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Kim H.K.W.,Center for Excellence in Hip Disorders
Journal of the American Academy of Orthopaedic Surgeons | Year: 2010

Legg-Calvé-Perthes disease is an idiopathic hip disorder that produces ischemic necrosis of the growing femoral head. Permanent femoral head deformity is the most significant sequela. Experimental studies indicate that the pathologic repair process, which is marked by an imbalance of bone resorption and formation, contributes to the pathogenesis of femoral head deformity. Important prognostic factors include degree of deformity, age at disease onset, extent of head involvement, head-at-risk signs, and lateral pillar collapse. Treatment should be guided by age at disease onset, current best evidence, and prognostic factors. Patients aged <6 years at onset are best managed nonsurgically, whereas older patients may benefit from surgical treatment. Good surgical results have been reported in 40% to 60% of older patients (>8 years), indicating the need to develop more effective treatments based on the pathobiology of the disease. Copyright 2010 by the American Academy of Orthopaedic Surgeons.

Kim H.K.W.,Center for Excellence in Hip Disorders
Journal of Pediatric Orthopaedics | Year: 2011

Legg-Calve-Perthes disease is a complex pediatric hip disorder with many uncertainties. Various theories on its etiology have been proposed but none have been validated conclusively. Through experimental studies, however, some insight into the pathogenesis of a femoral head deformity after ischemic necrosis has been gained. These studies reveal that mechanical and biological factors contribute to the development of the femoral head deformity. Better understanding of the pathobiology of Legg-Calve-Perthes disease will lead to the development of more effective treatments, which are able to specifically target the pathogenic processes. Copyright © 2011 by Lippincott Williams & Wilkins.

Kamiya N.,Center for Excellence in Hip Disorders | Mishina Y.,University of Michigan
BioFactors | Year: 2011

It is well known that Bone morphogenetic proteins (BMPs) induce bone formation and that some BMPs, including BMP2 and BMP7, are clinically used in orthopedics. Signaling by BMPs plays an important role in a variety of cell-types in bone such as osteoblasts, chondrocytes, and osteoclasts. It is recently reported using an osteoblast-targeted deletion of BMP signaling that BMP signaling in osteoblasts physiologically induces bone resorption by enhancing osteoclastogenesis via the RANKL-OPG pathway and reduces bone mass. In this review, The physiological function of BMP signaling in bone will be focused, and the current outcomes from mouse genetic studies will be discuss. © 2011 International Union of Biochemistry and Molecular Biology, Inc.

Young M.L.,Southwestern Medical Center | Little D.G.,Childrens Hospital at Westmead | Kim H.K.W.,Center for Excellence in Hip Disorders
Clinical Orthopaedics and Related Research | Year: 2012

Background: The rationale for using bisphosphonate (BP) therapy for Legg-Calvé-Perthes disease (LCPD) is the potential to prevent substantial femoral head deformity during the fragmentation phase by inhibiting osteoclastic bone resorption. However, it is unclear whether BP therapy decreases femoral head deformity. Questions/purposes: In this systematic review, we answered the following questions: (1) Does bisphosphonate (BP) therapy decrease femoral head deformity and improve pain and function in LCPD or other juvenile osteonecrotic conditions? And (2) does BP therapy decrease femoral head deformity in experimental studies of juvenile femoral head osteonecrosis? Methods: We searched the literature from 1966 to 2011 for clinical and experimental studies on BP therapy for juvenile femoral head osteonecrosis. Studies specifically addressing clinical and/or radiographic/histologic outcomes pertaining to pain and function and femoral head morphology were analyzed. Results: Three Level IV clinical studies met our inclusion criteria. Only one study initiated BP therapy during the precollapsed stage of osteonecrosis and reported prevention of femoral head deformity in nine of 17 patients. All studies noted subjective improvements of pain and gait in patients treated with intravenous BPs. Of the eight experimental studies reviewed, seven reported reduced femoral head deformity and six found better preservation of trabecular framework in animals treated with BPs. Conclusions: Clinical evidence lacks consistent patient groups and drug protocols to draw definitive conclusions that BP therapy can decrease femoral head deformity in juvenile osteonecrotic conditions. Experimental studies suggest BP therapy protects the infarcted femoral head from deformity, but it lacks bone anabolic effect. Further basic and clinical research are required to determine the potential role of BPs as a medical treatment for LCPD. © 2012 The Association of Bone and Joint Surgeons®.

Kim H.K.W.,Center for Excellence in Hip Disorders | Kim H.K.W.,Southwestern Medical Center | Herring J.A.,Southwestern Medical Center
Orthopedic Clinics of North America | Year: 2011

Since the original reports of Legg-Calvé-Perthes disease (LCPD), much research effort has been undertaken to improve understanding of this idiopathic hip disorder. This article focuses on the current knowledge of the pathophysiology, classifications, and natural history of LCPD. Although the cause of LCPD remains largely unknown, some insight has been gained on its pathophysiology through experimental studies using animal models of ischemic necrosis. The few available clinical studies on the natural history of LCPD suggest that femoral head deformity is well tolerated in short and intermediate terms, but 50% of patients develop disabling arthritis in the sixth decade of life. © 2011 Elsevier Inc.

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