James Odell, OMD, ND, L.Ac
Platelet rich plasma therapy (PRP) is a preparation of autologous plasma enriched with a platelet concentration above that is normally contained in whole blood. In clinical musculoskeletal medicine, PRP is classically prepared by centrifuging autologous, anticoagulated whole blood to separate its components and concentrate platelets above baseline levels. Typical protocols include either 1 or 2 centrifugation steps to separate whole blood into 3 layers: a top plasma layer, middle leukocyte layer, and bottom red blood cell (RBC) layer, to collect a concentrate of platelets in plasma. The rationale for the use and therapeutic potential of a high concentration of platelets is based on their capacity to supply and release supraphysiologic amounts of essential growth factors and cytokines from their alpha granules to provide a regenerative stimulus that augments healing and promotes repair in tissues with low healing potential.
PRP therapy has increased in recent years in several areas of medicine, especially regenerative medicine. Its clinical use is also applied in the areas of cardiac, cosmetic, dental, and maxillofacial surgery. In cardiac surgery, PRP has been shown to be an effective autologous source for transfusion to address surgical blood loss and hematologic derangements from cardiopulmonary bypass. In dentistry, PRP is applied to tooth extraction sites to facilitate bone regeneration in these sockets with compact mature bone that had normal morphology. In maxillofacial surgery, PRP is used on bone maturation rate and bone density in bone graft reconstructions of mandibular continuity defects, demonstrating that the addition of PRP to grafts resulted in increased bone formation.
In musculoskeletal and sports medicine, PRP therapy has become extremely utilized for its potential benefit and influence on repairing injured tissue and treating a wide range of degenerative disorders. It is primarily used in sports medicine to augment the healing of tendons, ligaments, muscles, and cartilage.
The utility of PRP in promoting healing is especially significant for tendons, ligaments, and cartilage, the repair processes of which can be particularly slow and poor due to their limited blood supply and slow cell turnover.
Although platelets play a major role in hemostasis, they are central to mediating the anabolic effects of PRP by virtue of releasing growth factors stored in their alpha granules. During the initial phases of wound repair, activated platelets attract and foster cell migration into the wound by aggregating and forming a fibrin matrix. This matrix then serves as a tissue scaffold for the sustained release of platelet growth factors and cytokines, which stimulate cell recruitment, differentiation, and communication. Although both angiogenic and antiangiogenic factors are stored in platelets, they are released differentially. Notable growth factors released from platelets that are involved in the healing process include platelet-derived growth factor (PDGF), transforming growth factor (TGF-b), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and insulin-like growth factor (IGF-1).
Indications and Therapeutic Considerations
Different physicians vary in their preference for and experience in using PRP. In some sports medicine practices, PRP therapy may be commonly reserved for second-line treatment of chronic conditions like tendinopathy or refractory osteoarthritis of large joints that have failed first-line conservative management, which may have included activity modification, PT, analgesics, complementary therapies (acupuncture), and steroid injections. Less frequently, PRP may be administered for acute myotendinous injuries. Indications for consideration of PRP can include the following:7
Pain duration greater than 3 to 6 months that averages higher than 4 on a 0 to 10 visual analog scale.
Physical examination, diagnostic imaging, and diagnostic procedures confirming the clinical suspicion of tendinopathy, osteoarthritis and/or myotendinous injuries.
Symptoms refractory to standard conservative care (activity modification, NSAIDs, PT).
Patient goals to prolong or avoid surgical intervention.
Anticipated recovery time consistent with the patient’s timeline to return to activity.
The patient is dedicated to committing to a postinjection course of PT of at least 6 weeks.
It is common to recommend courses of PT and/or acupuncture before and after PRP injection to maximize therapeutic effect; therefore, a patient is considered a better candidate for PRP. Athletes, however, require further counseling on the need for postprocedural activity restrictions and sufficient time off from play to allow for optimal recovery and to avoid reinjury by returning to sport too soon.
Drug Reactions and Contraindications
Application of PRP has generally not been recommended in individuals who take or cannot suspend taking antiplatelet therapy, which may inhibit platelet degranulation and release of growth factors and bioactive molecules, thereby significantly reducing the healing potential of this biologic approach. Such antiplatelet agents come from drug classes with various mechanisms of action that include reversible and irreversible cyclo-oxygenase inhibitors, adenosine diphosphate receptor inhibitors, adenosine reuptake inhibitors, phosphodiesterase inhibitors, glycoprotein IIB/IIIA inhibitors. Autologous PRP produced from subjects taking nonsteroidal anti-inflammatory drugs (NSAIDs), reversible cyclo-oxygenase inhibitors that are commonly taken for anti-inflammation and pain management, was shown to have significantly impaired platelet aggregation and thus potentially diminished the therapeutic effect.
Medical contraindications that warrant caution or avoidance of PRP therapy may include blood dyscrasias, current infections being treated by antibiotics, use of antiplatelet agents, and use of systemic immunosuppressant medications such as oral glucocorticoids. Non-medical contraindications may include being unable to tolerate injection therapies, commit to a PT program, or afford to undergo a potential series of injections.
The patient should be informed that PRP injections for musculoskeletal injuries are currently not covered by the Centers for Medicare and Medicaid Services and most medical insurance companies. Therefore, the patient should expect to pay “out of pocket” for PRP therapy. Notification of cost at the initial consultation is important because multiple injections may be needed to obtain a desirable clinical outcome.
Recent advances in published literature reflect the promise of PRP and regenerative biology in clinical practice. More recently, PRP has been studied in persons with chronic elbow tendinosis, plantar fasciitis, Achilles tendon repair, and augmentation of arthroscopic rotator cuff repairs, and anecdotal documentation has shown accelerated recovery in athletes who sustained muscular injuries. The regenerative properties of PRP also give it potential for use in the management of osteoarthritis.
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