Dr. Jeffrey Gladden explains why ACL tears don't heal on their own. When the ligament tears, synovial fluid in the knee dissolves any blood clot that would normally bridge the gap and allow healing. Without that clot, blood vessels and cells can't grow across to repair the damage, which is why surgical stitching rarely works unless the ligament is torn from the bone.
So when that ACL tears, it kind of, it's like a rope. It kind of breaks apart and it's kind of all shredded and the ends are all shredded and the inside of the knee is filled with fluid. So those ends can never meld back together. Even if you sew them back together, what happens is our knees hate having blood inside our knee because when you tear something, it bleeds, right? And usually, if that, it bleeds because it forms a clot in between the two torn ends and that acts like a bridge for your blood vessels, your cells. Your nerves to grow across so it heals. But inside the knee, that doesn't happen because it's fluid. And so that fluid's floating around and there's enzymes in there that dissolve the, the blood. And so even if in the old days, even the Greeks tried to sew the ACL back together, and it usually doesn't heal because you don't have that bridge gets dissolved unless it's torn right off the bone. And that's a different exception.
