Influence of stem geometry on mechanics of cemented femoral hip components with a proximal bond

✍ Scribed by Kenneth A. Mann; Donald L. Bartel; David C. Ayers

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 717 KB
• Volume: 15
• Category: Article
• ISSN: 0736-0266
• DOI: 10.1002/jor.1100150511

✦ Synopsis

Nonlinear, three-dimensional, finite element models of cemented femoral hip components with a proximal stem-cement bond were developed with use of a Charnley stem geometry and a modified Charnley stem geometry that had a cylindrical cross section over the distal two-thirds of the stem (Distal-Round). Peak tensile stresses in the proximal cement mantle increased 63 and 74% for the Charnley and Distal-Round stems, respectively, when the proximal stem-cement interface was debonded. The shear stresses over the stem-cement interface with a proximal bond were 29% larger for the Distal-Round stem than for the Charnley stem. After the proximal stem-cement interface was debonded, the peak tensile stresses in the cement mantle were 15% larger for the Distal-Round stem than for the Charnley stem. The results illustrate that stresses within the proximal cement mantle could be substantially reduced for both Charnley and Distal-Round stems through use of a proximal stem-cement bond. However, the risk of debonding may be higher for the Distal-Round stem because of increased shear stresses, and once debonded the risk of further loosening due to failure of the cement mantle would also be higher for the Distal-Round stem.