In vivo wear of Ti6A14V femoral heads: a retrieval study.
The surface characteristics of sixteen "monobloc" titanium-6% aluminum-4% vanadium (Ti6A14V) femoral components (two of the 6-Ti-28 type and 14 of the 6-Ti-32 type) retrieved after periods of 78-131 months following loosening of the femoral component, as well as two unimplanted controls, were studied. The femoral heads were examined by a combination of noncontact light profilometry, scanning electron microscopy, and energy-dispersive X-ray analysis. No consistent correlations were found between classical surface roughness parameters (average, root mean square, peak-to-valley roughness, and radius of curvature) and any clinical parameter studied (patient gender, weight, and height; primary diagnosis; implantation time; or calculated force applied on the hip joint). This extensive quantitative topographic analysis suggests that wear mechanisms in vivo are complex and that wear of titanium alloy femoral heads is partly attributed to a combination of an imperfect nature of the surface before implantation, removal of the oxide layer causing abrasion of the alloy, subsequent deformation of the bearing surface including polishing, and, to a very small degree, patient parameters.
Department of Bioengineering, Clemson University, South Carolina 29634, USA.
T E
TE
McGovern
J
J
Black
J J
JJ
Jacobs
R M
RM
Graham
M
M
LaBerge
D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D005260:Female; D005270:Femur Head / Q000473:pathology*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D016474:Weight-Bearing
D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium