Background: Hamstring tendon (HT) autograft ACL reconstruction (ACLR) is widely used in young athletes, yet graft survival and reinjury risk in skeletally mature patients returning to pivoting sports remain poorly defined. The aim of this study was to determine (1) the incidence of ACL graft rupture and contralateral ACL (CACL) injury, (2) return-to-sport (RTS) rates, and (3) risk factors for reinjury at 5-year follow-up in high-risk athletes aged 16–25 years undergoing primary HT ACLR.
Methods: A prospectively maintained database was used to identify 897 patients aged 16–25 years who underwent primary ACLR with HT autograft and without lateral extra-articular tenodesis between 2007 and 2015 and intended to return to pivoting sports. Five-year outcomes included ACL graft rupture, contralateral ACL injury, and RTS. Risk factors for graft rupture and contralateral injury were evaluated.
Results: Of the 715 patients with 5 year follow up, ACL graft rupture occurred in 138 (19%), and CACL injury in 88 (12%) within 5 years. Independent risk factors for graft rupture were age ≤19 years (HR, 1.5 [95% CI, 1.1–2.1]; P = .014) and male sex (HR, 2.8 [95% CI, 1.8–4.5]; P = .001). Age ≤19 years was the only independent risk factor for contralateral ACL injury (HR, 1.6 [95% CI, 1.1–2.5]; P = .024). Overall, 77% of patients returned to their preinjury level of sport, and 80% of those returned to jumping, pivoting, and cutting sports.
Conclusion: High-risk athletes aged 16–25 years undergoing HT ACLR demonstrate substantial reinjury rates at 5-year follow-up, with nearly one-third sustaining either graft rupture or contralateral ACL injury. Younger athletes ≤19 years, represent a subgroup at increased risk of both graft failure and contralateral injury. These findings support age-specific counselling, structured rehabilitation, and cautious return-to-sport decision-making, and provide a benchmark against which other reconstruction techniques may be compared.
