Scar Formation in Untreated Ligaments


What happens when injured ligaments are left to “heal” on their own? Does true healing occur? An article in The American Journal of Sports Medicine shed some light on injured medial collateral ligaments (MCL) left untreated.1 In this study, researchers studied injured MCLs in rabbits and discovered that true ligament healing does not occur. Rather, a ligament scar develops that is in many ways inferior to true ligament tissue.The researchers were curious on the healing of untreated ligaments: is there true ligament regeneration or is there scar healing only? How fast do these ligaments heal? Is healing complete when left untreated?

This study showed a number of things:

  • Untreated injured MCLs in the rabbit model did not have true ligament regeneration but rather formed a scar.
  • The scar tissue was chemically and mechanically abnormal in structure, showing changes in quality and quantity of collagen tissue.
  • The scar formation was slow but was a highly organized process of hemorrhaging, inflammation, proliferation and remodeling. 40 weeks after injury there were still changes taking place in the scar appearance.
  • The ligament scar tissue was mechanically inferior to normal ligament tissue and showed signs of plateauing or getting worse over time.
  • Researchers had reason to believe that the scar tissue would ultimately stretch out when placed under future stress.

About Prolotherapy Commentary: The bottom line from this study is that ligaments heal by scar unless treated. Ligaments that heal with scar are significantly inferior in strength to normal ligaments. And, weak ligaments lead to ligament laxity, joint instability, and osteoarthritis. The key to pain-free, healthy joints is healthy and strong ligaments and tendons. In the case of an injured MCL (or any injured ligament) is to treat it with Prolotherapy. Prolotherapy stimulates repair by inducing a mild inflammation in the weakened ligaments and tendons. The localized inflammation triggers a wound-healing cascade, resulting in the deposition of new collagen, the material that ligaments and tendons are made of. New collagen shrinks as it matures. The shrinking collagen tightens the ligament that was injected and makes it stronger. Prolotherapy has shown to be extremely effective at eliminating pain and sports injuries that are a result of ligament and/or tendon weakness. So instead of letting an injury “heal on its own” its best to treat injured ligaments with Prolotherapy to ensure proper regeneration of ligament tissue.

1. Frank C, Woo SL, Amiel D, Harwood F, Gomez M, Akeson W. (1983). Medial collateral ligament healing. A multidisciplinary assessment in rabbits. The Journal of Sports Medicine, 11(6).