Children of many ages can have legs of unequal lengths. The medical diagnosis for this condition is called leg length discrepancy. The difference in length can be as small as one centimeter and as large as six centimeters or more. The greater the discrepancy, the more your child will have difficulty walking and maintaining proper posture. Significant differences in leg length can also cause functional scoliosis and problems with other parts of the legs and lower body. This makes leg length discrepancy treatment very important in order to maintain proper health and function of the child. The greater the difference in leg length, the higher the likelihood of necessary treatment.
There are many causes of leg length discrepancy. Some include, A broken leg bone may lead to a leg length discrepancy if it heals in a shortened position. This is more likely if the bone was broken in many pieces. It also is more likely if skin and muscle tissue around the bone were severely injured and exposed, as in an open fracture. Broken bones in children sometimes grow faster for several years after healing, causing the injured bone to become longer. A break in a child's bone through the growth center near the end of the bone may cause slower growth, resulting in a shorter leg. Bone infections that occur in children while they are growing may cause a significant leg length discrepancy. This is especially true if the infection happens in infancy. Inflammation of joints during growth may cause unequal leg length. One example is juvenile arthritis. Bone diseases may cause leg length discrepancy, as well. Examples are, Neurofibromatosis, Multiple hereditary exostoses, Ollier disease. Other causes include inflammation (arthritis) and neurologic conditions. Sometimes the cause of leg length discrepancy is unknown, particularly in cases involving underdevelopment of the inner or outer side of the leg, or partial overgrowth of one side of the body. These conditions are usually present at birth, but the leg length difference may be too small to be detected. As the child grows, the leg length discrepancy increases and becomes more noticeable. In underdevelopment, one of the two bones between the knee and the ankle is abnormally short. There also may be related foot or knee problems. Hemihypertrophy (one side too big) or hemiatrophy (one side too small) are rare leg length discrepancy conditions. In these conditions, the arm and leg on one side of the body are either longer or shorter than the arm and leg on the other side of the body. There may also be a difference between the two sides of the face. Sometimes no cause can be found. This is known as an "idiopathic" difference.
The symptoms of limb deformity can range from a mild difference in the appearance of a leg or arm to major loss of function of the use of an extremity. For instance, you may notice that your child has a significant limp. If there is deformity in the extremity, the patient may develop arthritis as he or she gets older, especially if the lower extremities are involved. Patients often present due to the appearance of the extremity (it looks different from the other side).
The doctor carefully examines the child. He or she checks to be sure the legs are actually different lengths. This is because problems with the hip (such as a loose joint) or back (scoliosis) can make the child appear to have one shorter leg, even though the legs are the same length. An X-ray of the child?s legs is taken. During the X-ray, a long ruler is put in the image so an accurate measurement of each leg bone can be taken. If an underlying cause of the discrepancy is suspected, tests are done to rule it out.
Non Surgical Treatment
Heel lifts Raise the heel on the shorter leg. It is applied either to the heel of the custom orthotic or to the inside of the shoe under the insole at the heel. Generally if the discrepancy is greater than 3/8 of an inch, the modification is applied externally on the footwear. Custom made orthotics help to provide proper support and alignment to the foot, controlling conditions such as over pronation. Orthopedic Footwear, properly fitted, to which a lift might be applied inside or out.
Shortening techniques can be used after skeletal maturity to achieve leg length equality. Shortening can be done in the proximal femur using a blade plate or hip screw, in the mid-diaphysis of the femur using a closed intramedullary (IM) technique, or in the tibia. Shortening is an accurate technique and involves a much shorter convalescence than lengthening techniques. Quadriceps weakness may occur with femoral shortenings, especially if a mid-diaphyseal shortening of greater than 10% is done. If the femoral shortening is done proximally, no significant weakness should result. Tibial shortening can be done, but there may be a residual bulkiness to the leg, and risks of nonunion and compartment syndrome are higher. If a tibial shortening is done, shortening over an IM nail and prophylactic compartment release are recommended. We limit the use of shortenings to 4 to 5 cm leg length inequality in patients who are skeletally mature.