Effectiveness of extracorporeal shock wave therapy in the treatment of previously untreated lateral epicondylitis: a randomized controlled trial.

BACKGROUND: Extracorporeal shock wave therapy is a relatively new therapy used in the treatment of chronic tendon-related pain. Few randomized controlled trials have been performed on it, and no studies have examined the effectiveness of extracorporeal shock wave therapy as a frontline therapy for tendon-related pain.

HYPOTHESIS: Subjects treated with active extracorporeal shock wave therapy will have higher rates of treatment success than subjects treated with sham extracorporeal shock wave therapy.

DESIGN: Double-blind randomized controlled trial.

METHODS: Sixty subjects who had previously untreated lateral epicondylitis for less than 1 year and more than 3 weeks were included in this study. Subjects were randomly allocated to receive 1 session per week for 3 weeks of either sham or active extra-corporeal shock wave therapy. Subjects in the active therapy group received 2000 pulses (energy flux density, 0.03-0.17 mJ/mm(2)). All subjects were provided with a forearm-stretching program. After 8 weeks of therapy, subjects were classified as either treatment successes or treatment failures according to fulfillment of all 3 criteria: (1) at least a 50% reduction in the overall pain visual analog scale score, (2) a maximum allowable overall pain visual analog scale score of 4.0 cm, and (3) no use of pain medication for elbow pain for 2 weeks before the 8 week follow-up. Visual analog scale scores were also collected for pain at rest, during sleep, during activity, at its worst, and at its least, as well as for quality of life (using the EuroQoL questionnaire) and grip strength.

RESULTS: Success rates in the sham and active therapy groups were 31% and 39%, respectively. No significant difference was detected between groups (chi(2)(1)= 0.3880, P = .533). Mean change in quality of life over 8 weeks was an increase of 1.3 and 3.3 for sham and active therapy groups, respectively, and mean change in grip strength over 8 weeks was an increase of 7.4 kg and 6.8 kg for sham and active therapy groups, respectively.

CONCLUSIONS: Despite improvement in pain scores and pain-free maximum grip strength within groups, there does not appear to be a meaningful difference between treating lateral epicondylitis with extracorporeal shock wave therapy combined with forearm-stretching program and treating with forearm-stretching program alone, with respect to resolving pain within an 8-week period of commencing treatment.