Ever since ancient times, creating a small injury to prompt healing has been seen as a good idea. For horses, this was called “pin firing”. The technique was to take a hot poker and place it into a non-healing ligament to cause small amounts of damage to the area, which caused the body to kick up a repair response. While barbaric, it generally worked. For centuries doctors have created small injuries in a non-healing wound by “roughing” up the tissues. Physicians still use this concept today for tendons, ligaments, and joint capsules. For example, in a shoulder capsulorrhaphy a surgeon usually inserts a small catheter that heats up to prompt healing in a damaged shoulder capsule (the covering of the shoulder joint that helps control motion).
Surgeons still score ligaments with scalpels and needles in the technique called percutaneous tenotomy, also to prompt a healing response. Another example is micro-fracture surgery to fix a hole in the cartilage; this is where the surgeon pokes holes in the bone to cause the cartilage to heal. Finally, the procedure known as prolotherapy is in this same category. In this procedure, rather than a mechanical injury being initiated, the physician injects a chemical irritant to cause a chemical micro-injury. All of these types of treatment rely on the same concept that we get one bite of the healing “apple” and if something fails to heal completely the first time, we can get more bites at that apple simply by causing a small injury to the area. The big advantage to micro injury techniques is that these basic procedures are simple and often inexpensive ways to try to get an area to heal. The downside is that while many times they work well, sometimes they don’t have enough oomph to get the right type of healing or enough healing.