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Real And Apparent Leg Length Discrepancy

July 1, 2017
Overview

Surgical options in leg length discrepancy treatment include procedures to lengthen the shorter leg, or shorten the longer leg. Your child's physician will choose the safest and most effective method based on the aforementioned factors. No matter the surgical procedure performed, physical therapy will be required after surgery in order to stretch muscles and help support the flexibility of the surrounding joints. Surgical shortening is safer than surgical lengthening and has fewer complications. Surgical procedures to shorten one leg include removing part of a bone, called a bone resection. They can also include epiphysiodesis or epiphyseal stapling, where the growth plate in a bone is tethered or stapled. This slows the rate of growth in the surgical leg.Leg Length Discrepancy

Causes

LLDs are very common. Sometimes the cause isn?t known. But the known causes of LLD in children include, injury or infection that slows growth of one leg bone. Injury to the growth plate (a soft part of a long bone that allows the bone to grow). Growth plate injury can slow bone growth in that leg. Fracture to a leg bone that causes overgrowth of the bone as it heals. A congenital (present at birth) problem (one whole side of the child?s body may be larger than the other side). Conditions that affect muscles and nerves, such as polio.

Symptoms

LLD do not have any pain or discomfort directly associated with the difference of one leg over the other leg. However, LLD will place stress on joints throughout the skeletal structure of the body and create discomfort as a byproduct of the LLD. Just as it is normal for your feet to vary slightly in size, a mild difference in leg length is normal, too. A more pronounced LLD, however, can create abnormalities when walking or running and adversely affect healthy balance and posture. Symptoms include a slight limp. Walking can even become stressful, requiring more effort and energy. Sometimes knee pain, hip pain and lower back pain develop. Foot mechanics are also affected causing a variety of complications in the foot, not the least, over pronating, metatarsalgia, bunions, hammer toes, instep pain, posterior tibial tendonitis, and many more.

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

Heel lifts Raise the heel on the shorter leg. It is applied either to the heel of the custom orthotic or to the inside of the shoe under the insole at the heel. Generally if the discrepancy is greater than 3/8 of an inch, the modification is applied externally on the footwear. Custom made orthotics help to provide proper support and alignment to the foot, controlling conditions such as over pronation. Orthopedic Footwear, properly fitted, to which a lift might be applied inside or out.

Leg Length

shoe lifts for uneven legs

Surgical Treatment

Surgical operations to equalize leg lengths include the following. Shortening the longer leg. This is usually done if growth is already complete, and the patient is tall enough that losing an inch is not a problem. Slowing or stopping the growth of the longer leg. Growth of the lower limbs take place mainly in the epiphyseal plates (growth plates) of the lower femur and upper tibia and fibula. Stapling the growth plates in a child for a few years theoretically will stop growth for the period, and when the staples were removed, growth was supposed to resume. This procedure was quite popular till it was found that the amount of growth retarded was not certain, and when the staples where removed, the bone failed to resume its growth. Hence epiphyseal stapling has now been abandoned for the more reliable Epiphyseodesis. By use of modern fluoroscopic equipment, the surgeon can visualize the growth plate, and by making small incisions and using multiple drillings, the growth plate of the lower femur and/or upper tibia and fibula can be ablated. Since growth is stopped permanently by this procedure, the timing of the operation is crucial. This is probably the most commonly done procedure for correcting leg length discrepancy. But there is one limitation. The maximum amount of discrepancy that can be corrected by Epiphyseodesis is 5 cm. Lengthening the short leg. Various procedures have been done over the years to effect this result. External fixation devices are usually needed to hold the bone that is being lengthened. In the past, the bone to be lengthened was cut, and using the external fixation device, the leg was stretched out gradually over weeks. A gap in the bone was thus created, and a second operation was needed to place a bone block in the gap for stability and induce healing as a graft. More recently, a new technique called callotasis is being use. The bone to be lengthened is not cut completely, only partially and called a corticotomy. The bone is then distracted over an external device (usually an Ilizarov or Orthofix apparatus) very slowly so that bone healing is proceeding as the lengthening is being done. This avoids the need for a second procedure to insert bone graft. The procedure involved in leg lengthening is complicated, and fraught with risks. Theoretically, there is no limit to how much lengthening one can obtain, although the more ambitious one is, the higher the complication rate.

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