Incidence and characteristics of femoral deformities in the dysplastic hip.

UNLABELLED: Reorientation acetabular osteotomies can correct dysplastic deformities and provide marked improvement in hip function. Deformities of the proximal femur can produce suboptimal articulation or secondary impingement after acetabular reorientation, yet the incidence and characteristics of such deformities have not been well described. To describe the proximal femoral anatomy in patients with symptomatic acetabular dysplasia, we retrospectively analyzed the radiographs of 108 hips treated with periacetabular osteotomy. The radiographic findings were compared with those in 22 control hips. In the dysplastic group, 80 hips were in women and 28 in men, and the average age was 24.8 years. Of the 108 abnormal radiographs, 44% had coxa valga and 4% coxa vara. Seventy-two percent had an aspheric or deformed femoral head and the head-neck offset was insufficient in 75% of the hips. When compared with the control hips, dysplastic hips had differences in parameters of proximal femoral anatomy that we measured. These data demonstrate a high incidence of proximal femoral abnormalities associated with acetabular dysplasia. Identifying and treating these abnormalities may optimize joint congruency and minimize secondary impingement after acetabular reorientation. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.