Fifty hips in forty-four children with Legg-Calve-Perthes disease,
treated at the Shriners Hospital for Crippled Children, San Francisco, were
evaluated with a simplified method of Catterall's classification. Our data
indicate that the Catterall rating changed in 40 per cent of the hips when
they were classified before they had reached the fragmentation stage of
Waldenstrom compared with only 6 per cent when they were classified after
fragmentation had occurred.