Biomechanical analysis of five fixation techniques used in glenohumeral arthrodesis.
BACKGROUND
The purpose of the present study is to compare five fixation techniques in shoulder fusion. The most common complications resulting from shoulder fusion, non-union and unacceptable arm position, might reflect a failure to achieve rigid fixation during the surgical procedure.


METHODS
Twenty-five shoulder fusions were carried out on human cadaveric specimens using the following techniques: screw fixation, external fixation, external fixation supplemented with screw fixation, single plate fixation and double plate fixation. Each specimen was tested on a servohydraulic machine to determine stiffness.


RESULTS
There was a statistically significant difference in bending and torsional stiffness between all five fixation techniques. Normalized bending (B) and torsional stiffness (T), in descending order, were: double plate (B = 1.00, T = 1.00), single plate (B = 0.77, T = 0.89), external fixation with screws (B = 0.68, T = 0.74), external fixation alone (B = 0.40, T = 0.53), and screws alone (B = 0.13, T = 0.26).


CONCLUSIONS
The risk of the most common complications resulting from shoulder fusion might be minimized if these biomechanical findings are applied to surgical decision making.
Miller
Bruce S
BS
Orthopaedic Research Laboratories, The University of New South Wales, The Prince of Wales Hospital, Randwick, New South Wales, Australia. bsmiller@umich.edu
Harper
Wade P
WP
Gillies
R Mark
RM
Sonnabend
David H
DH
Walsh
William R
WR
D000368:Aged; D001174:Arthrodesis / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D008297:Male; D012785:Shoulder Joint / Q000502:physiology / Q000601:surgery*