Maturity Progression of the Entire Anterior Cruciate Ligament Graft of Insertion-Preserved Hamstring Tendons by 5 Years: A Prospective Randomized Controlled Study Based on Magnetic Resonance Imaging Evaluation

Background: It has been reported that insertion-preserved hamstring tendon autografts (IP-HT) have better maturity than free hamstring tendon autografts (FHT) at 2 years after anterior cruciate ligament reconstruction (ACLR); however, whether insertion preservation improves the maturity of the entire autograft and clinical outcomes at 5 years after ACLR is still unclear. Purpose: To investigate the clinical outcomes and maturity of different segments using insertion-preserved and free hamstring tendon autografts up to 5 years after ACLR. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: 45 patients who underwent isolated ACLR with hamstring tendon autografts were enrolled and randomized into 2 groups. The study group had ACLR with IP-HT, whereas the control group had ACLR with FHT. The International Knee Documentation Committee and Tegner scores, Lysholm activity score, and KT-1000 arthrometer measurements were evaluated preoperatively and at 6, 12, 24, and 60 months postoperatively. Three-dimensional-reconstruction MRI examinations were performed at 6, 12, 24, and 60 months to evaluate the signal/noise quotient (SNQ) values of femoral tunnel graft, intra-articular graft, and tibial tunnel graft. Results: At 60 months, the SNQ values of the intra-articular and tunnel sections for the grafts in both groups showed no difference; the clinical outcomes were improved compared with before surgery ( P < .001) and were similar in both groups. In the early stage, all graft segments in the IP-HT group had lower SNQ values than those of the FHT group. At 6 months, the entire graft in the FHT group and the femoral tunnel section in the IP-HT group had the maximum SNQ values, whereas the femoral tunnel graft had the highest SNQ value compared with intra-articular and tibial tunnel graft in each group. SNQ values of the intra-articular and tibial tunnel graft in the IP-HT group had no significant change within 60 months. Conclusion: All patients had similar clinical outcomes and graft maturity at 60 months postoperatively. The SNQ values and progressions varied at different graft sites and were highest for the femoral tunnel graft. All significantly changing SNQ values reached the maximum value at 6 months. Compared with FHT autograft, the graft maturity of IP-HT autograft recovered earlier and appeared more stable within the 60-month follow-up; however, no significant association was found between graft maturity and clinical scores.