A Closer Look At Platelet-Rich Plasma For Achilles Tendon Pathology
Researchers have shown that eccentric exercises to the Achilles tendon help tendon collagen synthesis.9,10 Patients with severe pain may respond well to immobilization of the tendon with a walking boot or ankle/foot orthosis. Nonsteroidal anti-inflammatory drugs (NSAIDs) and cryotherapy can help reduce any associated inflammation. Corticosteroid injections are not recommended due to an increased risk of tendon rupture.2,3,9 Shockwave therapy of the Achilles tendon may also help stimulate soft-tissue healing and inhibit pain receptors to the area.9,10
Surgical treatment for tendinosis involves removing any fibrotic lesions or degenerate nodules, and reapproximating the edges to one another. If reapproximation is not possible, one may perform an autogenous tendon transfer or allograft reconstruction. Surgeons may reinforce the tendon with the plantaris tendon or employ an aponeurosis flap in cases of partial rupture.2,3,9 When it comes to degenerative tendons, surgeons can perform radiofrequency microtenotomy in order to induce healing and/or ablate sensory nerve fibers to reduce pain.10
Regenerative medicine has undergone study more in the field of tendinopathy and the theory is that growth factors and/or stem cells can help treat the degenerative process of tendons.11,12 Injecting PRP, platelets derived from whole blood, allows one to directly deliver growth factors to the injury site, which results in angiogenesis, chemotaxis and cell proliferation.11-13
What The Literature Reveals About PRP For Achilles Tendon Pathology
Recent studies have shown that PRP can positively affect gene expression and matrix synthesis in tendon and tendon cells.14 It is important, however, to distinguish acute tendon injury from chronic cases when discussing and studying PRP and its use for tendon pathology.
Researchers have looked specifically at the use of PRP for the treatment of Achilles pathology. Tendon injury leads to a cascade of degenerating events leading to eventual rupture. These include hypovascularity, repetitive microtrauma and the addition of fibrous tissue, which can then lead to degeneration and weakness of the tendon. Platelet-rich plasma theoretically reverses the effects of tendinopathy by stimulating revascularization and improving healing at the microscopic level.15
Alfredson and Lorentzon categorize Achilles tendon pathology into paratendinitis, paratendinitis with tendinosis and pure tendinosis.15 In paratendinitis, there are adhesions formed between the paratenon and the tendon. Paratendinitis with tendinosis involves degenerative changes within the substance of the tendon as well as inflammation in the paratenon. In cases of pure tendinosis, there is a palpable nodule that often presents. It is hypothesized that the introduction of PRP into the pathologic tendon will aid in the repair and remodeling of the tendon by tenocytes.
Lyras and colleagues studied the effect of PRP on angiogenesis during tendon healing.16 The study authors used PRP on the Achilles tendon of rats against a control group injected with saline. They found a significant increase in angiogenesis in the PRP group in comparison to the control group during the first two weeks of the healing process (i.e., the inflammatory and proliferative phases). They also noted the number of newly formed vessels in the PRP group was significantly reduced at four weeks in comparison to the controls, suggesting the healing process was shortened. They observed that the orientation of collagen fibers in the PRP group was better organized. The study authors concluded that PRP seems to enhance neovascularization, which may accelerate the healing process and promote scar tissue of better histological quality.
Gaweda and co-authors performed a prospective study on 15 patients with Achilles tendonitis.17 After following patients for 18 months, they found improvement in regard to pain scores and ultrasound imaging. The American Orthopaedic Foot and Ankle Society (AOFAS) scores improved from a median of 55 points to 96 points and the VISA-A score improved from 24 points to 96 points. They concluded that PRP is a viable treatment alternative for Achilles tendonitis.