Proximal femoral focal deficiency: a 50-year experience.

The case histories of 91 patients (54 male, 37 female) with proximal femoral focal deficiency identified measurements which allow the physician to predict ultimate growth and pelvo-femoral stability early in the patient's life. For unilateral patients, the classification correlated with percentage of femoral inhibition, acetabular index, shelf index and acetabular dysplasia, enabling prediction to be made within the first two years of life. A constant percentage of femoral inhibition was confirmed in both unilateral and bilateral patients, and the effects of classification and associated anomalies were determined. Bilateral proximal femoral focal deficiency occurred twice as frequently among males, and function at maturity was primarily dependent upon leg-length differential, foot position and associated anomalies, and secondarily upon absolute leg-length and pelvo-femoral stability.