Leg length difference: The simple controversy

Can you guess which leg is longer?

I have been practicing for a while and have met many therapists over the years and an interesting topic that no one seems to be able to agree on is leg length discrepancy. Either they are a strong disciple to using a certain technique to measure the leg length and have a pile of heel lifts that they are giving out to a high percentage of their patients, or they consider it all garbage and do not subscribe to it.

Luckily, I fit into both camps, or so I think. Leg length discrepancies tend to come from two different problems. First is a true leg length difference. This can be measured by taking multiple Xrays of the legs and specifically measure the bone length. It seems that this could be one of the most accurate ways to measure but it is usually nonweight-bearing and other factors such as supinated midfoot and other asymmetries could weigh in on the end product. It is also believed that pelvic obliquity can be a factor, hence why so many pelvises need adjusting frequently. Another method, not widely accepted but possibly the most accurate, in my opinion, is taking a standing X-ray of the pelvis and measuring the femoral head heights. If there is a difference, it is very unlikely it could be coming from anything else other than a leg length discrepancy.

As a therapist, we do not always have that luxury of getting the patient to have Xrays taken. Surface measurements have not been shown to be reliable unless there is a significant difference. So how do I figure out a leg length when I am on the fence if there is truly one present without Xrays.

I use heel lifts as a diagnostic tool. If there is a difference the patient will be able to recognize it when ambulating. I usually do my surface testing and have a strong assumption that one side is going to belong. I ask the patient to put the heel lift in the shoe of the long leg and then ask them to walk. Usually, as a therapist, you will see an increase of vaulting on that side and a harder heel strike. After they walk a bit, I then change it to the side I feel is shorter. I have them walk again. If they can perceive that this side feels much better, then I assume they have a great enough difference that would justify using a heel lift. After they walk for a while with the lift in, I then have them walk again with no lift. There is usually a dislike of walking without the heel lift fairly rapidly. If there is not a significant change or perceived improvement, I do not pursue addressing any possible leg length discrepancy.

Footwear is also a tell-all. Over the years, I have always wondered if I have a leg length problem. I have poorly approached it by trying to self treat and diagnose it. Then one morning it came to me while staring at my sandals. The excessive wear of the left side compared to the right indicates that there is a difference in the impact from one side to the other. This could be from many other causes including habit but it at least lets me know that I am hitting harder on one side than the other. By using a heel lift on the right side you could bring the foot closer to the ground to prevent the excessive impact of the longer left. Hence, I really do not like wearing sandals for extended periods. My left foot will hurt.

These are just some ideas to play with next time you have a patient that you are suspecting may have a leg length problem!

About the author,

Rajesh is a Physical Therapist, who is passionate about health and wellness. He is interested in all aspects of general well being including fitness, nutrition and mindfulness. He continues to learn and grow from the profession he loves.

If this article is helpful to you or you would like to get more information, please do not hesitate to contact me at

0 views0 comments

Recent Posts

See All