Development of friction and wear full-scale testing for TKR prostheses with reliable low cost apparatus (original) (raw)
Related papers
Simple Method for Determine the Degree of Wear to a Total Knee Prosthesis in Vitro
ANNALS OF THE ORADEA UNIVERSITY. Fascicle of Management and Technological Engineering., 2014
This paper presents a simple methodology of ex in vitro testing of a Low Contact Stress (LCS) Mobile-Bearing Total Knee System, produced by DePuy Orthopaedics, Inc. USA, on an experimental stand. To be tested LCS Mobile-Bearing Total Knee System was designed and constructed two auxiliary devices. Testing the LCS System was made taking into account the provisions of international standards. The method for determining the degree of wear of the polyethylene component of the LCS System supposes several essential steps: cleaning and sterilization of the components (metallic and polymeric) of LCS System; weighing of polyethylene component; visual inspection of articulating surfaces; determining the average roughness of contact areas; determining the overall size of the system on a coordinate measuring machine (optional); performing a large number of cycles on experimental stand and determining of the specific parameters of wear and comparing them with data from the literature.
Comparison of wear in a total knee replacement under different kinematic conditions
Journal of materials science. Materials in medicine
A six station ProSim (Manchester, UK) knee simulator was used to assess the wear of six PFC (DePuy) fixed bearing total knee replacements under two different kinematic conditions defined as low and high kinematic inputs. The high kinematics displacement and rotation inputs were based on the kinematics of the natural knee with ISO standards used for the axial load and flexion. Low kinematics were defined as approximately half the magnitude. The six specimens were run for three million cycles under low kinematics and three million cycles under high kinematics. The mean wear rate found during the low kinematics phase was 7.7 +/- 2 mm3 per million cycles. This then increased significantly to an average wear rate of 41 +/- 14 mm3 during the high kinematics input phase. The wear areas were characterized by a predominant damage mode of burnishing with some abrasive wear occurring during the high kinematics phase. This study supports the findings that introduction of cross-shearing of the p...
Wear, 2008
Using a friction measurement system designed for such a purpose the frictional characteristics of a total knee replacement system have been assessed as a function of in vitro wear following wear simulation as described in Part I. The Stribeck analysis has been used to evaluate the data and to indicate the mode of lubrication. Using carboxymethyl cellulose (CMC) solutions as the lubricant it was observed that the UHMWPE total knee replacement (TKR) sets tested exhibited friction factors that fluctuated between 0.01 and 0.05. There was no relationship between the Stribeck plots of the TKRs at the different stages of wear testing. Overall, Stribeck analysis of the TKR sets appeared to indicate a mixed lubrication regime with decreasing friction factors as the Sommerfeld number increased. However, the analysis of Pearson's correlation confirmed that this was a statistically weak relationship. It is proposed that the observed variability in the frictional measurements can be accounted for by the joints operating in a mixed lubrication regime where the friction depends on asperity contacts between the articulating counterfaces. The friction factors of the joints depend on the type and content of the lubricant used. Protein containing lubricants caused an increase in friction relative to the CMC solutions and it is thought that this arises from interfacial contact of proteins adsorbed on the articulating surfaces. However, increasing protein content from 1.67 to 5.02 g/dl did not result in a significant increase in friction while the addition of a hyaluronic acid solution resulted in a decrease in the friction factor.
2009
A pneumatic simulator of the knee joint with five DOF was developed to determine the correlation between the kinematics of the knee joint, and the wear of the polyethylene componenent of a TKR prosthesis. A physical model of the knee joint with total knee replacement (TKR) was built by rapid-prototyping based on CT images from a patient. A clinically-available prosthesis was mounted on the knee model. Using a video analysis system, and two force and contact pressure plates, the kinematics and kinetics data were recorded during normal walking of the patient. The quadriceps muscle force during movement was computed using the Anybody software. Joint loadings were generated by the simulator based on recorded and computed data. Using the video analysis system, the precise kinematics of the artificial joint from the simulator was recorded and used as input for an explicit dynamics FE analysis of the joint. The distribution of the contact stresses in the implant was computed during the walking cycle to analyze the prosthesis behavior. The results suggest that the combination of axial loading and anterior-posterior stress is responsible for the abrasive wear of the polyethylene component of the prosthesis.
Journal of Biomechanics, 2004
The evaluation of contact areas and pressures in total knee prosthesis is a key issue to prevent early failure. The first part of this study is based on the hypothesis that the patterns of contact stresses on the tibial insert of a knee prosthesis at different stages of the gait cycle could be an indicator of the wear performances of a knee prosthesis. Contact stresses were calculated for a mobile bearing knee prosthesis by means of finite element method (FEM). Contact areas and stresses were also measured through in vitro tests using Fuji Prescale film in order to support the FEM findings.
2006
Survival time of total knee replacement represent today a great concern for orthopedic surgeons and prosthesis designers too. Loosening of the component, and especially of the tibial one, is the most important cause of total knee replacement failure. During the gait cycle, forces developed in the knee have a cyclic pattern and a value between 10 and 40 Mpa (megapascal), so the components of the artificial joint are subject to intensive stress and secondary for major wear. At the level of total knee replacement, the mechanism responsible for this is delaminating, scratching, pitting and abrasion. Our study tries to find, using the finite element method, the correlation between total knee replacement kinematics and stress concentration at the level of polyethylene during the gait cycle, related to position of tibial component in the frontal plane. The results showed that position of 15° of flexion, corresponding to middle phase of unipodal weight bearing (mid stance), is the most impo...
Biomechanics and Biotribology of Orthopaedic Knee Prostheses
This paper is a thorough analysis on the wear phenomenon of the total knee prosthesis, especially of the tibial tray insert of ultra-high molecular weight polyethylene (UHMWPE), due to cyclic biomechanical loading. The focus is on the evolution of the phenomenon, from adhesive wear pitting followed by delaminating and even breaking the insert. There are presented theoretical considerations regarding the non-conform contact between the femoral condyle and the tibial tray, experimental results, as well as the possibility to predict the fatigue wear of the UHMWPE tibial tray insert.
The effect of insert conformity and material on total knee replacement wear
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2014
The mean average life is increasing; therefore, there is a need to increase the lifetime of the prostheses. To fulfil this requirement, new prosthetic designs and materials are being introduced. Two of the design parameters that may affect wear of total knee replacements, and hence the expected lifetime, are the insert conformity and material. Computational models have been used extensively for wear prediction and optimisation of artificial knee designs. The objective of the present study was to use a previously validated non-dimensional wear coefficient-based computational wear model to investigate the effect of insert conformity and material on the predicted wear in total knee replacements. Four different inserts (curved, lipped, partial flat and custom flat), with different conformity levels, were tested against the same femoral and under two different kinematic inputs (intermediate and high), with different levels of cross-shear. The insert bearing materials were either conventional or moderately cross-linked ultra-high molecular weight polyethylene (UHMWPE). Wear predictions were validated against the experimental data from Leeds knee simulation tests. The predicted wear rates for the curved insert (most conformed) were more than three times those for the flat insert (least conformed). In addition, the computationally predicted average volumetric wear rates for moderately cross-linked UHMWPE bearings were less than half of their corresponding conventional UHMWPE bearings. Moreover, the wear of the moderately cross-linked UHMWPE was shown to be less dependent on the degree of cross-shear, compared to conventional UHMWPE. These results along with supporting experimental studies provide insight into the design variables, which may reduce wear in knee replacements.
Survival time of total knee replacement represent today a great concern for orthopedic surgeons and prosthesis designers too. Loosening of the component, and especially of the tibial one, is the most important cause of total knee replacement failure. During the gait cycle, forces developed in the knee have a cyclic pattern and a value between 10 and 40 Mpa (megapascal), so the components of the artificial joint are subject to intensive stress and secondary for major wear. At the level of total knee replacement, the mechanism responsible for this is delaminating, scratching, pitting and abrasion. Our study tries to find, using the finite element method, the correlation between total knee replacement kinematics and stress concentration at the level of polyethylene during the gait cycle, related to position of tibial component in the frontal plane. The results showed that position of 15° of flexion, corresponding to middle phase of unipodal weight bearing (mid stance), is the most impo...
Experimental Stress Analysis of Prosthetic Knee Joint - A Review
IJIREEICE, 2021
From this paper we came to know that ad its shown us how the work is done on the knee joint to test the joint in the different parameters are taken to know the various differential results and it tells us the importance of the knee joint stress capacity so lets us known that the amount loading conditions are developed in this input parameters .The main work is done based on the dynamic also by the static analysis is done and they are defined separately so that the this paper gives us idea about the knee capacity and stress conditions are to be developed that is also the important thing to know. And discussed about kinematics and that is to be analyzed here for the purpose of the experimentation. This paper concludes that condition of the business with the respect to knee inserts are assessed by mechanical testing techniques.