Platelet rich plasma (PRP) injections are an emerging therapy for the treatment of chronic musculoskeletal conditions. Foot and ankle conditions that may benefit from this therapy include plantar fasciosis (chronic plantar fasciitis) and Achilles tendinosis (chronic Achilles tendonitis). Plantar fasciitis is the tearing and inflammation of the ligament in the arch of the foot. Initially the pain is sharp and stabbing and the heel can become swollen and very tender. Pain is common at the first step in the morning, upon rising and placing the feet down. As this conditions progresses, the pain becomes dull and the swelling diminishes, but the area remains sore. The plantar fascia (the arch ligament) starts to thicken and degenerate and the condition progresses to plantar fasciosis.
At this stage, the condition becomes more difficult to treat. Achilles tendonitis is the tearing and inflammation of the tendon in the back of the heel. The pain is generally sharp and stabbing with walking and is particularly sore when going up and down hills or stairs. As the condition progresses, the pain and swelling lessen and a nodule may appear at the back of the tendon as it thickens. The tendon may start to degenerate and this is the progression to Achilles tendinosis. Redness, swelling and pain are a normal part of a repetitive injury. The body is sending more blood to the injured area, carrying important cells to clean up damaged tissue and start the healing process. But, some conditions will progress to a degenerative process where the inflammatory response is suppressed and the normal repair process is either reduced or has halted. The goal of platelet rich plasma injections is stimulate the inflammatory response and jump start the healing process.
Platelets are used because they contain bioactive proteins and growth factors which are important for tissue repair and healing. A small amount of blood is drawn and then placed in a centrifuge to prepare it for the injection. The centrifuge separates the platelets from the remainder of the blood. The end product is a high concentration of platelets and growth factors ready for injection. The injection is given at the point of pain. For plantar fasciosis, the injection is usually at the inside and bottom of the heel. For Achilles tendinosis, the injection is at the back of the heel. Some physicians, but not all, perform ultrasound guided injections. There is generally some pain and discomfort in the area of the injection for up to a week. In some cases, patients are placed in a walking boot with a heel lift for two weeks after the injection. Stretching therapy is usually resumed as soon as a patient can tolerate the therapy.