Irradiated Hamstring Tendon Allograft Versus Autograft for Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Midterm Clinical Outcomes

Background: Most studies on grafts for anterior cruciate ligament (ACL) reconstruction (ACLR) have been of autografts or nonirradiated allografts with a single-bundle (SB) technique. Outcome reports evaluating anatomic double-bundle (DB) ACLR with a hamstring tendon autograft versus irradiated allograft are rare. Purpose: To compare the clinical outcomes of arthroscopic anatomic DB ACLR with a hamstring tendon autograft versus irradiated allograft. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Between 2008 and 2009, a total of 107 patients undergoing arthroscopic DB ACLR were prospectively randomized consecutively into 1 of 2 groups (autograft [Auto] group and irradiated allograft [Ir-Allo] group). All the surgical procedures were performed by the same senior surgeon using the DB reconstruction technique. All irradiated hamstring tendon allografts were sterilized with 2.5 Mrad of irradiation before distribution and were obtained from a single certified tissue bank. Graft fixation on the femoral side was by an Endobutton, and on the tibial side by a bioabsorbable interference screw augmented with a staple. The same rehabilitation protocol was applied to all patients. Before surgery and at a mean of 6.9 years of follow-up, patients were evaluated by the same observer according to objective and subjective clinical evaluations including detailed history, physical examination, radiography, functional knee ligament testing, KT-2000 arthrometer testing, Harner vertical jump and Daniel 1-legged hop tests, Lysholm score, Tegner score, International Knee Documentation Committee (IKDC) standard evaluation form, and Cincinnati knee score. Results: A total of 83 patients (Auto: n = 40 [mean age, 29.2 6.9 years]; Ir-Allo: n = 43 [mean age, 28.6 7.2 years]) fulfilled follow-up and clinical evaluations. No significant differences were found between the 2 groups according to the overall IKDC functional and subjective evaluations as well as testing of activity levels. Significant between-group differences were found when comparing the results at final follow-up according to the Lachman test, anterior drawer test, pivot-shift test, and KT-2000 arthrometer measurements (P < .001). Most importantly, 87.5% of patients in the Auto group and 34.9% in the Ir-Allo group had a side-to-side difference <3 mm. The rate of laxity (side-to-side difference >5 mm) with an irradiated allograft (30.2%) was higher than that with an autograft (7.5%) (P < .001). The failure rate in the Ir-Allo group (30.2%) was higher than that in the Auto group (7.5%) (P < .001). Anterior and rotational stability decreased significantly in the Ir-Allo group; patients in the Ir-Allo group also had a shorter operation time. There were 10.0% (4/40) of patients in the Auto group and 32.6% (19/43) of patients in the Ir-Allo group who had arthritic progression (P < .05). Conclusion: There were no significant differences in postoperative activity levels and functional outcomes between the Auto and Ir-Allo groups. However, a significant increase in anterior and rotational laxity in the Ir-Allo group was found according to evaluations. We do not advocate an irradiated hamstring tendon allograft for DB ACLR. Trial Registration: Clinical Trial Register System of The Affiliated Hospital of Qingdao University (qdfy-ky2008-12)