scholarly journals A Computational Analysis of Squeaking Hip Prostheses

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Ehsan Askari ◽  
Paulo Flores ◽  
Danè Dabirrahmani ◽  
Richard Appleyard
Keyword(s):  
Femoral Head ◽  
Hip Prosthesis ◽  
Angular Speed ◽  
Initial Position ◽  
Force Model ◽  
Stick Slip ◽  
Hip Prostheses ◽  
Continuous Contact ◽  
Joint Friction ◽  
Implant Size

A ceramic-on-ceramic (CoC) hip prosthesis with clearance is modeled as a multibody dynamics system for the purpose of studying hip squeaking. A continuous contact force model provides the intrajoint forces developed at the hip joint. Friction effects due to the relative motion are also considered. A FFT analysis of the audible sounds from CoC hip acceleration is carried out to analyze hip squeaking. The effects of friction, hip implant size, and the head initial position on hip squeaking and the trajectory of femoral head are analyzed and discussed. It was shown that the causes of hip squeaking are stick/slip, friction-induced vibration, and the femoral head angular speed and force changes.

Modularity of total hip prosthesis and its tribological implications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liliana-Laura Badita ◽  
Virgil Florescu ◽  
Constantin Tiganesteanu ◽  
Lucian Capitanu
Keyword(s):  
Femoral Head ◽  
Hip Prosthesis ◽  
Femoral Stem ◽  
Fretting Wear ◽  
Fretting Corrosion ◽  
Content Type ◽  
Hip Prostheses ◽  
Total Hip ◽  
Starting Point ◽  
Modular Prostheses

Purpose The study aims to analyze the fretting phenomenon, manifested at the taper junctions of modular total hip prostheses (THP). Modularity of prostheses implies the micro-movement occurrence. Fractures can arise as a result of the fretting cracking of the prostheses components, affecting durability of modular THPs. Fretting corrosion is associated with the decrease in the clinical acceptance of hip modular implants. Design/methodology/approach Starting from the fretting phenomenon influence on modularity, monoblock THPs and prostheses with modular femoral head recovered from some review surgeries were investigated. Modular prostheses have a taper junction femoral head – femoral stem neck. Investigation consisted in the analysis of fretting wear and fretting corrosion, of the femoral heads’ taper and of the femoral stems’ trunnions. Findings The main result was that the micro-movement that provokes the fretting of the femoral head-femoral stem taper junction analyzed does not have the same direction. It is manifesting in the direction of the axis of the femoral head taper, around this axis or as a composed movement. The authors suspect that this is due to the different design of the taper. In this way, the inclination of the stem’s trunnion into the head hole has a different angular misalignment and may cause greater damages of the taper. Originality/value This result can be a starting point from the improvement of the future taper junctions design that will improve the quality, durability and modularity of THPs.

scholarly journals Reducing Contact Stress of the Surface by Modifying Different Hardness of Femoral Head and Cup in Hip Prosthesis

2021 ◽  
Vol 7 ◽  
Author(s):  
Eko Saputra ◽  
Iwan Budiwan Anwar ◽  
J. Jamari ◽  
Emile van der Heide
Keyword(s):  
Femoral Head ◽  
Contact Stress ◽  
Hip Prosthesis ◽  
Hip Prostheses ◽  
Wear Process ◽  
Element Simulation ◽  
Static Contact ◽  
Surface Contact ◽  
The Difference ◽  
Wear Law

The wear of hip prosthesis due to applied load and sliding distance during the patient's daily activity cannot be avoided. Wear causes osteolysis or metallosis due to the wear debris produced by the wear process. Several methods were used to reduce wear in metal-on-metal hip prostheses. One of the efforts performed to reduce wear was the differential-hardness concept. Based on the literature, the fine surface roughness of the femoral head are the reason why the hip prosthesis with differential-hardness reduces wear. Besides, the differential-hardness will contribute to the difference of modulus elasticity then influenced the contact stress on the surface contact. According to Archard's wear law, wear on the material pair is affected by contact stress. Therefore, the analysis of contact stress on the hip prosthesis with differential-hardness is important to investigate. The investigation performed by the static contact of two-dimensional axisymmetric with frictionless by using finite element simulation. The simulated models are the alumina vs. alumina, alumina vs. SS316L, CoCr vs. CoCr, CoCr vs. SS316L, and SS316L vs. UHMWPE. The purpose of this study is to determine the contact stress on the surface contact due to differential-hardness of the femoral head and cup. The results of simulations show that the differential-hardness marked by differences in the modulus of elasticity can reduce the contact stress on the surface contact if compare with the similar hardness.

The Function of Bipolar Hip Prostheses—A Laboratory Study Using Cadaveric Acetabula

1992 ◽  
Vol 206 (1) ◽  
pp. 37-42 ◽  
Author(s):  
R G Wetherell ◽  
A Unsworth ◽  
A A Amis
Keyword(s):  
Femoral Head ◽  
Laboratory Study ◽  
Hip Prosthesis ◽  
Weight Bearing ◽  
The Self ◽  
Head Size ◽  
Separate Study ◽  
Hip Prostheses ◽  
Hip Simulator

Cadaveric acetabula were mounted in a hip simulator and the friction developed in each during articulation with a series of metal femoral head prostheses of differing sizes was measured. In a separate study, assembled Hastings bipolar hip prostheses were subjected to weight-bearing forces in the same acetabula and their self-righting mechanism was observed. The self-righting mechanism was found to function efficiently, in most cases overcoming the combined friction of the inner and outer articulations of the Hastings hip. However, during motion in the hip simulator a wide variation of friction was observed between different acetabula and within the same acetabulum with differing head size. In several cases this acetabular friction was found to be less than the friction in the inner articulation of the Hastings bipolar hip prosthesis, and this may explain some cases of reported failure of biarticular function.

Novel methods for demonstrating osseointegration of hydroxylapatite-coated titanium hip prostheses

1991 ◽  
Vol 49 ◽  
pp. 34-35 ◽  
Author(s):  
P. Frayssinet ◽  
J. Hanker ◽  
D. Hardy ◽  
B. Giammara
Keyword(s):  
Hip Prosthesis ◽  
Ethanol Concentration ◽  
Bone Matrix ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Hip Prostheses ◽  
Cellular Inclusions ◽  
Microscopic Studies ◽  
Diamond Saw ◽  
Plasma Sprayed

Prostheses implanted in hard tissues cannot be processed for electron microscopic examination or microanalysis in the same way as those in other tissues. For these reasons, we have developed methods allowing light and electron microscopic studies as well as microanalysis of the interface between bone and a metal biomaterial coated by plasma-sprayed hydroxylapatite(HA) ceramic.An HA-coated titanium hip prosthesis (Corail, Landos, France), which had been implanted for two years, was removed after death (unrelated to the orthopaedic problem). After fixation it was dehydrated in solutions of increasing ethanol concentration prior to embedment in polymethylmethacrylate(PMMA). Transverse femur sections were obtained with a diamond saw and the sections then carefully ground to a thickness of 200 microns. Plastic-embedded sections were stained for calcium with a silver methenamine modification of the von Kossa method for calcium staining and coated by carbon. They have been examined by back-scatter SEM on an ISI-SS60 operated at 25 KV. EDAX has been done on cellular inclusions and extracellular bone matrix.

Analysis of 18F-FDG uptake patterns in PET for diagnosis of septic and aseptic loosening after total hip arthroplasty

2003 ◽  
Vol 42 (06) ◽  
pp. 234-239 ◽  
Author(s):  
T. Mumme ◽  
P. Reinartz ◽  
D. Wirtz ◽  
F. U. Niethard ◽  
U. Büll ◽  
...  
Keyword(s):  
Aseptic Loosening ◽  
Femoral Component ◽  
Hip Prosthesis ◽  
Prosthetic Infection ◽  
Clinical Value ◽  
Septic Loosening ◽  
Hip Prostheses ◽  
Fdg Uptake ◽  
Positron Emission ◽  
Painful Hip

Summary Aim: Identification of typical patterns for fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) to detect aseptic loosening of hip prosthesis (ace-tabular and/or femoral component) and prosthetic infection. Methods: 18 patients with painful hip prosthesis underwent PET using a dedicated full ring scanner after application of 200-300 MBq FDG. The interface between bone and surrounding soft tissue or bone as displayed on coronal slices was divided into 12 segments in accordance with the classifications of Delee and Gruen. FDG uptake in each of the segments was scored (0-3) by two independent observers. Intraoperative findings were regarded as the gold standard. Results: After surgical revision 14 acetabular components and 9 femoral components were found to be loose and prosthetic infection was present in 7 prostheses. Loosening of the acetabular component was correlated to enhanced uptake in the middle of the acetabular interface, while loosening of the femoral component was correlated to enhanced uptake in the proximal and middle segment of the lateral femoral interface and the proximal segment of the medial femoral interface. A similar pattern was found in prosthetic infection with high uptake along the middle portion of the lateral fe-moral interface. In 6 of 7 infected prostheses loosening of the acetabular and of the femoral component was present. Taking the typical uptake patterns as criteria for loosening and grade 3 uptake as an additional criterion for septic loosening the accuracy of PET imaging in the detection of loosening of the acetabular or the femoral component and of prosthetic infection was 72, 78 and 89%, respectively. Conclusion: This pilot study presents FDG-PET as a promising diagnostic tool for patients with painful hip prostheses. Its clinical value should be evaluated in a larger patient population.

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2005 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, being the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical characteristics of the contacting surfaces. The contact force is evaluated as function of the elastic pseudo-penetration between the impacting bodies, coupled with a nonlinear viscous-elastic factor representing the energy dissipation during the impact process. A spatial four bar mechanism is used as an illustrative example and some numerical results are presented, being the efficiency of the developed methodology discussed in the process of their presentation. The results obtained show that the inclusion of clearance joints in the modelization of spatial multibody systems significantly influences the prediction of components’ position and drastically increases the peaks in acceleration and reaction moments at the joints. Moreover, the system’s response clearly tends to be nonperiodic when a clearance joint is included in the simulation.

Improving Tribological Characteristics of Hip Prostheses Using Biocompatible Nanocoatings

2013 ◽  
Vol 741 ◽  
pp. 67-72 ◽  
Author(s):  
Gheorghe I. Gheorghe ◽  
Liliana Laura Badita
Keyword(s):  
Hip Prosthesis ◽  
Protective Coatings ◽  
Scratch Resistance ◽  
Hip Prostheses ◽  
Force Microscopy ◽  
Tin Coatings ◽  
Femoral Heads ◽  
Before And After ◽  
Tin Thin Films ◽  
Steel Substrates

Total hip prosthesis (THP) is the most success of the 20th century in orthopaedic biomedical engineering. However due to difficult conditions within the human body its durability is generally limited to 15-16 years. THP is a bio-tribosystem, on which many mechanical, thermal, chemical and biological factors act. This paper presents the results of an analysis regarding the topography and tribological parameters of femoral heads structures before and after TiN coating. We report on the synthesis of TiN thin films on steel substrates by pulsed laser deposition (PLD) method for improving the mechanical characteristics of the structures. Adhesion resistance of the coating on the sub-layer was evaluated by scratching tests accompanied by Optical Microscopy (OM), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). As a principal result, this work points out that TiN protective coatings deposited by PLD technique with the maximum number of pulses can represent an alternative technology to ensure adhesion and scratch resistance of TiN coatings on femoral heads.

scholarly journals Spontaneous Early Intraprosthetic Dislocation of 22 mm Skirted Femoral Head in Dual Mobility Hip Prosthesis: A Case Report

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Gur Aziz Singh Sidhu ◽  
Amit Kotecha ◽  
Sanjay Mulay ◽  
Neil Ashwood
Keyword(s):  
Case Report ◽  
Femoral Head ◽  
Revision Surgery ◽  
Hip Prosthesis ◽  
Weight Bearing ◽  
Femoral Stem ◽  
Acetabular Cup ◽  
Dual Mobility ◽  
Metal Head ◽  
Intraprosthetic Dislocation

Introduction: There is a trend for increasing use of dual mobility hip designs for both primary and revision hip arthroplasty settings. It provides dual articular surfaces along with increased jump distance to increase the stability of construct. However, this design has some unique complications of its own which surgeons should be aware of especially intraprosthetic dislocation (IPD). Case Report: A 76-year-old lady presented to clinic with painful hip hemiarthroplasty after fracture neck of femur. She underwent revision surgery with dual mobility uncemented acetabular cup and femoral stem was retained as it was well fixed. She was mobilizing well and around 5 weeks post her surgery, developed pain in hip region and difficulty in weight-bearing. Radiographs showed eccentric position of femoral neck in the socket. A diagnosis of IPD was established and revision surgery was planned. Intraoperatively, metal head had dislocated from the polyethylene head and both components were resting in the acetabular socket. No macroscopic erosion of acetabulum was noticed. The polyethylene component and femoral head were retrieved. With previous failed dual mobility, decision was made to achieve stability with larger head size and lipped liner posteriorly. Conclusion: IPD is a rare occurrence and unique complication to dual mobility implants. This report highlights that patients can have IPD without fall or trauma. Keywords: Intraprosthetic dislocation, dual mobility cup, dislocation, total hip replacement.

A continuous contact force model for impact analysis

2022 ◽  
Vol 168 ◽  
pp. 108739
Author(s):  
Jie Zhang ◽  
Xu Liang ◽  
Zhonghai Zhang ◽  
Guanhua Feng ◽  
Quanliang Zhao ◽  
...  
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Force Model ◽  
Continuous Contact ◽  
Contact Force Model

The Porous-Coated Anatomic (PCA) Total Hip Prosthesis

1994 ◽  
Vol 4 (2) ◽  
pp. 69-74
Author(s):  
P. Farsetti ◽  
R. Caterini ◽  
V. Barletta ◽  
A. E. Guarnieri ◽  
E. Ippolito
Keyword(s):  
Hip Prosthesis ◽  
Bone Ingrowth ◽  
Gluteus Medius ◽  
Radiographic Examination ◽  
Total Hip Prosthesis ◽  
Rating Score ◽  
Hip Prostheses ◽  
Total Hip ◽  
Total Hip Prostheses

Thirty uncemented porous-coated anatomic (PCA) total hip prostheses were implanted in 27 patients. The average age at the time of surgery was 54 years, and the average follow-up was 4.5 years. The average hip rating score was 88 points. Three patients had thigh pain at follow-up and fifteen had a mild limp, related to a weakness of the gluteus medius and minimus. On radiographic examination, we observed a good bone ingrowth of the implant in all patients. No aseptic loosening was radiographically demonstrated. No relationship was found between pain in the thigh and the various radiographic parameters studied (ra-diodense lines, sclerosis, varus position of the stem).

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