Bridge-Enhanced ACL Repair: Two Year Results of the First In Human Study

Objectives: The Bridge-Enhanced ACL Repair (BEAR) procedure is an alternate form of anterior cruciate ligament (ACL) surgery that involves suture repair of the ligament combined with a scaffold to bridge the gap between the torn ligament ends. In this paper, we report outcomes of this procedure and a non-randomized concurrent control group receiving ACL reconstruction with quadrupled hamstring tendon autograft. We hypothesized that patients treated with Bridge-Enhanced ACL Repair would have physical exam findings, patient reported outcomes and adverse events at one and two years that were similar to patients treated with ACL reconstruction. Methods: This was an observational cohort study. Twenty patients were enrolled. Ten patients received a Bridge-Enhanced ACL Repair (BEAR®) and 10 received a hamstring autograft ACL reconstruction. Outcomes were assessed at time points up to 2 years post-operatively, including the International Knee Documentation Committee (IKDC) Subjective Score, the IKDC Objective score, KT-1000 testing for AP laxity and functional testing. Results: There were no graft or repair failures in the first two years after surgery. The IKDC Subjective Scores in both groups improved significantly from baseline (p< 0.0001) but were similar in BEAR and ACL reconstruction groups at 12 and 24 months. An IKDC Objective score of A (normal) was found in 44% of the patients in the BEAR group and 29% of the patients in the ACL reconstruction group at two years; no patients in either group had a grade of C (abnormal) or D (severely abnormal). KT-1000 testing demonstrated a side to side difference that was similar in the two groups at 2 years (mean(±SD) 1.9(± 2.1) mm in the BEAR group, 3.1(± 2.7) mm in the ACLR group). Functional hop testing results were similar in the two groups at 1 and 2 years after surgery. Hamstring strength indices measured by dynamometer were significantly higher at all time points in the BEAR group than in the hamstring autograft group (mean percentages relative to contralateral side at two years, 98.6%(±10.5%) vs 56.3%(±19.0%), p=0.0001). Conclusion: In a small first-in-human study, Bridge-Enhanced ACL Repair produced similar outcomes to ACL reconstruction with autograft quadruple bundle hamstring tendon.