Joost Peerbooms

78 Chapter 5 explanation for the long-lasting effect of platelets could be that platelets improve the early neotendon properties so that the cells are able to perceive and respond to mechanical loading at an early time point. 1 The results of the present study confirm the suggested positive effect in vivo as described by Mishra and Pavelko. 10 They reported a significant improvement of symptoms after 8 weeks in 60% of the patients treated with PRP versus 16% of the patients treated with a local anaesthetic. After 6 months the improvement in patients treated with PRP was 81%. They compared PRP with a local anaesthetic, which is not an accepted treatment for lateral epicondylitis in the Netherlands. Furthermore, they injected only 15 patients with PRP and compared them with 5 patients treated with a local anaesthetic. The study was underpowered, and the patients were not randomized. Our results confirm the results of Edwards and Calandruccio. 3 They injected whole blood into patients with lateral epicondylitis. Treatment success was seen in 79% of patients; however, multiple injections were necessary in 32% of patients. The limitation of this study is that all patients had failed previous nonsurgical treatments, including prior steroid injections. Furthermore, some patients had a beneficial effect after receiving more than 1 injection. In our study, a single percutaneous injection of PRP or corticosteroid was used with a peppering technique. Repeated injections might be beneficial in patients who had suboptimal results after the initial injection, although no evidence for a beneficial effect of more than one injection exists. Twenty-six weeks (6 months) was chosen as the cut-off point to consider whether the therapy was successful or not; however, we achieved significant results after only 26 weeks. We know that the natural history of lateral epicondylitis predominantly results in healed patients (80%) within 1 year, but all patients in the present study had complaints for at least 6 months, thereby putting their improvement past the 1-year mark. In both the corticosteroid group and the PRP group, each patient has a natural history; as such and because the population was randomized, we can expect natural history to have the same influence on both groups. In conclusion, this report describes the first comparison of an autologous platelet concentrate with the gold standard, corticosteroid injection, as a treatment for lateral epicondylitis in patients who have failed nonoperative treatment. It demonstrates that a single injection of concentrated autologous platelets improves pain and function more so than corticosteroid injection. These improvements were sustained over time with no reported complications. Perhaps for athletes it is less optimal, but all depends on the demands of the patient. We had no elite athletes in our population.