Leg Shortening Procedures
Resectioning- 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. Surgically removing a segment of the longer bone is done for those patients who are not candidates for lengthening, who do not wish to undergo lengthening, or for those that are skeletally too old for epiphysiodesis (adults). Performing surgery on the "well-leg" is objectionable to some patients, but in experienced hands, shortening the longer bone poses low risk to the limb. This is a much larger operation than growth plate arrest, requiring several days to recover in the hospital, and 4 -6 weeks on crutches. Shortening the femur is safer than shortening the tibia. Femoral shortening is accomplished by a closed shaft resection with intramedullary rod fixation or an open resection with plate fixation.
Epiphysiodesis- Slowing or stopping the growth of the longer leg. Recovery is rapid, with little pain. Crutches are usually not needed. Sports are avoided for 2 -3 months while the drill hole fills in with bone, resulting in stoppage of growth at the growth plate. Growth continues normally elsewhere in the leg, and the legs gradually reach equal length at maturity. The greatest problem with epiphysiodesis is the difficulty in choosing the proper timing of surgery. This procedure is most commonly performed at age 11 or 12 in girls, and at age 13-14 in boys. Epiphysiodesis Procedure: By use of modern fluoroscopic equipment, the surgeon can visualize the growth plate, and by making small incisions and using multiple drilling's, 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 Epiphysiodesis is 5 cm.
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Leg Lengthening Procedure
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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Predicting the Final LLD
There are several ways your doctor can predict the final LLD, and thus the timing of the surgery. The easiest way is the so-called Australian method, popularized by Dr. Malcolm Menelaus, an Australian Orthopedic Surgeon. According to this method, growth in girls is estimated to stop at age 14, and in boys at age 16 years. The femur grows at the rate of 10 mm. a year, and the upper tibia at the rate of 6 mm. a year. Using simple arithmetic, one can get a fairly good prediction of future growth. This of course, is an average, and the patient may be an average. To cut down the risk of this, the doctor usually measures leg length using special X-ray technique (called a Scanogram) on three occasions over at least one year duration to estimate growth per year. He may also do an X-ray of the left hand to estimate the bone age (which in some cases may differ from chronological age) by comparing it with an atlas of bone age. In most cases, however, the bone age and chronological age are quite close.
Another method of predicting final LLD is by using Anderson and Green's remaining growth charts. This is a very cumbersome method, but was till the 1970's, the only method of predicting remaining growth. More recently,
however, a much more convenient method of predicting LLD was discovered by Dr. Colin Moseley from Montreal. His technique of using straight line graphs to plot growth of leg lengths is now the most widely used method of predicting leg length discrepancy.
Whatever method your doctor uses, over a period of one or two years, once he has a good idea of the final LLD, he can then formulate a plan to equalize leg lengths. Epiphysiodesis is usually done in the last 2 to 3 years of growth, giving a maximum correction of about 5 cm. Leg lengthening can be done at any age, and can give corrections of 5 to10 cm., or more. In some cases, both procedures may be necessary to equalize leg length successfully.
(Source: www.orthoseek.com) and (www.limblength.com)
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