Leg Length Discrepancy?

I've seen many patients come to our clinic being told by another health care practitioner they saw previously that they have an "obvious" leg length discrepancy. Meaning one leg is longer than the other. The patients are often worried about their difference in leg length and are usually prescribed orthotics by the doctor, physiotherapist, chiropractor, osteopath, podiatrist etc.

Remember my patient with collapsed arches? She was prescribed two pairs of orthotics and told that if they failed to help her, she will require surgery.

I usually just shrug my shoulders and explain it's not that big a deal usually. Almost everyone will have one leg longer or shorter than the other. It's perfectly normal. Don't believe anyone who tells you that it is abnormal. Nobody is perfectly symmetrical. My right leg is half a centimeter longer than my left. But my left foot is slightly longer than my right.

ASIS to medial malleolus

Some people measure a person's leg length from the umbilicus to the medial malleolus. Here's how I measure a patient's leg length in our clinic if I want to be absolutely sure. From the patient's anterior superior iliac spine (or ASIS) to the medial malleolus.

There are also "short cuts" we use without using measuring tapes if we're rushed for time. Getting the patient to bridge (or lift their buttocks) and straighten the legs. Just tricks of our trade ....

Get the patient to lift their bottom

Compare leg lengths

Many people will have a "temporary" leg length discrepancy due to overworked hamstrings, standing a lot on one leg or having hips that tilt forward.

See the difference?

Here's a more obvious picture, R hip higher

Problems that may arise from a temporary leg length difference are usually increased load to the muscles and joints working to counteract the imbalance.

Most of the pavements we run on are banked such that when it rains, water doesn't accumulate on the pavement. If you consistently run the same route during your daily training, (because of the sloping pavement) it creates a temporary difference in leg length. The "longer" leg is making more contact and taking slightly more load compared to the "shorter" leg.

If the muscles work too hard (when you increase your running distance or speed), they are not used to the new load, then an injury can happen.

In other cases, leg length discrepancies may be due to a structural problem like scoliosis in their spine. However, many patients that I have treated with scoliosis manage to adapt without any real issues. And that's probably a different post.

Now you know. So don't be too worried when your health care practitioner tells you that you have an "obvious" leg length difference.


Reference

Sabharwal S and Kumar A (2008). Methods For Assessing Leg Length Discrepancy. Clin Orthop Relat Res. 466(12): 2910-2922. DOI: 10.1007/s11999-008-0524-9.