If one of your child's legs is longer than the other leg, he or she has a common problem known as leg length discrepancy. A typical difference in leg length can be anywhere from one centimeter, which usually does not cause any problems, to more than six centimeters. The greater the discrepancy, the more your child must compensate his or her normal posture and walking pattern in day to day life, which can lead to a variety of symptoms, such as functional scoliosis, hip, knee and ankle problems.
There are many causes of leg length discrepancy. Structural inequality is due to interference of normal bone growth of the lower extremity, which can occur from trauma or infection in a child. Functional inequality has many causes, including Poliomyelitis or other paralytic deformities can retard bone growth in children. Contracture of the Iliotibial band. Scoliosis or curvature of the spine. Fixed pelvic obliquity. Abduction or flexion contraction of the hip. Flexion contractures or other deformities of the knee. Foot deformities.
As patients develop LLD, they will naturally and even unknowingly attempt to compensate for the difference between their two legs by either bending the longer leg excessively or standing on the toes of the short leg. When walking, they are forced to step down on one side and thrust upwards on the other side, which leads to a gait pattern with an abnormal up and down motion. For many patients, especially adolescents, the appearance of their gait may be more personally troublesome than any symptoms that arise or any true functional deficiency. Over time, standing on one's toes can create a contracture at the ankle, in which the calf muscle becomes abnormally contracted, a condition that can help an LLD patient with walking, but may later require surgical repair. If substantial enough, LLD left untreated can contribute to other serious orthopaedic problems, such as degenerative arthritis, scoliosis, or lower back pain. However, with proper treatment, children with leg length discrepancy generally do quite well, without lingering functional or cosmetic deficiencies.
There are several orthopedic tests that are used, but they are rudimentary and have some degree of error. Even using a tape measure with specific anatomic landmarks has its errors. Most leg length differences can be seen with a well trained eye, but I always recommend what is called a scanagram, or a x-ray bone length study (see picture above). This test will give a precise measurement in millimeters of the length difference.
Non Surgical Treatment
The most common solution to rectify the difference in your leg lengths is to compensate for the short fall in your shortest leg, thereby making both of your legs structurally the same length. Surgery is a drastic option and extremely rare, mainly because the results are not guaranteed aswell as the risks associated with surgery, not to mention the inconvenience of waiting until your broken bones are healed. Instead, orthopediatrician's will almost always advise on the use of "heel lifts for leg length discrepancy". These are a quick, simple and costs effective solution. They sit under your heel, inside your shoe and elevate your shorter leg by the same amount as the discrepancy. Most heel lifts are adjustable and come in a range of sizes. Such lifts can instantly correct a leg length discrepancy and prevent the cause of associate risks.
what happens if one leg is shorter than the other?
Epiphysiodesis is a surgical option designed to slow down the growth of the long leg over a period of months to years. It is only used in growing children. The operation involves a general anaesthetic. Small incisions are made around the knee near the growth plates of the thigh bone and the shin bone. The growth plates are prevented from growing by the use of small screws and plates (?8 - plates?). The screws are buried beneath the skin and are not visible. Stitches are buried beneath the skin and do not need to be removed. The child is normally in hospital for 2-3 days. The child can weight bear immediately and return back to normal activity within a few weeks. Long term follow up is required to monitor the effects of the surgery. The timing of the surgery is based on the amount of growth predicted for the child. Therefore, this procedure can under- and over-correct the difference in leg length. Occasionally the screws have to be removed to allow growth to continue. This procedure can be used on one half of the growth plate to correct deformity in a limb e.g. knock-knees or bow legs. This is known as hemiepiphysiodesis.