Irradiated allograft versus autograft for anterior cruciate ligament reconstruction: A meta-analysis and systematic review of prospective studies

Background: Irradiated allografts and autografts are commonly used for anterior cruciate ligament (ACL) reconstruction. The outcomes between these two grafts are controversial. This meta-analysis and systematic review of prospective comparative studies was performed to compare the clinical outcomes, including knee functionality, stability, subjective evaluation, complications, and failure, of irradiated allografts and autografts in primary ACL reconstruction. Materials and methods: PubMed, Embase, and the Cochrane Library were searched from database inception to 12 August 2017 to identify prospective studies that compared irradiated allografts with autografts for primary ACL reconstruction. Randomized controlled trials were included in the meta-analysis. Prospective cohort studies were included in the systematic reviews. Two reviewers independently assessed the study quality and extracted relevant data. Statistical heterogeneity among the trials was evaluated by the chi-square and I-square tests. Results: Four randomized controlled trials and two prospective cohort studies involving 18,835 patients met the inclusion criteria. In the meta-analysis, significant differences were observed in knee stability and subjective evaluation with respect to the KT-2000 score (p < .0001), pivot shift test (p = .001), anterior drawer test (p = .0001), Lachman test (p = .0002), subjective International Knee Documentation Committee (IKDC) score (p < .0001), Cincinnati knee score (p = .04), Lysholm score (p = .01), and Tegner score (p = .03). However, the differences in functional assessment in terms of the overall IKDC score (p = .21), range of motion (p = .94), Harner's vertical jump test (p = .09), Daniel's one-leg hop test (p = .50), and complication rate (p = .34) were not significant between the two groups. Failure was reported in two prospective cohort studies in 302 of 14,829 (2%) patients in the autograft group and 157 of 3941 (4%) patients in the irradiated allograft group. Conclusion: Irradiated allografts are inferior to autografts for patients undergoing primary ACL reconstruction with respect to knee stability and subjective evaluation. However, no significant differences were found between the two groups in terms of function and complication. The robustness of the findings might need to be further validated because of the limited number of randomized controlled trials. More randomized controlled trials with longer follow-ups are required to further evaluate the failure rate in the two groups.