Comparing Different Injection Therapies for Tennis Elbow

Barbie dolls, Corvettes, and Easy-Bake Ovens aren't the only things that have been around since the 1950s. Add steroid (glucocorticoid) injections for tennis elbow to that list. Since that time, other injectable treatments have been developed as well. In this systematic review and meta-analysis of the studies published so far, a comparison of results is provided for eight different injection treatments.

Tennis elbow (also known as lateral epicondylitis) is a fairly common work- or recreational-related problem caused by repetitive motions (e.g., gripping, bending wrist back into extension). Sometimes the elbow feels stiff and won't straighten out completely. Men and women are just as likely to develop symptoms of tenderness and pain that starts on the outside bump of the elbow, the lateral epicondyle.

There were 17 studies included in this review. All were randomized controlled trials (RCTs) and reported before and after results based on pain intensity. Safety and adverse effects were also compared. A total of 1,381 patients were involved using one of the following treatments: 1) glucocorticoid, 2) botulinum toxin, 3) autologous blood, 4) platelet-rich plasma, 5) polidocanol, 6) glycosaminoglycan, 7) prolotherapy, and 8) hyaluronic acid.

The authors provide details on how studies were selected, how the data was retrieved (called data extraction), and how the results were analyzed (using a tool known as the Cochrane risk of bias tool).

A large table including characteristics of the 17 studies was presented in the article for those readers who might like more details. Reasons for NOT including certain studies were also mentioned (e.g., pain was not measured as an outcome, patients had a traumatic injury, study was not a randomized controlled trial, study included patients with golfer's elbow or medial epicondylitis).

Final results of the overall analysis revealed some differences among the various injectable treatments. For example, although glucocorticoid (steroid) injections gave relief early on, the results after eight weeks were no different than if the person received a placebo (injection without the medication). Prolotherapy and hyaluronic acid worked better than a placebo injection. And the rest of the treatment choices resulted in the same outcomes as a placebo injection.

There were no serious side effects in any of the trial. Pain was felt at the time of injection and for a short time after injection for all eight treatment types. The steroid injections were most likely to cause skin atrophy and/or skin discoloration. Botulinum toxin (also known more commonly as BOTOX) caused temporary paralysis of the finger extensor tendons. But that's how BOTOX works - it is a paralyzing agent designed to give the tendons/muscles a rest. This effect was gone three months later.

The authors conclude that all injection treatment for lateral epicondylitis (tennis elbow) appears to be safe. Glucocorticoid, which has been studied the longest and most often really isn't any better than a placebo injection. The other types of injection therapies are still fairly new (developed in the last 10 years or so) and studies involving these agents are small or pilot studies and must be viewed with caution.

They suggest that further high quality, well-designed studies with low risk of bias of these newer treatments are needed before any firm treatment recommendations can be made. It would be helpful if results measured in terms of pain relief could be compared for the same number of injections over the same period of time from study-to-study. This type of approach would make it possible to pool data from several studies for greater statistical significance.

References: Thøger Persson Krogh, MD, et al. Comparative Effectiveness of Injection Therapies in Lateral Epicondylitis. In The American Journal of Sports Medicine. June 2013. Vol. 41. No. 6. Pp. 1435-1446.