[Natural course of Perthes disease].

The natural history of Perthes' disease can be followed in children with low Catterall rating, absent head-at risk signs and in the age group below 5 years. Thirty-one out of 34 patients who had been followed without active treatment healed with excellent results according to Stulberg's classification. Three unfavorable results were seen in patients who had refused treatment when suggested or who had failed to come in for the follow-up examination for an extensive period of time. Catterall's grading and head-at-risk signs must be watched carefully in order not to overlook cases where active treatment is mandatory. The described concept has been critically monitored and has proven to work with reliable results.