Abstract
A three dimensional finite element (FE) model of a novel carbon fibre polyamide 12 composite hip stem was used to compare with two commerically available (Exeter and Omnifit) hip stems to minimize stress shielding and bone resorption. A virtual axial load of 3000N was applied to the FE model which replicated the experimental study. Strain and stress distributions were computed and compared with experimental results. Experimentally, three hip stems had their distal portions rigidly mounted and had strain gauges placed along the surface at 3 medial and 3 lateral locations. From the FE analysis, the von mises stress range for the composite hip stem was 200% and 45% lower than that in the Omnifit and Exeter implants, respectively. The aggregate average difference between FE and experimental microstrains for four proximal strain gauge locations were 7.5% (composite), 11.5% (Exeter), 14.6% (Omnifit), and the composite hip stem's stiffness (1982N/mm) was lower than the metallic hip stem stiffnesses (Exter, 2460N/mm; Omnifit, 2543 N/mm). This study showed considerable improvement in stress transfer to bone tissue.
Highlights
Humans encounter many dangers from day to day life; some of these dangers are often masked
By dividing the microstrain values of corresponding finite element (FE) locations 1 to 6, the average microstrain ratios are: composite/Exeter= 3.26; composite/Omnifit = 3.82; and Exeter/Omnifit = 1.18, which shows that the composite hip stem is far less stiff than the standard metallic hip stems given in appendix, Table 12, Table 13, and Table 14
5.8.1 Common Verdicts This study compared a novel carbon-fibre polyamide12 (CF/polyamide 12 (PA12)) hip stem with two standard metallic commercially available hip stems i.e. Exeter and Omnifit, and tried to predict their mechanical performance using a finite element (FE) model which was validated by a series of experiments
Summary
Humans encounter many dangers from day to day life; some of these dangers are often masked. Located in the thigh area, the femur is usually very strong; when excess force is added, pressure builds and the femur becomes damaged. Osteoporosis is another form of damage to the bones. Found in the elderly, this disease can cause severe deterioration in the bones. In this particular illness, the bone mineral density (BMD) is reduced. It can cause the bones to become brittle which results in the weakening of the bones. The consequences of these illnesses can cause bones to break as well as develop cancer [3 , 4]
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