Leg Length Discrepancy: What It Is and Why It Can Start Hurting Years Later

Step Rite Shoe Lifts

A leg length discrepancy is a measurable difference in length between your two legs. Small differences are common and often go unnoticed. When the difference is enough to tilt the pelvis and change your walk, the usual correction is a lift on the shorter side, built into the sole of the shoe.

Two kinds of difference

A structural difference means the bones are different lengths, from birth, from a fracture that healed short, or from a joint replacement that lengthened one side. A functional difference means the bones match but a tilted pelvis, a tight hip, or a fused ankle makes one leg act shorter. Both get measured the same way and both can be corrected in the shoe.

Why it can go quiet for years

The body is good at compensating. It tilts the pelvis, shortens one stride, and bends one knee a little, and you walk without thinking about it. Then something uses up the slack: a new job on concrete floors, a walking habit, weight change, surgery, or simply age. The compensations that worked for twenty years start to ache.

Where the pain shows up

One-sided low back pain is the most common. The hip on the longer side works harder to clear the foot. The knee on the longer side stays slightly bent. The Achilles on the shorter side stretches with every step. Any of these on one side only is worth a measurement.

Who measures it

A surgeon, physical therapist, chiropractor, or podiatrist measures the difference, sometimes with a standing X-ray, and gives you a number in inches or millimeters. That number goes on the order form and the lab builds to it.

What a lift does

The lift levels the pelvis in the shoe. It is built at the heel and the ball of the foot so the foot keeps its normal pitch, and it goes on any shoe with a sole deep enough to split. "Started back in therapy today and myself and therapist are very pleased with my new shoes," wrote Connie Newsom after her first pair.