Slipped capital femoral epiphysis in southern Sweden 1910-1982.

This work is based on 532 cases of physiolysis colli femoris (PCF) in southern Sweden from 1910 through 1982. The material was analyzed epidemiologically. Subsets were used for different investigations aimed at surveying the etiology of PCF, and long-term follow-ups were conducted after various methods of treatment. Finally, the short-term results after hook-pinning, a new device, were evaluated. After radiographic examination of anatomic specimens and normal hips, a method to diagnose and grade PCF was developed. The calcar femoral was found to be of constant shape and position and was used as a landmark to which the position of the femoral head was related. The advantage of this method is that it is easy to use and it is able to determine PCF also after growthplate closure. Epidemiologic analysis of the total material revealed large changes during the 20th century. The disease is more common in males than in females, but the male predominance has decreased from about 90 per cent to about 60 per cent during the period of investigation. Mean age at onset of slipping has decreased by about 3 years in males to 12.7 years and by about 1 year in females to 11.8 years. The incidence has followed a periodic pattern with peaks approximately every 20th year. The mean incidence was 6/10,000 in boys and 3/10,000 in girls. Boys living in the country have always been at higher risk than those living in cities. They were also at higher risk of sustaining bilateral slipping. In girls, there is a seasonal variation, with a higher incidence between May and August. The etiologic investigations dealt with hereditary, mechanical, and hormonal aspects. Radiographic examination revealed PCF in about 10 per cent of the first-degree relatives of 50 consecutive patients with PCF. One third of the families had 2 or more members with PCF. This familial accumulation is much higher than shown in earlier investigations based on questionnaires or clinical reports, and higher than expected from the incidence calculations. The growth analysis using the ICP model showed in both sexes an above average body height before puberty. However, at maturity the heights were almost normal, and accordingly the pubertal gain in height was lower than normal. Both the boys and the girls were markedly overweight before puberty and remained so at maturity. The ICP model accords with what is known about hormonal regulation of growth, and the growth abnormalities indicate a disturbed hormonal growth regulation.(ABSTRACT TRUNCATED AT 400 WORDS)