Differences between the lengths of the upper and/or lower legs are called leg length discrepancies (LLD). A leg length difference may simply be a mild variation between the two sides of the body. This is not unusual in the general population. For example, one study reported that 32 percent of 600 military recruits had a 1/5 inch to a 3/5 inch difference between the lengths of their legs. This is a normal variation. Greater differences may need treatment because a significant difference can affect a patient's well-being and quality of life.
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.
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.
Infants, children or adolescents suspected of having a limb-length condition should receive an evaluation at the first sign of difficulty in using their arms or legs. In many cases, signs are subtle and only noticeable in certain situations, such as when buying clothing or playing sports. Proper initial assessments by qualified pediatric orthopedic providers can reduce the likelihood of long-term complications and increase the likelihood that less invasive management will be effective. In most cases, very mild limb length discrepancies require no formal treatment at all.
Non Surgical Treatment
Treatment depends on what limb has the deformity and the amount of deformity present. For example, there may be loss of function of the leg or arm. Cosmetic issues may also be a concern for the patient and their family. If there are problems with the arms, the goal is to improve the appearance and function of the arm. Treatment of leg problems try to correct the deformity that may cause arthritis as the child gets older. If the problem is leg length, where the legs are not "equal," the goal is equalization (making the legs the same length). Treatment may include the use of adaptive devices, prosthesis, orthotics or shoe lifts. If the problem is more severe and not treatable with these methods, then surgery may be necessary.
leg length discrepancy measurement
Surgeries to lengthen a leg are generally only performed when there is a difference in leg length of greater than four centimeters. These types of surgeries can be more difficult and have more complications, such as infections, delayed healing, dislocations, and high blood pressure. In a several step process, bone lengthening surgeries involve cutting a bone in two in order to allow new bone growth to occur. After the bone is cut, a special apparatus is worn with pins that will pull the bone apart at approximately one millimeter per day. This causes osteogenesis, or new bone growth, in between the cut bone segments. A cast or brace may be required for several months after surgery to allow the new bone growth to harden and provide extra support.