PRP and chronic tendinosis
Tom, a 45-year-old handyman, has suffered left elbow pain for years. He received several local cortisone injections as well as physical therapy. Although the initial treatment was somewhat effective, his elbow pain persisted and affected both his work and daily activities.
Acute tendinitis is the inflammation of the tendon due to micro tears from sudden or chronic repetitive overuse of tensile force. The healing process of an injured tendon proceeds through three stages: inflammation; healing; and remodeling. It is necessary that the body attracts inflammatory cells, such as white blood cells, to the injured area to initiate the inflammatory process. During the second stage (repair), new collagen is produced and lasts until the collagen content is sufficient and the tendon structure is near normal (remodeling).
If acute tendinitis does not properly heal, collagen degeneration and chronic tendinosis will develop. Moreover, some treatments for acute tendinitis to reduce inflammation adversely affect chronic tendinosis. Non-steroidal anti-inflammatory medications are associated with inhibited collagen repair. Frequently, corticosteroid injections inhibit collagen repair and may become a predictor of later tendon tear.
Growth factors and other cytokines in our body play a key role in the healing process. They are growth-enhancing proteins which stimulate cell proliferation, chemotaxis, angiogenesis and differentiation and influence different stages of wound healing. Platelets are the storage pools of growth factors, cytokines and many other proteins. When platelets come in contact with the exposed surface of the blood vessels, either within wounds or damaged tissues, these factors are released and work in harmony with other tissue-repair mechanisms to promote appropriate wound healing.
PRP (Platelet-rich plasma) is defined as plasma with a platelet level above peripheral blood concentration. PRP therapy has been used in orthopedic and sports medicine for treatment of injury, trauma or chronic tendinosis. This therapy is used to enhance natural healing and the regenerative process by delivering high concentrations of a patient’s own platelets to the affected areas.
There are many ways of preparing PRP. The most common way to prepare PRP involves centrifuging a patient’s blood sample and extracting the necessary blood components for PRP. Then PRP is injected into the injured tendon or even the joint. Due to a limited biological half-life of growth factors and the complexity of the healing process of tendons, a single injection of PRP is unlikely to be successful. Repeated local injections are generally necessary to maximize healing effects.
Achieving the optimal effects of PRP therapy depends on the right clinical conditions, proper processing of blood sample (to obtain maximal concentration of PRP) and the precision of the injection into the targeted area. Moreover, combined stem cell and PRP therapy has been investigated for potential clinical applications for chronic unhealed tendinosis, tendon tear, and even arthritis.
Dr. Yong H. Tsai is board-certified in rheumatology, allergy and clinical immunology and has been practicing in this area since 1993. His website is arthritis-allergy.net.