Hereditary Leg Length Discrepancy

posted on 29 Apr 2015 09:31 by gutierrezlukzqrnegj
Overview

Leg length difference (LLD) is primarily when the hips are not level, causing a limp from side to side. Most practitioners divide LLD into anatomical or functional. Anatomical is when there is a true difference in the length of the tibia/fibula or the femur bone, or both. While functional LLD are either the shortening or lengthening of a limb, secondary to joint contracture or muscle imbalances.Leg Length Discrepancy

Causes

The causes of LLD may be divided into those that shorten a limb versus those that lengthen a limb, or they may be classified as affecting the length versus the rate of growth in a limb. For example, a fracture that heals poorly may shorten a leg slightly, but does not affect its growth rate. Radiation, on the other hand, can affect a leg's long-term ability to expand, but does not acutely affect its length. Causes that shorten the leg are more common than those that lengthen it and include congenital growth deficiencies (seen in hemiatrophy and skeletal dysplasias ), infections that infiltrate the epiphysis (e.g. osteomyelitis ), tumors, fractures that occur through the growth plate or have overriding ends, Legg-Calve-Perthes disease, slipped capital femoral epiphysis (SCFE), and radiation. Lengthening can result from unique conditions, such as hemihypertrophy , in which one or more structures on one side of the body become larger than the other side, vascular malformations or tumors (such as hemangioma ), which cause blood flow on one side to exceed that of the other, Wilm's tumor (of the kidney), septic arthritis, healed fractures, or orthopaedic surgery. Leg length discrepancy may arise from a problem in almost any portion of the femur or tibia. For example, fractures can occur at virtually all levels of the two bones. Fractures or other problems of the fibula do not lead to LLD, as long as the more central, weight-bearing tibia is unaffected. Because many cases of LLD are due to decreased rate of growth, the femoral or tibial epiphyses are commonly affected regions.

Symptoms

Often there are few or no symptoms prior to the age of 25-35. The most common symptom is chronic lower back pain, but also is frequently middle and upper back pain. Same-sided and repeated injury or pain to the hip, knee and/or ankle is also a hallmark of a long-standing untreated LLD. It is not uncommon to have buttock or radiating hip pain that is non-dermatomal (not from a disc) and tends to go away when lying down.

Diagnosis

The most accurate method to identify leg (limb) length inequality (discrepancy) is through radiography. It?s also the best way to differentiate an anatomical from a functional limb length inequality. Radiography, A single exposure of the standing subject, imaging the entire lower extremity. Limitations are an inherent inaccuracy in patients with hip or knee flexion contracture and the technique is subject to a magnification error. Computed Tomography (CT-scan), It has no greater accuracy compared to the standard radiography. The increased cost for CT-scan may not be justified, unless a contracture of the knee or hip has been identified or radiation exposure must be minimized. However, radiography has to be performed by a specialist, takes more time and is costly. It should only be used when accuracy is critical. Therefore two general clinical methods were developed for assessing LLI. Direct methods involve measuring limb length with a tape measure between 2 defined points, in stand. Two common points are the anterior iliac spine and the medial malleolus or the anterior inferior iliac spine and lateral malleolus. Be careful, however, because there is a great deal of criticism and debate surrounds the accuracy of tape measure methods. If you choose for this method, keep following topics and possible errors in mind. Always use the mean of at least 2 or 3 measures. If possible, compare measures between 2 or more clinicians. Iliac asymmetries may mask or accentuate a limb length inequality. Unilateral deviations in the long axis of the lower limb (eg. Genu varum,?) may mask or accentuate a limb length inequality. Asymmetrical position of the umbilicus. Joint contractures. Indirect methods. Palpation of bony landmarks, most commonly the iliac crests or anterior iliac spines, in stand. These methods consist in detecting if bony landmarks are at (horizontal) level or if limb length inequality is present. Palpation and visual estimation of the iliac crest (or SIAS) in combination with the use of blocks or book pages of known thickness under the shorter limb to adjust the level of the iliac crests (or SIAS) appears to be the best (most accurate and precise) clinical method to asses limb inequality. You should keep in mind that asymmetric pelvic rotations in planes other than the frontal plane may be associated with limb length inequality. A review of the literature suggest, therefore, that the greater trochanter major and as many pelvic landmarks should be palpated and compared (left trochanter with right trochanter) when the block correction method is used.

Non Surgical Treatment

The key to treatment of LLD in a child is to predict what the discrepancy is at maturity. If it is predicted to be less than 2 cm., no treatment is needed. Limb length discrepancies of up to 2 or 2.5 cm. can be compensated very well with a lift in the shoe. Beyond 2.5 cm., it becomes increasingly difficult to compensate with a left in the insole. Building up the shoe becomes uncosmetic and cumbersome, and some other way of compensating for the discrepancy becomes necessary. The treatment of LLD is long-term treatment, and involves the physician and patient?s family working together as a team. The family needs to weigh the various options available. If leg lengthening is decided on, the family needs to understand the commitment necessary to see it through. The treatment takes 6 months to a year for completion, and complications can happen. But when it works, the results are gratifying.

LLD Insoles

Surgical Treatment

Bone growth restriction (epiphysiodesis) The objective of this surgical procedure is to slow down growth in the longer leg. During surgery, doctors alter the growth plate of the bone in the longer leg by inserting a small plate or staples. This slows down growth, allowing the shorter leg to catch up over time. Your child may spend a night in the hospital after this procedure or go home the same day. Doctors may place a knee brace on the leg for a few days. It typically takes 2 to 3 months for the leg to heal completely. An alternative approach involves lengthening the shorter bone. We are more likely to recommend this approach if your child is on the short side of the height spectrum.