The authors have studied the course and the efficacy of the surgical treatment of the hemimelic form of epiphyseal dysplasia in 15 children. Three roentgenologic types of epiphysis lesions have been distinguished. It has been determined that the pathologic changes are mainly localized in the posterior medial departments. In multiple severe lesions hyperfunction of the growth areas followed by their early asymmetric synostosis with the development of secondary deformations and focal disturbances in the ossification of the metaphyses have been observed. The necessity of early surgical treatment allowing to prevent the development of the pathologic changes in the growth areas and deforming arthrosis has been substantiated.