If someone has one leg shorter (or, if you prefer, longer) than the other, this is known as limb length discrepancy or LLD. And it is not rare. More than 50% of people have a difference in the lengths of their legs.

But don’t worry; an LLD is not a condition that automatically requires medical treatment. Sometimes it’s not even a problem; the difference is rarely very big and is usually only a few millimetres.

Cause

An LLD can develop at any stage in life. It can be visible at birth (congenital) or acquired later while growing as a child and/or adolescent, or it can happen as an adult. An LLD can be post-traumatic, resulting from surgery or a severe fracture affecting your thigh bone, tibia, fibula, foot or ankle. It can also be caused by a fracture that has healed badly, an infection, a bone cyst, a bone tumour, and so on.

Our bodies always keep our eyes level on the horizon; from head to toe, every joint at every level (ankle, knee, pelvis, shoulder, etc.) adapts in every body plane to ensure our eyes remain level. This sounds like a good thing, but it can result in problems. For example, it can lead to an antalgic gait, where we walk differently to avoid discomfort, which manifests as a limp.

At that point, it is a good idea to see an expert in Biomechanics who can look at your gait and help you to avoid unnecessary body pain, now and in the future.

When it comes to biomechanics, focusing on your alignment, balance, and posture–both static and dynamic–allows us to measure the risks associated with a leg length discrepancy in terms of direct damages or risks of developing osteoarthritis in the future.

Treatment

When addressing our fantastic human body, the main factors to consider are the structural factors (bones’ lengths and shapes) and the postural factors (positions and adaptations of bones and joints).

You will best address the postural problems with conservative treatments (non-surgical / non-invasive) or radical treatments (ones that aim to cure the disease rather than merely relieve symptoms). But you will only alter the structural factors by getting an orthopaedic surgeon onboard to either lengthen the shorter leg or shorten, the longer one.

This is rarely necessary, but sometimes it is. I cannot recommend enough getting opinions from two different consultants and making sure all conservative solutions have been tried and unsuccessful before going down this route.

Tips

Do not try to address an LLD alone. It is not always the source of your problems, and it takes knowledge and skill to properly diagnose it; addressing it is a tricky task, and, most importantly, the wrong solution will worsen the problem.

Heel lifts and wedges can be added as a conservative treatment, or a pair of orthotics or insoles within or on your shoes can be added straight away. Remember, they will only work when you wear them. This can be enough if you wear shoes a lot but becomes useless if you spend most of your time barefoot.

Keep an eye on your shoes, as they will wear unevenly, increase your asymmetry, affect your biomechanics and aggravate many symptoms.

Remember that it rarely matters whether you have one leg shorter/longer than the other. Up to a certain level of asymmetry or discomfort, we might not even address it with a heel lift or wedge.

What you need to do if you have LLD is to understand why you have it, to notice how it impacts your quality of life, comfort, or performance and most importantly, to find out how to deal with it.

Christophe Champs is an expert in biomechanics and the founder of PODO clinic and workshop.