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Mechanical axis limbs

Robert D Gregg, Anne E Martin
Recent work has extended the control method of virtual constraints, originally developed for autonomous walking robots, to powered prosthetic legs for lower-limb amputees. Virtual constraints define desired joint patterns as functions of a mechanical phasing variable, which are typically enforced by torque control laws that linearize the output dynamics associated with the virtual constraints. However, the output dynamics of a powered prosthetic leg generally depend on the human interaction forces, which must be measured and canceled by the feedback linearizing control law...
July 2016: Proceedings of the ... American Control Conference
John A Heflin, Scott Ford, Peter Stevens
Blount's disease is commonly attributed to an intrinsic, idiopathic defect in the posteromedial proximal tibial physis resulting in progressive bowing of the leg, intoeing, and lateral knee thrust. Treatment has historically included bracing, physeal stapling, or corrective osteotomy, and was determined primarily by age at presentation. As we feel the pathology is not necessarily age dependent, we have elected to use the technique of guided growth using a lateral tension band plate to correct limb alignment as a first-line treatment in all patients presenting to our clinic as long as they had growth remaining and no evidence of a physeal bar...
October 2016: Medicine (Baltimore)
Adam H Breiteneicher, Bo Norby, Kurt S Schulz, Sharon C Kerwin, Don A Hulse, Derek B Fox, W Brian Saunders
OBJECTIVE: To determine the effect of sliding humeral osteotomy (SHO) on frontal plane thoracic limb alignment in standing and recumbent limb positions. STUDY DESIGN: Canine cadaveric study. SAMPLE POPULATION: Canine thoracic limbs (n=15 limb pairs). METHODS: Limbs acquired from healthy Labrador Retrievers euthanatized for reasons unrelated to this study were mounted in a limb press and aligned in a standing position followed by axial loading at 30% body weight...
October 13, 2016: Veterinary Surgery: VS
Michael P O'Malley, Ayoosh Pareek, Patrick J Reardon, Michael J Stuart, Aaron J Krych
Coronal limb malalignment is a significant contributor to asymmetric joint wear, gait abnormalities, and the development and progression of degenerative joint disease. Osteotomies about the knee were developed to realign the mechanical axis of the limb to unload the affected compartment. Valgus malalignment is less common than varus malalignment, but can contribute to a variety of clinical conditions, including lateral compartment cartilage defects and arthritis, lateral patellofemoral instability, and medial collateral ligament laxity...
August 2016: Arthroscopy Techniques
Ki-Mo Jang, Jong-Hee Lee, Il Youp Cho, Bong-Kyung Park, Seung-Beom Han
BACKGROUND: The purpose of this study was to assess the reliability of pre-, intra operative, and postoperative limb alignment measurements and investigate the correlation between the measurements in biplanar medial opening-wedge high tibial osteotomy. METHODS: This study enrolled 59 knees undergoing biplanar opening-wedge high tibial osteotomy for primary medial osteoarthritis with varus deformity. Preoperative and postoperative standing lower leg radiographs and intraoperative fluoroscopic images were taken...
August 27, 2016: Journal of Arthroplasty
Sebastian Farr, Hamza M Alrabai, Elisabeth Meizer, Rudolf Ganger, Christof Radler
BACKGROUND: Despite the popularity of tension band plating (TBP) current literature lacks clinical data concerning recurrence ("rebound") of frontal plane malalignment. This study investigated the rebound phenomenon after TBP in idiopathic genu varum/valgum deformities. We analyzed factors that may contribute to the development of rebound after removal of TBP. METHODS: Patients who had correction of idiopathic valgus or varus deformities by TBP at the distal femoral and/or proximal tibial growth plate were selected from a prospective consecutive database...
August 29, 2016: Journal of Pediatric Orthopedics
Joon Ho Wang, Jung Min Shin, Hyun Ho Kim, Seung-Hoon Kang, Byung Hoon Lee
PURPOSE: To evaluate the differences in the amount of varus malalignment and valgus (over) correction in relation to three different weight bearing conditions from whole leg AP radiographs (single-limb (SL) stance, double-limb (DL) stance, supine position (S)) before and after high tibial osteotomy (HTO), and to evaluate which alignment parameters affect the changes for patients in three different weight bearing conditions. METHODS: A total of 40 consecutive patients (43 knees) with varus osteoarthritis underwent navigation assisted open wedge HTO...
August 18, 2016: International Orthopaedics
Kyohei Nishida, Tomoyuki Matsumoto, Koji Takayama, Kazunari Ishida, Naoki Nakano, Takehiko Matsushita, Ryosuke Kuroda, Masahiro Kurosaka
PURPOSE: Postoperative neutral limb alignment [femorotibial mechanical axis (FTMA) 180° ± 3°] is generally considered to be one of the prerequisites for successful total knee arthroplasty (TKA). However, the influence of residual malalignment on clinical and functional outcomes after TKA is unknown. Therefore, the purpose of this study was to investigate the relationship between postoperative limb alignment and clinical outcomes in Asian patients who underwent primary TKA. METHODS: The study included 220 knees with a mean age of 73...
August 9, 2016: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
Jagannath Kamath, Raja Shekar Danda, Nikil Jayasheelan, Rohit Singh
INTRODUCTION: Various methods of measuring mechanical axis deviation of lower limb have been described including radiographic and CT scanogram, intraoperative fluoroscopy with the use of an electrocautery cord. These methods determine the mechanical axis in a supine, non-weight bearing position. Although long cassette standing radiographic view is used for the purpose but is not available at most centres. A dynamic method of determining the mechanical axis in a weight bearing position was devised in this study...
June 2016: Journal of Clinical and Diagnostic Research: JCDR
Tsan-Wen Huang, Po-Yao Chuang, Chien-Yin Lee, Shih-Jie Lin, Kuo-Chin Huang, Shih-Hsun Shen, Yao-Hung Tsai, Mel S Lee, Robert Wen-Wei Hsu
BACKGROUND: Proper limb and component alignments as well as soft tissue balance are vital for the longevity and optimal long-term outcomes of total knee arthroplasty (TKA). This procedure is technically demanding in patients with Ranawat type-II valgus arthritic knees with marked coronal femoral bowing. Computer-assisted surgery (CAS) and intra-articular bone resection with TKA are the treatments of choice for patients with ipsilateral extra-articular deformity. In theory, both CAS and intra-articular bone resection are beneficial in Ranawat type-II valgus arthritic knees with marked coronal femoral bowing deformity, but the literature on this topic is sparse...
2016: Journal of Orthopaedic Surgery and Research
Michael J Neil, Jereme B Atupan, Juan Paulo L Panti, Robert A J Massera, Stewart Howard
BACKGROUND: For patients with knee osteoarthritis, even slight anatomical variations in the femur or the tibia could affect total limb alignment during total knee replacement (TKR). Our hypothesis implies that the femoral valgus correction angle (VCA) in patients indicated for TKR, is variable and higher than the reported norm of 6° utilized in most intramedullary instrumentation systems, and that tibial bowing may result to a disparity of the tibial mechanical axis to the anatomical axis...
December 2016: Journal of Orthopaedics
Benjamin V Herman, J Robert Giffin
High tibial osteotomy (HTO) has traditionally been used to treat varus gonarthrosis in younger, active patients. Varus malalignment increases the risk of progression of medial compartment osteoarthritis and an HTO can be performed to realign the mechanical axis of the lower limb towards the lateral compartment, thereby decreasing contact pressures in the medial compartment. Anterior cruciate ligament (ACL) insufficiency may lead to post-traumatic arthritis due to altered joint loading and associated injuries to the menisci and articular cartilage...
September 2016: Journal of Orthopaedics and Traumatology: Official Journal of the Italian Society of Orthopaedics and Traumatology
Thomas Gicquel, Jean Christophe Lambotte, Jean Louis Polard, Mickael Ropars, Denis Huten
PURPOSE: Our purpose was to assess medial unicompartmental knee arthroplasty with navigation alone for the tibial cut and limb alignment. We hypothesised that this technique could be used routinely in practice. METHODS: Outcome measures were tibial cut orientation and residual varus. Six-month post-operative radiographs of 59 knees were assessed. RESULTS: Tibial cut orientation was within 2° of planned in 70.2 and 76.3 % of knees in the coronal and sagittal planes, respectively (49...
June 30, 2016: International Orthopaedics
Lior Koren, Yaniv Keren, Mark Eidelman
BACKGROUND: Taylor Spatial Frame (TSF) is a modern circular external fixator that, using a virtual hinge, is able to correct six axis deformities simultaneously. Despite the growing popularity of this method, few reports exist about its use in children and adolescents. To evaluate the effectiveness of TSF in correcting multiplanar deformities in patients with open physis, we reviewed the results of treatment in children who had at least two planes deformities of lower limbs. METHODS: Over a period of 8 years, we treated 51 patients, 40 boys, 11 girls, with a mean age of 12...
2016: Open Orthopaedics Journal
Paola Koenen, Marco M Schneider, Matthias Fröhlich, Arne Driessen, Bertil Bouillon, Holger Bäthis
Axial alignment is one of the main objectives in total knee arthroplasty (TKA). Computer-assisted surgery (CAS) is more accurate regarding limb alignment reconstruction compared to the conventional technique. The aim of this study was to analyse the precision of the innovative navigation system DASH® by Brainlab and to evaluate the reliability of intraoperatively acquired data. A retrospective analysis of 40 patients was performed, who underwent CAS TKA using the iPod-based navigation system DASH. Pre- and postoperative axial alignment were measured on standardized radiographs by two independent observers...
2016: Advances in Orthopedics
Ioannis Sgouralis, Roger G Evans, Anita T Layton
Renal hypoxia could result from a mismatch in renal oxygen supply and demand, particularly in the renal medulla. Medullary hypoxic damage is believed to give rise to acute kidney injury, which is a prevalent complication of cardiac surgery performed on cardiopulmonary bypass (CPB). To determine the mechanisms that could lead to medullary hypoxia during CPB in the rat kidney, we developed a mathematical model which incorporates (i) autoregulation of renal blood flow and glomerular filtration rate, (ii) detailed oxygen transport and utilization in the renal medulla and (iii) oxygen transport along the ureter...
June 8, 2016: Mathematical Medicine and Biology: a Journal of the IMA
Carlos De la Fuente, Gabriel Carreño, Miguel Soto, Hugo Marambio, Hugo Henríquez
PURPOSE: The purpose of this study was to describe the angle of clinical failure during cyclical mobilization exercises in the Achilles tendon of human cadaveric specimens that were repaired using the Dresden technique and FiberWire(®) No. 2. The secondary aim was to identify the secure limit of mobilization, the type of failure, and the type of apposition. METHODS: The lower limbs of eight males (mean age: 60.3 ± 6.3 years) were repaired with the Dresden technique following complete, percutaneous mid-substance Achilles tendon rupture...
June 2, 2016: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
Erik S Blomain, Dante J Merlino, Amanda M Pattison, Adam E Snook, Scott A Waldman
Obesity has emerged as a principal cause of mortality worldwide, reflecting comorbidities including cancer risk, particularly in colorectum. Although this relationship is established epidemiologically, molecular mechanisms linking colorectal cancer and obesity continue to be refined. Guanylyl cyclase C (GUCY2C), a membrane-bound guanylyl cyclase expressed in intestinal epithelial cells, binds the paracrine hormones guanylin and uroguanylin, inducing cGMP signaling in colorectum and small intestine, respectively...
September 2016: Molecular Pharmacology
Kenichi Mishima, Hiroshi Kitoh, Koji Iwata, Masaki Matsushita, Yoshihiro Nishida, Tadashi Hattori, Naoki Ishiguro
Fibular hemimelia is a rare but the most common congenital long bone deficiency, encompassing a broad range of anomalies from isolated fibular hypoplasia up to substantial femoral and tibial shortening with ankle deformity and foot deficiency. Most cases of fibular hemimelia manifest clinically significant leg length discrepancy (LLD) with time that requires adequate correction by bone lengthening for stable walking. Bone lengthening procedures, especially those for pathological bones, are sometimes associated with severe complications, such as delayed consolidation, fractures, and deformities of the lengthened bones, leading to prolonged healing time and residual LLD at skeletal maturity...
May 2016: Medicine (Baltimore)
Seung-Hun Lee, Eun-Kyoo Song, Jong-Keun Seon, Young-Jun Seol, Jatin Prakash, Won-Gyun Lee
Patient-specific instrumentation (PSI) was developed to improve the accuracy of component positioning through custom cutting blocks constructed based on preoperative 3-dimensional imaging in total knee arthroplasty (TKA). The purpose of this study was to compare the clinical and radiological outcomes between the patients who underwent PSI-assisted TKA or conventional TKA. Sixty-four patients (64 knees) underwent TKA by a single surgeon: 32 patients (32 knees) underwent TKA with PSI, 32 patients (32 knees) underwent TKA with conventional instrumentation...
May 2016: Orthopedics
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