Limb length discrepancy (anisomelia)

The fact is, most people have a small difference in the length or structure of their legs, but when the difference is very small—the average discrepancy is less than 1 cm—it typically goes unnoticed and has no impact on a person’s ability to function. When the discrepancy approaches 1/4 of an inch, however, it can cause lower back pain and other problems.

Walking is basically a constant and controlled shift in the center of gravity, so it is easy to see why a significant difference in the length of one’s legs can cause a problem. Sometimes a difference in leg length is caused by poor alignment of the pelvis, or because of a functional problem or deformity in the hip, knee or ankle. It also can be caused by an injury or disease. For others, one leg is simply a little longer.

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Whatever the case, symptoms include poor posture, uneven gait, and pain in the lower back, hip, ankle or knee. Your doctor can work with you to relieve the pain or improve symmetry of your legs using orthotics or heel lifts.