title: Biomechanical and computational evaluation of two loading transfer concepts for pancarpal arthrodesis in dogs.
abstract: OBJECTIVE
  To evaluate 2 plate designs for pancarpal arthrodesis and their effects on load transfer to the respective bones as well as to develop a computational model with directed input from the biomechanical testing of the 2 constructs.
  
  
  METHODS
  Both forelimbs from the cadaver of an adult castrated male Golden Retriever.
  
  
  METHODS
  CT imaging was performed on the forelimb pair. Each forelimb was subsequently instrumented with a hybrid dynamic compression plate or a castless pancarpal arthrodesis plate. Biomechanical testing was performed. The forelimbs were statically loaded in the elastic range and then cyclically loaded to failure. Finite element (FE) modeling was used to compare the 2 plate designs with respect to bone and implant stress distribution and magnitude when loaded.
  
  
  RESULTS
  Cyclic loading to failure elicited failure patterns similar to those observed clinically. The mean ± SD error between computational and experimental strain was < 15% ± 13% at the maximum loads applied during static elastic loading. The highest bone stresses were at the distal extent of the metacarpal bones at the level of the screw holes with both plates; however, the compression plate resulted in slightly greater stresses than did the arthrodesis plate. Both models also revealed an increase in bone stress at the proximal screw position in the radius. The highest plate stress was identified at the level of the radiocarpal bone, and an increased screw stress (junction of screw head with shaft) was identified at both the most proximal and distal ends of the plates.
  
  
  CONCLUSIONS
  The FE model successfully approximated the biomechanical characteristics of an ex vivo pancarpal plate construct for comparison of the effects of application of different plate designs.
authors.affiliation: AO Research Institute, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Rothstock
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kowaleski
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Boudrieau
authors.forename: Brian S
authors.initials: BS
authors.lastname: Beale
authors.forename: Alessandro
authors.initials: A
authors.lastname: Piras
authors.forename: Mark
authors.initials: M
authors.lastname: Ryan
authors.forename: Ludovic
authors.initials: L
authors.lastname: Bouré
authors.forename: Stefano
authors.initials: S
authors.lastname: Brianza
mesh_terms: D000818:Animals; D001174:Arthrodesis / Q000379:methods / Q000662:veterinary*; D001696:Biomechanical Phenomena; D001860:Bone Plates / Q000662:veterinary*; D001863:Bone Screws / Q000662:veterinary*; D003198:Computer Simulation; D004285:Dogs; D005552:Forelimb; D007593:Joint Instability / Q000662:veterinary; D008297:Male; D008422:Materials Testing / Q000662:veterinary; D008954:Models, Biological