scholarly journals A Parametric Analysis of Femoral Stem Impaction

2021 ◽  
Author(s):  
Nicholas E Bishop ◽  
Phil Wright ◽  
Martin Preutenborbeck
Keyword(s):  
Simple Model ◽  
Parametric Analysis ◽  
Soft Tissues ◽  
Femoral Stem ◽  
Stress Waves ◽  
Energy Component ◽  
Material Stiffness ◽  
Component Design ◽  
Basic Understanding ◽  
Mass Increase

Abstract BackgroundPress-fitted implants are implanted by impaction to ensure adequate seating, but without overloading the components, the surgeon, or the patient. To understand this interrelationship a uniaxial discretised model of the hammer/introducer/implant/bone/soft-tissues was developed. A parametric analysis of applied energy, component materials and geometry, and interaction between implant-bone and bone-soft-tissue was performed, with implant seating and component stresses as outcome variables. ResultsTo reduce stresses without compromising seating, the following outcomes were observed: Less energy per hit with more hits / Increase hammer mass / Decrease introducer mass / Increase implant-bone resistance (eg stem roughness). Material stiffness and patient mechanics were found to be less important.ConclusionsThis simple model provides a basic understanding of how stress waves travel through the impacted system, and an understanding of their relevance to component design.

scholarly journals Massive Pseudotumor in a 28mm Ceramic-Polyethylene Revision THA: A Case Report

2014 ◽  
Vol 4 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Edward McPherson, M.D., FACS ◽  
Matthew Dipane, BA ◽  
Sherif Sherif, MD
Keyword(s):  
Soft Tissues ◽  
Polyethylene Wear ◽  
Femoral Stem ◽  
High Rate ◽  
Zirconia Ceramic ◽  
Porous Coating ◽  
Metal Debris ◽  
Ultrafine Metal Particles ◽  
Revision Tha ◽  
Therapeutic Study

This report reviews the findings of a massive pseudotumor detected pre-operatively in a 13-year-old revision total hip arthroplasty. The case is unique in that the bearing involved was a 28mm zirconia ceramic head on a polyethylene liner. We propose that the pseudotumor arose from ultrafine titanium particles liberated from the proximal porous coating of the femoral stem. We suspect that the osteolysis produced from polyethylene wear exposed the proximal porous coating and, via a process of mechanical abrasion with the surrounding soft tissues, liberated ultrafine titanium particles. We believe the pseudotumor formed because the patient was pre-sensitized to metal debris based upon a pre-operative lymphocyte T-cell proliferation test (LTT). Based upon this unique case, we feel that pseudotumors more likely form when there is a high rate of ultrafine metal particles generated in a pre-sensitized patient. Finally, we introduce what we believe are the main biologic wear responses in THA. Further research is needed to validate this proposed model.Keywords: pseudotumor, ceramic, polyethylene, osteolysis, THA, bearing wear eesponse, titanium debrisLevel of Evidence:  AAOS Therapeutic Study Level IV

Simple model for the parametric analysis of grid amplifiers

2009 ◽  
Vol 3 (5) ◽  
pp. 877
Author(s):  
I. Russo ◽  
L. Boccia ◽  
G. Amendola ◽  
G. Di Massa ◽  
P.S. Hall
Keyword(s):  
Simple Model ◽  
Parametric Analysis ◽  
Grid Amplifiers

scholarly journals Short term analysis of total hip replacement done with constrained acetabular component - functional and radiological outcome

2022 ◽  
Author(s):  
Pravin K. Vanchi ◽  
Raghav Ravi Veeraraghavan ◽  
Saravanan Vasudevan ◽  
Mohan Kumar Murugesan
Keyword(s):  
Aseptic Loosening ◽  
Femoral Stem ◽  
Implant Design ◽  
Harris Hip Score ◽  
Age Group ◽  
Gradual Improvement ◽  
Total Hip ◽  
Component Design ◽  
Number Of Patients ◽  
One Year

<p class="abstract"><strong>Background:</strong> Dislocation remains at the forefront of complications after primary total hip arthroplasty (THA). In our study, we talk about the use of constrained liners and its outcomes in an unstable hip.</p><p class="abstract"><strong>Methods:</strong> The total number of patients included in the study was 15. The total number of hips in the study were 15. The age group of the patients varied between 51 years and 89 years with mean age group of 73 years. The most common indication in our study was dislocation contributing 60% (n=9) of the hips.<strong></strong></p><p class="abstract"><strong>Results:</strong> The post-operative mean Harris hip score (HHS) at immediate post-operative was 67.6. There was a gradual improvement in the HHS through 6 months (77.6), one year (83.3), two years (86.7) and 3 years (90.33). There were no cases with post-operative septic or aseptic loosening in the radiological analysis. The mean cup inclination was 34.3. Out of the 13 hips, in eight hips the femoral stem was in varus. Five hips had a centrally placed femoral stem. Stability management in THA have seen the component design take centre stage, primarily with the use of larger diameter femoral heads and the rise in popularity of constrained acetabular liners (CAL). Several authors have done studies which talk about the stability of this implant design and the reliability of this implant in unstable hips and in hips where instability was expected.</p><p class="abstract"><strong>Conclusions:</strong> In our study, proximal femur tumours, dislocated total hips, abductor insufficiencies and aseptic loosening all showed good results.</p>

scholarly journals A Parametric Analysis of Femoral Stem Impaction

2021 ◽  
Keyword(s):  
Full Text ◽  
Parametric Analysis ◽  
Femoral Stem

Abstract The full text of this preprint has been withdrawn, as it was submitted in error. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

On the Length of the Transition Zone in Unconfined Buckle Propagation

1987 ◽  
Vol 109 (2) ◽  
pp. 155-162 ◽  
Author(s):  
S. U. Bhat ◽  
T. Wierzbicki
Keyword(s):  
Experimental Data ◽  
Hydrostatic Pressure ◽  
Simple Model ◽  
Transition Zone ◽  
Plastic Deformations ◽  
Transition Phenomenon ◽  
Underwater Pipeline ◽  
Basic Understanding ◽  
Theoretical Predictions ◽  
Buckle Propagation

When a buckle propagates down an underwater pipeline due to excessive hydrostatic pressure, the permanent plastic deformations and sectional collapse of the tube are restricted to a finite length transition zone. The existing theoretical predictions of the propagation pressure Pp are based on ring models neglecting the axial effects in the transition zone. An analysis of the transition phenomenon has not been reported so far. The present paper analyzes the transition zone in an unconfined propagating buckle using a simple model of the pipe consisting of rings and stringlike generators. The thrust of this paper is toward establishing a basic understanding of the transition phenomenon, necessary to improve the theoretical predictions of the propagation pressure further. Expressions for the length of the transition zone have been derived in terms of the material and geometric parameters of the pipe. The results are compared with limited experimental data kindly provided to us by Kyriakides.

Parametric Analysis in Tug-of-War Based on Ideal Biomechanical Model

2012 ◽  
Vol 192 ◽  
pp. 207-210
Author(s):  
Bing Zhang
Keyword(s):  
Simple Model ◽  
Parametric Analysis ◽  
Biomechanical Model ◽  
Mechanical Analysis ◽  
Maximum Energy ◽  
Maximum Pressure ◽  
Force Analysis ◽  
Maximum Friction

This paper, in perspective of biomechanics, analyzes tug-of-war, on condition of maximum friction and stable rope, and achieves the sequence which can exert maximum energy. The key to exert maximum energy is to achieve maximum friction. Firstly, build an ideal and simple model, with mechanical analysis, and get that point. Secondly, analyze the maximum pressure and conduct force analysis of rope, with a conclusion that if the sequence is arrayed from short to tall and only when the heights are the same, the athletes with greater weight should stand behind.

Rapid Critical Point Drying of Tissues in a Parr Bomb

1972 ◽  
Vol 30 ◽  
pp. 400-401
Author(s):  
C.A. Baechler ◽  
W. C. Pitchford ◽  
J. M. Riddle ◽  
C.B. Boyd ◽  
H. Kanagawa ◽  
...  
Keyword(s):  
Critical Point ◽  
Critical Pressure ◽  
Soft Tissues ◽  
Biological Tissues ◽  
Critical Temperatures ◽  
Air Drying ◽  
The Past ◽  
Critical Point Drying ◽  
Great Stress ◽  
Infiltration Techniques

Preservation of the topographic ultrastructure of soft biological tissues for examination by scanning electron microscopy has been accomplished in the past by using lengthy epoxy infiltration techniques, or dehydration in ethanol or acetone followed by air drying. Since the former technique requires several days of preparation and the latter technique subjects the tissues to great stress during the phase change encountered during air-drying, an alternate rapid, economical, and reliable method of surface structure preservation was developed. Turnbill and Philpott had used a fluorocarbon for the critical point drying of soft tissues and indicated the advantages of working with fluids having both moderately low critical pressures as well as low critical temperatures. Freon-116 (duPont) which has a critical temperature of 19. 7 C and a critical pressure of 432 psi was used in this study.

SEM analysis of fish scale cross sections: A technique study

1992 ◽  
Vol 50 (1) ◽  
pp. 744-745
Author(s):  
M.E. Lee ◽  
A. Moller ◽  
P.S.O. Fouche ◽  
I.G Gaigher
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Sections ◽  
Soft Tissues ◽  
Close Association ◽  
Sem Analysis ◽  
Fish Scale ◽  
Fish Scales ◽  
Micro Structures ◽  
Scanning Electron

Scanning electron microscopy of fish scales has facilitated the application of micro-structures to systematics. Electron microscopy studies have added more information on the structure of the scale and the associated cells, many problems still remain unsolved, because of our incomplete knowledge of the process of calcification. One of the main purposes of these studies has been to study the histology, histochemistry, and ultrastructure of both calcified and decalcified scales, and associated cells, and to obtain more information on the mechanism of calcification in the scales. The study of a calcified scale with the electron microscope is complicated by the difficulty in sectioning this material because of the close association of very hard tissue with very soft tissues. Sections often shatter and blemishes are difficult to avoid. Therefore the aim of this study is firstly to develop techniques for the preparation of cross sections of fish scales for scanning electron microscopy and secondly the application of these techniques for the determination of the structures and calcification of fish scales.

Biological and biomedical applications of collagenous biomaterials

1990 ◽  
Vol 48 (3) ◽  
pp. 856-857
Author(s):  
Yasushi P. Kato ◽  
Michael G. Dunn ◽  
Frederick H. Silver ◽  
Arthur J. Wasserman
Keyword(s):  
Biomedical Applications ◽  
Soft Tissues ◽  
Collagen Fibers ◽  
Bone Collagen ◽  
Cover Slip ◽  
Fibroblast Migration ◽  
Cellular Expression ◽  
Defect Repair

Collagenous biomaterials have been used for growing cells in vitro as well as for augmentation and replacement of hard and soft tissues. The substratum used for culturing cells is implicated in the modulation of phenotypic cellular expression, cellular orientation and adhesion. Collagen may have a strong influence on these cellular parameters when used as a substrate in vitro. Clinically, collagen has many applications to wound healing including, skin and bone substitution, tendon, ligament, and nerve replacement. In this report we demonstrate two uses of collagen. First as a fiber to support fibroblast growth in vitro, and second as a demineralized bone/collagen sponge for radial bone defect repair in vivo.For the in vitro study, collagen fibers were prepared as described previously. Primary rat tendon fibroblasts (1° RTF) were isolated and cultured for 5 days on 1 X 15 mm sterile cover slips. Six to seven collagen fibers, were glued parallel to each other onto a circular cover slip (D=18mm) and the 1 X 15mm cover slip populated with 1° RTF was placed at the center perpendicular to the collagen fibers. Fibroblast migration from the 1 x 15mm cover slip onto and along the collagen fibers was measured daily using a phase contrast microscope (Olympus CK-2) with a calibrated eyepiece. Migratory rates for fibroblasts were determined from 36 fibers over 4 days.

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