title: Interlocking Nailing Versus Interlocking Plating in Intra-articular Calcaneal Fractures: A Biomechanical Study.
abstract: BACKGROUND
  Open reduction and internal fixation with a plate is deemed to represent the gold standard of surgical treatment for displaced intra-articular calcaneal fractures. Standard plate fixation is usually placed through an extended lateral approach with high risk for wound complications. Minimally invasive techniques might avoid wound complications but provide limited construct stability. Therefore, 2 different types of locking nails were developed to allow for minimally invasive technique with sufficient stability. The aim of this study was to quantify primary stability of minimally invasive calcaneal interlocking nail systems in comparison to a variable-angle interlocking plate.
  
  
  METHODS
  After quantitative CT analysis, a standardized Sanders type IIB fracture model was created in 21 fresh-frozen cadavers. For osteosynthesis, 2 different interlocking nail systems (C-Nail; Medin, Nov. Město n. Moravě, Czech Republic; Calcanail; FH Orthopedics SAS; Heimsbrunn, France) as well as a polyaxial interlocking plate (Rimbus; Intercus GmbH; Rudolstadt, Germany) were used. Biomechanical testing consisted of a dynamic load sequence (preload 20 N, 1000 N up to 2500 N, stepwise increase of 100 N every 100 cycles, 0.5 mm/s) and a load to failure sequence (max. load 5000 N, 0.5 mm/s). Interfragmentary movement was detected via a 3-D optical measurement system. Boehler angle was measured after osteosynthesis and after failure occurred.
  
  
  RESULTS
  No significant difference regarding load to failure, stiffness, Boehler angle, or interfragmentary motion was found between the different fixation systems. A significant difference was found with the dynamic failure testing sequence where 87.5% of the Calcanail implants failed in contrast to 14% of the C-Nail group (P < .01) and 66% of the Rimbus plate. The highest load to failure was observed for the C-Nail. Boehler angle showed physiologic range with all implants before and after the biomechanical tests.
  
  
  CONCLUSIONS
  Both minimally invasive interlocking nail systems displayed a high primary stability that was not inferior to an interlocking plate.
  
  
  CONCLUSIONS
  Based on our results, both interlocking nails appear to represent a viable option for treating displaced intra-articular calcaneal fractures.
authors.affiliation: Department of Trauma, Rostock University Medical Center, Hand and Reconstructive Surgery, Rostock, Germany sophia.labs@gmx.de.
authors.forename: Sophia
authors.initials: S
authors.lastname: Reinhardt
authors.affiliation: Department of Biomedical Engineering, Rostock University Medical Center, Rostock, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Martin
authors.affiliation: Department of Orthopaedics, University of Ulm, Ulm, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ulmar
authors.affiliation: Department of Trauma and Reconstructive Surgery, University of Tübingen, Tübingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Döbele
authors.affiliation: UniversitätsCentrum für Orthopädie und Unfallchirurgie, Universitätsklinikum "Carl Gustav Carus" der TU Dresden, Dresden, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Zwipp
authors.affiliation: UniversitätsCentrum für Orthopädie und Unfallchirurgie, Universitätsklinikum "Carl Gustav Carus" der TU Dresden, Dresden, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Rammelt
authors.affiliation: Klinik für Fuß- und Sprunggelenkchirurgie, Nuremberg and Rummelsberg, Germany.
authors.forename: Martinus
authors.initials: M
authors.lastname: Richter
authors.affiliation: Department of Traumatology, Pardubice Regional Hospital, Pardubice, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Pompach
authors.affiliation: Department of Trauma, Rostock University Medical Center, Hand and Reconstructive Surgery, Rostock, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mittlmeier
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001860:Bone Plates; D002111:Calcaneus / Q000293:injuries* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D016474:Weight-Bearing
keywords: biomechanical testing; calcaneal fracture; interlocking nail; locking plate; minimally invasive fixation; stability