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Comparison of Double Dynamic Compression Plating Versus Two Configurations of an Internal Veterinary Fixation Device: Results of In Vitro Mechanical Testing Using a Bone Substitute
Author(s) -
HaerdiLanderer Christina,
Steiner Adrian,
Linke Berend,
Wahl Dieter,
Schneider Erich,
Hehli Markus,
Frei Reto,
Auer Jörg A.
Publication year - 2002
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1053/jvet.2002.34667
Subject(s) - torsion (gastropod) , fixation (population genetics) , dynamic compression plate , composite material , implant , stiffness , compression (physics) , bending stiffness , biomechanics , bending , internal fixation , materials science , medicine , biomedical engineering , orthodontics , anatomy , surgery , population , environmental health
Objective— To compare the mechanical properties of 2 configurations of a veterinary fixation system (VFS) for large animal long bones with dynamic compression plating (DCP). Sample Population— Eighteen pairs of Canevasit tubes (Canevasit; Amsler und Frei, Schinznach Dorf, Switzerland) (length, 170 mm; diameter, 47.5 mm; cortex thickness, 10 mm), aligned with a 10‐mm gap, and stabilized with 2 DCP or 2 VFS implants. Methods— Three groups ( n = 6 ) were compared. Group 1 Canevasit tubes were stabilized with two 10‐hole, broad 4.5‐mm stainless steel DCP applied with both plates centered over the gap, in orthogonal planes parallel to the long axis of the tubes and staggered to allow bicortical fixation with ten 4.5‐mm, 52‐mm‐long cortex screws each. Group 2 tubes were stabilized similarly with 2 VFS implants, each composed of a stainless steel rod (length, 167 mm; diameter, 8 mm), and 10 clamps were applied in alternating fashion left and right on the rod and fixed bicortically with ten 4.5‐mm, 52‐mm‐long, cortex screws. Group 3 tubes were stabilized similarly, but using only 6 clamps/rod. All groups were tested initially in torsion within elastic limits and subsequently in 4‐point bending, with 1 implant on the tension side, until gap closure occurred. Results— None of the constructs failed, but all had plastic deformation after 4‐point bending. No statistically significant differences were found among the 3 groups in torsional stiffness. Double DCP fixation was significantly stiffer and stronger in 4‐point bending, compared with both configurations of double VFS fixation. Conclusions— The plate design was favored in this study. The VFS system may have to be adapted before further tests are conducted. Test modalities have to be chosen closer to clinical conditions (real bone, cyclic loading, closed gap). Clinical Relevance— The veterinary fixation system has not yet proven its advantages for large animal long bone fracture repair. From the pure mechanical point of view, double DCP is the favored method for the treatment mentioned.