsHyperpronation and greater anterior pelvic tilt were the two malalignments most associated with history of ACL injury.Females had larger quadriceps angles than males, but this measure was not significantly related to ACL injury history.Not all structural differences between genders help explain the increased risk of ACL injuries in female athletes.