Joost Peerbooms

67 PRP in lateral epicondylitis INTRODUCTION Lateral epicondylitis is the most commonly diagnosed condition of the elbow, affecting approximately 1% to 3% of the population. The condition mostly occurs in patients whose activities require strong gripping or repetitive wrist movements. Individuals between the ages of 35 and 50 years are at high risk. The dominant arm is most frequently affected. 7,8,13 The cause of lateral epicondylitis is unknown. It is thought that lesions occur in the common origin of the wrist and finger extensors on the lateral epicondyle owing to a combination of mechanical overloading and abnormal microvascular responses. 12,19,24 Numerous methods have been advocated for treating elbow tendinosis, including rest, nonsteroidal anti-inflammatory medication, bracing, physical therapy, extracorporeal shock wave therapy, and botulism toxin injection. Injection of corticosteroids (once considered the gold standard but now controversial), whole blood injections, and various types of surgical procedures have also been recommended. 2,3,16,18,25 In an animal model, the addition of growth factors to the ruptured tendon has been shown to increase the healing of the tendon. 1,11 In humans, it has been shown that the injection of whole blood into the tendon decreases the pain. 3 Platelet-rich plasma (PRP) is promoted as an ideal autologous biological blood-derived product that can be exogenously applied to various tissues, where it releases high concentrations of platelet-derived growth factors that enhance wound healing, bone healing, and tendon healing. 14 In addition, PRP possesses antimicrobial properties that may contribute to the prevention of infections. 5 When platelets become activated, growth factors are released and initiate the body’s natural healing response. In a double-blind randomized trial, we investigated whether injection of concentrated autologous platelets improves the outcome of patients with lateral epicondylitis more so than corticosteroid injection. The primary outcome parameters were pain and daily use of the elbow. METHODS This double-blinded randomized trial included 100 consecutive patients with lateral epicondylitis scheduled for injection therapy in 2 Dutch training hospitals between May 2006 and January 2008. All procedures used the same injection procedure, performed by an orthopaedic consultant or a supervised orthopaedic resident. Criteria for participation included lateral epicondylitis for longer than 6 months and pain of at least 50 on a visual analogue 5