Early assessment of prognosis in Perthes' disease.

A new method or early prognostication of Perthes' disease is presented. It is based entirely on radiological assessment and was developed from a review of 69 radiologic examinations performed during the first year of the disease in 27 patients with unilateral Perthes' disease. A simple mathematical function was constructed with the aid of discriminant analysis of four parameters, viz the metaphyseal width of the femur, the position of the femoral head in relation to the acetabulum, and the acetabular height and breadth.