Stresses in a Harrington Distraction Rod: Their Origin and Relationship to Fatigue Fractures In Vivo

[+] Author and Article Information
J. B. Brunski, D. C. Hill

Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, N.Y. 12181

A. Moskowitz

Division of Orthopaedic Surgery, Albany Medical College, Albany, N.Y. 12208

J Biomech Eng 105(2), 101-107 (May 01, 1983) (7 pages) doi:10.1115/1.3138392 History: Received January 11, 1982; Revised October 05, 1982; Online June 15, 2009


As illustrated by the case study described in this paper, in-vivo fractures of distraction rods often occur by metallurgical fatigue at the junction between the smooth and ratcheted parts of the rod (i.e., at the first ratchet junction, FRJ). To clarify causative factors of fatigue at the FRJ, stresses are analyzed in a standard 11-in. rod using both experimental and theoretical methods. The analyses reveal how distraction force, eccentricity of loading, rod geometry and material determine the stresses at the FRJ. These stresses can exceed the fatigue endurance limit for certain clinically encountered conditions.

Copyright © 1983 by ASME
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