title: A finite element analysis of bone plates available for prophylactic internal fixation of the radial osteocutaneous donor site using the sheep tibia model.
abstract: BACKGROUND
  The strengthening effect of prophylactic internal fixation (PIF) with a bone plate at the radial osteocutaneous flap donor site has previously been demonstrated using the sheep tibia model of the human radius. This study investigated whether a finite element (FE) model could accurately represent this biomechanical model and whether stress or strain based failure criteria are most appropriate.
  
  
  METHODS
  An FE model of an osteotomised sheep tibia bone was strengthened using 4 types of plates with unilocking or bicortical screw fixation. Torsion and 4-point bending simulations were performed. The maximum von Mises stresses and strain failure criteria were studied.
  
  
  RESULTS
  The strengthening effects when applying stress failure criteria [factor 1.76-4.57 bending and 1.33-1.80 torsion] were comparable to the sheep biomechanical model [factor 1.73-2.43 bending and 1.54-2.63 torsion]. The strongest construct was the straight 3.5mm stainless steel unilocking plate. Applying strain criteria the strongest construct was the straight 3.5mm stainless DCP plate with bicortical screw fixation.
  
  
  CONCLUSIONS
  The FE model was validated by comparison with the sheep tibia model. The complex biomechanics at the bone-screw interface require further investigation. This FE modelling technique may be applied to a model of the human radius and other sites.
authors.affiliation: University Hospitals of Leicester, Department of Maxillofacial Surgery, Leicester, United Kingdom. chrisavery@doctors.org.uk
authors.forename: C M E
authors.initials: CM
authors.lastname: Avery
authors.forename: Péter
authors.initials: P
authors.lastname: Bujtár
authors.forename: János
authors.initials: J
authors.lastname: Simonovics
authors.forename: Tamás
authors.initials: T
authors.lastname: Dézsi
authors.forename: Károly
authors.initials: K
authors.lastname: Váradi
authors.forename: George K B
authors.initials: GK
authors.lastname: Sándor
authors.forename: Jingzhe
authors.initials: J
authors.lastname: Pan
mesh_terms: D000818:Animals; D001860:Bone Plates; D019245:Compressive Strength; D020342:Finite Element Analysis; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D008422:Materials Testing; D011884:Radius; D012756:Sheep; D013314:Stress, Mechanical; D013524:Surgical Flaps; D013977:Tibia / Q000293:injuries / Q000601:surgery*
keywords: Biomechanics; Bone plate; Finite element analysis; Fracture; Morbidity; Radius; Sheep tibia