This Article Full Text Full Text (PDF) Letters to the Editor: Submit a response Alert me when this article is cited Alert me when Letters to the Editor are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Reprints and Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by TURNER, T. M. Articles by GALANTE, J. O. Search for Related Content PubMed PubMed Citation Articles by TURNER, T. M. Articles by GALANTE, J. O. Social Bookmarking             What's this?

Maintenance of Proximal Cortical Bone with Use of a Less Stiff Femoral Component in Hemiarthroplasty of the Hip without Cement. An Investigation in a Canine Model at Six Months and Two Years*

T. M. TURNER, D.V.M., D. R. SUMNER, PH.D., R. M. URBAN, , R. IGLORIA, M.S. and J. O. GALANTE, M.D., CHICAGO, ILLINOIS

Investigation performed at Rush Institute of Arthritis and Orthopedics, Department of Orthopedic Surgery, Rush-Presbyterian-St. Luke's Medical Center, Chicago

A canine model of hemiarthroplasty of the hip was used to determine if the use of a less stiff femoral stem can reduce the amount of bone loss induced by stress-shielding. Two types of stem were used: the stiffer stems were made of a titanium alloy, and the less stiff stems were composed of a cobalt-chromium-alloy core with an outer polymer layer. The stems were identical in shape, and both types were circumferentially coated along their entire length (except for the distal five millimeters) with commercially pure titanium fiber metal. Ten dogs with each type of stem were followed for six months, and twelve dogs with each type of stem were followed for two years. Loss of cortical bone from the proximal part of the femur was associated with both types of stem, but typically 50 per cent less bone was lost with the less stiff implants. Most of the cortical loss occurred at the subperiosteal surface. The amount of medullary bone adjacent to the proximal and distal aspects of both types of stem increased; the less stiff stems were associated with a greater increase in the proximal region, and the stiffer stems were associated with a greater increase in the distal region. Similarly, there were peaks in the amount of bone growth into the proximal and distal portions of both types of stem, with a greater peak in proximal bone growth into the less stiff stems and a greater peak in distal bone growth into the stiffer stems. CLINICAL RELEVANCE: The data indicate that an effective means of promoting proximal transfer of load from the implant to the host femur is to reduce the stiffness of the stem. This is a design-related mechanism to decrease stress-shielding, thereby suppressing the loss of bone in the proximal part of the femur following hemiarthroplasty of the hip performed without cement. Such bone loss can eventually lead to loosening of the component and make subsequent reconstruction difficult.

CiteULike    Connotea    Del.icio.us    Technorati    What's this?

This article has been cited by other articles:

				E. J. HARVEY, J. D. BOBYN, M. TANZER, G. J. STACKPOOL, J. J. KRYGIER, and S. A. HACKING Effect of Flexibility of the Femoral Stem on Bone-Remodeling and Fixation of the Stem in a Canine Total Hip Arthroplasty Model without Cement J. Bone Joint Surg. Am., January 1, 1999; 81(1): 93 - 107. [Abstract] [Full Text]

Stanford University Libraries' HighWire Press (TM) assists in the publication of JBJS Online.
Copyright © 1997 by The Journal of Bone and Joint Surgery, Inc. Online ISSN: 1535-1386.
The Journal of Bone and Joint Surgery®, JBJS®, JB&JS®, and eJBJS® are registered in the U.S. Patent and Trademark Office.