What is a Leg Length Discrepancy?

Podiatrists routinely examine for leg length discrepancy. In this article, podiatrist Joel Bell discusses why it is important.  

PART 1 of 2 – read part two here.

For our updated guide on everything you need to know about leg length differences (limb length discrepancies), see here.

By Joel Bell, Podiatrist, Masterton Foot Clinic

Lately, I have seen a few people with a difference in leg length (a leg length discrepancy) that is causing injuries and pain on one side of the body. A difference in the length of the leg can cause pain at the feet, ankles, knees, hips and spine.

There are several types of limb length discrepancy. They can be intrinsic (within the body) or extrinsic (outside of the body). An example of a limb length difference coming from within the body is a difference in the length of the thigh bone after having a hip operation.  Below is an image of a person with a relatively short femur.

Most roads have a camber which makes one leg have to function as a short limb and the other as a longer limb. You will also see this in track athletes who always run the same way around the track. When running around the bend; the leg closest to the inside has to act as if it is shorter and the outside leg works as if it is longer.

We think of limb length discrepancies as either structural or functional as well. An example of a functional leg length difference would be in someone who has muscles on one side that are weaker than the other. Below is a picture of Trendelenburg sign where the Gluteus medius muscle is weak causing one side of the pelvis to drop lower.

Having a difference in leg length can lead the body to make a whole range of compensations which could lead to pain and deterioration of joints. Next time we’ll talk about how we assess for leg length discrepancies and ways to treat them.