If your child has one leg that is longer than the other, he or she has a common problem known as leg length discrepancy.
The greater the discrepancy between the legs, the more problems it can cause. The child will compensate for uneven leg lengths by standing and walking abnormally, and may develop problems in his or her posture, spine, hip, knee and ankle.
The treatment depends on the difference between the legs, the underlying cause and the age of your child. It can occur in adults very rarely, with one cause being a complication of hip or knee surgery, in which LLD is a very small risk.
Symptoms
The symptoms can vary from person to person with some people with a LLD being barely noticeable to others who are blatantly obvious. The main symptom is noticing that one leg is significantly shorter than the other. Other than this:
- Your posture may be affected with one shoulder tilting towards the side of the shorter limb.
- You could have gait problems like limping or unusual rotation of the limb.
- You may notice pain in the back, hip, knee or ankle.
Causes
Some causes of LLD are:
- Injury-After a break in a leg bone sometimes it heals in a shortened position. This is more likely to happen if the bone is broken into many pieces or if it breaks the skin. In kids the growth of bone is faster, so a break may mean it heals and grows longer than it should.
- Infection-You can get an infection of the bone, and if it affects the growth plate (the area where bone growth mainly occurs) the growth can be impaired.
- Congenital (from birth)-Some kids can be born with a LLD. Others can be predisposed to getting it due to bowed legs, malalignment of the hips, postural issues and even neuromuscular conditions like cerebral palsy.
- Tumours-Similar to infection, if the tumour grows into your child’s growth plate it can affect your child’s growth.
Risk Factors
As most cases of LLD occur in children due to congenital factors, there aren’t really any risk factors for this condition other than those you are born with.
Investigations
Your doctor may confirm your diagnosis with the aid of an x-ray. Sometimes in kids, the doctor may order subsequent x-rays at 6 monthly intervals to see if the LLD is resolving or still present.
Complications
The main complication that can arise due to long term LLD is osteoarthritis. This is the degeneration of a joint, including cartilage and bone, which causes pain and stiffness. The main joint that LLD causes osteoarthritis in is the knee.
There is some controversy as to whether LLD causes lower back pain or not, and there are studies which have confirmed this and others which find no correlation between the two.
Treatment
Treatment can be divided into non-surgical or surgical.
Non-surgical
Orthotics that can be slipped into your shoe can be used to treat discrepancies from 2-6 cm. These are relatively cheap and effective and if you find they don’t work you can just remove them.
Surgical
As surgery carries risks, non-surgical options must be excluded first and also your child’s growth rate must be recorded as the discrepancy may correct itself with age. Thus your surgeon/doctor may need to monitor your child’s growth over a couple of years before surgery is considered.
To treat the discrepancy surgically there are either lengthening or shortening procedures. In growing children shortening can be done by slowing the growth of the longer leg so the shorter leg can catch up. Here timing is crucial as bone growth usually ends in the mid to late teenage years. Another option is to resect a piece of the bone from the longer leg. In lengthening procedures usually an external frame is surgically implanted. This is kept in a state of tension and continuously adjusted over a period of time until eventually an acceptable length is reached.
Seeking Advice
Your Family Doctor (GP)
Your Family Doctor will be able to diagnose and help treat your problem. He or she will be able to
- tell you about your problem
- advise you of the best treatment methods
- prescribe you medications
- and if necessary, refer you to Specialists (Consultants) for further treatment
Prevention
There isn’t really any way to prevent a LLD other than good control of the factors which were pre-determined from birth. For example, there is a study which advocates steroid injections into the knees of children suffering from juvenile onset rheumatoid arthritis (JRA). JRA is very rare condition but can cause LLD.
Sherry DD, Stein LD, Reed AM, et al. Prevention of leg length discrepancy in young children with pauciarticular juvenile rheumatoid arthritis by treatment with intraarticular steroids. Arthritis Rheum. 1999;42:2330–2334.
F.A.Q. | Frequently Asked Questions
My child has a fixator to treat his LLD, what do I need to do the lengthening?
You will need an allen wrench for a fixator. The doctor will tell you which parts to tighten, how often, and by how much.Are there any problems once the frame is removed?
There is a chance that the newly healed bone may break once the frame is removed. To avoid this, your child should only put some of their weight on their leg and they have to use crutches for the first six weeks. Your child will continue to have physiotherapy and hydrotherapy during this time to build up their muscles and help get the joint moving again.