This project was performed in the Comparative Orthopaedics and Biomechanics Laboratory at the University of Florida, College of Veterinary Medicine.
Original Article - Research
A Biomechanical Comparison of Three Hybrid Linear-Circular External Fixator Constructs
Article first published online: 7 SEP 2012
© Copyright 2012 by The American College of Veterinary Surgeons
Volume 41, Issue 8, pages 954–965, November 2012
How to Cite
Hudson, C. C., Lewis, D. D., Cross, A. R., Dunbar, N. J., Horodyski, M., Banks, S. A. and Pozzi, A. (2012), A Biomechanical Comparison of Three Hybrid Linear-Circular External Fixator Constructs. Veterinary Surgery, 41: 954–965. doi: 10.1111/j.1532-950X.2012.01035.x
Part of the material in this article was presented at the 2010 Veterinary Orthopedic Society Meeting in Breckenridge, CO and at the 2011 ACVS Veterinary Symposium in Chicago, IL.
- Issue published online: 30 NOV 2012
- Article first published online: 7 SEP 2012
- Manuscript Accepted: FEB 2012
- Manuscript Received: DEC 2011
To evaluate the stiffness, displacement, ring deformation and bone model motion of 3 configuations of linear-circular hybrid fixator constructs loaded in axial compression, craniocaudal and mediolateral bending, and torsion.
Three hybrid construct configurations with 8 replicates/configuration.
Construct Ia used a single, 84 mm, incomplete ring and 2 tensioned olive wires to stabilize 1 bone segment and a primary hybrid rod with 3 fixation pins to stabilize the other bone segment. Constructs Iad and Ib were similar to Ia with the addition of a secondary diagonal hybrid rod. Construct Ib had a fixation pin inserted orthogonally from the diagonal rod. Constructs were loaded for 10 cycles in each mode of loading using a materials testing machine. Ring deformation was assessed by obtaining serial ring measurements. Bone model motion at the fracture gap as a result of loading was also calculated.
Axial compression: constructs Iad and Ib were significantly stiffer than construct Ia. Craniocaudal bending: Construct Ib was significantly stiffer than construct Ia. Mediolateral bending: there were no significant differences between constructs. Torsion: Construct Ib was significantly stiffer than constructs Ia and Iad. Permanent ring deformation did not occur. Bone model translational motion decreased in constructs Iad and Ib compared to construct Ia.
Addition of a secondary hybrid rod as well as biplanar fixation pin placement improved construct stiffness in several loading modes.