Perthes' disease associated with osteogenesis imperfecta.

Primary hip disorders, such as congenital hip dislocation, have rarely been reported in children with osteogenesis impefecta (OI). Protrusio acetabuli and coxa vara secondary to severe osteopenia and recurrent fractures are common. Perthes' disease in association with osteogenesis imperfecta has not been reported previously. Epiphyseal and growth plate changes may occur in the more severe forms of OI. There was no evidence of growth plate disruption or severe osteopenia in our case. Approximately two-thirds of OI patients have a tendency to bleed easily but the association of clotting and bleeding disorders with Perthes' disease has yet to be clarified.