This year (2010) represents 100 years since the simultaneous publications by Arthur Legg from the United States, Jacque Calve of France, and George Perthes of Germany of the disorder that is now known by the eponym of their names. It is presently recognized that this disorder represents idiopathic avascular necrosis or osteonecrosis of the capital femoral epiphysis. It has been one of the most controversial disorders during the past century. Although significant progress has been made in our understanding of the pathogenesis, natural history, classification, and treatment options, we still have minimal knowledge of the etiology or etiologies of this controversial disorder. At the suggestion of In Ho Choi, MD it was decided to dedicate the premeeting of the 2010 Annual Meeting of the Korean Pediatric Orthopaedic Society to this disorder. This meeting was co-sponsored by the International Federation of Pediatric Orthopaedic Societies. As the Scientific Chairman for International Federation of Pediatric Orthopaedic Societies, I cochaired this meeting with Dr Choi. It was our goal to assemble as many of the world leaders on Legg-Calve-Perthes Disease (LCPD) as possible to present the current status of the various aspects of this disorder (Fig. 1). There were 22 faculty members from 3 continents. This daylong course consisted of 4 sessions covering 23 topics and 1 session for case discussion. This included etiology, pathogenesis, stages and classifications, diagnosis, imaging, natural healing, prognosis, nonoperative treatment, pharmaceutical studies, surgical treatment (transphyseal femoral head drilling, core decompression, proximal femoral varus osteotomy, Salter osteotomy, combined femoral and pelvic osteotomy, and shelf procedures), results of the LCPD Study Group, and treatment of deformed femoral heads including the noncontainable femoral heads (valgus osteotomy), distraction, femoroacetabular impingement, transtrochanteric rotational osteotomy, and femoral head resurfacing. Each lecture was not expected to provide the definitive information but only the present status. Each speaker presented information based on their opinions coupled with intensive review of the literature published between 1910 and 2010. Although we have come a long way with respect to our understanding of LCPD, we still have much to learn regarding this common and controversial disorder. We hope the information from this symposium will be of benefit to you in the management of involved children and adolescents, and perhaps stimulate your interest in participating in future research studies.