There are generally two kinds of leg length discrepancies. Structural discrepancy occurs when either the thigh (femur) or shin (tibia) bone in one leg is actually shorter than the corresponding bone in the other leg. Functional discrepancy occurs when the leg lengths are equal, but symmetry is altered somewhere above the leg, which in turn disrupts the symmetry of the legs. For example, developmental dislocation of the hip (DDH) can cause a functional discrepancy. In DDH, the top of the leg bone (femur) that is not properly positioned in the hip socket may hang lower than the femur on the other side, giving the appearance and symptoms of a leg length discrepancy.
A patient?s legs may be different lengths for a number of reasons, including a broken leg bone may heal in a shorter position, particularly if the injury was severe. In children, broken bones may grow faster for a few years after they heal, resulting in one longer leg. If the break was near the growth center, slower growth may ensue. Children, especially infants, who have a bone infection during a growth spurt may have a greater discrepancy. Inflammation of joints, such as juvenile arthritis during growth, may cause unequal leg length. Compensation for spinal or pelvic scoliosis. Bone diseases such as Ollier disease, neurofibromatosis, or multiple hereditary exostoses. Congenital differences.
If your child has one leg that is longer than the other, you may notice that he or she bends one leg. Stands on the toes of the shorter leg. Limps. The shorter leg has to be pushed upward, leading to an exaggerated up and down motion during walking. Tires easily. It takes more energy to walk with a discrepancy.
A doctor will generally take a detailed medical history of both the patient and family, including asking about recent injuries or illnesses. He or she will carefully examine the patient, observing how he or she moves and stands. If necessary, an orthopedic surgeon will order X-ray, bone age determinations and computed tomography (CT) scans or magnetic resonance imaging (MRI).
Non Surgical Treatment
The treatment of LLD depends primarily on the diagnosed cause, the age of the patient, and the severity of the discrepancy. Non-operative treatment is usually the first step in management and, in many cases, LLD is mild or is predicted to lessen in the future, based on growth rate estimates in the two legs. In such cases, no treatment may be necessary or can be delayed until a later stage of physical maturity that allows for clearer prognostic approximation. For LLD of 2cm to 2.5cm, treatment may be as simple as insertion of a heel lift or other shoe insert that evens out leg lengths, so to speak. For more severe cases, heel lifts can affect patient comfort when walking, decrease ankle stability, and greatly increase the risk of sprains. For infants with congenital shortening of the limb, a prosthetic ? often a custom-fit splint made of polypropylene ? may be successful in treating more severe LLD without surgery. In many instances, however, a surgical operation is the best treatment for LLD.
leg length discrepancy measurement
Surgery is another option. In some cases the longer extremity can be shortened, but a major shortening may weaken the muscles of the extremity. In growing children, lower extremities can also be equalized by a surgical procedure that stops the growth at one or two sites of the longer extremity, while leaving the remaining growth undisturbed. Your physician can tell you how much equalization can be attained by surgically halting one or more growth centers. The procedure is performed under X-ray control through very small incisions in the knee area. This procedure will not cause an immediate correction in length. Instead, the LLD will gradually decrease as the opposite extremity continues to grow and "catch up." Timing of the procedure is critical; the goal is to attain equal length of the extremities at skeletal maturity, usually in the mid- to late teens. Disadvantages of this option include the possibility of slight over-correction or under-correction of the LLD and the patient?s adult height will be less than if the shorter extremity had been lengthened. Correction of significant LLDs by this method may make a patient?s body look slightly disproportionate because of the shorter legs.