Perthes' disease is a common form of juvenile orthopaedic ailment of generally unknown etiology. In this paper, the patient's status is evaluated. The popular method of hip status evaluation by numerical grading based on the clinician's subjective impression is critically examined before making a comparison between a recently used numerical grading method and a biomechanical gait study method developed by the authors in evaluating the followup status of 10 male Legg-Calve-Perthes' patients, two treated by Salter's innominate osteotomy, two by subtrochanteric varus osteotomy, two by conservative plaster method, one by ischial weight bearing caliper and three having no treatment at all. This comparative study has led to a positive indication about the relatively better reliability of the gait study method because of its objectivity.