Risk of Retear Following Anterior Cruciate Ligament Reconstruction Using a Hybrid Graft of Autograft Augmented With Allograft Tissue: A Systematic Review and Meta-analysis

Purpose To compare the risk of anterior cruciate ligament reconstruction failure in patients who undergo anterior cruciate ligament reconstruction with either autograft tissue or hybrid grafts. Methods A systematic search was performed on February 28, 2018, on PubMed, Scopus, Arthroscopy, and Cochrane Library. Included studies were clinical outcome studies of primary anterior cruciate ligament reconstructions that compared failure risk for hybrid grafts versus autografts. Baseline and outcomes data were extracted, and reporting quality was assessed via modified Coleman criteria. A random effects meta-analysis was conducted for both randomized and nonrandomized studies. Results Nine studies were identified with a mean of 40.1 months of follow-up. The mean Coleman methodology score was 66.5 (standard deviation, 12.8). One randomized study (Level II evidence) was identified with no difference in failure rates (0% for both groups, 8-mm minimum graft diameter for all patients). Eight nonrandomized studies (all Level III evidence) were identified with no difference in failure risk for hybrid grafts versus autograft (pooled odds ratio, 1.29; 95% confidence interval, 0.57-2.92; P  = .55; I 2  = 34%). Mean graft diameters were significantly larger in hybrid groups (range, 8.5-9.9 mm) than in autograft groups (range, 6.4-8.8 mm) in nonrandomized studies (mean difference, 0.5-2.5 mm; P ≤ .003). There was no evidence of small study bias or bias owing to reporting quality, and adjustment for length of follow-up, mean patient age, percentage of male patients, year of publication, or reporting quality did not improve statistical heterogeneity. Conclusions Based on the current literature, although it may be theoretically detrimental to add allograft to a small-diameter autograft, it cannot be definitively shown based on the findings of this review with meta-analysis. Currently, it remains unclear that there is an advantage or disadvantage to hybridization of small autograft with allograft, although randomized studies of patients with small ( Level of Evidence Level III, systematic review of Level II and III studies.