How Leg Length Discrepancy Is Measured in Clinics (and What to Ask For)

Step Rite Shoe Lifts

Clinicians measure leg length with a tape between bony landmarks, with blocks under the shorter foot until the pelvis levels, and with a standing X-ray for the most exact figure. Ask for the difference in millimeters or inches and which leg is shorter.

The tape

From the front of the pelvis to the inside of the ankle, both sides. Quick, and good enough to say whether a difference exists.

The blocks

You stand on a flat floor and the clinician slides blocks of known thickness under the shorter foot until your pelvis is level. The stack is the correction. This is the test that most directly answers "how much lift."

The standing X-ray

A scanogram measures the bones themselves. Surgeons order it before deciding on staging or when the difference is large.

What to ask for

Three things: the number, the unit, and the side. "Sixteen millimeters, left" is a complete prescription. Ask too whether they want the full difference corrected now or part of it first.

What happens to the number

It goes on the order form and the lab builds to it. One customer arrived with a 16 mm prescription after two local shops had offered to round it to a half inch. Write the millimeters. We build the millimeters.