Surgical reconstruction of the anterior cruciate ligament (ACL) after injury has been associated with a 3-fold increased incidence of post-traumatic knee osteoarthritis (OA) when compared to the contralateral, uninjured knee.1  Efforts have been made to identify novel approaches to repairing ACL tears to minimize the morbidity associated with OA.  A team of doctors at the Boston Children’s Hospital utilizing a new surgical approach to ACL repair that makes use of a scaffold made from autologously donated blood appears to be safe, according to preliminary results of a new study.2

The Bridge-Enhanced ACL Repair (BEAR) technique utilizes stitches and a bridging scaffold made from a sponge impregnated with autologous blood to stimulate healing of the torn ACL. The hypothesis is that the bio-enhanced scaffold containing extracellular matrix proteins will activate release of growth factors, including fibroblast growth factor and transforming growth factor beta, enhancing the healing of the ACL.3

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The new technique requires an open incision to insert the scaffold, obviating the need for graft harvest of a tendon and allowing the patient’s ACL to remain in place.

Preliminary results suggest that this new technique was safe in all 10 patients studied at the 3 months, marking the first time this approach has been tried in humans.

Summary and Clinical Applicability

While ACL reconstruction remains the gold standard treatment for ACL injury, it does not reduce the risk of post-traumatic OA. A preliminary study was conducted to assess the safety of a novel, minimally invasive approach to surgical ACL repair. In the small group of patients examined in this study, the use of a bio-enhanced scaffold appeared to be safe.  It is unknown whether this new method will decrease future rates of post-traumatic OA.

The researchers have announced plans to recruit patients for a randomized trial to compare this method of ACL repair method with standard reconstruction surgery.


1. Barenius B, Ponzer S, Shalabi A, Bujak R, Norlén L, Eriksson K. Increased risk of osteoarthritis after anterior cruciate ligament reconstruction: a 14-year follow-up study of a randomized controlled trial. Am J Sports Med. 2014;42(5):1049-57. 

2. Boston Children’s Hospital Orthopedic Center Press Release. Bridge-Enhanced ACL Repair (BEAR) Clinical Trial. Accessed March 25, 2016. Source Code.

3.  Murray MM, Fleming BC. Use of a bioactive scaffold to stimulate anterior cruciate ligament healing also minimizes posttraumatic osteoarthritis after surgery. Am J Sports Med. 2013;41(8):1762-70.