Leg-Length Discrepencies

Congenital discrepancy: Some children are born with one leg longer than the other. In some each leg is  normal except for the fact that its length does not match the other. In others, one particular part of the leg is underdeveloped or absent. In such cases the leg length discrepancy is only part of the problem.  

Acquired discrepancy: Other children are completely normal at birth but some event during their lives damages a growth plate, slowing its growth, and results in a leg length discrepancy that increases as long as the child grows.

Treatment
The type of treatment required to resolve the discrepancy depends on its predicted magnitude at maturity. The rough guidelines are:

Discrepancy Treatment

< 2 cm. No treatment required
2-5 cm. Femoral shortening or epiphysiodesis
5-18 cm. Lengthening, perhaps multiple
> 18 cm. Prosthetic fitting

Prediction of discrepancy: Our hospital, using the most sophisticated techniques, analyzes leg length data to determine growth patterns, to predict the discrepancy at maturity, and to determine the timing of epiphysiodesis.

Epiphysiodesis: This surgical procedure arrests the growth of one or more of the growth plates of the leg. This, if done at exactly the correct time, allows the short leg to catch up and reach equality just at maturity. It is the simplest and least risky of all treatments but requires precise timing to avoid under or overcorrection.

Femoral shortening: A part of the femur is resected and internal fixation used to stabilize the femoral segments. It is used if there is not enough growth remaining to allow epiphysiodesis to be effective.

Leg Lengthening: Bones can be transected and then lengthened slowly by means of an external device. Although the most intuitively obvious treatment choice, lengthening is always the last choice because of the very high morbidity and the high risk of complications. This process can take up to a year and is extremely difficult for children and their parents. They require a high level of expert support with available doctors, physical therapists, nurses, and social workers who are familiar with the demands of lengthening.