Among the variety of injections that have been tested for lateral epicondylitis - tennis elbow - it remains unclear which ones work and which ones don't, a new systematic review concludes.
Tennis elbow affects 1% to 3% of the population and peaks between the ages of 45 and 54 years. Injection therapies have included glucocorticoids, platelet-rich plasma (PRP), autologous blood, prolotherapy, hyaluronic acid, botulinum toxin, polidocanol, and glycosaminoglycan polysulfate.
In an effort to determine which injection therapies work best, Dr Robin Christensen from Copenhagen University Hospital, Frederiksberg, Denmark and colleagues conducted a systematic review of 17 randomised controlled trials that evaluated eight different injection therapies in 1 381 patients.
They considered only two outcomes: change in pain intensity and adverse events (including the number of adverse events leading to withdrawal).
Further trials are needed
Glucocorticoid, polidocanol, and glycosaminoglycan polysulfate proved to be no better than placebo in relieving pain of tennis elbow, according to the report online in the American Journal of Sports Medicine.
Botulinum toxin was marginally effective compared with placebo but was associated with significant side effects (transient paresis and weakness). Moreover, all trials of botulinum toxin had high or unclear risk of bias.
Autologous blood, PRP, prolotherapy, and hyaluronic acid were all significantly more effective than placebo, but only prolotherapy was significantly better than placebo after excluding results from trials with high or unclear bias.
Transient pain after injection was common in all the trials, but there were no withdrawals due to adverse events and no serious adverse events.
Overall, only three of the trials (18%) were judged to be low risk of bias.
The researchers conclude, "Our systematic review and network meta-analysis found a paucity of evidence from unbiased trials on which to base treatment recommendations regarding injection therapies for lateral epicondylitis."
"Further high-quality trials are needed and should have an adequate sample size, valid inclusion criteria, including confirmation of the diagnosis with imaging, and valid and reliable patient-relevant outcome measures," they add.
Dr Christensen did not respond to a request for comments.
(Reuters Health, September 2012)
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