How To Assess A Leg Length Discrepancy

posted on 28 Apr 2015 12:12 by humorousalmanac6
Overview

Many people undergo surgery for various reasons - arthritis, knee replacement, hip replacement, even back surgery. However, the underlying cause of leg length inequality still remains. So after expensive and painful surgery, follow by time-consuming and painful rehab, the true culprit still remains. Resuming normal activities only continues to place undue stress on the already overloaded side. Sadly so, years down the road more surgeries are recommended for other joints that now endure the excessive forces.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

In addition to the distinctive walk of a person with leg length discrepancy, over time, other deformities may be noted, which help compensate for the condition. Toe walking on the short side to decrease the swaying during gait. The foot will supinate (high arch) on the shorter side. The foot will pronate (flattening of the arch) on the longer side. Excessive pronation leads to hypermobility and instability, resulting in metatarsus primus varus and associated unilateral juvenile hallux valgus (bunion) deformity.

Diagnosis

Limb length discrepancy can be measured by a physician during a physical examination and through X-rays. Usually, the physician measures the level of the hips when the child is standing barefoot. A series of measured wooden blocks may be placed under the short leg until the hips are level. If the physician believes a more precise measurement is needed, he or she may use X-rays. In growing children, a physician may repeat the physical examination and X-rays every six months to a year to see if the limb length discrepancy has increased or remained unchanged. A limb length discrepancy may be detected on a screening examination for curvature of the spine (scoliosis). But limb length discrepancy does not cause scoliosis.

Non Surgical Treatment

Treatment for an LLD depends on the amount of difference and the cause, if known. The doctor will discuss treatment options carefully with you and your child before any decisions are made. It is important to note that treatment is planned with the child?s final height and leg lengths in mind, not the current leg lengths. Treatment is generally not needed if the child?s final LLD is predicted to be 2 centimeters or less at full height. However, the child should return to an orthopaedic doctor by age 10 for re-evaluation. Treatment is often recommended for LLDs predicted to be more than 2 centimeters at full height. If treatment is done, it usually doesn?t begin until the child starts walking. Possible treatment options include, A ?lift? in one shoe to level the child?s hips. This is often the only treatment needed for small discrepancies.

Leg Length

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%).