The incidence of physiolysis of the hip:A population-based study of 175 patients

Abstract

We studied the epidemiology of physiolysis of the hip (or slipped capital femoral epiphysis) between 1946 and 1992 in 175 patients from a well-defined population. The incidence of physiolysis of the hip was calculated using the attack rate method, i.e., the sum of the annual incidences in each 1-year group. The risk of developing physiolysis was 1:998 for boys, 1:1756 for girls and 1:1267 for both sexes and did not change significantly during this period. The average age at diagnosis was 13.6 (7–17) years in boys and 12.1 (8–15) years in girls and did not change to a significant degree during this period. The difference in the boy:girl ratio (1.8:1) and in the preponderance of the left hip being affected first (64% for boys and 52% for girls) did not change significantly during this period. No significant monthly variation was found in the onset of symptoms of physiolysis of the hip.