title: Biomechanical comparison of a lateral polyaxial locking plate with a posterolateral polyaxial locking plate applied to the distal fibula.
abstract: BACKGROUND
  Polyaxial locking plates are becoming popular for the fixation of distal fibula fractures. This study establishes how construct stiffness and plate loosening, measured as range of motion, differs between lateral and posterolateral plate location.
  
  
  METHODS
  Seven matched pairs of cadaver fibulae were osteotomized in standardized fashion to produce a Weber type B distal fibula fracture. The fragments were fixated with an interfragmentary lag screw and polyaxial locking plates, with one fibula in each pair receiving a posterolateral anti-glide-plate, and the other a lateral neutralization-plate. In a biomechanical test, the bending and torsional stiffnesses of the constructs and the ranges of motion (ROM) were measured and subjected to a paired comparison.
  
  
  RESULTS
  The laterally plated group had a higher median (interquartile range) bending stiffness (29.2 (19.7) N/mm) and a smaller range of motion (2.06 (1.99) mm) than the posterolaterally plated group (14.6 (20.6) N/mm, and 4.11 (3.28) mm, respectively); however, the results were not statistically significant (pbending=0.314; pROM=0.325). Similarly, the torsional stiffness did not differ significantly between the two groups (laterally plated: 426 (259) Nmm/°; posterolaterally plated: 248 (399) Nmm/°; ptorsion=0.900). The range of motion measurements between the two groups under torsional loading were also statistically insignificant (laterally plated: 8.88 (6.30) mm; posterolaterally plated: 15.34 (12.64) mm; pROM=0.900).
  
  
  CONCLUSIONS
  In biomechanical cadaver-model tests of Weber type B fracture fixation with polyaxial locking plates, laterally plated constructs and posterolaterally plated constructs performed without significantly difference. Therefore, other considerations, such as access morbidity, associated injuries, patient anatomy, or surgeon's preference, may guide the choice of plating pattern. Further clinical studies will be needed for the establishment of definitive recommendations.
  
  
  CONCLUSIONS
  Information on the behavior of polyaxial locking plates is relevant to surgeons performing internal fixation of distal fibula fractures.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Jena University Hospital, Jena, Germany. Electronic address: Jakob.Hallbauer@med.uni-jena.de.
authors.forename: Jakob
authors.initials: J
authors.lastname: Hallbauer
authors.affiliation: Department of Foot and Ankle Surgery, St. Vincenz and Elisabeth Hospital Mainz, Germany.
authors.forename: Kajetan
authors.initials: K
authors.lastname: Klos
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Jena University Hospital, Jena, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Rausch
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, HELIOS Clinical Centre, Erfurt, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Gräfenstein
authors.affiliation: Stryker Trauma AG, Selzach, Switzerland.
authors.forename: Felix
authors.initials: F
authors.lastname: Wipf
authors.affiliation: Stryker Trauma GmbH, Schönkirchen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Beimel
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Jena University Hospital, Jena, Germany; Department of Trauma and Reconstructive Surgery, BG Centres Bergmannstrost, Halle, Germany.
authors.forename: Gunther
authors.initials: G
authors.lastname: Hofmann
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, HELIOS Clinical Centre, Erfurt, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mückley
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D004867:Equipment Design; D005360:Fibula / Q000293:injuries* / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D010027:Osteotomy; D016059:Range of Motion, Articular; D054159:Torsion, Mechanical; D016474:Weight-Bearing
keywords: Ankle; Biomechanical tests; Fibula fracture; Locking plate; Polyaxial