Background: This review is one in a series of reviews of interventions for lateral elbow pain. Lateral elbow pain, or tennis elbow, is a common condition causing pain in the elbow and forearm and lack of strength and function of the elbow and wrist. Shock wave therapy (ESWT) involves the application of single pulsed acoustic wave. Since the 1990's reports of benefit of ESWT in the treatment of tendon disorders have been appearing in the literature. A systematic review published in the German language appeared in 2000 (Boddeker 2000)
Objectives: To determine the effectiveness and safety of ESWT in the treatment of adults with lateral elbow pain.
Search strategy: Comprehensive electronic searches of MEDLINE, CINAHL, EMBASE and SCISEARCH were combined with searches of the Cochrane Clinical Trails Registrar and the Musculoskeletal Review Group's specialist trial database. Identified keywords and authors were searched again in an effort to identify as many trials as possible.
Selection criteria: Two independent reviewers assessed all identified trials against pre-determined inclusion criteria. Randomised and pseudo randomised trials in all languages were evaluated for inclusion in the review provided they described individuals with lateral elbow pain and were comparing the use of ESWT as a treatment strategy.
Data collection and analysis: For continuous variables means and standard deviations were extracted or imputed to allow the analysis of weighted mean difference. Weighted mean difference using a random effects model was selected when outcomes were measured on standard scales. A fixed effects model was used to interpret results and assess heterogeneity. For binary data numbers of events and total population were analysed and interpreted as relative risk.
Main results: Two trials of ESWT versus placebo are included in this review (~~Rompe 1996~~, ~~Haake 2001~~). Both trials included similar study populations consisting of participants with chronic symptoms who had failed other conservative treatment. The frequency of ESWT application and the doses and techniques used were similar in both trials. The first trial demonstrated highly significant differences in favour of ESWT whereas the second trial found no benefits of ESWT over placebo. When the data from the two trials were pooled, the benefits observed in the first trial were no longer statistically significant. The relative risk for treatment failure (defined as Roles-Maudsley score of 4) of ESWT over placebo was 0.40 (95% CI, 0.08 to 1.91) at six weeks and 0.44 (95% CI, 0.09 to 2.17) at one year. After 6 weeks, there was no statistically significant improvement in pain at rest [WMD pain out of 100 = - 11.40 (95% CI, -26.10 to 3.30)], pain with resisted wrist extension [WMD pain out of 100 = -16.20 (95% CI, -47.75 to 15.36)] or pain with resisted middle finger extension [WMD pain out of 100 = -20.51(95% CI, -56.57 to 15.56)]. Results after 12 or 24 weeks were similar.
Reviewer's conclusions: The two trials included in this review yielded conflicting results. Further trials are needed to clarify the value of ESWT for lateral elbow pain.