Purpose: The hypothesis of this randomized controlled trial is patients undergoing ACL reconstruction using contralateral hamstring harvest will have better quality of life and strength than using ipsilateral graft.

Method: One hundred participants were assigned to the ipsilateral (IG) or contralateral (CG) group. Primary and secondary outcomes were ACL Quality of Life (ACL-QOL) and concentric isovelocity knee flexion/extension strength measured on a dynamometer at five speeds. Data was gathered pre-surgery, and at 3, 6, 12, and 24 months post-surgery. Findings to 12 months are presented.

Results: ACL-QOL scores and knee flexion/extension strength were not significantly different between groups across time. Comparing side-to-side strength within each group, knee extension strength was consistently higher on the non-reconstructed side. In the IG, there were no side-to-side differences in knee flexion strength. In the CG, flexion on the reconstructed side was stronger than the grafted side early post surgery (3, 6 months) at 60 degrees/s, but this pattern was reversed at 90, 150, and 210 degrees/s. Post-hoc comparisons revealed hamstring/ quadriceps (H/Q) ratios were not different between limbs in the CG or for the uninvolved limb for the IG. However, at most time points and speeds, the H/Q ratio for the involved limb in the IG was higher than the uninvolved limb in the IG and either limb in the CG.

Conclusion: This study reveals that ipsilateral graft harvest may alter the H/Q ratio. It was also demonstrated that contralateral graft harvest may normalize this effect. This may have some bearing on function and re-injury risk that should be further investigated.