Gender Differences In Gait Mechanics Following an ACL Rupture: Implications For Early Onset Knee Osteoarthritis In Females

Abstract

Females are 2-8 times as likely to sustain an ACL rupture compared to their male counterparts. In addition, females who have sustained an ACL rupture have been reported to exhibit signs of early knee OA progression. However the mechanism of the early knee OA development has not been fully examined. Medial compartment loads at the knee, as measured by the internal knee abduction moment, have been suggested to lead to knee OA progression. However this mechanism has not been examined in females following an ACL rupture. PURPOSE: To determine if females who have sustained an ACL rupture and subsequent repair exhibit altered gait mechanics that would suggest a more rapid progression of knee OA than males. METHODS: Five females, who had previously sustained an ACL rupture and subsequent repair in the past 10 years, volunteered to participate in the study. An age, activity level, and BMI matched male group, who also had a previous ACL rupture and repair within the last 10 years, was recruited for comparison. All participants completed a gait analysis at a selfselected intentional walking speed that allowed for calculation of frontal plane knee and hip joint angles and internal joint moments. Five trials were recorded and averaged to extract discrete variables in gait associated with knee OA progression. Due to the small sample size, effect size indices were performed to examine differences in the discrete variables between genders. All reported moments are internal. RESULTS: Large effect size indices (d>1.00) were apparent in the peak knee abduction moment, the peak knee adduction angle, knee adduction excursion, and the peak hip abduction moment. The peak knee abduction moment was 31% greater in the females compared to males (d=1.10). In addition, both peak knee adduction and knee adduction excursion were increased 49% and 52%, respectively, in the female group (d=1.23 and d=1.21). The peak hip abduction moment of the female group was 32.7% greater (d=1.54) compared to the male group. CONCLUSION: Females who have sustained an ACL rupture exhibit alterations in gait mechanics at the knee and hip joint suggesting they are at increased risk for early onset knee OA progression compared to ACL deficient males.