Leg length differences and back pain.

It’s actually the norm for people to have slight differences in the lengths of their legs, with only around 10% of people having perfectly equal limbs.  As for the other 90%, the majority will have a 1 cm or less difference. 

When I trained, we were taught that people can usually cope with  leg length differences of around 1-2 cm without causing major problems. However, recent research has shown that even differences of as little as 5 mm can lead to more problems with your hips and knees, and that differences of 10 mm or more are regarded as clinically significant. 

Importantly, leg length differences can alter the biomechanics of the body, affecting how we walk, and how forces are distributed up our spines. This in turn can then lead to  back and neck pain, extra curves in the spine (scoliosis), and increased degeneration of intervertebral discs and spinal joints (arthritis).

The problem caused by leg length differences is actually pretty easy to understand, and can be seen in the two figures below. The second figure is an X-ray of someone who had one leg 2 cm longer than the other.

If you think of the sacrum (tailbone) as being the base of the spine - this base should ideally be even. Having different leg lengths can create an uneven pelvis that in turn affects the orientation of the sacrum, tipping the bottom of the spinal column slightly in one direction. As we generally don't like walking around tipped over to the side, the body will correct for this slight bend by bending further up, producing an unnatural curve (scoliosis) further up the back.

There are two causes of leg length discrepancy - structural and functional. A structural discrepancy means that there is a measured difference in the length of the bones of the leg, or a fixed difference in the structures of the hip, knee, or ankle joints. You may have just been born with this, or it may have been caused by an injury or illness. A functional difference is where one leg just appears to be longer as it is wrongly-positioned due to an imbalance in muscles, tendons, and ligaments.

So if you have a leg length discrepancy, what can you do about it? 

If you have a leg length difference and aren't really experiencing any issues, then congratulations you have a strong  and adaptable body that is able to compensate for the problem, and you don’t really need to do anything! However, in my experience, as people  grow older, their bodies become less adaptable, and they are less able to compensate for problems such as leg length differences.  These people are ideal candidates for treatment with osteopathy.

I like to look at addressing both the leg length discrepancy itself, and also the knock-on effects it has generated in the body - the main ones being back, neck and sacroiliac pain. For functional leg length differences, in my experience, it’s often possible to eliminate or reduce the difference through targeted work on key muscles and joints. For structural (fixed) differences, in addition to working on the body, small pads (‘lifts’) can be used in the shoe of the shorter leg to even the lengths up. 

If you have a problem that you think may be related to a leg length discrepancy, please contact me by phone or email, or better still book an appointment for a full assessment. 

If you are looking for an East Grinstead Osteopath please get in touch with:

Cliff Russell, Registered Osteopath

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