Late sequelae of Perthe's disease (long-term follow-up of 34 hips).

The long-term results were studied in 31 patients (34 hips) with Perthe's disease. The patients were divided into two groups (above and below 25 years of age) in order to study the time at which the late complications become clinically and radiologically evident. The incidence of painful hip and radiological arthrosis is reported in each group in relation to age and initial grade of the disease. The significant prognostic factors were the initial severity of the disease (Types 1-3), the age at which it appeared, and the shape of the femoral head as assessed by the method of Mose. Treatment had been so varied that it was excluded as a factor in our analysis. The development of painful hip and radiological arthrosis (not always painful) only appeared to a significant extent in patients over the age of 25 at follow-up, and both were directly related to the initial grade of the disease.