Treatment of Lateral Epicondylitis with Botulinum Toxin

A Randomized, Double-Blind, Placebo-Controlled Trial

6 December 2005 | Volume 143 Issue 11 | Pages 793-797

Background: Lateral epicondylitis is a common condition for which botulinum toxin has been reported to have a therapeutic role in uncontrolled studies.

Objective: To determine if an injection of botulinum toxin is more effective than placebo for reducing pain in adults with lateral epicondylitis.

Design: Randomized, double-blind, placebo-controlled trial conducted from September 2002 to December 2004.

Setting: Outpatient clinics at a university hospital and a district hospital in Hong Kong.

Participants: 60 patients with lateral epicondylitis.

Measurements: The primary outcome was change in subjective pain as measured by a 100-mm visual analogue scale (VAS) ranging from 0 (no pain) to 10 (worst pain ever) at 4 weeks and 12 weeks. All patients completed post-treatment follow-up.

Interventions: A single injection of 60 units of botulinum toxin type A or normal saline placebo.

Results: Mean VAS scores for the botulinum group at baseline and at 4 weeks were 65.5 mm and 25.3 mm, respectively; respective scores for the placebo group were 66.2 mm and 50.5 mm (between-group difference of changes, 24.4 mm [95% CI, 13.0 to 35.8 mm]; P < 0.001). At week 12, mean VAS scores were 23.5 mm for the botulinum group and 43.5 mm for the placebo group (between-group difference of changes, 19.3 mm [CI, 5.6 to 32.9 mm]; P = 0.006). Grip strength was not statistically significantly different between groups at any time. Mild paresis of the fingers occurred in 4 patients in the botulinum group at 4 weeks. One patient's symptoms persisted until week 12, whereas none of the patients receiving placebo had the same complaint. At 4 weeks, 10 patients in the botulinum group and 6 patients in the placebo group experienced weak finger extension on the same side as the injection site.

Limitations: The trial was small, and most participants were women. The blinding protocol may have been ineffective because the 4 participants who experienced paresis of the fingers could have correctly assumed that they received an active treatment.

Conclusions: Botulinum toxin injection may improve pain over a 3-month period in some patients with lateral epicondylitis, but injections may be associated with digit paresis and weakness of finger extension.

Editors' Notes Context Do botulinum toxin injections help or hurt patients with tennis elbow? Contribution Sixty adults with pain from lateral epicondylitis that had persisted for longer than 3 months were randomly assigned to receive a single injection of botulinum toxin or normal saline. Pain scores, which were assessed 4 and 12 weeks later, were significantly lower in the botulinum group than in the group receiving saline injections. Four weeks after the injections were administered, the investigators observed finger extension weakness in 10 patients in the botulinum group versus 6 patients in the saline group. Four of the patients who received the botulinum toxin also experienced digit paresis. Implications We need larger, longer trials to establish the benefits (degree and duration of pain relief) and harms of botulinum injections for tennis elbow. —The Editors

 

Author and Article Information

From North District Hospital, The Chinese University of Hong Kong, and Prince of Wales Hospital, Hong Kong, China.

ClinicalTrials.gov Identifier: NCT00119704

Grant Support: By a donation from New World Development Ltd.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Shiu Man Wong, MB BCh, PacifiCare, 12th Floor, Oterprise Square, 26 Nathan Road, Tsim Sha Tsui, Hong Kong, China; e-mail, jsmwong{at}hkstar.com.

Current Author Addresses: Dr. S.M. Wong: Department of Medicine, North District Hospital, 9 Po Kin Road, Sheung Shui, Hong Kong, China.

Drs. Hui and L.K.S. Wong, Ms. Tong, and Ms. Yu: Division of Neurology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.

Ms. Poon: Department of Occupational Therapy, Prince of Wales Hospital, Shatin, Hong Kong, China.

Author Contributions: Conception and design: S.M. Wong, A.C.F. Hui, L.K.S. Wong.

Analysis and interpretation of the data: S.M. Wong, A.C.F. Hui, L.K.S. Wong.

Drafting of the article: S.M. Wong, A.C.F. Hui.

Critical revision of the article for important intellectual content: S.M. Wong, A.C.F. Hui, L.K.S. Wong.

Final approval of the article: S.M. Wong.

Provision of study materials or patients: S.M. Wong, P.-Y. Tong, D.W.F. Poon.

Statistical expertise: S.M. Wong, P.-Y. Tong, E. Yu.

Obtaining of funding: S.M. Wong.

Administrative, technical, or logistic support: S.M. Wong, P.-Y. Tong, D.W.F. Poon.

Collection and assembly of data: S.M. Wong, P.-Y. Tong, D.W.F. Poon.

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