Orthopedic Clinics of North America RSS feed: Current Issue. Orthopedic Clinics of North America updates you on the latest trends in patient management; keeps you up to date on the newest advances; and provides a sound basis for choosing treatment options. Each issue focuses on a single topic in orthopedics and is presented under the direction of an experienced guest editor. http://www.orthopedic.theclinics.com/?rss=yesElsevier Inc.en © 2012 Published by Elsevier Inc. All rights reserved. Orthopedic Clinics of North America0030-5898432April 2012 © 2012 Published by Elsevier Inc. All rights reserved. healthpermissions@elsevier.comhttp://www.orthopedic.theclinics.com/article/PIIS003058981200017X/abstract?rss=yesContributors10.1016/S0030-5898(12)00017-XOrthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8iiiivhttp://www.orthopedic.theclinics.com/article/PIIS0030589812000181/abstract?rss=yesContents10.1016/S0030-5898(12)00018-1Orthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8vviihttp://www.orthopedic.theclinics.com/article/PIIS0030589812000193/abstract?rss=yesForthcoming Issues10.1016/S0030-5898(12)00019-3Orthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8viiiviiihttp://www.orthopedic.theclinics.com/article/PIIS0030589812000120/abstract?rss=yesThe April 2012 issue of the Orthopedic Clinics of North America focuses on the various aspects of cartilage in the pediatric knee. Articular cartilage is a dynamic, robust, and complex tissue that intrigues as well as perplexes many who are interested in this field. The knee is one of the joints most commonly injured during sport-related activities in children. Articular cartilage in children is a highly organized structure with an extracellular matrix containing varying concentrations of macro- and micromolecules, which repeatedly undergo resorption and formation while maintaining the shape of the joint throughout growth. Injury to any part of this complex system can disrupt the functional properties of cartilage, which may lead to further joint degeneration. Although articular cartilage has intrinsic capacity for repair and regeneration, the organized structure of immature cartilage is particularly difficult to restore or duplicate once it is damaged or lost. The purpose of this issue is to gain a basic understanding of articular cartilage biology in children in terms of normal structure and function during the various stages of development and growth, and to integrate that knowledge with the clinical aspects of diagnosis and treatment of diseased or injured cartilage.PrefaceHarpal K. Gahunia10.1016/j.ocl.2012.03.002Orthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8ixxhttp://www.orthopedic.theclinics.com/article/PIIS0030589812000041/abstract?rss=yesIn this article, development of articular cartilage and endochondral ossification is reviewed, from the perspective of both morphologic aspects of histogenesis and molecular biology, particularly with respect to key signaling molecules and extracellular matrix components most active in cartilage development. The current understanding of the roles of transforming growth factor β and associated signaling molecules, bone morphogenic proteins, and molecules of the Wnt-β catenin system in chondrogenesis are described. Articular cartilage development is a highly conserved complex biological process that is dynamic and robust in nature, which proceeds well without incident or failure in all joints of most young growing individuals.Articular Cartilage Development: A Molecular PerspectiveFacundo Las Heras, Harpal K. Gahunia, Kenneth P.H. Pritzker10.1016/j.ocl.2012.01.003Orthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8155171http://www.orthopedic.theclinics.com/article/PIIS0030589812000065/abstract?rss=yesThe size and shape of joints markedly affect their biomechanical properties, but the macroscopic 3-dimensional (3-D) mechanism and extent of cartilage and joint maturation during normal growth are largely unknown. This study qualitatively illustrates the development of the bone-cartilage interface in the knee during postnatal growth in humans and C57BL/6 wild-type mice, quantitatively defines the 3-D shape using statistical shape modeling, and assesses growth strain rates in the mouse distal femur. Accurate quantification of the cartilage-bone interface geometry is imperative for furthering the understanding of the macroscopic mechanisms of cartilage maturation and overall joint development.Structural and Functional Maturation of Distal Femoral Cartilage and Bone During Postnatal Development and Growth in Humans and MiceElaine F. Chan, Ricky Harjanto, Hiroshi Asahara, Nozomu Inoue, Koichi Masuda, William D. Bugbee, Gary S. Firestein, Harish S. Hosalkar, Martin K. Lotz, Robert L. Sah10.1016/j.ocl.2012.01.005Orthopedic Clinics of North America 43, 2 (2012)2012-02-23Orthopedic Clinics of North America2012-02-23432S0030-5898(11)X0006-8173185http://www.orthopedic.theclinics.com/article/PIIS0030589812000119/abstract?rss=yesThis review primarily focuses on how the macromolecular composition and architecture of articular cartilage and its unique biomechanical properties play a pivotal role in the ability of articular cartilage to withstand mechanical loads several magnitudes higher than the weight of the individual. Current findings on short-term and long-term effects of exercise on human articular cartilage are reviewed, and the importance of appropriate exercises for individuals with normal and diseased or aberrated cartilage is discussed.Effect of Exercise on Articular CartilageHarpal K. Gahunia, Kenneth P.H. Pritzker10.1016/j.ocl.2012.03.001Orthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8187199http://www.orthopedic.theclinics.com/article/PIIS0030589812000028/abstract?rss=yesOsteochondritis dissecans (OCD) is a localized process that affects the subchondral bone and can progress to the overlying articular cartilage. The cause of this lesion remains elusive. With the vague clinical symptoms and signs of OCD, imaging plays a vital role in making the diagnosis and helping with the prognosis of OCD lesions. This article reviews current imaging modalities for the assessment of OCD including conventional radiography, nuclear medicine, computed tomography (CT), CT arthrography, magnetic resonance (MR) and MR arthrography. The role of imaging in evaluating healing of the OCD and articular congruity after surgical and nonsurgical management is discussed.Imaging of Osteochondritis DissecansAiden Moktassi, Charles A. Popkin, Lawrence M. White, M. Lucas Murnaghan10.1016/j.ocl.2012.01.001Orthopedic Clinics of North America 43, 2 (2012)2012-02-23Orthopedic Clinics of North America2012-02-23432S0030-5898(11)X0006-8201211http://www.orthopedic.theclinics.com/article/PIIS0030589812000077/abstract?rss=yesJuvenile idiopathic arthritis is a broad term used to describe a series of chronic arthritis occurring in children younger than 16 years of age. Even though the cause is not fully understood, several clues regarding the pathogenesis have been found. Diagnosis of the different types of juvenile idiopathic arthritis is made clinically, and imaging plays a role in answering specific questions pertaining to disease classification, staging, and outcome of treatment options.Epidemiology, Pathogenesis, and Imaging of Arthritis in ChildrenRicardo Restrepo, Edward Y. Lee10.1016/j.ocl.2012.01.006Orthopedic Clinics of North America 43, 2 (2012)2012-03-16Orthopedic Clinics of North America2012-03-16432S0030-5898(11)X0006-8213225http://www.orthopedic.theclinics.com/article/PIIS0030589812000089/abstract?rss=yesAdolescents are predisposed to osteochondral (OC) injuries in the knee. The medial facet of the patella, the femoral trochlea, and the lateral femoral condyle are the most common sites of injury. Most of these injuries are classically traumatic but noncontact injuries. Surgery is warranted in most cases of OC fracture. Depending on size, condition, and location of the lesion, options include OC fragment reduction and internal fixation or excision and cartilage resurfacing. Understanding of how to diagnose and treat OC fractures will help optimize outcomes.Acute Traumatic and Sports-Related Osteochondral Injury of the Pediatric KneeDennis E. Kramer, J. Lee Pace10.1016/j.ocl.2012.02.001Orthopedic Clinics of North America 43, 2 (2012)2012-03-05Orthopedic Clinics of North America2012-03-05432S0030-5898(11)X0006-8227236http://www.orthopedic.theclinics.com/article/PIIS0030589812000107/abstract?rss=yesOsteochondritis dissecans (OCD) is an increasingly common cause of knee pain and dysfunction among skeletally immature and young adult patients. An ideal treatment strategy with an optimal surgical technique to repair the osteochondral lesions in these patients is still controversial. The goal of this study is to evaluate and report the clinical and MRI findings for the treatment of OCD in the pediatric knee with bone marrow–derived cell transplantation by using a one-step surgical technique.“One Step” Treatment of Juvenile Osteochondritis Dissecans in the Knee: Clinical Results and T2 Mapping CharacterizationFrancesca Vannini, Milva Battaglia, Roberto Buda, Marco Cavallo, Sandro Giannini10.1016/j.ocl.2012.02.003Orthopedic Clinics of North America 43, 2 (2012)2012-03-16Orthopedic Clinics of North America2012-03-16432S0030-5898(11)X0006-8237244http://www.orthopedic.theclinics.com/article/PIIS0030589812000090/abstract?rss=yesThe repair of articular cartilage defects in patients' knees presents a particular challenge to the orthopedic surgeon because cartilage lacks the ability to repair or regenerate itself. Various cartilage repair techniques have not produced a superior or uniform outcome, which has led to a new generation of cartilage repair based on tissue-engineering strategies and the use of biological scaffolds. Clinical advances have been made regarding the regeneration of articular cartilage, and continue to be made toward the achievement of a suitable treatment method for resurfacing osteochondral defects, through cartilage tissue engineering and the use of pluripotent cells seeded on bio-scaffolds.Clinical Relevance of Scaffolds for Cartilage EngineeringThomas F. LaPorta, Alexander Richter, Nicholas A. Sgaglione, Daniel A. Grande10.1016/j.ocl.2012.02.002Orthopedic Clinics of North America 43, 2 (2012)2012-03-09Orthopedic Clinics of North America2012-03-09432S0030-5898(11)X0006-8245254http://www.orthopedic.theclinics.com/article/PIIS003058981200003X/abstract?rss=yesThe treatment of articular cartilage lesions is complicated, but novel tissue engineering approaches seem to improve the outcome. A tissue engineering approach is less invasive and reduces surgical time, periosteal hypertrophy, and morbidity. Cell-based therapies using scaffolds have advantages compared with microfracture techniques, but the efficacy and cost-effectiveness need to be investigated. Second-generation cell-based therapies have lower morbidity and the ease of the technique is not significantly different from that of first-generation autologous chondrocyte implantation techniques. Third-generation cell-based therapies such as the use of tissue engineered scaffolds need to be studied in more detail.Implantation of Orthobiologic, Biodegradable Scaffolds in Osteochondral RepairJames H.P. Hui, Kizher S. Buhary, Ashwin Chowdhary10.1016/j.ocl.2012.01.002Orthopedic Clinics of North America 43, 2 (2012)2012-02-16Orthopedic Clinics of North America2012-02-16432S0030-5898(11)X0006-8255261http://www.orthopedic.theclinics.com/article/PIIS003058981200020X/abstract?rss=yesIndex10.1016/S0030-5898(12)00020-XOrthopedic Clinics of North America 43, 2 (2012)2012-04-01Orthopedic Clinics of North America2012-04-01432S0030-5898(11)X0006-8263267