Anterior cruciate ligament (ACL) tears are currently repaired by replacing the torn ligament with a
tendon graft, a painful operation that doesn't fully restore knee mechanics. Children's Hospital Boston orthopedic surgeon Martha Murray, MD, may have found a better fix through regenerative medicine.
Looking at torn ACL tissue under the microscope, Dr. Murray discovered that the injury tries to heal on its own—cells proliferate, blood vessels grow—but the ligament ends never join. When most ligaments tear, a blood clot forms, creating a temporary scaffold for cells to migrate onto, but in ACL tears, fluid in the knee joint washes the clot away. So Dr. Murray's team created a more durable scaffolding material and found that partial ACL tears injected with a specially made gel showed more tissue healing and a greater increase in strength than untreated tears. The study appears in the April Journal of Orthopaedic Research.