This prospective study of 130 patients treated at 16 study centers in Germany evaluates the treatment of chronic lateral epicondylitis with a botulinum toxin A injection. Sixty-eight patients completed the study that compared botulinum toxin A injection to 62 patients in a placebo group that were administered a NaCl injection. The injections were performed 3 to 4 cm. distal to the tender area of the lateral epicondyle with infiltration of the muscle in this location followed by withholding therapy for 6 weeks and routine evaluations at 2, 6, 12 and 18 weeks post-injection. Overall, the clinical pain score showed significant improvement during the entire follow up period. From 6 weeks onward, the patients' global assessment of their satisfaction compared with that before the injection was significantly better in the botulinum group. There was no significant difference in side affects between the two groups. Strength of middle finger extension was significantly decreased in the botulinum group at 2 weeks and persisted until 14 weeks but improved by 18 weeks. Fist closure between groups.
This study adds to the growing body of literature related to the possible use of botulinum toxin A for the treatment of chronic lateral epicondylitis. Most previous studies have shown some early benefit with the use of botulinum toxin for this condition with few sustained side affects. This study includes the largest series to date but only to 18 months post injection. The presumed mechanism of action is that of reversible paralysis of the extensor muscles by temporarily blocking the nerve muscular end plate preventing repetitive micro trauma of the tendinous fibers at the origin from the lateral epicondyle. Future studies with more long-term outcome would be beneficial to understand the long-term benefits.
Lateral, Epicondylitis, Tennis, Elbow, Botulinum, Toxin, Injections