Krogh TP, Fredberg U, Stengaard-Pedersen K, Christensen R, Jensen P, Ellingsen T.. Am J Sports Med. 2013 Jan 17. [Epub ahead of print]
Take Home Message: Among patients with chronic lateral epicondylitis, glucocorticoid injections were more effective at reducing elbow pain than platelet-rich plasma or placebo injections at 1 month post-injection but all three treatments had similar effects at 3 months post injection.
Lateral epicondylitis (tennis elbow) continues to be a common musculoskeletal disorder that is associated with substantial costs, health care use, and frustration among patients competing in sports or activities that involve the upper extremities Recent research has focused on platelet-rich plasma (PRP) injections for epicondylitis, but very few studies have compared PRP and glucocorticoid injections to a placebo injection. Therefore, the purpose of this double-blind, randomized clinical trial was to compare the effectiveness of PRP, glucocorticoid, or isotonic saline injections for reducing elbow symptoms among patients with lateral epicondylitis (tennis elbow). Patients were included if they had symptoms of lateral epicondylitis for more than 3 months and signs of tendinopathy on ultrasound. Each injection was performed under ultrasound guidance, with the glucocorticoid injection being injected in one pass, while the PRP and saline were injected using a peppering technique with 7 tendon perforations. All 60 patients received the same post-treatment protocol, which included minimal use of the affected arm for 3-4 days, use of acetaminophen for pain control if needed, and then starting a standard tennis elbow stretching and training home program once the pain level was acceptable. The primary efficacy outcome was changes in pain intensity 1 and 3 months after the injection using the pain section of the Patient-Rated Tennis Elbow Evaluation questionnaire (Scale of 0-50). The original goal of the study was to collect data at 6 and 12 months as well, but there was a large drop-out rate that did not allow this. At the one month follow-up, the glucocorticoid group had a mean decrease in pain of 9.8, which was better than the saline group (-1.7) and the PRP group (-0.5). At 3 months there were no differences between the 3 groups: glucocorticoid group (-7.1), PRP group (-6.0), and saline group (-3.3).
This study matches results to previous studies showing that glucocorticoid injections have a benefit in the short-term, but that effect does not last. Unfortunately, with the large dropout rate, the authors were not able to assess if there were any long-term benefits of PRP or placebo at 6 and 12 months. This may be relevant since the Hart et al review found that it was at the long-term follow-up visits that physical therapy was more effective than a glucocorticoid injection. As the authors mentioned, this is one of the first randomized clinical trials for lateral epicondylitis that included a placebo group for PRP. By having the placebo group undergoing the same needling procedure, there was potential to assess if the PRP itself makes a difference, rather than just the needling or tenotomy. This also brings up a limitation to the study since the glucocorticoid group only had 1 needle pass into the tendon. One could argue that this would be less painful than the 7 tendon perforations in the other groups, and be a reason for the results. However, the PRP group had more post-injection pain than the saline group. This study also had a large dropout rate, which may have been attributed to patients having the option of discontinuing the study after 3 months if they were not satisfied with their results. Patients are looking for treatments that will take away their pain as soon as possible and allow them to return to work or sport quicker. It can be hard for a patient to think about waiting a year for improvement, when there’s a chance to have a short-lived relief of pain. This study does not support PRP injections for short-term pain relief of lateral epicondylitis compared to a placebo or glucocorticoid injection. Further studies will have to examine if long-term relief is possible and will hopefully be able to include a true placebo group, such as a physical therapy only group that does not receive an injection. Does this study change your recommendation of treatment for your patients or your view on PRP injections?
Written by: Kris Fayock, MD
Reviewed by: Jeffrey Driban
Reviewed by: Jeffrey Driban