Background: The use of extracorporeal shock wave therapy for the
treatment of lateral epicondylitis is controversial. The purpose of this study
was to evaluate the use of extracorporeal shock wave therapy without local
anesthesia to treat chronic lateral epicondylitis.
Methods: One hundred and fourteen patients with a minimum six-month
history of lateral epicondylitis that was unresponsive to conventional therapy
were randomized into double-blind active treatment and placebo groups. The
protocol consisted of three weekly treatments of either low-dose shock wave
therapy without anesthetic or a sham treatment. Patients had a physical
examination, including provocation testing and dynamometry, at one, four,
eight, and twelve weeks and at six and twelve months after treatment.
Radiographs, laboratory studies, and electrocardiograms were also evaluated
prior to participation and at twelve weeks. A visual analog scale was used to
evaluate pain, and an upper extremity functional scale was used to assess
function. Crossover to active treatment was initiated for nonresponsive
patients who had received the placebo and met the inclusion criteria after
twelve weeks.
Results: A total of 108 of the 114 randomized patients completed all
treatments and the twelve weeks of follow-up required by the protocol.
Sixty-one patients completed one year of follow-up, whereas thirty-four
patients crossed over to receive active treatment. A significant difference (p
= 0.001) in pain reduction was observed at twelve weeks in the intent-to-treat
cohort, with an improvement in the pain score of at least 50% seen in 61%
(thirty-four) of the fifty-six patients in the active treatment group who were
treated according to protocol compared with 29% (seventeen) of the fifty-eight
subjects in the placebo group. This improvement persisted in those followed to
one year. Functional activity scores, activity-specific evaluation, and the
overall impression of the disease state all showed significant improvement as
well (p < 0.05). Crossover patients also showed significant improvement
after twelve weeks of active treatment, with 56% (nineteen of thirty-four)
achieving an improvement in the pain score of at least 50% (p <
0.0001).
Conclusions: These results demonstrate that low-dose shock wave
therapy without anesthetic is a safe and effective treatment for chronic
lateral epicondylitis.
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.