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Updated: Aug 5, 2026

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models
Published on: October 9, 2014
External fixators for pelvic fractures: comparison of the stiffness of current systems
Kees J Ponsen1, Gilbert A Hoek van Dijke, Pieter Joosse
1Department of Traumatology, Academisch Medisch Centrum, University of Amsterdam, Amsterdam, The Netherlands. K.J.Ponsen@amc.uva.nl
Abstract:
We evaluated the stiffness of external fixation (EF) systems with a reproducible, standardized human pelvic replica of aluminum and perspex in which a type C pelvic ring injury was created. 12 EF systems were analyzed in 2 situations that necessarily occur during a walking cycle. Endpoints were defined as 15 mm of dislocation or tolerance of the maximum load in each situation. In the no weightbearing situation, all except 2 fixators failed; in the weightbearing situation, all fixators failed. Single bar systems performed better than frame configurations. Stability provided by any external fixator is low, and in the case of a type C pelvic ring injury, it is insufficient for patient mobilization and weightbearing. Single bar systems provide more stability than frames.

