Ultrasonographic evaluation of hip morphology in osteochondrodysplasias.

The developing hip in children with osteochondrodysplasias has not been well-described because of delayed ossification and limitations of conventional radiologic techniques. Twenty-four children with various osteochondrodysplasias were evaluated by ultrasonography. Variation in the configuration of the acetabulum included a horizontal acetabular roof owing to delayed iliac development and a notched acetabular roof with lateral bone deficiency. All children had thickened acetabular cartilage except for one child with osteogenesis imperfecta. Coxa vara was a common finding. All neonates displayed a very small beta angle (mean, 42 degrees) because the labrum lay more vertically, secondary to deep engagement of the femoral head in the acetabulum. Proximal femoral ossification was delayed in most children, which allows use of ultrasonography at a later age than is possible in the normal pediatric population. Hip ultrasonography in children with skeletal dysplasias can aid in early diagnosis and is useful in assessing hip morphology and development.