Torn Knee Ligament: Can It Be Healed?
New Technique May Some Day Allow Torn ACL to Be Healed, Not Just Replaced
Torn ACL: Current, Future Options continued...
Murray and Paulos note that doctors used to try to repair the ACL by stitching it back together. That didn't work very well. After a year or two, the ACL would rupture again.
So doctors gave up on trying to repair a torn ACL. Instead, they took it out and replaced it. Paulos says the first choice for replacement is tendon from another part of the patient's leg. The second choice is using tendon from a deceased organ donor.
Surgeons now have learned to do this operation using arthroscopic techniques, which require only small incisions. Even so, it's a big operation. About six months are needed for recovery.
Original ACL vs. Replacement ACL
Even when everything goes perfectly, the replaced ACL isn't as good as the old one, Murray and Paulos note. The original ACL has all kinds of muscle fibers that may rest or fire as the knee goes through its motions. Moreover, the original ACL is shot through with nerve fibers that tell other muscles to help. Replacement ACLs just don't do all these things.
And there's another problem.
"With ACL reconstruction, you are at increased risk of arthritis in that knee," Murray says. "If you do get arthritis -- well, there is not a good solution for patients in their mid-30s who already have knee arthritis. They are pretty young for a knee replacement, and we don't have a good way to make their knee cartilage come back."
Murray says her team is working hard to bring the new technique to humans. They're now working with pigs, whose knee anatomy is much like that of humans. But it will take time to know whether the healed ACLs in these animals are durable.
"Our patients are really important to us," Murray says. "It will be at least two or three years before we are confident enough this will work before we do this in people. If everything goes perfectly every step of the way, it could be before then. But the reality of research is we find something we have to fix. We would rather get this right than get this fast."