Growth of the acetabular lateral cartilage in relation to congenital and developmental dysplasia of the hip. An histological study.

There are no clear explanations for the spectrum of hip dysplasia nor for the observation that in normal and dysplastic hips, final development may be unpredictable with or without treatment. Immunohistochemical and histological studies of a three month old child's acetabulae were performed. Multiple inclusions were found in the lateral ring epiphysis and in the three flanges of the triradiate cartilage. These inclusions may represent cartilage vessel systems pre-destined to form the secondary centres of ossification. Damage to the primary acetabular growth plates may occur congenitally and help to explain the spectrum of acetabular dysplasia. Damage to one or more of these centres, whether due to instability, displacement or iatrogenic injury, may cause failure of late acetabular development. Hips at risk of damage to the acetabular cartilages should be followed up longer.

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.

An aetiological classification for developmental synostoses at the elbow.

Synostoses at the elbow joint are rare. The literature divides them into three groups based on the nature of bony ankylosis; the commonest are humeroradial synostoses. Approximately 150 cases have been reported. There are 29 reported cases of humeroradioulnar synostosis and five of humeroulnar synostosis. An anatomical classification was previously described for humeroradial synostoses. Due to significant phenotypic variability we believe a classification based solely on anatomical characteristics will in some cases be misleading. No classification exists for humeroradioulnar and humeroulnar synostosis. By re-examining the literature we have produced a combined classification for all elbow synostoses which more accurately predicts causes. Congenital elbow synostoses often cause little functional disability. Treatment by soft tissue release and osteotomy has been attempted, but although range of movement is initially, improved re-ossification is the norm. Investigation is more complicated and may be helped by classification which identifies syndrome association, risk of organ anomaly, and inheritance pattern.