Platelet Rich Plasma (PRP) Therapy for Tendon Injuries

Typically when we talk about platelets, we think of its effective ability to clot bleed. In recent years, scientific research has provided a new perspective on understanding the wound healing process and have learned that platelets also release many bioactive proteins responsible for attracting macrophages, mesenchymal stem cells, and osteoblasts which enhances tissue regeneration and healing as well as promotes removal of necrotic tissue. This brings up an interesting therapy called Platelet-Rich Plasma (PRP) Therapy. Athletes and active individuals who endure chronic pain from tendon injuries or osteoarthritis may get relief from this safe and non-surgical procedure. Plus, it utilizes platelets from the athletes' own blood to rebuild a damaged tendon or cartilage. In this article we will discuss what exactly is PRP, how does it work, its indications for use in the clinic, and some safety concerns.

What is PRP and what's in it?

PRP stands for "Platelet-Rich Plasma", and is defined as autologous blood with concentrations of platelets above baseline levels, which contains at least seven growth factors. They are prepared by centrifuging the patient's blood and extracting the platelet-rich portion of the blood. Normal blood typically contain only 6% platelets, however in PRP there is a concentration of 94% platelets. Furthermore, platelets contain a number of proteins, cytokines and other bioactive factors that initiate and regulate basic aspects of natural wound healing. Circulating platelets secrete growth factors, such as platelet-derived growth factor, vascular endothelial growth factor, fibroblast growth factor, and insulin- like growth factor-1. These factors are responsible for promoting vascular growth, cell replication, growth, and repair.

How does it work?

PRP is injected into the site of injury to promote healing. The idea is that PRP will "signal” to distant repair cells, including adult stem cells, to come to the injury site. Upon platelet activation within the injury site, they begin to secrete growth  factors within 10 minutes and continues for seven days. The platelets also stimulate the influx of macrophages, stem cells and other repair cells. Once the platelets die, the macrophages continue wound healing regulation by secreting some of the same growth factors as the platelets did, as well as others. In the long run, the goal of PRP therapy is to assist the patient in healing damaged tendons or cartilage naturally.

What are some indications for using PRP?

PRP therapy have been use extensively throughout the body, especially in musculoskeletal issues. PRP have been used to treat elbow, knee, foot-and-ankle, non-healing wounds, and and even in the spine. A study from Chen et al. demonstrated that PRP might potentially play a role in prevention of disc degeneration.

What are some safety issues?

PRP therapy has low risk and few side effects. There have been no documented cases of carcinogenesis, hyperplasia, or tumor growth associated with the use of PRP. The growth factors never enter the cell and act through the stimulation of external cell membrane receptors, therefore PRP has no ability to induce tumor formation. Also, because PRP uses the patient's own blood, the risk of allergy or infectious disease is considered negligible.

I'm interested! What should I do next?

If you are interested in knowing more about PRP therapy, schedule an appointment to meet with your physician to see if PRP therapy would be a good fit for you.


Albert Hsia, MSIV

Dr. David Carfagno, DO, CAQSM



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