Modelling debonded stem–cement interface for hip implants: effect of residual stresses

2002 ◽  
Vol 17 (1) ◽  
pp. 41-48 ◽  
Author(s):  
N Nuño ◽  
M Amabili
Keyword(s):  
Residual Stresses ◽  
Hip Implants ◽  
Cement Interface

Effect of Tapered Geometry on the Load Transfer of an Idealized Cemented Hip Implant

2002 ◽  
Author(s):  
N. Nun˜o
Keyword(s):  
Residual Stresses ◽  
Bone Cement ◽  
Chemical Bond ◽  
Polymethyl Methacrylate ◽  
Load Transfer ◽  
Hip Implants ◽  
Cement Interface ◽  
Grouting Material ◽  
Surrounding Bone ◽  
Causes Of Failure

Implant looseining of cemented hip implants is one of the major causes of failure of the arthroplasty. In cemented hip implants, the polymethyl methacrylate (PMMA), also called bone cement, is used as grouting material between the stem and the surrounding bone. During polymerisation of the cement, residual stresses are generated in the bulk cement. The bone cement does not have a chemical bond with the stem nor the bone; however, it fills completely the space between the two and serves to distribute the load being transferred from the stem to the bone. Numerical analyses on the load transfer of cemented hip implants usually do not include the residual stresses due to cement curing at the stem-cement interface [1–2].

Effect of Tapered Geometry on the Load Transfer of an Idealized Cemented Hip Implant

2002 ◽  
Author(s):  
N. Nun˜o
Keyword(s):  
Residual Stresses ◽  
Bone Cement ◽  
Chemical Bond ◽  
Load Transfer ◽  
Hip Implants ◽  
Implant Loosening ◽  
Cement Interface ◽  
Grouting Material ◽  
Surrounding Bone ◽  
Causes Of Failure

Implant loosening of cemented hip implants is one of the major causes of failure of the arthroplasty. In cemented hip implants, the polymethyl methacrylate (PMMA), also called bone cement, is used as grouting material between the stem and the surrounding bone. During polymerisation of the cement, residual stresses are generated in the bulk cement. The bone cement does not have a chemical bond with the stem nor the bone; however, it fills completely the space between the two and serves to distribute the load being transferred from the stem to the bone. Numerical analyses on the load transfer of cemented hip implants usually do not include the residual stresses due to cement curing at the stem-cement interface [1–2].

Transient and Residual Stresses and Displacements in Self-Curing Bone Cement—Part II: Thermoelastic Analysis of the Stem Fixation System

1982 ◽  
Vol 104 (1) ◽  
pp. 28-37 ◽  
Author(s):  
A. M. Ahmed ◽  
R. Nair ◽  
D. L. Burke ◽  
J. Miller
Keyword(s):  
Adverse Effects ◽  
Residual Stresses ◽  
Bone Cement ◽  
Cancellous Bone ◽  
Thermal Stresses ◽  
Curing Process ◽  
Hardening Material ◽  
Cement Interface ◽  
Fixation System ◽  
Curing Cement

In this second part of a two-part report, an idealized model of the stem fixation system is analyzed to determine the adverse effects of the thermal stresses and displacements of bone cement during its curing process. The Shaffer-Levitsky stress-rate strain-rate law for chemically hardening material has been used. The results show that if the cement is surrounded by cancellous bone, as opposed to cortical bone, then transient tensile circumferential stresses in the cement and similar radial stresses at the stem/cement interface are generated. The former may cause flaws and voids within the still curing cement, while the latter may cause gaps at the interface.

MODELLING THE BONE-CEMENT INTERFACE IN CEMENTED HIP IMPLANTS

2008 ◽  
Vol 41 ◽  
pp. S68
Author(s):  
M.A. Pérez ◽  
J.M. García-Aznar ◽  
M. Doblaré
Keyword(s):  
Bone Cement ◽  
Hip Implants ◽  
Cement Interface

Measurements of the Residual Stresses due to Cement Polymerization for Cemented Hip Implants

2005 ◽  
Vol 490-491 ◽  
pp. 571-576
Author(s):  
Natalia Nuño ◽  
Dominic Plamondon
Keyword(s):  
Body Temperature ◽  
Residual Stresses ◽  
Bone Cement ◽  
Hip Prosthesis ◽  
Outer Diameter ◽  
Liquid Form ◽  
Synthetic Bone ◽  
Cement Interface ◽  
Initial Fixation

The initial fixation of the cemented hip prosthesis relies on the resistance of the interface between the metallic stem of the implant, the PMMA, and the adjacent bone. During the operation, the bone cement still in a liquid form is inserted between the implant and the bone. During polymerisation of the cement, residual stresses are generated in the bulk cement. An experiment has been devised to reproduce the in vivo behaviour of a cemented hip prosthesis, and to develop a technique to measure the residual stresses of the bone cement at the stem-cement interface. An idealized prosthesis (19-mm diameter) was placed inside a synthetic bone (outer diameter of 40 mm, inside diameter of 30 mm). The bone cement was poured between the stem and the bone. A sub-miniature load cell was inserted inside the idealized stem to measure directly the radial stresses generated by the cement curing on the hip stem. The tests are conducted at body temperature of 37°C to simulate the in-vivo conditions.

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