A bridge to a 21st century ACL repair

Tears of the knee’s anterior cruciate ligament — or ACL — are on the rise in middle school and high school athletes. The current treatment involves grafting in a piece of tendon from elsewhere in the body. It works very well, but requires six months to two years of post-op rehabilitation to regain strength in the knee and the place where the tendon was taken from (often the hamstring). Plus, up to 80 percent of patients develop arthritis within 15 years of the procedure.

Orthopedic surgeon Martha Murray, MD, wondered, “What if we could somehow stimulate the original ACL to heal back together?”

In research over the past decade, Murray realized why ACLs can’t simply heal on their own. That inspired her solution, which she described at Boston Children’s Hospital’s Global Pediatric Innovation Summit + Awards: A temporary scaffold made of collagen to bridge the torn ends, saturated in five times its weight in blood carrying natural healing factors. In a pig model, the scaffold promoted healing and knee strength — without the subsequent arthritis.

First-in-human studies began this year, and by October, Murray’s team had enrolled all 20 patients: Ten had the bridge-enhanced ACL repair (BEAR) and 10 underwent standard ACL reconstruction.

Team member Corey Peak of the Harvard School of Public Health — doubling as the trial’s first patient — reported the results thus far. BEAR did as well as standard ACL reconstruction in terms of overall knee function and knee stability — and better in terms of muscle recovery. Whether patients will be arthritis-free remains to be seen.

Check out other sessions from the Summit.