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Biomechanics external fixator

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https://www.readbyqxmd.com/read/28822222/biomechanical-comparison-of-a-novel-monocortical-and-two-common-bicortical-external-fixation-systems-regarding-rigidity-and-dynamic-stability
#1
Patrick A Varady, Markus Greinwald, Peter Augat
AIM: To biomechanically compare a monocortical single frame external fixator (Orthofix UNYCO) with two bicortical fixator systems (dual frame: Stryker Hoffmann and single frame: Synthes LEF) with respect to system rigidity and stability under cyclic loading. METHODS: The fixator systems were assessed for axial rigidity under loads which would occur clinically during fixator application and dynamic stability (cyclic fatigue) under loads which would occur in the first week postoperatively...
August 19, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28816898/timing-of-postoperative-mechanical-loading-affects-healing-following-anterior-cruciate-ligament-reconstruction-analysis-in-a-murine-model
#2
Christopher L Camp, Amir Lebaschi, Guang-Ting Cong, Zoe Album, Camila Carballo, Xiang-Hua Deng, Scott A Rodeo
BACKGROUND: Following anterior cruciate ligament (ACL) reconstruction, the mechanical loading of the tissues has a significant impact on tendon-to-bone healing. The purpose of this study was to determine the effect of the timing of the initiation of mechanical loading on healing of a tendon graft in a bone tunnel. METHODS: ACL reconstruction using a flexor tendon autograft was performed in 56 mice randomized to 4 groups with differing times to initiation of postoperative mechanical loading: (1) immediate, (2) 5 days, (3) 10 days, or (4) 21 days following surgery...
August 16, 2017: Journal of Bone and Joint Surgery. American Volume
https://www.readbyqxmd.com/read/28795328/severe-hemorrhagic-shock-leads-to-a-delayed-fracture-healing-and-decreased-bone-callus-strength-in-a-mouse-model
#3
Katrin Bundkirchen, Christian Macke, Janin Reifenrath, Luisa Marilena Schäck, Sandra Noack, Borna Relja, Philipp Naber, Bastian Welke, Michael Fehr, Christian Krettek, Claudia Neunaber
BACKGROUND: Multiple trauma is frequently associated with hemorrhagic shock and fractures of the extremities. Clinically, the rate of impaired fracture healing (delayed healing and nonunion) seems to be increased in patients with multiple injuries compared with patients with isolated fractures. As the underlying pathogenesis remains poorly understood, we aimed to analyze the biomechanical properties during fracture healing in a murine model. QUESTIONS: The aim of this study was to determine whether fracture healing after severe hemorrhagic shock results in (1) delayed bridging as determined by macroscopic and radiographic assessment, (2) altered conditions of callus components as determined by µCT, and (3) decreased maximum bending moment measured by a three-point-bending test compared with ordinary fracture healing...
August 9, 2017: Clinical Orthopaedics and related Research
https://www.readbyqxmd.com/read/28771373/biomechanical-evaluation-of-glenoid-reconstruction-with-an-implant-free-j-bone-graft-for-anterior-glenoid-bone-loss
#4
Leo Pauzenberger, Felix Dyrna, Elifho Obopilwe, Philipp R Heuberer, Robert A Arciero, Werner Anderl, Augustus D Mazzocca
BACKGROUND: The anatomic restoration of glenoid morphology with an implant-free J-shaped iliac crest bone graft offers an alternative to currently widely used glenoid reconstruction techniques. No biomechanical data on the J-bone grafting technique are currently available. PURPOSE: To evaluate (1) glenohumeral contact patterns, (2) graft fixation under cyclic loading, and (3) the initial stabilizing effect of anatomic glenoid reconstruction with the implant-free J-bone grafting technique...
August 1, 2017: American Journal of Sports Medicine
https://www.readbyqxmd.com/read/28747337/comparisons-of-external-fixator-combined-with-limited-internal-fixation-and-open-reduction-and-internal-fixation-for-sanders-type-2-calcaneal-fractures-finite-element-analysis-and-clinical-outcome
#5
M Pan, L Chai, F Xue, L Ding, G Tang, B Lv
OBJECTIVES: The aim of this study was to compare the biomechanical stability and clinical outcome of external fixator combined with limited internal fixation (EFLIF) and open reduction and internal fixation (ORIF) in treating Sanders type 2 calcaneal fractures. METHODS: Two types of fixation systems were selected for finite element analysis and a dual cohort study. Two fixation systems were simulated to fix the fracture in a finite element model. The relative displacement and stress distribution were analysed and compared...
July 2017: Bone & Joint Research
https://www.readbyqxmd.com/read/28715124/chemical-imaging-of-fresh-vascular-smooth-muscle-cell-response-by-epi-detected-stimulated-raman-scattering
#6
Delong Zhang, Wei Chen, Huan Chen, Han-Qing Yu, Ghassan Kassab, Ji-Xin Cheng
An understanding of deformation of cardiovascular tissue under hemodynamic load is crucial for understanding the health and disease of blood vessels. In the present work, an epi-detected stimulated Raman scattering (epi-SRS) imaging platform was designed for in situ functional imaging of vascular smooth muscle cells (VMSCs) in fresh coronary arteries. For the first time, the pressure-induced morphological deformation of fresh VSMCs was imaged with no fixation and in a label free manner. The relation between the loading pressure and the morphological parameters, including angle and length of the VSMCs, were apparent...
July 17, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28689459/biomechanical-comparison-of-supraacetabular-external-fixation-and-anterior-pelvic-bridge-plating
#7
Ali Turgay Çavuşoğlu, Fatma Kübra Erbay, Mehmet Hakan Özsoy, Teyfik Demir
Unstable pelvic ring injuries are complex and risky injuries due to high morbidity and mortality. Although anterior pelvic external fixator is a suitable method for rapid stabilization of an injured pelvic ring, due to some disadvantages such as high complication rate, nerve damage, and difficulties of patient's mobility and comfort, there has recently been increased searching for alternative methods for stabilization of the pelvic ring. Pubic symphysis zone freely moves in pelvic models. This study aims to evaluate the biomechanical stability of anterior pelvic bridge plating and compare it with supraacetabular external fixators in an untreated unstable pelvic fracture model...
July 1, 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/28660106/biomechanical-evaluation-of-unilateral-versus-bilateral-c1-lateral-mass-c2-intralaminar-fixation
#8
Nitin Bhatia, Asheen Rama, Brandon Sievers, Ryan Quigley, Michelle H McGarry, Yu-Po Lee, Thay Q Lee
STUDY DESIGN: Biomechanical, cadaveric study. OBJECTIVES: To compare the relative stiffness of unilateral C1 lateral mass-C2 intralaminar fixation to intact specimens and bilateral C1 lateral mass-C2 intralaminar constructs. METHODS: The biomechanical integrity of a unilateral C1 lateral mass-C2 intralaminar screw construct was compared to intact specimens and bilateral C1 lateral mass-C2 intralaminar screw constructs. Five human cadaveric specimens were used...
May 2017: Global Spine Journal
https://www.readbyqxmd.com/read/28641837/corrigendum-to-metaphyseal-locking-plate-as-an-external-fixator-for-open-tibial-fracture-clinical-outcomes-and-biomechanical-assessment-injury-48-2-2017-501-505
#9
Ching-Hou Ma, Chin-Hsien Wu, Jiun-Ru Jiang, Yuan-Kun Tu, Ting-Sheng Lin
No abstract text is available yet for this article.
June 19, 2017: Injury
https://www.readbyqxmd.com/read/28574414/impaired-fracture-healing-with-high-non-union-rates-remains-irreversible-after-traumatic-brain-injury-in-leptin-deficient-mice
#10
F Graef, R Seemann, A Garbe, K Schmidt-Bleek, K D Schaser, J Keller, G Duda, S Tsitsilonis
Patients with traumatic brain injury (TBI) and long-bone fractures can show increased callus formation. This effect has already been reproduced in wild-type (wt) mice. However, the mechanisms remain poorly understood. Leptin is significantly increased following TBI, while its role in bone healing remains unclear. The aim of this study was to evaluate fracture healing in leptin-deficient ob/ob mice and to measure any possible impact of TBI on callus formation. 138 female, 12 weeks old, ob/ob mice were divided into four groups: Control, fracture, TBI and combined trauma...
June 1, 2017: Journal of Musculoskeletal & Neuronal Interactions
https://www.readbyqxmd.com/read/28566775/orthopedic-surgery-in-cerebral-palsy-instructional-course-lecture
#11
Deepak Sharan
Orthopedic surgery (OS) plays an important role in the management of cerebral palsy (CP). The objectives of OS are to optimize functions and prevent deformity. Newer developments in OS for CP include emphasis on hip surveillance, minimally invasive procedures, use of external fixators instead of plates and screws, better understanding of lever arm dysfunctions (that can only be corrected by bony OS), orthopedic selective spasticity-control surgery, and single-event multilevel lever arm restoration and anti spasticity surgery, which have led to significant improvements in gross motor function and ambulation, especially in spastic quadriplegia, athetosis, and dystonia...
May 2017: Indian Journal of Orthopaedics
https://www.readbyqxmd.com/read/28458187/torsional-stiffness-after-subtalar-arthrodesis-using-second-generation-headless-compression-screws-biomechanical-comparison-of-2-screw-and-3-screw-fixation
#12
Markus Riedl, Richard R Glisson, Takumi Matsumoto, Stefan G Hofstaetter, Mark E Easley
BACKGROUND: Subtalar joint arthrodesis is a common operative treatment for symptomatic subtalar arthrosis. Because excessive relative motion between the talus and calcaneus can delay or prohibit fusion, fixation should be optimized, particularly in patients at risk for subtalar arthrodesis nonunion. Tapered, fully-threaded, variable pitch screws are gaining popularity for this application, but the mechanical properties of joints fixed with these screws have not been characterized completely...
June 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28420623/externalised-locking-compression-plate-as-an-alternative-to-the-unilateral-external-fixator-a-biomechanical-comparative-study-of-axial-and-torsional-stiffness
#13
B F H Ang, J Y Chen, A K S Yew, S K Chua, S M Chou, S L Chia, J S B Koh, T S Howe
OBJECTIVES: External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF)...
April 2017: Bone & Joint Research
https://www.readbyqxmd.com/read/28391395/biomechanical-analysis-of-anterior-ring-fixation-of-the-ramus-in-type-c-pelvis-fractures
#14
S McLachlin, M Lesieur, D Stephen, H Kreder, C Whyne
PURPOSE: This biomechanical study compared the stability of four different ramus fracture fixation methods for Type C pelvic ring injuries in the absence of posterior fixation. METHODS: A 5-mm vertical osteotomy of the mid-superior and inferior pubic ramus was created in 12 synthetic pelvic models. Four surgical constructs were compared: (1) two-pin AIIS external fixation, (2) 3.5-mm reconstruction plating, (3) bicortical, fully threaded 3.5-mm, and (4) 6.5-mm pubic ramus screws...
April 8, 2017: European Journal of Trauma and Emergency Surgery: Official Publication of the European Trauma Society
https://www.readbyqxmd.com/read/28349769/finite-element-analysis-of-implant-supported-prosthesis-with-pontic-and-cantilever-in-the-posterior-maxilla
#15
Victor Eduardo de Souza Batista, Fellippo Ramos Verri, Daniel Augusto de Faria Almeida, Joel Ferreira Santiago Junior, Cleidiel Aparecido Araújo Lemos, Eduardo Piza Pellizzer
The aim of this study was to evaluate the influence of pontic and cantilever designs (mesial and distal) on 3-unit implant-retained prosthesis at maxillary posterior region verifying stress and strain distributions on bone tissue (cortical and trabecular bones) and stress distribution in abutments, implants and fixation screws, under axial and oblique loadings, by 3D finite element analysis. Each model was composed of a bone block presenting right first premolar to the first molar, with three or two external hexagon implants (4...
May 2017: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/28321479/novel-anatomical-reconstruction-of-distal-tibiofibular-ligaments-restores-syndesmotic-biomechanics
#16
Jian Che, Chunbao Li, Zhipeng Gao, Wei Qi, Binping Ji, Yujie Liu, Ming Han Lincoln Liow
PURPOSE: To date, there is a paucity of literature on syndesmotic reconstruction techniques that restore both anatomic stability and physiologic syndesmotic biomechanics. In this cadaveric study, (1) a novel syndesmotic reconstruction surgical technique using autogenous peroneus brevis tendon was described and (2) the biomechanical properties of the reconstruction was investigated. METHODS: Ten fresh-frozen lower extremities were used in this study. Reconstruction of the anterior and posterior, as well as the interosseous tibiofibular ligaments was performed with a halved peroneus brevis tendon...
June 2017: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
https://www.readbyqxmd.com/read/28299551/comparative-biomechanical-analysis-of-three-implants-used-in-bicondylar-tibial-fractures
#17
Cosmin Ioan Faur, Bogdan Niculescu
BACKGROUND: Currently, the most difficult-to-treat tibial plateau fractures are complex, comminuted fractures, which result from high-energy trauma. The anatomical reconstruction of the articular surface and the preservation of the soft tissue envelope are required for a good functional result. The aim of this study is to perform a biomechanical evaluation of three constructs used in the treatment of bicondylar fractures: the L‑shaped plate, the LCP locking plate, and the hybrid external fixator...
March 15, 2017: Wiener Medizinische Wochenschrift
https://www.readbyqxmd.com/read/28298055/the-effect-of-graft-pretensioning-on-bone-tunnel-diameter-and-bone-formation-after-anterior-cruciate-ligament-reconstruction-in-a-rat-model-evaluation-with-micro-computed-tomography
#18
Jian-Chun Zong, Richard Ma, Hongsheng Wang, Guang-Ting Cong, Amir Lebaschi, Xiang-Hua Deng, Scott A Rodeo
BACKGROUND: Moderate graft pretensioning in anterior cruciate ligament (ACL) reconstruction is paramount to restore knee stability and normalize knee kinematics. However, little is known about the effect of graft pretensioning on graft-to-bone healing after ACL reconstruction. HYPOTHESIS: Moderate graft pretensioning will improve bone formation within the bone tunnel after ACL reconstruction, resulting in superior load to failure. STUDY DESIGN: Controlled laboratory study...
May 2017: American Journal of Sports Medicine
https://www.readbyqxmd.com/read/28270223/biomechanical-characteristics-of-fixation-methods-for-floating-pubic-symphysis
#19
COMPARATIVE STUDY
Wenhao Song, Dongsheng Zhou, Yu He
BACKGROUND: Floating pubic symphysis (FPS) is a relatively rare injury caused by high-energy mechanisms. There are several fixation methods used to treat FPS, including external fixation, subcutaneous fixation, internal fixation, and percutaneous cannulated screw fixation. To choose the appropriate fixation, it is necessary to study the biomechanical performance of these different methods. The goal of this study was to compare the biomechanical characteristics of six methods by finite element analysis...
March 7, 2017: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/28255487/difficulty-in-fixation-of-the-volar-lunate-facet-fragment-in-distal-radius-fracture
#20
Hiroyuki Obata, Tomonori Baba, Kentaro Futamura, Osamu Obayashi, Atsuhiko Mogami, Hideki Tsuji, Yoshiaki Kurata, Kazuo Kaneko
Recent reports suggest the presence of a rare fracture type for which reduction and fixation cannot be achieved with volar locking plate (VLP). In particular, it is difficult to achieve reduction and fixation with volar lunate facet (VLF) fragments present on the volar ulnar aspect of the lunate facet, because of the anatomical structure and biomechanics in this region. Herein, we report two challenging cases of difficulty in fixation of the VLF fragment in distal radius fracture. For this fracture type, it is most important to identify the volar ulnar bone fragment before surgery; it may also be necessary to optimize distal placement of the VLP via a dual-window approach and to apply additional fixations, such as a small plate, anchor, and/or external fixation...
2017: Case Reports in Orthopedics
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