Prospective MRI-based comparison of graft maturation after ACL reconstruction using quadriceps versus hamstring tendon autograft

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. Interob server 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 alterna tive to HT autografts in athletic populations.