Tendon Injury and PRP Treatment
With repetitive overuse motions, the collagen fibers in the tendon can suffer from micro tears, leading to tendon damage. This is known as tendinopathy. The injured tendons heal via scarring which adversely affects function and increases risk of re-injury. Furthermore, tendons heal at slower rates compared with other tissues due to poor blood supply
In regards to research in this arena, there is an adequate number of studies that reveal increased collagen deposition. There is growing clinical research in humans supporting the use of PRP in chronic tendon injuries, most notably tennis elbow.
Recently it has been demonstrated that a significant improvement in treating tendon injury with PRP versus Steroid injection, with PRP demonstrating superiority up to 1 year post treatment. The authors have extensive experience with PRP treatments of tendon injuries in both upper and lower extremities.
Often, PRP is not recommended as a first line treatment with the exceptions being elite athletes or patients with extensive tissue damage hoping to avoid sur-gery. Additionally, patients need managed expectations as this treatment generally takes weeks for improvement to be noted, but long term benefits are continued to be noticed. Rarely, patients may have prolonged inflammation following an injection and it is generally not known why. In cases of persistent post injection pain, range of motion and rehabilitation are critical to accelerate healing.
In contrast, we have seen a subset of patients that develop an incredibly quick recovery in function. We term these patients ‘‘rapid responders.’’ It is unknown if there is a placebo response contributing to this phenomenon or alternatively, a potential serotonin response (serotonin is released from dense granules of platelets), altering the subjective experience of pain. Further research is warranted to better understand the subjective and objective symptomatic inflammatory response following treatment and the underlying role of nutritional status, medical history, and psychological components.
In many cases, the patients will require 1-3 PRP injection treatments. In cases of severe partial tendon tears, calcific tendinopathies, or chronic resistant tendon injuries, 2-5 PRP treatments may be needed to heal the tendon and sustain long term clinical benefit. Typically, patients are followed up between 4 and 6 weeks following initial injection to determine the need for further treatments. At that point however, it is frequently too premature to visualise improvements of tendon and ligament which may require several weeks to months. The authors recently published a case report of a near achilles tendon rupture that demonstrated substantial reduction of torn fibers at 6 weeks following a single injection with PRP. At 24 weeks post-injection, the tear was completely resolved on MRI and the patient returned to full functional activity (Sampson et al. 2011).