Joost Peerbooms

85 2-year follow-up of PRP in lateral epicondylitis INTRODUCTION Lateral epicondylitis is the most commonly diagnosed condition of the elbow and affects 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. 11,12,19 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 because of a combination of mechanical overloading and abnormal microvascular responses. 18,29,34 Numerous methods have been advocated for treating elbow tendinosis, including rest, nonsteroidal anti-inflammatory medication, bracing, physical therapy, extracorporeal shockwave therapy, and botulinum toxin injection. Injection of corticosteroids, which was considered to be the gold standard before but is actually currently controversial, or whole-blood injections and various types of surgical procedures have also been recommended. 2,6,25,28,35 In an animal model, the addition of growth factors to the ruptured tendon has been shown to increase the healing of the tendon. 1,16 In humans, the injection of whole blood into the tendon at least decreases pain. 6 Platelet-rich plasma (PRP) is promoted as an ideal biologic autologous blood-derived product. It can be exogenously applied to various tissues where, upon platelet activation, a release of high concentrations of platelet-derived growth factors occurs. Platelet-rich plasma applications enhance wound healing, bone healing, and also tendon healing. 22 In addition, PRP also possesses antimicrobial properties that may contribute to the prevention of infections. 8 As nowadays various different ways to produce PRP are available, it is of eminent importance to discriminate between leukocyte-enriched or leukocyte-deleted PRP. Accordingly, platelet concentrates have been categorized in either pure PRP (P-PRP), in which leukocytes are purposely eliminated from the PRP, or leukocyte and PRP (L-PRP), containing a high concentration of leukocytes. 5 We recently published the 1-year results of a double-blind randomized trial showing the improved outcome of patients with epicondylitis after an injection of concentrated autologous leukocytes and platelets compared with corticosteroid injection. 20 Few studies have examined the effectiveness of PRP against corticosteroids. The primary outcome parameters were pain and daily use of the elbow. However, as data on a longer follow-up regarding the effectiveness of PRP are currently lacking, we now present the 2-year follow-up of this trial using the same outcome parameters. 6