Computed tomographic analysis of bone support for three acetabular cup designs.
The initial stability and long-term survivorship of cementless acetabular components is partially dependent on bone-prosthesis contact patterns. This study addresses the question: What are the differences in contact patterns for hemispheric, dual geometry, and spiked designs? Quantitative and qualitative assessment of contact patterns was achieved using a novel, nondestructive computed tomography-based analysis. Eighteen cadaveric hemipelvis specimens were randomly assigned to receive one of three cup designs. The mean amount of cup contact was 48.6% in the hemisphere group, 31.9% in the dual geometry group, and 35.1 percent in the spiked group. The hemispheric design showed more contact and a more uniform contact pattern than the dual geometry design. The dual geometry design featured a tight fit at the rim of the implant. In the spiked group, the amount of bone-prosthesis contact was affected by the distance that the spikes advanced into the pelvic bone. This nondestructive imaging technique has potential future uses in in vitro and in vivo studies.
Howard
James L
JL
Division of Orthopaedic Surgery, London Health Sciences Centre-University Campus, London, Ontario, Canada. jhoward@uwo.ca
Hui
Andrew J
AJ
Bourne
Robert B
RB
Holdsworth
David W
DW
D000077:Acetabulum / Q000000981:diagnostic imaging; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008422:Materials Testing; D016348:Osseointegration / Q000502:physiology*; D011336:Probability; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011897:Random Allocation; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed / Q000379:methods*