Platelet rich plasma, commonly called PRP, has been promoted widely as a potential treatment for helping injured musculoskeletal tissues to heal. Platelet rich plasma contains high concentrations of several growth factors. The alpha granules that are present in platelets are full of these growth factors. Platelet rich plasma has been used worldwide for multiple indications of knee pain, most commonly accelerate ligament healing or to augment tissue repair.
The philosophy behind using platelet rich plasma to augment tissue healing is based upon growth factors that are present in an individual’s own blood. Platelets naturally gravitate toward an injured area of the body and the alpha granules, which contain the growth factors, are released by the platelets. For platelet rich plasma, blood is drawn from a patient and the platelets are spun down with a centrifuge to much higher levels than are normally seen in a person’s own blood. These concentrated platelets are then injected into the injured or surgically repaired area.
Over the last few years, platelet rich plasma has emerged as an accessible and relatively inexpensive source of growth factors to treat musculoskeletal injuries. PRP contains growth factors that are very important for musculoskeletal healing, such as TGF-beta, platelet-derived growth factor (PDGF) insulin-like growth factor (IGF-I) in fibroblast growth factor (FGF). The growth factor concentration in platelets, coupled with the normal platelets that are present in blood, are sufficient to yield increases of measureable growth factors in the blood to help reduce knee pain. Laboratory studies have confirmed that PRP has beneficial effects on ligament fibroblast migration and the differentiation and production of collagen. This means that it assists with healing knee pain. In addition to the effects of the growth factors directly on healing, platelet rich plasma has also been reported to enhance the gene expression of important healing factors. This includes collagen type 1, decorin, and cartilage oligomeric matrix protein (COMP) in ligaments.
Our research team at the Steadman Philippon Research Institute is actively involved with several studies with our veterinary colleagues at Colorado State University on the effects of ligament healing using PRP. In addition, Dr. LaPrade commonly uses platelet rich plasma to augment healing for isolated meniscal repairs, and other complicated ligament surgeries where previous surgical procedures and injuries may have hindered the overall blood supply to the area. While ongoing studies are necessary to determine the long-term effects of the use of platelet rich plasma in these situations clinically, our early outcomes are very encouraging that they do augment healing in these complex situations.
The future of PRP is encouraging. Using the patient’s own growth factors and platelets is cost effective and research does indicate that it stimulates damaged ligaments and facilitates repairs in both basic science and animal models. While ongoing studies are still required to determine the ideal concentration of platelets, whether or not the addition of white cells is beneficial, and other factors, we do believe that the use of biologic agents to enhance healing is the next major breakthrough in sports medicine for treating knee pain.
