ABSTRACT
Hip developmental disorders are the most common musculoskeletal disease in newborns in Central Europe. The definition of hip developmental disorder includes both dysplastic and dislocated joints. In a dysplastic joint, shearing forces induce a growing disorder in the acetabulum. If this growing disorder persists, the femoral head first displaces the acetabular cartilage cranially and finally the femoral head dislocates posteriorly into the gluteal fossa - progressively losing contact to the acetabulum. Therefore nowadays there is general support for the concept of a developmental instead of a congenital dislocation of the hip. From the first day of life, the different stages of hip developmental disorder be exactly classified by an ultrasound examination of the infant hip joint according to Graf. Therefore the Graf hip ultrasound examination has been an integral part of the paediatric guidelines in Germany since 1996. All newborns must receive Graf hip ultrasound screening examination, ideally at the age of 4-5 (maximal 8) weeks as part of the U3 screening examination. Newborns with historical or clinical risk factors must receive an ultrasound examination in the first week of life, additionally to the clinical examination of the hip joints of all newborns according to the second screening examination U2. In the case of pathological results, therapy should be initiated according to measured hip type within one week. Dislocated joints need reduction and as soon as the contact between the femoral head and the acetabulum has been restored, the head should be retained securely within the acetabulum. This phase of retention is followed by the maturation phase for dislocated joints, which is also sufficient therapy for dysplastic joints. In order to avoid femoral head necrosis as an early complication or as a new hip developmental disorder in the course of further growth, the femoral head during the retention phase and the maturation phase should be placed deeply into the socket. This can be achieved by retaining hip flexion of 100-110° with simultaneous hip abduction of 50° to a maximum of 60°.
