Abstract
PURPOSE: To evaluate short-term anterior cruciate ligament (ACL) graft maturity in skeletally immature patients undergoing ACL reconstruction (ACLR) with physeal-sparing over-the-top (OTT) technique using hamstring tendon (HT) autograft with preserved tibial insertion, and to compare the results with adult patients operated using an OTT technique with similar features. METHODS: Skeletally immature patients who underwent primary ACLR with OTT between February 2022 and January 2025 with post-operative Magnetic Resonance Imaging (MRI) performed between 10 weeks and 6 months were retrospectively reviewed. Graft maturation was evaluated via the Howell grading system and ACL signal/noise quotient (SNQ) on MRI. Additionally, graft continuity, tunnel widening, fluid collection within the graft, and bone oedema of the tibial tunnel wall were assessed. Skeletally immature patients were propensity-matched at a 1:1 ratio to adult patients, and comparisons were performed. RESULTS: A total of 22 skeletally immature patients (average skeletal age 12.9 ± 2.3 years) out of 79 patients were included. MRI assessment of graft maturity was performed at an average of 4.0 ± 1.3 months postoperatively. All patients presented graft continuity, with Grade I or II Howell grade in 86% of cases. For the comparative analysis, a subset of 10 skeletally immature patients (those with a tibial tunnel) was matched with 10 adult patients (90% males, mean age 25.9 ± 10.0 years) who underwent MRI 4.0 ± 1.2 and 18.0 ± 2.1 months after surgery. No significant differences were reported for all individual items, such as the Howell graft score, SNQ, and tunnel features, between skeletally immature and adult patients at the 4-month assessment (p > 0.05). CONCLUSION: ACLR with OTT technique via HT autograft with preserved tibial insertion may provide satisfactory ligamentization in skeletally immature patients. Graft maturity was comparable to that of the adult population. These data suggest that graft maturation using this specific surgical approach is satisfactory in skeletally immature patients and is comparable to adults. LEVEL OF EVIDENCE: Level IV, retrospective study.