My chiropractor told me I have a half-inch leg length difference that could explain why I have so much back pain. He suggested I put an insole inside my shoe to make up the difference. Is there a certain kind of insole that works better than others for this problem?

There have been many studies done looking at the effects of insoles for leg length differences. Both custom-made and off-the-shelf types have been examined. Different materials have also been compared.

Clinical experience of chiropractors, physical therapists, and orthopedic surgeons suggest that insoles or shoe lifts to correct a significant leg length difference can make a difference. But studies on this topic have been full of problems.

First, defining significant leg length discrepancy has been a problem. Is one-quarter of an inch difference enough to cause problems and/or require treatment? One-half an inch? A full inch or more? Does having a leg-length difference really contribute to back pain?

Second, there are many different designs of insoles (both custom and noncustom varieties). But studies comparing each type have not been done. Other variables such as age and gender might make a difference. There is some evidence that older adults tend to have worse results with insoles compared to younger patients.

The fact that so many people experience back pain every year has motivated scientists to take a closer look at ways this could be prevented and/or managed. So far, there is strong evidence that insoles don't prevent back pain.

More trials are needed to come to any conclusions about the use of insoles to treat back pain. Whether or not there's one single insole that's the best or if certain insoles work better for some problems than others remains an unanswered question. For now, patients find they are on a trial-and-error basis in finding what works for them.