Leg length discrepancy is the difference in lengths of an individual?s legs. This difference may be anatomical or may be due to scoliosis, trauma/injury, arthritis, overpronation (collapse) of one foot, bowing of one leg or unequal bowing, surgery (hip or knee replacement), pelvic tilting or ageing. The difference can also be functional caused by differing forces of the soft tissues, such as weakness in muscle tissue on one side, or a weakness/tightness in joint tissue. A difference in leg lengths also results when running on indoor banked tracks, beaches and banked streets and side walks (for drainage). Many people have a measurable difference in their leg lengths which is compensated for by their bodies. As we age this compensation does not work as well. An x-ray and physical measurements will define the discrepancy and the adjustment needed.
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.
Patients with significant lower limb length discrepancies may walk with a limp, have the appearance of a curved spine (non-structural scoliosis), and experience back pain or fatigue. In addition, clothes may not fit right.
A systematic and well organized approach should be used in the diagnosis of LLD to ensure all relevant factors are considered and no clues are overlooked which could explain the difference. To determine the asymmetry a patient should be evaluated whilst standing and walking. During the process special care should be used to note the extent of pelvic shift from side to side and deviation along the plane of the front or leading leg as well as the traverse deviation of the back leg and abnormal curvature of the spine. Dynamic gait analysis should be conducted during waling where observation of movement on the sagittal, frontal and transverse planes should be noted. Also observe head, neck and shoulder movements for any tilting.
Non Surgical Treatment
In order to measure for correction, use a series of blocks or sheets of firm material (cork or neoprene) of varying thickness, e.g., 1/8", 1/4", and 1/2". Place them under the short limb, either under the heel or the entire foot, depending on the pathology, until the patient feels most balanced. Usually you will not be able to correct for the full amount of the imbalance at the outset. The longer a patient has had the LLD, the less likely he or she will be able to tolerate a full correction immediately. This is a process of incremental improvements. 2 inch External Platform Lift Bear in mind that the initial lift may need to be augmented as the patient's musculoskeletal system begins to adjust. It is often recommended that the initial buildup should be 50 percent of the total. After a suitable break-in period, one month say, another 25 percent can be added. If warranted, the final 25 percent can be added a month later. Once you determine how much lift the patient can handle, you then need to decide how to best apply it. There are certain advantages and disadvantages to using either internal or external heel lifts.
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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.