Joost Peerbooms

77 PRP in lateral epicondylitis Now controversial, corticosteroid injection was once considered the gold standard in the treatment of lateral epicondylitis. However, studies show that it is merely the best treatment option in the short-term, when compared with physiotherapy and wait- and-see policy. Poor results are often seen after the 12-week follow-up. 18 Treatment with corticosteroids has a high frequency of relapse and recurrence, probably because intratendinous injection may lead to permanent adverse changes within the structure of the tendon and because patients tend to overuse the arm after injection as a result of direct pain relief. 18 In a meta-analysis, Smidt and colleagues 17 showed that the effects of steroid injections as compared with placebo injection, injection with local anaesthetics, injection with another steroid, or another conservative treatment are not significantly different in the intermediate and long-term. However, the patients who were examined all had short-term lateral epicondylitis. There are various types of surgical procedures for patients with chronic lateral epicondylitis. Verhaar and colleagues noted an improvement in 60% to 70% of the patients after surgical treatment, although higher success rates (80% to 90%) have more recently been reported. 21,23 Patients remain, however, interested in an alternative to surgical intervention. Platelet-rich plasma is promoted as an ideal autologous biological blood-derived product that can be exogenously applied to various tissues where, after being activated, it releases high concentrations of platelet-derived growth factors that enhance tissue healing. 5,26 With the Recover System, the patient’s own platelets can be collected into a highly concentrated formula. No activation agent was used during our procedure. The activation of the platelets will occur through the exposure of platelets to the thrombin, which is released from the tendon tissue during the peppering technique. During the first 2 days of tendon healing, an inflammatory process is initiated by migration of neutrophils and, subsequently, macrophages to the degenerative tissue site. In turn, activated macrophages release multiple growth factors, including platelet- derived growth factor, transforming growth factors alpha and beta, interleukin-1, and fibroblast growth factor. 4 Angiogenesis and fibroplasia start shortly after day 3, followed by collagen synthesis on days 3 to 5. This process leads to an early increase in tendon breaking strength, which is the most important tendon healing parameter, followed by epithelization and, ultimately, the remodelling process. This was confirmed in an animal study. 1 The treatment of tendinosis with an injection of concentrated autologous platelets may be a nonoperative alternative. Injection of autologous platelets has been shown to improve repair in tendinosis in several animal and in vitro models. 9,15 A possible 5