Effects of Fit and Bonding Characteristics of Femoral Stems on Adaptive Bone Remodeling

[+] Author and Article Information
H. Weinans, R. Huiskes

Section of Biomechanics, Institute of Orthopedics, University of Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands

H. J. Grootenboer

Department of Biomedical Engineering, University of Twente, Twente, The Netherlands

J Biomech Eng 116(4), 393-400 (Nov 01, 1994) (8 pages) doi:10.1115/1.2895789 History: Received February 01, 1993; Revised November 16, 1993; Online March 17, 2008


Bone atrophy caused by stress-shielding may cause serious complications for the long-term fixation of hip stems. In particular, uncemented total hip arthroplasty is threatened by this problem, because the stems are usually larger and, as a consequence, stiffer than those of cemented implants. In the present study, the effects of fit and bonding characteristics of femoral hip stems were investigated, using the (nonlinear) finite element method in combination with adaptive bone remodeling theory to predict the bone density distribution in a bone or bone/implant configuration. Unknown parameters used in the theory, such as a reference equilibrium loading stimulus and a threshold (dead) zone of this stimulus, were established (triggered) by using the method to predict the density distributions in the natural femur and around fully coated uncemented implants. The computer simulation method can provide long term predictions of remodeling patterns around various implant configurations. Several cases were analyzed, whereby the coating conditions (fully, partly, or noncoated) and the fit characteristics (press fitted or overreamed) were varied. The computer predictions showed that partly coating can only significantly reduce bone atrophy relative to fully coated stems, when the coating is applied at a small region at the utmost proximal part of the stem. For smooth press-fit stems the predicted amount of bone loss (35 percent in the proximal medial region) was less than for a one-third proximally coated or a fully coated stem (50 to 54 percent predicted bone loss in the proximal medial region). The results showed that overreaming the femoral canal in the press fit case can have important effects. Distal overreaming gave reduced proximal atrophy. Proximal overreaming (or undersizing) resulted in a distal jam of the stem, a proximal “stress-bypass,” and dramatic proximal bone loss (up to 90 percent).

Copyright © 1994 by The American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.






Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In