About 1 to 3 percent of Americans develop tennis elbow — an overuse injury that causes chronic pain around the outside of the elbow — but the treatments given to many sufferers appear to be ineffective in the long run.

A clinical trial published last week in the Journal of the American Medical Association found that patients who received standard treatments such as a cortisone injection and physical therapy fared no better after one year than those who went untreated, with most recovering completely.