Computational Analysis of Microstructure of Ultra High Molecular Weight Polyethylene for Use in Total Joint Replacement

2012 ◽  
Author(s):  
Kelly M. Seymour ◽  
Sara A. Atwood
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Joint Replacement ◽  
Hip Replacement ◽  
Computational Analysis ◽  
Total Joint Replacement ◽  
Cause Of Failure ◽  
Ultra High Molecular Weight

Ultra-High Molecular Weight Polyethylene, or UHMWPE, is a material commonly used as a bearing between metal components of a knee or hip replacement joint. The ultra-high component is frequently the cause of failure of the joint due to wear, fatigue, or fracture [1,2].

Nanoindentation properties of compression-moulded ultra-high molecular weight polyethylene

2003 ◽  
Vol 217 (5) ◽  
pp. 357-366 ◽  
Author(s):  
S P Ho ◽  
L Riester ◽  
M Drews ◽  
T Boland ◽  
M LaBerge
Keyword(s):  
Molecular Weight ◽  
Elastic Modulus ◽  
High Molecular Weight ◽  
Mechanical Response ◽  
Total Joint Replacement ◽  
Scanning Calorimetry ◽  
Nanomechanical Properties ◽  
Significant Difference ◽  
Ultra High Molecular Weight ◽  
Penetration Depths

This paper investigates the elastic modulus and hardness of untreated and treated compression-moulded ultra-high molecular weight polyethylene (UHMWPE) tibial inserts of a total knee replacement (TKR) prosthesis. Investigations were carried out at a nanoscale using a Nanoindenter™ at penetration depths of 100, 250 and 500 nm. The nanomechanical properties of surface and subsurface layers of the compression-moulded tibial inserts were studied using the untreated UHMWPE. The nanomechanical properties of intermediate and core layers of the compression-moulded tibial insert were studied using the cryoultrasectioned and etched UHMWPE treated samples. The cryoultrasectioning temperature (-150°C) of the samples was below the glass transition temperature, Tg(-122± 2°C), of UHMWPE. The measurement of the mechanical response of crystalline regions within the nanostructure of UHMWPE was accomplished by removing the amorphous regions using a time-varying permanganic-etching technique. The percentage crystallinity of UHMWPE was measured using differential scanning calorimetry (DSC) and the Tg of UHMWPE was determined by dynamic mechanical analysis (DMA). Atomic force microscopy (AFM) was used to assess the effect of surface preparation on the samples average surface roughness, Ra. In this study, it was demonstrated that the untreated UHMWPE samples had a significantly lower ( p<0.0001) elastic modulus and hardness relative to treated UHMWPE cryoultrasectioned and etched samples at all penetration depths. No significant difference ( p > 0.05) in elastic modulus and hardness between the cryoultrasectioned and etched samples was observed. These results suggest that the surface nanomechanical response of an UHMWPE insert in a total joint replacement (TJR) prosthesis is significantly lower compared with the bulk of the material. Additionally, it was concluded that the nanomechanical response of material with higher percentage crystallinity (67 per cent) was predominantly determined by the crystalline regions within the semi-crystalline UHMWPE nanostructure.

scholarly journals Research into the thermal stability and mechanical properties of vitamin E diffusion modified irradiation cross-linked graphene oxide/ultra-high molecular weight polyethylene composites

RSC Advances ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 4175-4188 ◽  
Author(s):  
Weipeng Duan ◽  
Meiping Wu ◽  
Jitai Han ◽  
Zifeng Ni
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Graphene Oxide ◽  
Vitamin E ◽  
High Molecular Weight ◽  
Joint Replacement ◽  
Artificial Joint ◽  
Artificial Joint Replacement ◽  
Ultra High Molecular Weight

Recently, there has been increasing interest in modifying ultra-high molecular weight polyethylene (UHMWPE) due to glaring needs in the artificial joint replacement field.

A Micro Constitutive Model for Ultra-High Molecular Weight Polyethylene Orthopaedic Implant Bearings

2018 ◽  
Vol 382 ◽  
pp. 201-207
Author(s):  
Chen Yuan Chung
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Total Joint Replacement ◽  
Amorphous Polymer ◽  
Micromechanical Model ◽  
Crystalline Polymer ◽  
Polymer Chains ◽  
Lamellar Thickness ◽  
Orthopaedic Implant ◽  
Ultra High Molecular Weight

Ultra-high molecular weight polyethylene (UHMWPE) is a tough semi-crystalline polymer employed widely as a bearing material in total joint replacements. The micromechanical model has been presented that predicts stiffness of UHMWPE as an aggregate of crystalline inclusions (lamellae) embedded in a rubbery matrix of amorphous polymer chains. The differential scheme was chosen for its ability to represent the interaction between an inclusion and the matrix. Numerical simulations show that increasing lamellar thickness results in less stiffness, less shear stress imposed on the lamellae, indicates that thick lamellae are desirable for UHMWPE materials utilized in total joint replacement bearings.

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