What is Platelet Rich Plasma (PRP)?
Platelets are small blood cells that cause blood to clot and initiate healing at the site of the injury.  Platelets release growth factors that have been shown to lead to the healing of tendons.  The process involves drawing the patient’s own blood, centrifuging the blood to remove the platelets, and then injecting these concentrated platelets into the diseased tendon.  The concentrated platelets are terms PRP (platelet rich plasma).

How are the injections given?
An ultrasound machine is used to identify the painful tendon.  The skin is then sterilized with an alcohol-based solution and a local anesthetic is used to numb the skin.  A needle is directed into the tendon under direct visualization using the ultrasound machine.  The PRP solution is then injected throughout the diseased tendon.  Often the PRP injection is done in conjunction with a tenotomy.

Does the injection hurt?
The injections are relatively comfortable and as pain free as a simple blood test or injection into the muscle in the arm.  You may feel some pressure in the area from the injected solution.

How long does it take for the injection to work?
The PRP stimulates healing of the diseased tendon.  The injection does not provide the instant relief that a cortisone injection does, but the big difference is that PRP can actually heal the tendon over a period of time.  Cortisone stops inflammation but does not cause the tendon to heal.  Most PRP injections typically take several weeks to months to work.

How long will it last?
Studies vary in the success of PRP injections.  A study published in the American Journal of Sports Medicine in November 2006 showed that over 90% of patients were “completely satisfied” with their results for the treatment of tennis elbow.1 Another study comparing cortisone to PRP for tennis elbow showed that the PRP had a much greater long term benefit.2 However, a third study showed it was no better than a saline injection for Achilles tendinosis.3

What should I feel after an injection?
When the local anesthetic wears off, it is common to feel a mild increase in discomfort in the tendon. You may treat this discomfort by applying an ice pack and by using acetaminophen. You should not use ibuprofen or other anti-inflammatory medicines that may interrupt the healing process started by the PRP.  For a number of weeks after the injection, heavy repetitive motions should be avoided in order to allow the tendon to heal. Physical therapy may be recommended.

What are the possible side effects of an injection?
Most tendon injections result in no side effects. The side effect of greatest concern is an infection of the deep tissues around the tendon.

1 Mishra A, Pavelko T. Treatment of chronic elbow tendinosis with buffered platelet rich plasma. Am J Sports Med. 2006 Nov; 34(11):1774 8 PRP Injection for chronic tennis elbow.

2 Peerboom J, et. Al.  Positive Effect of an Autologous Platelet Concentrate in Lateral Epicondylitis in a Randomized Controlled Trial.  Am J Sports Med February 2010 vol. 38 no. 2 255-262

3 De Vos RJ, et. Al.  Platelet-Rich Plasma Injection for Chronic Achilles Tendinopathy.  JAMA 2010 Jan 13; 303 (2): 144-9