True And Apparent Leg Length Discrepancy

Overview

A Leg Length Inequality or Leg Length Discrepancy is exactly as it sounds. One or more bones (the Femur or thigh bone, the Tibia or shin bone, and/or the joint spacing within the knee) are unequal in total length when measured in comparison to the same structures on the opposite side. It is common for people to have one leg longer than the other. In fact, it is more typical to be asymmetrical than it is to be symmetrical.Leg Length Discrepancy

Causes

An anatomical short leg is due to several orthopedic or medical condition mechanisms. Often, one leg simply stops growing before the other one does and is called ?congenital?. We often see mother-daughters or father-sons who exhibit virtually the same degree of shortness on the same side. Often it is not known why this occurs, but it seems to account for approximately 25% of the population demonstrating a true LLD. Other causes of a true LLD include trauma or broken bones, surgical repair, joint replacement, radiation exposure, tumors or Legg-Calves-Perthes disease.

Symptoms

The symptoms of limb deformity can range from a mild difference in the appearance of a leg or arm to major loss of function of the use of an extremity. For instance, you may notice that your child has a significant limp. If there is deformity in the extremity, the patient may develop arthritis as he or she gets older, especially if the lower extremities are involved. Patients often present due to the appearance of the extremity (it looks different from the other side).

Diagnosis

On standing examination one iliac crest may be higher/lower than the other. However a physiotherapist, osteopath or chiropractor will examine the LLD in prone or supine position and measure it, confirming the diagnosis of structural (or functional) LLD. The LLD should be measured using bony fixed points. X-Ray should be taken in a standing position. The osteopath, physiotherapist or chiropractor will look at femoral head & acetabulum, knee joints, ankle joints.

Non Surgical Treatment

Structural leg length discrepancy can be treated with a heel lift in the shorter leg?s shoe, if the leg length is greater than 5 mm. The use and size of the heel lift is determined by a physical therapist based on how much lift is needed to restore proper lumbopelvic biomechanics. In certain cases, surgical intervention may be needed to either shorten or lengthen the limb. An important component to any surgical procedure to correct leg length discrepancies is physical therapy. Physical therapy helps to stretch muscles and maintain joint flexibility, which is essential in the healing process. For a functional leg length discrepancy no heel lift is required, but proper manual therapy techniques and specific therapeutic exercise is needed to treat and normalize pelvic and lower extremity compensations. The number of treatments needed to hold the pelvis in a symmetrical position is different for each patient based on their presentation and biomechanical dysfunctions in their lower back, pelvis, hip, knee, and foot/ankle. If you have pain in your lower back or lower extremity and possibly a length discrepancy; the two symptoms could be related. A good place to start would be a physical therapy evaluation to determine whether you have a leg length discrepancy and if it could be contributing to your lower back pain, hip pain, knee pain, or leg pain.

LLD Insoles

what are shoe lifts?

Surgical Treatment

In growing children, legs can be made equal or nearly equal in length with a relatively simple surgical procedure. This procedure slows down the growth of the longer leg at one or two growth sites. Your physician can tell you how much equalization can be gained by this procedure. 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 limb length discrepancy will gradually decrease as the opposite extremity continues to grow and "catch up." Timing of the procedure is critical. The goal is to reach equal leg length by the time growth normally ends. This is usually in the mid-to-late teenage years. Disadvantages of this option include the possibility of slight over-correction or under-correction of the limb length discrepancy. In addition, the patient's adult height will be less than if the shorter leg had been lengthened. Correction of significant limb length discrepancy by this method may make a patient's body look slightly disproportionate because of the shorter leg. In some cases the longer leg can be shortened, but a major shortening may weaken the muscles of the leg. In the thighbone (femur), a maximum of 3 inches can be shortened. In the shinbone, a maximum of 2 inches can be shortened.