Promising Phase 1 Results from ACL “Bridge” Repair

Last week, The Boston Globe reported that Martha Murray, MD, an orthopaedist at Boston Children’s Hospital, had announced results from the Phase 1 safety study of “bridge-enhanced” ACL repair, which OrthoBuzz first told you about in April 2015 (see “ACL Self-Repair Moving Toward Reality”). According to the Globe, “all 10 BEAR [Bridge-Enhanced ACL Repair] patients…have new, healthy ACLs regrowing where there were originally tears.”

The Globe article quoted Jo Hannafin, MD, past president of the American Orthopaedic Society for Sports Medicine (AOSSM), as saying that BEAR “has the potential to be a game-changer.” But Dr. Hannifin was quick to add that “these patients will have to be followed for a minimum of two years to determine whether the ACL heals and does that healed ACL stay competent or stretch over time and fail.”

Another key question is how much arthritis will develop in the BEAR knees 15 or 20 years from now. In preclinical studies of BEAR on pigs’ knees, the rates of subsequent knee arthritis were lower than those seen with traditional reconstruction techniques.

The Globe reported that Dr. Murray will start enrolling 100 patients for a Phase 2 randomized trial this summer. She will be seeking people from 14 to 35 years of age with torn ACLs that occur within 30 days of enrollment. Additional inclusion criteria include a tibial ligament stump that is at least 6 to 8 mm in length and no serious concomitant knee damage. Two-thirds of the Phase 2 study enrollees will be randomized to undergo the BEAR procedure, and the other group will undergo traditional ACL reconstruction. Patients will be followed for up to 10 years to assess the competence of the repair and track the development of arthritis.

OrthoBuzz will keep you posted on this important ongoing research.

One thought on “Promising Phase 1 Results from ACL “Bridge” Repair

  1. I enjoyed your Need to Know article regarding the preliminary results on the BEAR trials. I applaud Dr. Murray’s work and hope that the trials add another effective technique with which to treat our ACL injured patients short of reconstruction.

    However, I wanted to point out a recently published article detailing clinical results on a new arthroscopic technique for primary ACL Repair in the November issue of the journal Arthroscopy. We presented the clinical results, with 3.5 year average follow-up on 11 patients that underwent primary arthroscopic suture anchor ACL repair. 10/11 patients had good to excellent results. I have included the citation for this article, and another systematic review on ACL repair below.

    In a nutshell, with careful review of the older literature, there was clear evidence that proximally torn ACLs were likely the cohort that did well with the old repair techniques. Currently, using MRI to identify those tears amenable to surgical repair, in addition to a modern arthroscopic suture anchor technique to minimize morbidity, in combination with early motion, excellent outcomes are being achieved. I will add that, to date, I have performed this procedure on >60 patients and continue to have excellent clinical results on >90% of the patients out to 8 years follow-up.

    It is likely that there exists a spectrum of ACL injuries that should be treated with a customized surgical approach, rather than the “one size fits all” reconstructive approach that is currently used. Perhaps, proximal tears should be repaired, proximal 1/3 tears should be repaired/augmented, and mid-substance tears should be treated with either the BEAR approach (if the results pan out), or reconstruction. This tailored approach is what I describe as “ACL Preservation.” Currently in my practice, using this approach, I only need to reconstruct 1/3 or less of the patients who present to me with ACL injuries. Obviously further study of these topics are warranted.


    Greg DiFelice, MD
    Hospital for Special Surgery
    New York, New York

    DiFelice, Gregory S., Christine Villegas, and Samuel Taylor. “Anterior Cruciate Ligament Preservation: Early Results of a Novel Arthroscopic Technique for Suture Anchor Primary Anterior Cruciate Ligament Repair.”Arthroscopy: The Journal of Arthroscopic & Related Surgery 31.11 (2015): 2162-2171.

    Taylor, Samuel A., M. Michael Khair, Timothy R. Roberts, and Gregory S. DiFelice. “Primary repair of the anterior cruciate ligament: A systematic review.” Arthroscopy: The Journal of Arthroscopic & Related Surgery 31, no. 11 (2015): 2233-2247.

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