Platelet-rich plasma (PRP) therapy/injection utilizes the natural components of human blood in order to help heal damaged musculoskeletal tissue. PRP therapy was first introduced in the early 1990s but was mainly used in dentistry. It was not until recently that orthopedics and sports medicine began to utilize PRP therapy in hopes of treating injuries to tendons and ligaments. It is now commonly used to aid in the healing of tendinosis, ACL injuries, and tennis elbow. Understanding the makeup of tendons, ligaments, and human blood will give a better understanding as to why PRP therapy helps heal these injuries.
The most common injury sustained to tendons and ligaments is due to overuse of them in a specific area. Overuse causes tiny tears in the tissue which is known as tendinosis; this can occur from playing sports, high intensity exercising, and repetitive motions of the tissue on a daily basis. Tendons and ligaments are difficult to heal because they do not receive a good supply of blood. The fibers and tissue that make up tendons and ligaments is poorly vascular. They are composed of dense regular connective tissue. This type of connective tissue is composed of tightly packed collagen fibers which make tendons and ligaments extremely strong and able to withstand a lot of force and stress however when they do tear or become injured, they do not receive the beneficial healing factors that blood provides.
Our blood is made up of three components: red blood cells, white blood cells, and plasma. Plasma is mostly water however it also contains the proteins albumin, globulin, and fibrinogen. Fibrinogen is what assists with blood clotting: when a clot needs to be formed at a site of injury, fibrinogen turns into fibrin which then acts as a sticky net that catches platelets around the area that is bleeding. In the past, platelets were only recognized as being able to form blood clots, however now we know that they are actually responsible for so much more. When platelets become activated, meaning they start to clot, they release proteins and growth factors through organelles called granules. The growth factors that are released stimulate cell replication, collagenase activity, angiogenesis, and fibroblast activity.
We now know that the stimulation of these growth factors also attracts macrophages which promotes the removal of dead tissue and helps with repairing tissue and wounds. The majority of the proteins released are done within an hour of activation however platelets continue to produce proteins and growth factors for the next several days.
Platelet-rich plasma therapy utilizes the natural healing factors that blood has on injured tissue and wounds and delivers it to parts of the body that are poorly vascular. PRP therapy is typically done in a doctor’s office. The first step of the process is drawing the patient’s blood; usually 30-60 ml is taken. Once the blood is drawn, it is placed in a centrifuge which then separates the blood into its component parts. The plasma and a small amount of red blood cells are then extracted from the sample. Calcium chloride is added to the sample which activates the platelets to release their growth factors and proteins as well as turns the fibrinogen in the plasma into fibrin; in essence, the addition of calcium chloride “tricks” the platelets and plasma into thinking a clot needs to be formed. Once the sample is ready, the area on the patient where the PRP is going to be injected is given lidocaine to numb the area. In some cases the injection is done under ultrasound guidance but not always. The entire process of receiving PRP injections takes about 30 minutes. The patient is able to go on with their day but asked not to do anything strenuous. In most cases the patient will receive 3-6 injections over a year’s time.
When people experience damage to their tendons and ligaments, they often are taking anti-inflammatory medications which can lead to peptic ulcers if taken over a long period of time. Sometimes a doctor will recommend a cortisone injection however these are not always the safest when there is a tendon involved; the cortisone can actually cause the tendon to rupture. PRP therapy is more beneficial than these options because it attempts to heal the injury instead of mask the pain and there almost no safety concerns. PRP therapy has become quite popular in professional sports because of these benefits. Alex Rodriguez, Kobe Bryant, and Tiger Woods are among a growing list of professional athletes who have received PRP injections. More studies are being done to see if PRP therapy can help heal other areas of the body, including wounds and bone degeneration.
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Wroblewski, Andrew P., Hector A. Mejina, and Vonda J. Wright. “Application of Platelet- Plasma to Enhance Tissue Repair.” Operative Techniques in Orthopaedics (2010): 98- 105. ScienceDirect. Web. 28 Apr. 2012.
Colletti, Thomas. “Well-designed clinical studies are needed, as well as policies and protocols: platelet-rich plasma: effective treatment for sports injuries?” The Journalof Musculoskeletal Medicine 28.5 (2011): 185. Academic OneFile. Web. 30 Apr. 2012.