Increased contralateral dynamic valgus in female athletes following ACL reconstruction.

PURPOSE: Female athletes have a higher risk of anterior cruciate ligament (ACL) injury, which has been associated with neuromuscular deficits and dynamic valgus, while contralateral risk profiles after ACL reconstruction remain insufficiently characterized. The purpose of this study was to investigate whether female patients after ACL reconstruction exhibit greater contralateral valgus angles compared with male patients, indicating a higher risk profile for secondary ACL injury. It was hypothesized that dynamic valgus would be more pronounced in women than in men.

METHODS

In this predefined subanalysis of a controlled laboratory study, 26 patients (17 male and 9 female) were analysed approximately eight months after primary ACL reconstruction with either semitendinosus or quadriceps tendon autograft. Isokinetic strength testing and three-dimensional (3D) motion capture analysis were performed. Participants executed vertical drop jumps and single-leg jumps for distance. The primary outcome was the maximal contralateral knee valgus angle; secondary outcomes included hip and knee flexion angles, valgus moments and hamstrings-to-quadriceps (H/Q) ratio. Mann-Whitney U test was used for testing between male and female patients after testing for parametric distribution using Shapiro-Wilk test.

RESULTS

In the vertical drop jump, females demonstrated a significantly larger median maximal valgus angle compared to males (-2.9° [valgus] [interquartile range, IQR (-9.8) to 2.0] vs. 6.7° [varus] [IQR (-0.2) to 8.5], p = 0.016). No significant sex-specific differences were observed in secondary kinematic parameters, single-leg jump performance or isokinetic strength measures.

CONCLUSION

Female patients exhibited greater contralateral dynamic valgus during drop jump landings after ACL reconstruction, suggesting sex-specific neuromuscular risk patterns. These findings support the need for individualized rehabilitation and prevention strategies with a focus on dynamic valgus in female athletes.

LEVEL OF EVIDENCE: Level III.