Platelet-Rich Plasma Therapy and Sports-Related Injuries
Despite lack of FDA approval, PRP therapy is gaining unproven acceptance as treatment for sports-related injuries.
Musculoskeletal injuries are a common cause of severe long-term pain and physical disability. Increasing in popularity in sports medicine is the use of autologous platelet-rich plasma (PRP) therapy to biologically enhance healing. The prominence provided by professional athletes in a variety of fields including football, baseball, basketball, figure skating, and golf,1-3 who credit PRP therapy with faster return to competition after a joint injury, has brought exposure to PRP therapy as a desirable treatment for a range of sports-related injuries, compared to the more traditional treatment approach that may involve medications, physical therapy, or surgery. While basic science and preclinical data support some benefit of PRP for a variety of sports-related injuries, robust randomized trials are limited. Despite lack of approval by the US Food and Drug Administration (FDA), PRP therapy is gaining unproven acceptance as treatment for sports-related injuries.4
Platelet rich plasma therapy is not a new concept. Over the past 2 decades, PRP therapy has been used to improve wound healing and bone grafting procedures in several clinical areas including neurosurgery; oral, periodontal, cosmetic, and maxillofacial surgery; otolaryngology; head and neck surgery; urology; orthopedic/spinal surgery; and cardiothoracic and general surgery.5, 6 In recent years PRP therapy has gained prominence among sports medicine specialists, professional athletes, and increasingly among individuals engaged in recreational sports. According to Michael Hall, MD, senior orthopedic surgery resident at the NYU Hospital for Joint Diseases in New York, “Use of PRP has increased, in large part due to new devices that enable fast preparation in the outpatient setting. A patient gives a blood sample and 30 minutes later can receive their injection….. There is always a risk of infection with any injection, and some have reported increased pain or inflammation at the injection site, but otherwise the risks with PRP appear minimal." 7
It is important to clarify what PRP therapy is, the current understanding of its mechanism of action, and evidence for its effectiveness in treating common sports injuries.
Platelet-rich plasma, also referred to as platelet-enriched plasma, platelet-rich concentrate, autologous platelet gel, and platelet releasate, is defined as a plasma fraction of autologous blood having platelet concentration above baseline, and prepared from blood drawn from the patient. Platelets are separated from other blood cells and then concentrated by centrifugation. The concentrated platelets are recombined with the remaining blood, and the platelet-rich blood is injected directly into the patient's injured area. Despite its pervasive use, the clinical efficacy of PRP therapy and its precise mechanisms of action have yet to be clearly defined.
In addition to platelets, PRP contains a variety of growth factors, including transforming growth factor-β, platelet-derived growth factor, insulin-like growth factor-I, vascular endothelial growth factor, epidermal growth factor, and hepatocyte growth factor.4,8 Many of these growth factors have been shown to enhance one or more phases of bone and soft tissue healing. Basic research suggests that PRP exerts its effects through many downstream events secondary to the degranulation of platelets releasing growth factors and other bioactive agents into the local environment, resulting in chemotaxis of inflammatory cells and activation and proliferation of local progenitor cells. It is believed that PRP can augment or stimulate healing by turning on the same biological processes that normally occur to initiate healing after musculoskeletal injury. 8,9