Abstract
Acute Achilles tendon pain is a common clinical entity, particularly in sportsmen and women. Fortunately, the majority of such pain is self limiting. However, there are a significant number of people for whom the pain becomes chronic and debilitating. A recent Cochrane review found that there was no randomised controlled evidence of an effective treatment for chronic Achilles pain. The aim of this study was to test the efficacy of shockwave therapy in a double-blind randomised controlled trial. The study has the approval of Local Research Ethics Committees.
Forty nine patients with Achilles tendon pain for a minimum of 4 months were included in the study. Patients were randomised to either shockwave therapy (n=27) or sham dose control therapy (n=22). Ultrasound was used to focus the shocks onto the affected area of tendon. The treatment group were given 2000 shocks at upto 1500mJ per shock, titrated to the patients pain tolerance. The control (sham) treatment was applied using the same parametres but with bubble-wrap interposition between the shockwave generator and the Achilles, to disperse the shockwaves. Each patient was treated once a month over 3 months. Primary outcome measure was pain on walking indicated on a 100mm visual analogue score (VAS) at 3 months. Secondary outcome measures included clinical and patient centred questionnaire scores. . An intention-to-treat approach was used for the analysis. Where patients had missing pain scores at 3 month follow-up, the last available pain score was carried forward.
The walking pain scores were very similar at baseline between the two groups. In the treatment group the mean (standard deviation) was 55.5mm (30.6) and in the control group 55.6mm (26.5). By 3 months, the pain scores had reduced in both groups to a mean (standard deviation) of 34.5 mm (34.2) and 50.3 mm (36.3). Although lower in the treatment group this difference was not statistically significant at the 5% level (t-test, p = 0.127, 95% C.I. : −4.7 to 36.2). No statistically significant differences were found with respect to any of the other clinical variables.
Two elderly patients in the treatment group sustained spontaneous rupture of the tendon after falls, during the course of the trial.
The results of this trial provided no evidence for the use of shockwave therapy in the treatment of patients with chronic Achilles tendinopathy. However, a treatment effect cannot be ruled out since the 95% confidence interval was wide and included a potential clinically relevant difference. The 2 cases of rupture suggest extreme caution in treating the elderly.
Correspondence should be addressed to Carlos Widgerowitz, Honorary Secretary BORS, Division of Surgery and Oncology, Section of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Tort Centre, Dundee DD1 9SY, Scotland.
