O’Donoghue Sports Injury Award: Bridge-Enhanced ACL Repair is Non-Inferior to Autograft ACL Reconstruction at 2-Years: Results of a Prospective Randomized Clinical Trial

OBJECTIVES: Preclinical studies and an early clinical cohort study have suggested that for complete midsubstance ACL injuries, the technique of suture repair of the anterior cruciate ligament (ACL) augmented with a protein implant placed in the gap between the torn ends (bridge-enhanced ACL repair) may be a viable alternative to ACL reconstruction. We hypothesized that patients treated with bridge-enhanced ACL repair would have non-inferior patient reported outcomes and anteroposterior (AP) laxity, and superior hamstring strength at 2 years after surgery when compared with subjects who had ACL reconstruction with autograft. STUDY DESIGN: Prospective Randomized Control Trial (NCT02664545). METHODS: One hundred patients, ages 13 to 35, with complete mid-substance ACL injuries, were enrolled and underwent surgery within 45 days of injury. Sixty-five patients were randomized to receive a bridge-enhanced ACL repair (BEAR group) and 35 were randomized to receive autograft ACL reconstruction (ACLR group). Outcomes, including the International Knee Documentation Committee (IKDC) Subjective score, instrumented AP laxity and muscle strength were assessed at 2 years post-operatively. Both patients and assessors were blinded as to surgical assignment until after the 2-year assessment. RESULTS: Ninety-six percent of the subjects returned for follow-up at 2 years. The median age of the subjects in both groups at enrollment was 17 years and the median pre-operative Marx score in both groups was 16 points. Non-inferiority criteria were met for both the IKDC subjective score and AP laxity. The BEAR group had significantly better recovery of hamstring strength than the ACLR group (p<0.001). The number of subjects who were reinjured and required a second ACL surgery was not statistically different between the two groups. Subjects who converted from BEAR to ACLR in the study period had outcomes at the 2-year point that were similar to those for subjects who had only a single ipsiateral ACL procedure (BEAR or ACLR). CONCLUSION: Bridge-enhanced ACL repair using a specific protein-based implant led to non-inferior outcomes to that of ACL reconstruction for patient reported and instrumented knee laxity measures at 2 years after surgery in a young and active cohort of patients with acute mid-substance ACL tears.