Tendonitis is a common problem in performance horses and there are multiple recommended treatments for the condition including ice and rest, injections into the tendons, and even surgery. Tendonitis is due to strain on the tendon, and after the strength of the tendon is overcome, physical disruption occurs. One of the most common areas of tendonitis in horses is the superficial digital flexor tendon that is located at the back of the horse's lower leg, just above the fetlock. When tendons heal, the tendon with scar tissue is just like all other tissues, and scar tissue is not as strong or as effective in doing the tendon's job as normal tendon tissue. Because of this, if a treatment could cause more normal tissue to develop rather than a scar, it would be beneficial.
One product developed to attempt to treat tendonitis is a powder that is derived from the urinary bladder of pigs called urinary bladder matrix or UBM. This product is thought to recruit regenerative cells into injured tissue to help tissue regenerate into normal tissue. To determine if this product did help tendons heal, a study was performed at Colorado State University in which horses with experimentally-induced tendonitis were injected in the tendons with UBM and a control of saline. In this study, UBM did not seem to be any more effective at tendon healing than saline. However, experimentally-induced tendonitis may not heal the same as naturally-occurring tendonitis and the dosage of UBM used was less than recommended by the manufacturer. It is difficult to test a product on natural tendon injuries because none are the same and it is difficult to judge the response, so further studies are needed.