Comparison of Outcomes between Hamstring Autograft and Synthetic (LARS) ACL Reconstructions

Objectives: This study compared the short term (24 month) clinical outcomes in a prospective, comparative case series of participant selected hamstring autograft and synthetic (LARS) ACL reconstructions.Methods: 64 ACL reconstructed participants (32 hamstring,32 LARS), completed a “goal-oriented” rehabilitation protocol. They were assessed for joint laxity (KT1000), clinical outcome (IKDC Knee Examination) and activity (Tegner Activity Scale-TAS) pre-operatively and at 12,16,20 and 24 weeks, and at 12 and 24 months post-operatively.Results: KT 1000 results did not differ significantly between the 2 treatment groups at 24 months. Differences were noted in joint laxity measurements between the 2 groups at varying time points. The LARS group had immediate stability of the joint at 12 weeks followed by a gradual increase in laxity over the follow-up period, while the hamstring group showed an increase in laxity up to 16-20 weeks, followed by a gradual decrease over the follow-up period. The LARS group had significantly higher TAS scores in the early post-operative period, but there was no significant difference between the 2 groups at 12 months and beyond. At 24 months, 32 of the hamstring group and 30 of the LARS group achieved IKDC Scores “A” or “B”. There were 5 reported graft failures (15.6%) in the LARS group between 7 and 22 months post-op, and none in the hamstring group.Conclusion: ACL reconstruction using synthetic (LARS) grafts produced earlier return of some activities compared to autograft reconstructions, but this difference was no longer evident by 12 months post-op. When the substantially differing failure rates are taken into consideration, this early benefit does not appear to justify their use in place of autografts for ACL reconstruction.