Allograft for Anterior Cruciate Ligament Reconstruction (ACLR): A Systematic Review and Meta-Analysis of Long-Term Comparative Effectiveness and Safety. Results of a Health Technology Assessment

PURPOSE: To evaluate whether allograft anterior cruciate ligament reconstruction (ACLR) is superior or inferior to autograft ACLR or conservative management in terms of effectiveness and safety. METHODS: A systematic review of the evidence for allograft ACLR was conducted. Randomized controlled trials with a minimum mean follow-up time of 5 years were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and the EUnetHTA-Core-Model were used as reporting standards. A meta-analysis was conducted for selected crucial outcomes using a random-effects model. The strength of the available evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Six randomized trials were included comparing allograft with autograft. Patients were on average between 28 and 32.8 years of age (allograft group) and 28.9 and 31.7 years of age (autograft group). Based on the crucial outcomes, the meta-analyses showed no statistically significant differences in Lysholm score, Tegner score, and Cincinnati Knee Score between groups. A small statistical difference favoring autografts was found across studies in the subjective International Knee Documentation Committee score (–2.25; 95% confidence interval –3.02 to –1.47; I(2) = 0%; range of all scores: 73.7-90). Two of six studies reported on graft failure, with a statistically significant difference to the detriment of using allografts (13/49 [26.5%] vs 4/48 [8.3%] in one study, 13/43 [30.2%] vs 3/40 [7.5%] in the other study). CONCLUSIONS: Although no substantial difference in patient-reported function, activity level, and symptoms was demonstrated, evidence from the included studies showed a greater risk for graft failure or revision that may make allograft a less safe treatment modality in ACLR. The strength of available evidence is low based on the crucial outcomes due to the lack of high-quality research and the present increased risk of bias in primary studies. Priority should be shifted toward reflecting on whether there is a subpopulation for whom allograft ACLR may still be advantageous in theory (e.g., less-active older patients) and further conduct RCTs in this population. LEVEL OF EVIDENCE: Level II, systematic review of Level II evidence studies.