Orthopaedic surgeon Martha Murray, MD reports that a collagen gel, enriched with blood platelets, can stimulate natural healing of a partial ACL tear, encouraging the body's cells to fill in the defect and restore mechanical strength to the ligament.

"This is a first important step in showing that the ACL can heal if we give it the right conditions," Murray says. "That's an important shift from thinking that the ACL has to be completely replaced after an injury."

ACL injuries are notorious for not healing well. Epidemic among teenage girls – who are five times likelier than boys to tear the ligament – they typically occur during sports that involve jumping and pivoting. ACLs are currently reconstructed by replacing the torn ligament with a tendon graft. This painful operation allows patients to return to sports after significant rehabilitation, but it does not fully restore knee mechanics, and does not prevent arthritis from developing years later.

Working with an animal model of a partial ACL tear, Murray's team inserted a collagen gel, mixed with platelet-rich blood plasma, into the wound. The gel provided a physical "bridge" between the torn ligament ends, while the platelets churned out a variety of growth factors. Compared with untreated knees, treated knees showed greater defect filling at 6 weeks (43 percent versus 23 percent). The gel-treated ACL defects also had a 40 percent increase in mechanical strength at 6 weeks, compared with just 14 percent for untreated defects.

Although she cautions that these results are preliminary and that more work needs to be done, Murray hopes to eventually extend her ACL regeneration technique to human patients, using platelets from their own blood plasma to create a less invasive ACL repair that would decrease recovery time and give athletes a knee with more normal function.

MEDICA.de; Source: Children's Hospital Boston