Can PRP Enhance Hamstring Recovery Post-ACL Reconstruction? Retrospective Insights from Non-Professional Athletes

Background and Objectives: Hamstring strength deficits are common after ACL reconstruction and may impair stability and increase reinjury risk. Despite structured rehabilitation, early postoperative asymmetries frequently persist. Platelet-rich plasma (PRP) has emerged as a potential biologic adjunct that may enhance tissue healing and facilitate muscle strength recovery. This study aimed to evaluate the efficacy of intra-articular PRP injections on hamstring strength restoration in non-professional athletes undergoing ACLR. Materials and Methods: This retrospective cohort study analyzed 68 non-professional athletes who underwent primary ACLR between 2020 and 2024. Participants followed a standardized, phase-appropriate rehabilitation program and were allocated to either a PRP group (n = 34; five intra-articular PRP injections every 4 weeks starting at week 4 postoperatively) or a control group (n = 34; rehabilitation alone). Data were analyzed with linear mixed-effects models to examine group, time, and group-by-time interactions. Results: Both groups improved over time, but PRP influenced faster hamstring strength recovery and greater symmetry. At 20 weeks, the PRP group achieved higher concentric strength (15.6 ± 4.3 vs. 13.6 ± 3.5; p = 0.040) and markedly reduced asymmetry (isometric: -1.1 vs. 0.6; p < 0.001; concentric: -0.6 vs. 1.9; p < 0.001). Conclusions: The addition of serial PRP injections to a structured rehabilitation protocol after ACLR influenced faster hamstring strength recovery and improved interlimb symmetry compared to rehabilitation alone. These findings suggest that PRP may serve as a potential biologic adjunct to optimize postoperative outcomes and facilitate a safer return to sport in non-professional athletes.