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Edge loading inclination

Jim Pierrepont, Long Yang, Jevan Arulampalam, Catherine Stambouzou, Brad Miles, Qing Li
Edge-loading of a ceramic-on-ceramic total hip replacement can lead to reproducible squeaking and revision. A patient's functional acetabular cup orientation, driven by their pelvic tilt, has been shown to be a significant factor in squeaking during hip flexion. The aim of this study was to investigate the effect of seated pelvic tilt on the contact mechanics at the ceramic bearing surface. A finite element model of a ceramic-on-ceramic total hip replacement was created. The cup was orientated at 40° inclination and 15° anteversion relative to the anterior pelvic plane...
January 1, 2018: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
Michal Szczodry, Giovanni F Solitro, Farid Amirouche, Priyesh Patel
STUDY DESIGN: Comparison, in terms of insertion accuracy and biomechanical performance, between an increased cortical purchase and straightforward pedicle screw trajectory. OBJECTIVE: This study aims to compare a trajectory with increased cortical purchase to the more common straightforward trajectory in terms of strength and insertion accuracy using real-time navigation. SUMMARY OF BACKGROUND DATA: In previous studies, it was suggested that pedicle screw pullout strength is strongly correlated with bone mineral density, and using a more cortical tract allows a greater portion of the denser bone, the cortex, to be in contact with the screw...
January 2018: Spine Deformity
Jason Chow, Simon Pearce, Kuk-Ki Cho, William Walter
The accuracy of cup position in total hip arthroplasty is essential for a satisfactory result as malpositioning increases the risk of complications including dislocation, high wear rate, loosening, squeaking, edge loading, impingement and ultimately failure. We studied 166 patients in a single-surgeon-series of matched cohorts of patients who underwent total hip arthroplasties. Four separate groups were identified comprising of the posterior approach +/- navigation and the direct anterior approach +/- navigation...
July 17, 2017: Curēus
O O'Dwyer Lancaster-Jones, S Williams, L M Jennings, J Thompson, G H Isaac, J Fisher, M Al-Hajjar
The aim of this study was to develop a preclinical in vitro method to predict the occurrence and severity of edge loading condition associated with the dynamic separation of the centres of the head and cup (in the absence of impingement) for variations in surgical positioning of the cup. Specifically, this study investigated the effect of both the variations in the medial-lateral translational mismatch between the centres of the femoral head and acetabular cup and the variations in the cup inclination angles on the occurrence and magnitude of the dynamic separation, the severity of edge loading, and the wear rate of ceramic-on-ceramic hip replacement bearings in a multi-station hip joint simulator during a walking gait cycle...
September 23, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Richard J Napier, Owen Diamond, Chris K J O'Neill, Seamus O'Brien, David E Beverland
INTRODUCTION: Acetabular liner dissociation is a complication exclusive to modular designs. We present a single surgeon series of 8 polyethylene liner dissociations with the Pinnacle Acetabular System (DePuy Orthopaedics) from over 4,750 cases. We also present a review of the literature and data from the UK National Joint Registry (NJR) on dissociation in total hip arthroplasty (THA). METHODS: The Pinnacle Acetabular System has been used exclusively by the senior author since April 2003, and to date 5,882 have been implanted (837 ceramic liners, 4,751 polyethylene liners (1,606 Enduron/3,145 Marathon) and 294 metal liners)...
November 21, 2017: Hip International: the Journal of Clinical and Experimental Research on Hip Pathology and Therapy
Joanna Leng, Mazen Al-Hajjar, Ruth Wilcox, Alison Jones, David Barton, John Fisher
Variation in the surgical positioning of total hip replacement can result in edge loading of the femoral head on the rim of the acetabular cup. Previous work has reported the effect of edge loading on the wear of hip replacement bearings with a fixed level of dynamic biomechanical hip separation. Variations in both rotational and translational surgical positioning of the hip joint replacement combine to influence both the biomechanics and the tribology including the severity of edge loading, the amount of dynamic separation, the force acting on the rim of the cup and the resultant wear and torque acting on the cup...
April 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
Tarak N Nandi, Andreas Herrig, James G Brasseur
Relevant to drivetrain bearing fatigue failures, we analyse non-steady wind turbine responses from interactions between energy-dominant daytime atmospheric turbulence eddies and the rotating blades of a GE 1.5 MW wind turbine using a unique dataset from a GE field experiment and computer simulation. Time-resolved local velocity data were collected at the leading and trailing edges of an instrumented blade together with generator power, revolutions per minute, pitch and yaw. Wind velocity and temperature were measured upwind on a meteorological tower...
April 13, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Michael Hackl, Kilian Wegmann, Stephanie L Kahmann, Nicolai Heinze, Manfred Staat, Wolfram F Neiss, Martin Scaal, Lars P Müller
PURPOSE: Shortening osteotomy of the proximal radius might represent a potential salvage procedure in symptomatic radiocapitellar osteoarthritis, which could decrease radiocapitellar load while preserving the native radial head. In an in-vitro biomechanical investigation, we sought to determine whether shortening osteotomy of the proximal radius (1) decreases the radiocapitellar joint pressure upon axial loading and (2) retains valgus stability of the elbow. In addition, the anatomic configuration of the lesser sigmoid notch was evaluated to assess possible contraindications...
July 2017: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
Allahyar Gerami, Sepideh Dadgar, Vahid Rakhshan, Puya Jannati, Farhad Sobouti
BACKGROUND: Fixed orthodontic retainers have numerous advantages, but it is not known whether they can exert pathological forces on supporting tissues around the splinted teeth. The purpose of this study was to investigate how the inclination of the lower anterior teeth can affect dental displacement and also change the direction of occlusal loads exerted to dental and its supporting tissues. METHODS: Four three-dimensional finite element models of the anterior part of the mandible were designed...
December 2016: Progress in Orthodontics
Xijin Hua, Junyan Li, Zhongmin Jin, John Fisher
The occurrence of edge loading in hip joint replacement has been associated with many factors such as prosthetic design, component malposition and activities of daily living. The present study aimed to quantify the occurrence of edge loading/contact at the articulating surface and to evaluate the effect of cup angles and edge loading on the contact mechanics of a modular metal-on-polyethylene (MoP) total hip replacement (THR) during different daily activities. A three-dimensional finite element model was developed based on a modular MoP bearing system...
June 2016: Medical Engineering & Physics
Willem B Hiddema, Johan F van der Merwe, Werner van der Merwe
BACKGROUND: The success of a total hip arthroplasty relies on optimal acetabular cup placement to ensure mating of the femoral head and acetabular cup throughout all positions of the hip joint. Poor cup placement is associated with dislocation, impingement, microseparation, component loosening, and accelerated wear due to rim loading. This study examined a novel method of using the transverse acetabular ligament (TAL) to guide cup inclination during primary total hip arthroplasty. METHODS: A descriptive study using 16 hips from 9 cadavers...
July 2016: Journal of Arthroplasty
Li Liu, Timo Michael Ecker, Steffen Schumann, Klaus-Arno Siebenrock, Guoyan Zheng
Modern computerized planning tools for periacetabular osteotomy (PAO) use either morphology-based or biomechanics-based methods. The latter relies on estimation of peak contact pressures and contact areas using either patient specific or constant thickness cartilage models. We performed a finite element analysis investigating the optimal reorientation of the acetabulum in PAO surgery based on simulated joint contact pressures and contact areas using patient specific cartilage model. Furthermore we investigated the influences of using patient specific cartilage model or constant thickness cartilage model on the biomechanical simulation results...
2016: PloS One
Hiroaki Suzuki, Yoshiaki Hata, Fumihiko Watanabe
The purpose of this study was to investigate the relationship between implant fracture under cyclic-fatigue loading at different embedding angles, embedding depths, and loading forces. Twenty-four cylinder-type implants 3.3 mm in diameter and 10 mm in length were used. Test specimens were 30 mm(3) resin blocks with one surfaces inclined at angles of either 5°, 10°, 15° and 20° and embedded vertically with implants at depths of either 5 or 10 mm to the these surfaces. A straight abutment was connected to the implant and cut to 5 mm in length, and a hemispherical crown 5 mm in diameter and 7 mm in length was cast with a 12 % gold-silver-palladium alloy and cemented onto the abutment...
September 2016: Odontology
Fei Li, Hejuan Chen, Ken Mao
Stripe wear occurs when the components of hip prostheses move a sufficient distance laterally to contact the edge of the acetabular cup, causing abnormally high contact stresses. In this research, edge loading contact of prosthetic hip is analyzed in the most commonly used material pairs. The contact dimensions and maximal contact pressure are investigated in mutative normal edge loading with 3 different inclination angles (15°, 20°, 25°) and in alterable edge torus radius with edge loading of 2500 N and inclination of 20°...
2015: Acta of Bioengineering and Biomechanics
Mariska Wesseling, Christophe Meyer, Friedl De Groote, Kristoff Corten, Jean-Pierre Simon, Kaat Desloovere, Ilse Jonkers
Following metal-on-metal hip arthroplasty, edge loading (i.e., loading near the edge of a prosthesis cup) can increase wear and lead to early revision. The position and coverage angle of the prosthesis cup influence the risk of edge loading. This study investigates the effect of altered gait patterns, more specific hip, and pelvis kinematics, on the orientation of hip contact force and the consequent risk of antero-superior edge loading using muscle driven simulations of gait. With a cup orientation of 25° anteversion and 50° inclination and a coverage angle of 168°, many gait patterns presented risk of edge loading...
June 2016: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Asheesh Gupta, Sivashankar Chandrasekaran, John M Redmond, Jon E Hammarstedt, T Luke Cramer, Yuan Liu, Benjamin G Domb
BACKGROUND: Hip dysplasia has been shown to be a cause of early arthritis. The decrease in bony coverage has shown increased stress on the acetabular labrum as it shares an increased load. PURPOSE/HYPOTHESIS: The purpose of this study was to divide a cohort of patients by radiographic measures of dysplastic and nondysplastic hips for comparison with regard to labral size at 4 anatomic locations. The hypothesis was that dysplastic hips will have significantly larger labral size compared with nondysplastic hips...
February 2015: Orthopaedic Journal of Sports Medicine
Li-hui Han, Xiao-xia Qiu, Xu-na Xing, Liu-yi Cai
PURPOSE: To provide theoretical reference for maxillary anterior restoration designment in clinics by observing the masticatory stress distribution of the implant-bone interface and the displacement of implant. METHODS: This study built simplified 3 dimensional finite models with different angles, which included partial implant (4.3 mm×11.5 mm), abutment and all ceramic crown (Zirconia) and combined with angle of implant A between the long axis of ideal implant and factual implant (0°, 5°, 10°, 15°, 20°, 25°), as well as angle of abutment B between the long axis of abutment and implant (0°, 5°,10°,15°,20°,25°)...
April 2015: Shanghai Kou Qiang Yi Xue, Shanghai Journal of Stomatology
Herzl Chai
Extracted human molar teeth are indented by hard balls laid at the central fossa, sectioned, and their interior examined for damage. Contact on the fissured enamel coat generally occurs on three distinct spots. The main forms of damage are radial cracks growing from the DEJ to the occlusal surface and median radial and cylindrical cracks growing from a contact spot to the DEJ. For large balls failure by edge chipping near a cusp apex may occur. The median cracks tend to run unstably to the DEJ upon reaching the middle part of the enamel coat...
April 2015: Journal of the Mechanical Behavior of Biomedical Materials
Stephen J Mellon, George Grammatopoulos, Michael S Andersen, Hemant G Pandit, Harinderjit S Gill, David W Murray
Edge-loading in patients with metal-on-metal resurfaced hips can cause high serum metal ion levels, the development of soft-tissue reactions local to the joint called pseudotumours and ultimately, failure of the implant. Primary edge-loading is where contact between the femoral and acetabular components occurs at the edge/rim of the acetabular component whereas impingement of the femoral neck on the acetabular component's edge causes secondary or contrecoup edge-loading. Although the relationship between the orientation of the acetabular component and primary edge-loading has been identified, the contribution of acetabular component orientation to impingement and secondary edge-loading is less clear...
January 21, 2015: Journal of Biomechanics
LaQuawn Loving, Lizeth Herrera, Samik Banerjee, Christopher Heffernan, Jim Nevelos, David C Markel, Michael A Mont
Steep cup abduction angles with adverse joint loading may increase traditional polyethylene bearing wear in total hip arthroplasties. However, there have been few reports evaluating the effect of cup inclination on the wear of dual-mobility devices. In a hip joint simulation, we compared the short-term wear of two-sizes of modular highly cross-linked dual-mobility bearings (28 mm femoral head diameter/42 mm polyethylene insert outer diameter/54 mm acetabular shell diameter; 22.2 mm femoral head diameter/36 mm polyethylene insert outer diameter/48 mm acetabular shell diameter) at 50 and 65° of cup inclination with modular 28 mm femoral head on 54 mm cup diameter metal-on-highly cross-linked polyethylene bearings...
March 2015: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
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