By Spencer M. Wheeler, M.D.
Over the past several decades many advances have been made in the treatment of musculoskeletal disorders. Many of these advances have been the result of improvements in surgical techniques and diagnostic imaging. While it is possible to reliably repair soft tissues during surgery, the long term outcomes of these repairs are not always as successful as the immediate surgical result. One of the reasons for long term suboptimal outcomes is the eventual failure of surgical fixation (sutures, screws, anchors) when repaired structures do not heal themselves and regain their native strength.
New focus on optimizing the biology of the healing environment to stimulate the body’s natural healing process and improve long term outcomes is currently underway. Many of the structures we are trying to repair in orthopaedic surgery (menisci, rotator cuff) have poor blood flow and thus a limited capacity to heal. New methods to improve the biologic environment at these soft tissue repair sites have become available over recent years. One of these methods involves the use of platelet-rich plasma. Platelet–rich plasma can be used in both the operative and non-operative settings to improve or stimulate the healing response.
Platelet–rich plasma is essentially plasma that has been processed to contain a high concentration of platelets and growth factors. It is derived from the patient’s whole blood. The blood is spun down in a centrifuge, allowing the platelet rich layer to be extracted. The platelet–rich plasma can then be activated with the use of thrombin or calcium chloride. The activation step causes the release of growth factors by the platelets. Plate- let–rich plasma can also be injected in its inactivated form allowing it to be acti-vated once it is in the body.
There are many different commercial systems to create platelet–rich plasma but the essential concepts behind creating platelet–rich plasma are similar for each system. The platelet–rich plasma contains platelets as well as specific growth factors. These growth factors include: transforming growth factor beta (TGF-B), platelet derived growth factor (PDGF), insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and fibroblast growth factor-2 (FGF-2). Many of these factors have been shown to enhance one or more phases of soft tissue and bone healing.
In order to understand the mechanism of action of platelet–rich plasma it is necessary to review the normal healing process of musculoskeletal tissue. The repair response starts with the formation of a blood clot and degranulation of platelets. The degranulation of platelets releases growth factors and cytokines into the local environment. This in turn results in chemotaxis of inflammatory cells as well as the activation and proliferation of local progenitor cells.
It is believed that platelet–rich plasma can augment or stimulate healing by turning on the same biological process that normally occurs after musculoskeletal injury. In vitro (test tube) studies have demonstrated that platelet–rich plasma can enhance the proliferation of stem cells and fibroblasts.
Platelet–rich plasma likely has the ability to stimulate and enhance healing of soft tissue injuries in humans. Nevertheless, its exact role in the treatment of musculoskeletal disorders remains to be determined. We are still in the infancy of evaluating platelet–rich plasma in clinical trials and deriving evidence based guidelines by which to use it.
Currently, we have little more than animal data and anecdotal evidence by which to guide us. The use of platelet–rich plasma is probably best relegated to soft tissue injuries such as tendinosis or tendonitis.
In my experience, platelet–rich plasma has been successfully used to treat lateral epicondylitis (tennis elbow), Achilles tendonitis, plantar fasciitis, patella tendonitis, and soft tissue injuries in elite athletes.
The simple process of drawing blood from a patient, centrifuging that blood and then re-injecting a concentrated portion of that blood full of healing factors is easily done in an office setting. The entire process takes less than 30 minutes and is repeated three to four times in a chronic condition on a weekly basis and three to four times every four to five days for an acute injury. The process itself is minimally painful and does not interfere with post injection plans by the patient.
Platelet–rich plasma is a new technology that may prove to have numerous applications in the treatment of musculoskeletal injuries. Platelet–rich plasma has the ability to promote soft tissue healing in vitro (lab) and is likely that this will translate into improved healing in human trials. The true value and the role of platelet–rich plasma in musculoskeletal healing is currently unknown.
For more information about platelet–rich plasma technology or other orthopedic concerns, contact Dr. Wheeler at Chatham Orthopaedics, 4425 Paulsen Street, Savannah, GA 31405, (912) 355-6615