Prospective MRI-Based Comparison of Graft Maturation After ACL Reconstruction Using Quadriceps Versus Hamstring Tendon Autograft

Abstract

Background: Biological graft maturation after anterior cruciate ligament (ACL) reconstruction is a prolonged and heterogeneous process that may not directly correlate with clinical recovery. Magnetic resonance imaging (MRI)-based signal intensity ratio (SIR) is widely used as an indirect marker of graft remodeling and early maturation. However, comparative data regarding MRI-based graft maturation between quadriceps tendon (QT) and hamstring tendon (HT) autografts remain limited. Purpose: To compare graft maturation between all-soft tissue QT autografts and HT autografts using quantitative MRI-based SIR at 6 and 12 months after primary all-inside ACL reconstruction in athletes. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 76 athletes undergoing primary all-inside ACL reconstruction were prospectively enrolled. QT autografts were used in 39 patients and HT autografts in 37 patients. All patients followed a standardized postoperative rehabilitation protocol and underwent 3.0-T MRI evaluation at 6 and 12 months. Graft maturation was assessed using SIR measurements obtained from standardized regions of interest along the intra-articular graft, with the posterior cruciate ligament used as reference. Interobserver reliability was evaluated using intraclass correlation coefficients (ICCs). Results: Baseline patient characteristics and associated surgical procedures did not differ between groups (all P > .05). At both 6 and 12 months postoperatively, the mean SIR values were similar between QT and HT autografts (P > .05). Within-group analysis showed a significant decrease in SIR values from 6 to 12 months in both groups (P < .05), indicating progressive graft maturation. The magnitude of SIR change did not differ between groups (P > .05). Interobserver reliability was excellent, with ICC(2,1) values of 0.98 at 6 months and 0.98 at 12 months. Conclusion: Quantitative MRI-based assessment using SIR demonstrated no significant difference in graft maturation between all-soft tissue QT and HT autografts at 6 and 12 months after primary all-inside ACL reconstruction. Both graft types showed comparable MRI-based maturation profiles during the early postoperative period, supporting QT autografts as a reliable alternative to HT autografts in athletic populations. Registration: NCT06617559 (ClinicalTrials.gov identifier).