Avascular necrosis is an iatrogenic complication of the treatment of congenital dislocation of the hip. In order to assess the incidence of this and other complications, we have reviewed a consecutive series of 211 children treated at some stage with the modified Denis Browne splint used in Adelaide. In 173 children treated with this splint alone for 238 subluxed or dislocated hips which were stable when reduced, six hips (2.5%) developed radiographic avascular necrosis, though there was progressive growth deformity in only one. There was a much higher incidence among cases treated for unstable reduction by tenotomy, plaster spica and then the splint, 20 of 33 hips (60.6%) showing radiographic signs, though only one led to progressive abnormality. Of seven patients treated by adductor tenotomy and the splint no case of avascular necrosis was encountered. In the whole series the incidence of significant long-term growth disturbance in children treated in this splint was 0.7%. The great majority of our cases of avascular necrosis were attributable to manipulation and plaster, not to the subsequent use of a splint.

The term "congenital scoliosis" contributes little to our understanding of aetiology, for "congenital" simply means "to be born with" and is applicable to deformities present at birth whether these are genetically determined or acquired in utero. The presentation of monozygotic twins, one of whom has congenital scoliosis (vertebral anomalies) while the other is normal, provides a rare opportunity to study the cause of this deformity. Three pairs of monozygotic twins, previously unreported, are presented with a review of the previous literature. These cases add weight to the argument that congenital scoliosis may be acquired in utero rather than being genetically determined.