Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 75-81 |
| Number of pages | 7 |
| Journal | Medical Engineering & Physics |
| Volume | 53 |
| Early online date | 1 Feb 2018 |
| DOIs | |
| Publication status | Published - Mar 2018 |
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Keywords
- Cementless fixation
- Acetabulum
- Bone
- Mechanical properties
- Mechanical testing
- Viscoelastic
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Mechanical properties of cancellous bone from the acetabulum in relation to acetabular shell fixation and compared with the corresponding femoral head. / Van Ladesteijn, Rianne; Leslie, Holly; Manning, William A.; Holland, James P.; Deeham, David J.; Pandorf, Thomas; Aspden, Richard M.
In: Medical Engineering & Physics, Vol. 53, 03.2018, p. 75-81.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Mechanical properties of cancellous bone from the acetabulum in relation to acetabular shell fixation and compared with the corresponding femoral head
AU - Van Ladesteijn, Rianne
AU - Leslie, Holly
AU - Manning, William A.
AU - Holland, James P.
AU - Deeham, David J.
AU - Pandorf, Thomas
AU - Aspden, Richard M.
N1 - Acknowledgments We thank Phil Jackson for help sourcing donated cadavers and transportation of samples and Dr. F.R. Saunders for help with core preparation and advice. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
PY - 2018/3
Y1 - 2018/3
N2 - To gain initial stability for cementless fixation the acetabular components of a total hip replacement are press-fit into the acetabulum. Uneven stiffness of the acetabular bone will result in irregular deformation of the shell which may hinder insertion of the liner or lead to premature loosening. To investigate this, we removed bone cores from the ilium, ischium and pubis within each acetabulum and from selected sites in corresponding femoral heads from four cadavers for mechanical testing in unconfined compression. From a stress-relaxation test over 300 s, the residual stress, its percentage of the initial stress and the stress half-life were calculated. Maximum modulus, yield stress and energy to yield (resilience) were calculated from a load-displacement test. Acetabular bone had a modulus about 10–20%, yield stress about 25% and resilience about 40% of the values for the femoral head. The stress half-life was typically between 2–4 s and the residual stress was about 60% of peak stress in both acetabulum and femur. Pubic bone was mechanically the poorest. These results may explain uneven deformation of press-fit acetabular shells as they are inserted. The measured half-life of stress-relaxation indicates that waiting a few minutes between insertion of the shell and the liner may allow seating of a poorly congruent liner.
AB - To gain initial stability for cementless fixation the acetabular components of a total hip replacement are press-fit into the acetabulum. Uneven stiffness of the acetabular bone will result in irregular deformation of the shell which may hinder insertion of the liner or lead to premature loosening. To investigate this, we removed bone cores from the ilium, ischium and pubis within each acetabulum and from selected sites in corresponding femoral heads from four cadavers for mechanical testing in unconfined compression. From a stress-relaxation test over 300 s, the residual stress, its percentage of the initial stress and the stress half-life were calculated. Maximum modulus, yield stress and energy to yield (resilience) were calculated from a load-displacement test. Acetabular bone had a modulus about 10–20%, yield stress about 25% and resilience about 40% of the values for the femoral head. The stress half-life was typically between 2–4 s and the residual stress was about 60% of peak stress in both acetabulum and femur. Pubic bone was mechanically the poorest. These results may explain uneven deformation of press-fit acetabular shells as they are inserted. The measured half-life of stress-relaxation indicates that waiting a few minutes between insertion of the shell and the liner may allow seating of a poorly congruent liner.
KW - Cementless fixation
KW - Acetabulum
KW - Bone
KW - Mechanical properties
KW - Mechanical testing
KW - Viscoelastic
U2 - 10.1016/j.medengphy.2018.01.005
DO - 10.1016/j.medengphy.2018.01.005
M3 - Article
VL - 53
SP - 75
EP - 81
JO - Medical Engineering & Physics
JF - Medical Engineering & Physics
SN - 1350-4533
ER -