I've heard there's a new treatment for chronic tennis elbow. It's called Botulinum injection. What can you tell me about it?

You may know botulinum toxin type A as the more common trade name of Botox. Botox was first made and used in the 1980s for blepharospasm. This is a condition in which the eyelid won't stay open because of a muscle spasm. Botox has also been used to treat neck and arm muscle spasms. More recently it has gained in popularity as a treatment for facial wrinkles.

It has been used on a trial basis for tennis elbow. The injection works as a nerve block. It binds to the nerves that lead to the elbow extensor muscles. By preventing the release of a neurotransmitter called acetylcholine it keeps the muscle from contracting. Botox injection works for three or four months. When used for tennis elbow, this amount of time may give the muscle a chance to heal.

A recent study from England compared Botox injections for chronic tennis elbow to a placebo (saline) injection. All patients had pain and loss of function from tennis elbow for at least six months. They had all had at least one corticosteroid injection and physical therapy without results.

There was no difference between the two groups after three months. Pain levels, quality of life, and grip strength remained the same before and after treatment. Other studies comparing Botox injections to surgery showed Botox to be more effective. More studies are needed before Botox can become a primary treatment for tennis elbow.