Apparent Leg Length Discrepancy Measurement

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Overview

There are many different conditions in childhood and adult life that can lead to deformity of a limb or difference in leg lengths. Treatment for these conditions depends on the condition being treated, the age of the child and the amount of deformity or shortening. Generally, only a final difference of leg length of 2cm or more requires surgical treatment. An outline of treatment options is given below.Leg Length Discrepancy

Causes

From an anatomical stand point, the LLD could have been from hereditary, broken bones, diseases and joint replacements. Functional LLD can be from over pronating, knee deformities, tight calves and hamstrings, weak IT band, curvature in the spine and many other such muscular/skeletal issues.

Symptoms

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.

Diagnosis

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

People with uneven leg lengths may be more prone to pain in their back, hips, and knees; uneven gait; and lower leg and foot problems. Due to its risks, surgery is typically not recommended unless the difference is greater than one inch. In cases where the difference is less than one inch, providing the same support for both feet is the most effective. This can be achieved by getting custom-fitted orthotics for both feet. Orthotics are inserts that you wear in the shoes. Your chiropractor will request to measure your feet and possibly your legs. You can step on a device that will take the measurements or you might have a plaster cast of your feet taken. Orthotics are typically made from plastic and leather, and function biomechanically with your foot. If a leg length discrepancy is not properly corrected with orthotics, your chiropractor may recommend a heel lift, also known as a shoe lift. You simply place it in the back of your shoe along with the orthotic. Typically, you will only wear the heel lift in one shoe to assist the shorter leg.

LLL Shoe Insoles

Surgical Treatment

Lengthening is usually done by corticotomy and gradual distraction. This technique can result in lengthenings of 25% or more, but typically lengthening of 15%, or about 6 cm, is recommended. The limits of lengthening depend on patient tolerance, bony consolidation, maintenance of range of motion, and stability of the joints above and below the lengthened limb. Numerous fixation devices are available, such as the ring fixator with fine wires, monolateral fixator with half pins, or a hybrid frame. The choice of fixation device depends on the desired goal. A monolateral device is easier to apply and better tolerated by the patient. The disadvantages of monolateral fixation devices include the limitation of the degree of angular correction that can concurrently be obtained; the cantilever effect on the pins, which may result in angular deformity, especially when lengthening the femur in large patients; and the difficulty in making adjustments without placing new pins. Monolateral fixators appear to have a similar success rate as circular fixators, especially with more modest lengthenings (20%).
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