Changes in the lateral pillar classification in Perthes' disease.

The purpose of this study was to examine the correlation between the changes in the lateral pillar grades and the factors influencing such changes. We reviewed 102 patients with Perthes' disease. Changes were observed in 32 (31%) hips. The percentage of the changes in each treatment group showed significant differences. Patients with extensive involvement showed significantly more changes. There was no difference in the age at the onset. We recommend that treatment methods be used that more effectively relieve the mechanical force on the capital femoral epiphysis for patients with extensive involvement regardless of the age at the onset.