Allograft versus autograft for anterior cruciate ligament reconstruction: an up-to-date meta-analysis of prospective studies

Although a large number of anterior cruciate ligament (ACL) reconstructions are performed annually, there remains a considerable amount of controversy over whether an autograft or an allograft should be used. The aim of this meta-analysis was to compare the clinical outcomes of allograft and autograft in primary ACL reconstruction.

The authors systematically searched electronic databases to identify prospective studies which compared allografts with autografts for primary ACL reconstruction. The results of the eligible studies were analysed in terms of instrumented laxity measurements, Lachman test, Pivot Shift test, objective International Knee Documentation Committee (IKDC) Scores, Lysholm Scores, Tegner Scores, and clinical failures. Study quality was assessed and relevant data were extracted independently by two reviewers. A random effect model was used to pool the data. Statistical heterogeneity between trials was evaluated by the chi-square and I-square tests.

Nine studies, with 410 patients in the autograft and 408 patients in the allograft group, met the inclusion criteria. Five studies compared bone-patellar tendon-bone (BPTB) grafts, and four compared soft-tissue grafts. Four studies were randomized controlled trials, and five were prospective cohort studies. The results of the meta-analysis showed that there were no significant differences between allograft and autograft on all the outcomes in terms of instrumented laxity measurements (P = 0.59), Lachman test (P = 0.41), Pivot Shift test (P = 0.88), objective IKDC Scores (P = 0.87), Lysholm Scores (P = 0.79), Tegner Scores (P = 0.06), and clinical failures (P = 0.68). These findings were still robust during the sensitivity analysis. However, a subgroup analysis of Tegner scores by involving only BPTB grafts showed a statistical difference in favour of autografts (P = 0.005).

There was insufficient evidence to identify which of the two types of grafts was significantly better for ACL reconstruction, though the subgroup analysis indicated that reconstruction with BPTB autograft might allow patients to return to higher levels of activity in comparison with BPTB allograft. More high-quality randomized controlled trials with specified age and activity level are highly required before drawing a reliable conclusion.