A Study of the Wear Characteristics of Sliding Pairs of High Density Polycrystalline Aluminium Oxide with Particular Reference to Their Use in Total Replacement Human Joints

1983 ◽  
Vol 12 (1) ◽  
pp. 23-28 ◽  
Author(s):  
N Wallbridge ◽  
D Dowson ◽  
E W Roberts
Keyword(s):  
Femoral Head ◽  
High Density Polyethylene ◽  
High Density ◽  
Wear Testing ◽  
Distilled Water ◽  
Acetabular Cup ◽  
Wear Characteristics ◽  
Total Replacement ◽  
Ceramic Femoral Head ◽  
Dry Conditions

The introduction of ceramic components into total replacement joints for the human body in the last decade has attracted considerable attention. In most cases in which a ceramic component is used a ceramic femoral head is located on a metallic femoral stem, whilst the acetabular cup is made from ultra high molecular weight polyethylene. In some designs a ceramic acetabular cup is used in association with the ceramic femoral head. A study of the basic wear characteristics of sliding pairs of high density polycrystalline ceramics is reported in this paper. Tests have been carried out under both ‘dry’ and ‘wet’ (distilled water) conditions in a tri-pin-on-disc wear testing machine. It is shown that sliding pairs of alumina ceramics exhibit remarkably low wear under dry conditions when subjected to small loads, but that high loads lead to rapid deterioration of the interacting surfaces and the onset of very high wear rates. The presence of distilled water generally permits smooth sliding at higher loads than are possible under dry conditions, but the wear rate increases by a factor of about ten over those encountered at low loads in air. The slight advantage of sliding pairs of alumina over high density polyethylene sliding on stainless steel as far as wear is concerned is not evident if the comparison is made with high density polyethylene sliding on high density ceramic in the presence of distilled water.

Alumina Femoral Head Fracture: An in Vitro Study

2000 ◽  
Vol 23 (4) ◽  
pp. 256-260 ◽  
Author(s):  
S. Affatato ◽  
E. Ghisolfi ◽  
G.L. Cacciari ◽  
A. Toni
Keyword(s):  
Stainless Steel ◽  
Femoral Head ◽  
In Vitro Study ◽  
Detailed Examination ◽  
Femoral Head Fracture ◽  
Acetabular Cup ◽  
Ceramic Ball ◽  
Ceramic Femoral Head ◽  
Hip Simulator

A fracture of a ceramic femoral head is reported in this study. Fractures of ceramic femoral heads are uncommon and reports on this complication are rare. After 3 million cycles, on a twelve station hip simulator that tested alumina femoral head against polyethylene acetabular cup, fracture of the ceramic ball was observed. The retrieved specimen consisted of three large ceramic fragments from the same ceramic femoral head, a polyethylene acetabular cup and a stainless steel jig. Careful and detailed examination of the removed components was made. The fracture of the ceramic ball resulted in damage to the metal taper of the jig component which was fixed into the simulator.

High Density Polyethylene Prosthetic Femoral Head Replacement in the Dog

1975 ◽  
Vol 111 ◽  
pp. 274-283 ◽  
Author(s):  
David G. Mendes ◽  
Fernando Figarola ◽  
Peter G. Bullough ◽  
Patricia Loudis
Keyword(s):  
Femoral Head ◽  
High Density Polyethylene ◽  
High Density

A Simulator Study of Friction in Total Replacement Hip Joints

1992 ◽  
Vol 206 (4) ◽  
pp. 201-211 ◽  
Author(s):  
V Saikko
Keyword(s):  
Femoral Head ◽  
Alumina Ceramic ◽  
Frictional Torque ◽  
Acetabular Cup ◽  
Hip Joints ◽  
Total Replacement ◽  
Flexion Extension ◽  
Ultra High Molecular Weight ◽  
Hip Joint Simulator ◽  
Frictional Behaviour

Frictional behaviour of 22 different femoral head-acetabular cup combinations was studied on a new servo-hydraulic microcomputer-controlled hip joint simulator using various flexion-extension angle and superior-inferior load set value waveforms and using distilled water at 37 ± 1°C as lubricant. Six different head materials were included in the study, whereas all cups were ultra-high molecular weight polyethylene (UHMWPE). Most head-cup combinations studied are commercially available. No distinctly superior joint design can he pointed out, but the frictional behaviour of alumina ceramic against UHMWPE proved overall most favourable ( μmin was 0.02), whereas that of non-ion-implanted titanium alloy Ti-6Al-4V against UHMWPE proved strikingly poor ( μmax was 0.15). The lowest frictional torque was in 22 mm joints, but frictional torque did not always increase straightforwardly with increasing diameter of the femoral head. The measurements form an extensive comparison between a wide variety of head-cup combinations. The simulator is apparently a useful instrument in the study of frictional behaviour of new designs, materials, surface treatments and coatings that are frequently introduced.

Composition and Surface Topography Effects on Apatite-Forming Ability of Ceramic-Polymer Composites

2003 ◽  
Vol 774 ◽  
Author(s):  
Susan M. Rea ◽  
Serena M. Best ◽  
William Bonfield
Keyword(s):  
Surface Topography ◽  
High Density Polyethylene ◽  
High Density ◽  
Apatite Layer ◽  
Biologically Active ◽  
Human Blood Plasma ◽  
Apatite Formation ◽  
Polyethylene Matrix ◽  
Composite Surface ◽  
X Ray

AbstractHAPEXTM (40 vol% hydroxyapatite in a high-density polyethylene matrix) and AWPEX (40 vol% apatite-wollastonite glass ceramic in a high density polyethylene matrix) are composites designed to provide bioactivity and to match the mechanical properties of human cortical bone. HAPEXTM has had clinical success in middle ear and orbital implants, and there is great potential for further orthopaedic applications of these materials. However, more detailed in vitro investigations must be performed to better understand the biological interactions of the composites and so the bioactivity of each material was assessed in this study. Specifically, the effects of controlled surface topography and ceramic filler composition on apatite layer formation in acellular simulated body fluid (SBF) with ion concentration similar to those of human blood plasma were examined. Samples were prepared as 1 cm × 1 cm × 1 mm tiles with polished, roughened, or parallel-grooved surface finishes, and were incubated in 20 ml of SBF at 36.5 °C for 1, 3, 7, or 14 days. The formation of a biologically active apatite layer on the composite surface after immersion was demonstrated by thin-film x-ray diffraction (TF-XRD), environmental scanning electron microscopy (ESEM) imaging and energy dispersive x-ray (EDX) analysis. Variations in sample weight and solution pH over the period of incubation were also recorded. Significant differences were found between the two materials tested, with greater bioactivity in AWPEX than HAPEXTM overall. Results also indicate that within each material the surface topography is highly important, with rougher samples correlated to earlier apatite formation.

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