The purpose of this study is to determine whether Botulinum A toxin is effective in the treatment of tennis elbow (lateral epicondylitis).

Tennis elbow (lateral epicondylitis) is a common cause of chronic elbow pain and wrist extensor dysfunction in adults, affecting 1% to 3% of the general population per year.

There is currently no consensus on its optimal treatment with wide-ranging options available. The best available scientific evidence suggests that only topical non-steroidal anti-inflammatory drugs and possibly, oral non-steroidal anti-inflammatory drugs may be useful for short term pain relief, while corticosteroid injections presented both benefits and harms as a short term measure.

Botulinum toxin has been reported in the treatment of lateral epicondylitis with promising results but these studies lack a control group bringing up the question whether recovery was a result of intervention or the natural history of the disease.

Method:

A twin-center, prospective, randomized, double-blind, placebo-controlled trial in which all patients received either a botulinum injection or a placebo saline injection.

Consecutive patients over 18 years old with tennis elbow referred to the outpatient clinic at the investigators' institution will be screened for this study. Eligible patients will be invited to participate in the study.

Inclusion Criteria:

• Patients aged 18 years and up
• Pain at the lateral side of the elbow
• Pain at the lateral epicondyle during resisted dorsiflexion of the wrist with the elbow in full extension
• Pain for longer than 3 months

Exclusion Criteria:

• Previous operations (including previous steroid injections for the disorder)
• Nerve entrapment
• Pregnancy and while breast-feeding
• Presence of systemic neuromuscular disorders such as myasthenia gravis