STAND FOR TRIBOLOGICAL TESTING OF HIP ENDOPROSTHESES

Tribologia ◽  
2016 ◽  
Vol 270 (6) ◽  
pp. 167-177 ◽  
Author(s):  
Tomasz WIŚNIEWSKI ◽  
Adrian MRÓZ ◽  
Janusz MAGDA ◽  
Agnieszka WIELOWIEJSKA-GIERTUGA
Keyword(s):  
Hip Joint ◽  
Friction Pair ◽  
Friction Torque ◽  
Continuous Control ◽  
Acetabular Cup ◽  
Liquid Lubricant ◽  
Tribological System ◽  
New Construction ◽  
Number Of Cycles ◽  
Hip Joint Simulator

The paper presents a new construction of hip-joint simulator. The SBT-01.2 simulator is designed for conducting tribological testing of hip endoprostheses based on ISO 14242-1, which specifies the requirements for the range of motion and load characteristics of the friction pair (femoral head vs. acetabular cup) during one test cycle. The construction of the simulator is based on the anatomical structure of the human hip joint. The prosthesis acetabulum is mounted in the upper part of the mounting head while maintaining the inclination angle relative to the axis of the socket to the direction of the loading force. The head of the prosthesis is mounted on a pin embedded in the bottom, movable base. After placing a special sleeve on the lower base, liquid lubricant is applied on the head-cup tribological system. The employed software enables continuous control, online visualization, and data recording. During testing, parameters such as lubricant temperature, instantaneous loading force, friction torque, and the number of cycles are recorded.

scholarly journals Laser Surface Texturing of Alumina/Zirconia Composite Ceramics for Potential Use in Hip Joint Prosthesis

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 369 ◽  
Author(s):  
Francesco Baino ◽  
Maria Angeles Montealegre ◽  
Joaquim Minguella-Canela ◽  
Chiara Vitale-Brovarone
Keyword(s):  
Hip Joint ◽  
Surface Texturing ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Surface Texturing ◽  
Joint Prosthesis ◽  
Composite Ceramics ◽  
Acetabular Cup ◽  
Repetition Number ◽  
Number Of Cycles

The use of metal shell to fix an acetabular cup to bone in hip joint prosthesis carries some limitations, including restrictions in prosthetic femur ball diameter and in patient’s range of motion. These drawbacks could be ideally overcome by using a monolithic ceramic acetabular cup, but the fixation of such an implant to host bone still remains a challenge. Since porous surfaces are known to promote more bone tissue interlocking compared to smooth materials, in this work the surfaces of sintered alumina/zirconia composite ceramics were treated by a pulsed laser radiation at 1064 nm with a pulse width in the nanosecond range, in order to impart controlled textural patterns. The influence of laser process parameters (e.g., energy per pulse, repetition rate, scanning speed, repetition number, angle of laser beam, and number of cycles) on the roughness and texture orientation was systematically investigated. The obtained surface topographies were inspected by optical and scanning electron microscopy, and the roughness was assessed by contact profilometry. Surface roughness could be modulated in the range of 3 to 30 µm by varying the processing parameters, among which the number of cycles was shown to play a major role. The laser treatment was also successfully adapted and applied to ceramic acetabular cups with a curved profile, thus demonstrating the feasibility of the proposed approach to process real prosthetic components.

FRETTING CORROSION OF COBALT AND TITANIUM IMPLANT ALLOYS IN SIMULATED BODY FLUIDS

Tribologia ◽  
2016 ◽  
Vol 270 (6) ◽  
pp. 149-158
Author(s):  
Joanna SULEJ-CHOJNACKA ◽  
Agnieszka WIELOWIEYSKA-GIERTUGA ◽  
Adrian MRÓZ ◽  
Daniel DELFOSSE
Keyword(s):  
Stainless Steel ◽  
Hip Joint ◽  
Friction Pair ◽  
Fretting Wear ◽  
Reciprocating Motion ◽  
Fretting Corrosion ◽  
Acetabular Cup ◽  
Mechanical Destruction ◽  
Friction Resistance ◽  
Static Conditions

The most important advantage of using modular hip joint endoprostheses is the possibility to adapt the endoprosthesis to the morphology and size of individual patients. However, the additional contact surface is subjected to fretting wear due to mutual micro displacements and the aggressive chemistry of the environment inside the human body (fretting corrosion). Today’s hip endoprostheses are generally composed of a hip stem, a femoral ball head and an acetabular cup (Figure 1). The hip stem is made of stainless steel, CoCrMo or a Ti alloys. The femoral ball head is made of stainless steel, CoCrMo, or a ceramic material. In the case of a modular hip stem, i.e. with a modular neck portion, the materials used are generally CoCrMo and Ti6Al 4V. (The interface between femoral ball head and the acetabular cup is an articulating surface and not the subject of this research project.) In this framework, a comparative study of the fretting corrosion resistance of the three most common metallic material combinations occurring in a modular, the non-articulating connection of total hip joint endoprostheses (CoCrMo-CoCrMo, CoCrMo-Ti6Al4V, and Ti6Al4V-Ti6Al4V) was undertaken. Studies were performed with a tribological tester, working in articulating-reciprocating motion, integrated with a potentiostat equipped with a tri-electrode system. The tribosystem consisted of a fixed stem pressed with a constant force to a plate performing the reciprocating motion of a predetermined frequency and amplitude. The tests were performed in diluted bovine serum at 37°C. Based on the obtained results, it was found that the greatest resistance to corrosion in static conditions was exhibited by the CoCrMo-CoCrMo friction pair, while the lowest ΔE value was obtained by CoCrMo-Ti6Al4V. It also confirmed the existence of a correlation between the intensity of the depassivation process caused by the mechanical destruction of the surface layer and the friction resistance values in the tribological system.

RESEARCH ON FRICTION WEAR OF HIP JOINT ENDOPROSTHESES OF POLYETHYLENE-METAL MATERIAL COMBINATION ON HIP JOINT SIMULATOR

Tribologia ◽  
2018 ◽  
Vol 281 (5) ◽  
pp. 153-158
Author(s):  
Tomasz WIŚNIEWSKI ◽  
Agnieszka WIELOWIEJSKA-GIERTUGA ◽  
Rafał RUBACH ◽  
Łukasz ŁAPAJ ◽  
Janusz MAGDA
Keyword(s):  
Hip Joint ◽  
Friction Pair ◽  
Accurate Determination ◽  
Control Group ◽  
Liquid Absorption ◽  
Ultra High Molecular Weight ◽  
Hip Joint Simulator ◽  
Wear Tests ◽  
Friction And Wear Tests

The article presents the results of friction wear tests of hip joint endoprostheses. The study comprised tests of endoprostheses, commercially available on the European market, used in total hip arthroplasty. The friction pair was formed by an actual cupacetabular cup made of ultra-high molecular weight polyethylene (PE-UHMW) along with a head having a diameter of 28 mm made of stainless steel FeCrNiMnMoNbN. The friction and wear tests were performed using an SBT 01.2 hip joint simulator of the authors’ own design, which was constructed taking into account the ISO 14242-1 standard. Bovine serum was used as the lubricant. The tests of each friction pair were made up to 5·106cycles of motion. During the tests, simulator operation was interrupted every 5·105 cycles to replace the lubricating liquid, and mass control was performed every 1·106 cycles. Prior to testing, the polyethylene cup was soaked in the lubricant to minimize liquid absorption during the test. Proper preparation of the cup and testing by taking into account a control group weight measurement allowed an accurate determination of the mass loss of the polyethylene cup.

Methods for determining the bearing capacity and extreme pressure properties of lubricants used in heavy-loaded tribodynamic couplings of metallurgical machines and units

2021 ◽  
pp. 30-39
Author(s):  
M.V. Kharchenko ◽  
S.P. Nefediev ◽  
R.R. Dema ◽  
O.R. Latypov
Keyword(s):  
Friction Pair ◽  
Contact Problems ◽  
Operating Conditions ◽  
Extreme Pressure ◽  
Standard Equipment ◽  
Liquid Lubricant ◽  
Friction Machine ◽  
Contact Loads ◽  
Tribological System ◽  
Acceleration Mode

To solve contact problems related to the study of the interaction between a lubricated or non-lubricated friction pair, we used standard equipment - friction machines and tribometers. However, the use of factory-made research equipment does not always allow us to accurately answer the questions concerning the tribotechnical characteristics of friction and wear processes under specific operating conditions. A review of the literature on the technical capabilities of testing machines showed that their main drawback is the inability to programmatically set the modes of acceleration of the tribological system and tracking slippage in real-time. The study revealed the need to develop a methodology for investigating the extreme pressure properties of liquid lubricants in the tribocoupling acceleration mode, which is caused primarily by the effect of high contact loads acting in the contact areas of friction pairs, e.g. gears, rolling bearings, etc. when technological machines and equipment start and reach the operating speed. The paper considers a modernized friction machine capable of programmatically setting acceleration modes and investigating tribodynamic processes of lubricated frictional couplings. We developed a technique that makes it possible to evaluate the efficiency of a liquid lubricant during acceleration and its effect on the wear of a lubricated contact based on the use of the modernized friction machine.

Effect of Head Surface Roughness and Sterilization Method on Wear of UHMWPE Acetabular Cups: Preliminary Hip Joint Simulator Results

2006 ◽  
Author(s):  
Anneli Jedenmalm ◽  
Walther Leardini ◽  
Mara Zavalloni ◽  
Saverio Affatato
Keyword(s):  
Surface Roughness ◽  
Hip Joint ◽  
Calf Serum ◽  
The Body ◽  
Acetabular Cup ◽  
Sterilization Method ◽  
Metal Head ◽  
Head Surface ◽  
The Impact ◽  
Hip Joint Simulator

More than one million hip joint replacements are performed each year in the world. However, the implants do not last forever due to material limitations, even though the operation is successful. The most common material combination used today is a CoCr head articulating against an UHMWPE (Ultra High Molecular Weight Polyethylene) acetabular cup. Several investigations have shown that the metal head is roughened inside the body and thus accelerating wear of the polymer cup. The sterilization method is also known to have effect on the wear properties. In vitro wear tests are however usually performed with as new implants. This investigation aimed at study the impact of head surface roughness on wear of both sterilized and non-sterilized acetabular cups. A total of nine acetabular cup and head pairs were wear tested in a hip joint simulator for 2Million cycles (Mc) with bovine calf serum as lubricant. Wear was determined by weighing of all cups. The heads were of CoCrMo and the average initial head surface roughness was 15nm (Ra), measured with a white light interference profilometer. The roughening was produced with a SiC paper producing circular multidirectional wear tracks to a surface roughness of about 400nm (Ra). The cups were of UHMWPE and the sterilized cups were 3Mrad gamma-radiated in nitrogen. The surface roughness after wear test was unchanged for the roughened heads, while the initially smooth heads were slightly roughened. Preliminary results show that the rough heads increase the wear of the cups 2-fold. The γ-irradiation affected both wear- and soak rate.

Simplified motion and loading compared to physiological motion and loading in a hip joint simulator

2000 ◽  
Vol 214 (3) ◽  
pp. 233-238 ◽  
Author(s):  
S L Smith ◽  
A Unsworth
Keyword(s):  
Hip Joint ◽  
Wear Test ◽  
Test Duration ◽  
Acetabular Cup ◽  
Single Plane ◽  
Wear Rates ◽  
Physiological Loading ◽  
Flexion Extension ◽  
Physiological Motion ◽  
Hip Joint Simulator

Two wear tests were conducted using the Durham Hip Joint Wear Simulator to investigate the effects of simplified motion and loading on ultra-high molecular weight polyethylene (UHMWPE) acetabular cup wear rates. Bovine serum was used as a lubricant and a gravimetric technique was used to measure wear. The first wear test duration was 7.1 × 106 cycles and investigated the effect of simplified loading. This was achieved by using full physiological motion and loading for the first 5 × 106 cycles of the test, then physiological motion with simplified loading for the final 2.1 × 106 cycles of the wear test. The UHMWPE acetabular cup wear rates using full physiological motion and loading were 32.2 and 51.7 mm3/106 cycles against zirconia and CoCrMo femoral heads respectively. Using simplified loading the cup wear rates were 30.1 and 49.2 mm3/106 cycles against zirconia and CoCrMo respectively which was not significantly different from wear rates with physiological loading. The effect of simplified motion was investigated in a second wear test of 5.0 × 106 cycles duration. Physiological loading was applied across the prosthesis with physiological motion in the flexion/extension plane only. Mean wear of the acetabular component dropped to 0.197 mm3/106 cycles. The surfaces of all the actabular cups were subject to gross examination, optical microscopy and scanning electron microscopy. No notable difference was observed between the cups subjected to physiological motion and loading and those subjected to simplified loading. The cups worn with a single plane of motion had a much smaller worn area and a notable difference in surface features to the other cups. Simplifed loading is therefore an acceptable simplification in simulator testing but simplifying motion to the flexion/extension plane axis only is unacceptable.

scholarly journals Study of Sensor Deflection in Hip Simulator : Numerical and Experimental Method

2018 ◽  
Vol 73 ◽  
pp. 01022
Author(s):  
Fabian Singgih Wicaksono ◽  
T Towijaya ◽  
Eko Saputra ◽  
Rifky Ismail ◽  
Mohammad Tauviqirrahman ◽  
...  
Keyword(s):  
Femoral Head ◽  
Hip Joint ◽  
Estimation Error ◽  
Wear Volume ◽  
Acetabular Cup ◽  
Hip Simulator ◽  
Artificial Hip ◽  
Process Simulator ◽  
Dial Indicator ◽  
Hip Joint Simulator

A lot of Hip Joint Simulator have been made nowadays, most of them use different structure and method. This research reports a pin-on-ring tribometer design that is used to became hip joint simulator based on the movement of the salat (salat gait). Modified femoral head and acetabular cup holder are performed, to design a reciprocating motion for simulation of artificial hip movement. An interesting finding from this study is a new linked-bar mechanism that leads to the ability to move femoral head against the acetabular cup and measure wear volume of an THR patients during normal salat gait. The designed motion angle is 121.5° in the flexion direction and 15.5° in the direction of abduction. Linked bar for sensor dial indicator have enough adjustment, but there is still a movement that is not rigid upon running hip joint process simulator. This research concentrates on the bar is already linked in accordance or not when compared with the data in the simulate on a computer. Estimation error and deviations that occur between numerical and experimental is going forward to improve hip joint simulator Undip to be more precise and relevant research to use THR Undip.

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