ACL Reconstruction Timing in Older Adults: Function and Osteoarthritis Outcomes—A Retrospective Cohort Study

Background: Anterior cruciate ligament (ACL) reconstruction has been proven effective in improving knee joint function in middle-aged and elderly patients. However, few studies have focused on the surgical timing of ACL reconstruction in middle-aged and elderly patients.The purpose of this study was to evaluate clinical efficacy in patients aged 40 and above with ACL injuries, comparing the effects of early (injury-to-surgery interval <6 months) versus delayed (interval >6 months) surgery on functional recovery and osteoarthritis development. Methods: A retrospective analysis was performed on 64 patients who underwent ACL reconstruction, with 37 cases in the early surgery group and 27 cases in the delayed surgery group. Five-year postoperative assessments included, clinical scores, osteoarthritis severity, and complication incidence. Results: The early group demonstrated significantly better outcomes compared to the delayed group in terms of International Knee Documentation Committee (IKDC) scores (88 vs. 80), The Knee Injury and Osteoarthritis Outcome Score (KOOS) symptom scores (85.7 vs. 75), KOOS pain scores (91.7 vs. 80.6), and KOOS daily activity scores (90.5 vs. 82.4) (all P<0.05). Additionally, the early group had a lower incidence of osteoarthritis (18.9% vs. 44.4%, p =0.027). No significant differences were observed between the two groups in Tegner scores or KOOS subscores for sport and quality of life. All patients remained free from graft rupture or secondary surgery during the follow-up period. Conclusion: Early ACL reconstruction in middle-aged and elderly patients with ACL injury can more effectively alleviate knee symptoms, improve daily functional performance, and reduce the risk of osteoarthritis, with reliable medium-and long-term efficacy.