Autograft versus allograft in anterior cruciate ligament reconstruction: A meta-analysis with trial sequential analysis

Abstract

Background: Anterior cruciate ligament (ACL) reconstruction is considered as the standard surgical procedure for the treatment of ACL tear. However, there is a crucial controversy in terms of whether to use autograft or allograft in ACL reconstruction. The purpose of this meta-analysis is to compare autograft with allograft for patients undergoing ACL reconstruction.

Methods: PubMed, EMBASE, and the Cochrane Library were searched for randomized controlled trials that compared autograft with allograft in ACL reconstruction up to January 31, 2016. The relative risk or mean difference with 95% confidence interval was calculated using either a fixed- or random-effects model. The risk of bias for individual studies according to the Cochrane Handbook. The trial sequential analysis was used to test the robustness of our findings and get more conservative estimates.

Results: Thirteen trials were included, involving 1636 participants. The results of this meta-analysis indicated that autograft brought about lower clinical failure, better overall International Knee Documentation Committee (IKDC) level, better pivot-shift test, better Lachman test, greater Tegner score, and better instrumented laxity test (P < 0.05) than allograft. Autograft was not statistically different from allograft in Lysholm score, subjective IKDC score, and Daniel 1-leg hop test (P > 0.05). Subgroup analyses demonstrated that autograft was superior to irradiated allograft for patients undergoing ACL reconstruction in clinical failure, Lysholm score, pivot-shift test, Lachman test, Tegner score, instrumented laxity test, and subjective IKDC score (P < 0.05). Moreover, there were no significant differences between autograft and nonirradiated allograft.

Conclusions: Autograft is superior to irradiated allograft for patients undergoing ACL reconstruction concerning knee function and laxity, but there are no significant differences between autograft and nonirradiated allograft. However, our results should be interpreted with caution, because the blinding methods were not well used.

Figure 1

Flow diagram of study selection.

Figure 2

Risk of bias assessment of each included study: (a) Risk of bias graph and (b) risk of bias summary.

Figure 3

Results of meta-analysis of outcomes between autograft and allograft for clinical failure.

Figure 4

Trial sequential analysis of 8 trials comparing autograft with allograft for clinical failure. Trial sequential analysis of 8 trials (black square fill icons) illustrating that the cumulative z-curve crossed both the traditional boundary and the trial sequential monitoring boundary and the required information size had been reached, suggesting further trials were not necessary and the inferences would not be changed. A diversity adjusted required information size of 679 patients was calculated using α = 0.05 (2 sided), β = 0.20 (power 80%), a RR reduction of 49.76% based on trials with adequate allocation concealment, and an event proportion of 12.70% in the control arm. X-axis: the number of patients randomized; Y-axis: the cumulative Z-score; Horizontal green dotted lines: conventional boundaries (upper for benefit, Z-score = 1.96, lower for harm, Z-score = −1.96, 2-sided P = 0.05); Sloping red full lines with black square fill icons: trial sequential monitoring boundaries calculated accordingly; Blue full line with black square fill icons: Z-curve; Vertical red full line: required information size calculated accordingly.