No association between anterior cruciate ligament reconstruction using hamstring autograft and knee flexion strength deficits at 4 months on seated isokinetic testing at 180°/s in adolescents

Abstract Purpose This study aimed to analyse the effect of using an ipsilateral hamstring (HS) autograft on early postoperative knee strength following anterior cruciate ligament reconstruction (ACLR) in adolescents. Methods This retrospective, single‐centre study included patients aged ≤18 years who underwent primary ACLR with HS tendon autografts between January 2022 and January 2025. Demographic and operative data were collected. Isokinetic knee flexion and extension peak torque was assessed bilaterally at 180°/s using a standardized dynamometer protocol, and Limb Symmetry Index (LSI) was calculated preoperatively and at 4 months postoperatively. Results Ninety‐three patients met the inclusion criteria (mean age, 15.6 ± 1.3 years). No significant postoperative strength deficits were detected in the operated limb for either flexion ( p = 0.672) or extension ( p = 0.316) compared with preoperative values. The contralateral healthy limb demonstrated significant strength gains in both flexion and extension ( p < 0.001). The LSI decreased significantly postoperatively ( p < 0.001), with a greater reduction in extension compared with flexion (12% vs. 7%). There were no differences in LSI between female and male patients. Conclusions ACLR in adolescents using an ipsilateral HS autograft was not found to be associated with significant postoperative flexion or extension strength deficits on the operated limb at 4 months. The postoperative asymmetry seemed primarily driven by strength gains in the contralateral healthy limb. These findings highlight the importance of not overlooking quadriceps strengthening even when using an HS autograft and support the continued use of this graft choice in adolescents, especially regarding the preservation of flexion strength. Level of Evidence Level III, retrospective case‐control study.