An in vitro biomechanical investigation of the mechanical properties of dynamic compression plated osteotomized adult equine tibiae.
OBJECTIVE
To determine the monotonic mechanical properties of osteotomized adult equine tibiae stabilized with two dynamic compression plates (DCP) and to compare the mechanical properties with those of intact tibiae and in vivo loads.


METHODS
The compressive, bending, and torsional mechanical properties of plated and intact tibiae were assessed in vitro.


METHODS
Twelve pairs of adult equine tibiae.


METHODS
Tibiae were loaded in axial compression, craniocaudal 3-point bending, or torsion in external rotation in a single cycle to failure. Mechanical properties were determined from load-displacement data.


RESULTS
Compared to intact tibiae, the mean yield load, failure load and stiffness of plated tibiae were significantly lower (P < .05) (compression and torsion); and the mean yield and failure bending moments, and bending stiffness, of the plated tibiae were lower (P < .075 for yield), or significantly lower, respectively. The mean compression and bending yield loads for plated tibiae were greater than in vivo loads. The mean torsional yield load for plated tibiae approximated the torsional load determined for the adult horse at a walk.


CONCLUSIONS
Simple, anatomically reduced, DCP plated tibiae should have adequate strength to withstand immediate, postoperative in vivo compressive loads and bending moments placed on the tibia in vivo during immediate postoperative activities, however, may not have adequate torsional strength during immediate postoperative weight-bearing at a walk.


CONCLUSIONS
Additional supportive methods, to decrease torsional loads, may be beneficial in maintaining stability of plate repaired tibiae during recovery from anesthesia and postoperative healing.
McDuffee
L A
LA
Department of Veterinary Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616, USA.
Stover
S M
SM
Taylor
K T
KT
D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates / Q000662:veterinary; D001863:Bone Screws / Q000662:veterinary; D005593:Fracture Fixation, Internal / Q000662:veterinary; D006736:Horses / Q000293:injuries* / Q000502:physiology; D010027:Osteotomy / Q000662:veterinary; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology*; D013978:Tibial Fractures / Q000601:surgery / Q000662:veterinary*