Knee Joint Function in Healthy and ACL-Reconstructed Collegiate Female Lacrosse Players: A Pilot Study

Purpose To investigate knee joint function during an unanticipated cutting task between healthy and ACL-reconstructed (ACL-R) females within the same NCAA Division I collegiate female lacrosse team (WLAX) via knee mechanics and estimated vasti and hamstring muscle forces. Methods Knee mechanics during three unanticipated cutting trials were observed using 3D motion analysis techniques for 26 healthy female lacrosse players, five which had previous history of ACL-R. Knee flexion angle and knee extensor moment were calculated via Visual3D. Modified musculoskeletal models were used to estimated vasti and hamstrings muscle forces obtained from static optimization. The 2 × 2 (group × limb) repeated measures ANOVAs were used to identify differences in knee mechanics, and vasti and hamstring muscle groups among healthy/ACL-R between their preferred and involved limbs. Results There was an interaction between group and limb for knee extensor moment. ACL-R females had less knee extensor moments in their involved limb compared to their uninvolved limb ( P < 0.001). There was also a group main effect found for knee flexion angle. ACL-R females cut with less knee flexion angle compared to healthy females ( P < 0.013). No significant differences were found for estimated vasti or hamstring forces. Conclusions These pilot results indicate that despite all female WLAX players undergoing the same strength and conditioning programming, training sessions, with the same coaching staff, differences in knee joint mechanics still exist between healthy and ACL-R players. These data should help inform larger-scaled studies investigating the impact of ACL-R on athletes within the same sports team.