It’s not uncommon for physicians and patients to refer to ACL surgery as ACL repair. The current standard of care, however, does not repair a torn ACL. The surgeon removes the ends of the torn ACL and replaces the ligament with a tendon graft. It’s ACL reconstruction.
Bridge-enhanced ACL repair (BEAR) is a promising new approach to ACL surgery that uses a protein-enriched sponge to encourage the torn ends of an ACL to reconnect and heal.
Martha Murray, MD, Boston Children’s Hospital orthopedic surgeon, and a team of researchers have spent nearly 25 years developing the BEAR surgery. The U.S. Food and Drug Administration (FDA) approved a 100-patient clinical trial at Boston Children’s to see if the BEAR surgery is as effective as ACL reconstruction.
Murray answers some questions about her ACL research and the BEAR trial.
Notes: Why do surgeons need a better way to treat ACL injuries?
Murray: An ACL tear can be a devastating sports injury. A growing number of young athletes face ACL injuries, or ACL tears, every year. The current standard of care, ACL surgery — or ACL reconstruction — is a good solution.
But it requires taking a graft of tendon, so the patient has to recover from that part of the procedure as well. In addition, young active patients have a 20 percent risk of re-tearing the ACL, and many young patients face an increased risk of arthritis. The risk of premature arthritis in the knee is as high as 80 percent 14 years after an ACL tear.
Notes: Other ligaments heal without surgery. Why doesn’t the ACL heal after it tears?
Murray: When other ligaments, like the medial collateral ligament (or MCL), tear or rupture, a blood clot forms around the two torn ends of the ligament. This clot provides a scaffold for the torn ends to grow into and re-connect. In contrast, the ACL lives in the fluid of the knee joint, which washes away the blood at the tear site and prohibits a clot from forming.
Notes: Can anything be done to mimic the effective MCL healing process in the ACL?
Murray: We hypothesized that providing a bridging scaffold could hold a blood clot between the torn ends of the ACL and give them a space to re-connect and heal. We developed a protein-enriched sponge to serve this purpose. During surgery, the sponge is saturated with a small amount of the patient’s own blood and inserted between the torn ends of the ACL. With this procedure, the surgeon doesn’t need to use a tendon graft. (Watch an animated video of the procedure).
Notes: What are the results so far?
Murray: First, we studied the technique in pigs’ knees. These studies showed the scaffold promoted ligament healing.
Late in 2014, the FDA approved a 20-patient safety study. Ten patients had ACL reconstruction, and 10 had the BEAR procedure in 2015.
Corey Peak was the first patient to undergo BEAR surgery as part of the safety study in February 2015. His follow-up MRIs and strength assessments show his torn ACL is healing and at one year, looks like a relatively normal ACL.
Follow-up data on other patients demonstrated the sponge was safe for patients (none had an infection or developed a stiff knee); however, the data for all patients is still coming in and will continue to come over the next year as they hit their one year post-operative time point.
After reviewing these data, the FDA approved a 100-patient clinical trial. Up to 66 patients will have ACL reconstruction, and up to 34 will have the BEAR procedure. Patients will be randomly assigned (like flipping a coin) to one surgery or the other – they won’t be able to pick.
Notes: How can patients enroll in the clinical trial?
Murray: Boston Children’s expects to begin enrolling patients in the clinical trial in April 2016. To learn more, contact Brett Flutie.
Dr. Murray is internationally recognized as an expert in the care of sports injuries of the knee, including injuries to the anterior cruciate ligament (ACL) and meniscus. She is an orthopedic surgeon at Boston Children’s Hospital and has specialized in the care of patients with knee injuries, including ACL, meniscus and osteochondritis dissecans lesions, for the past 15 years.
Learn more about bridge-enhanced ACL repair.