We describe a little-known variety of hip dysplasia, termed ‘acetabular retroversion’, in which the alignment of the mouth of the acetabulum does not face the normal anterolateral direction, but inclines more posterolaterally.

The condition may be part of a complex dysplasia or a single entity. Other than its retroversion, the acetabulum is sited normally on the side wall of the pelvis, and its articular surface is of normal extent and configuration. The retroverted orientation may give rise to problems of impingement between the femoral neck and anterior acetabular edge.

We define the clinical and radiological parameters and discuss pathological changes which may occur in the untreated condition. A technique of management is proposed.

The results are reported of 44 consecutive Chiari innominate osteotomies performed on 39 adult patients aged between 18 and 55 years for symptoms arising from disproportion between the acetabulum and the femoral head. Predisposing causes included congenital dysplasia of the acetabulum, congenital subluxation of the hip, and Perthes' disease. Follow-up averaged 5 years 2 months. Four pre-operative categories of dysplasia and degeneration were recognised. The analysis of the results from each category made possible the recognition of clinical and radiological features likely to provide a satisfactory result. Of 32 cases now considered to have been selected appropriately, 29 (90%) achieved a significant and apparently lasting improvement. In the other 12 cases there were 9 failures--an unacceptable proportion. The features predisposing to these poor results are discussed. The operation is not difficult. It is safe, and is less demanding than the complex alternative "double", "triple" and "dial" osteotomies. In successful cases there is reduction in symptoms and in limp, and improvement of radiological appearances beginning six months after surgery and progressing to a maximum recovery two to three years later.

In this study of fractures of the shaft of the tibia and femur in children, the growth rate of these long bones after injury was assessed by serial radiographical measurements of bone length, accurate to the nearest millimetre. Within three months of injury the rate of growth was at its maximum and was 38 per cent in excess of normal. The rate then decreased but remained significantly raised for two years and returned to normal in the tibia approximately 40 months after injury and in the femur between 50 and 60 months. The uninjured tibia in the same limb as a fractured femur also underwent an acceleration of growth, but to a lesser degree. An uninjured femur was not so affected by an injured tibia. The growth rate in these limbs was unaffected by the age or sex of the child, or the site or direction of the fracture. These findings may be of clinical use in the timing of corrective treatment where a leg length discrepancy exists as a result of injury to, or malunion of, a long bone in the lower limb of a child.