SYMPOSIA PAPER Published: 01 January 1985
STP33249S

Fatigue of Ball-Joint Rods for External Fixation

Source

Twenty-three Hoffmann ball-joint rods were subjected to sinusoidal loads, each at approximately constant amplitude, between ±400 and ±975 N at a frequency of 5 Hz. Ball-joint rod compliance was plotted against number of cycles for each specimen. The point of component failure was defined as an increase of compliance of 5% from its initial value. Fractographic methods were employed to substantiate a similarity of failure mode in specimens tested and a clear difference from non-tested specimens taken to failure. Experimental loads and number of cycles to failure were well within the clinical range. The fatigue limit of the ball-joint rods is less than 400 N (550 N/mm2). The likelihood of a given component failing is not predictable by inspection or manual manipulation.

Author Information

Donald, GD
, Burlington, VT
Seligson, D
University of Louisville School of Medicine, Louisville, KY
Brown, CA
University of Vermont, Hinesburg, VT
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Details
Developed by Committee: F04
Pages: 160–167
DOI: 10.1520/STP33249S
ISBN-EB: 978-0-8031-4926-7
ISBN-13: 978-0-8031-0427-3