Femoral anteversion in Perthes' disease with observations on irritable hips. Application of a new method using ultrasound.

A new ultrasound method was used to measure femoral anteversion (torsion) of both hips in children with unilateral Perthes' disease, children with previous irritable hips, and healthy children of a similar age. In children with Perthes' disease, the mean femoral anteversion of affected hips is significantly higher compared with normal controls. In the opposite hips, femoral anteversion for right and left hips separately is not significantly different from that of controls. The affected hips show a significantly greater scatter of anteversion than do normal hips, which could be secondary to the disease; but the opposite hips also show a significantly wider scatter of anteversion than do normal hips, which suggests a developmental abnormality of femoral torsion in the femur of the unaffected limb. In children with Perthes' disease, femoral anteversion asymmetry is characteristic, marked, and significantly different from that of normal hips, with the affected hips usually being the more anteverted (with two exceptions). Irritable hips show significantly greater femoral anteversion asymmetry than do normal hips, with the affected femur usually being less anteverted than the opposite femur. These observations may have relevance in Perthes' disease with respect to both etiology, femoral osteotomy, and prognosis.