title: Angular stable lateral plating is a valid alternative to conventional plate fixation in the proximal phalanx. A biomechanical study.
abstract: BACKGROUND
  Dorsal plating is commonly used in proximal phalanx fractures but it bears the risk of interfering with the extensor apparatus. In this study, dorsal and lateral plating fixation methods are compared to assess biomechanical differences using conventional 1.5mm non-locking plates and novel 1.3mm lateral locking plates.
  
  
  METHODS
  Twenty-four fresh frozen human cadaveric proximal phalanges were equally divided into four groups. An osteotomy was set at the proximal metaphyseal-diaphyseal junction and fixed with either dorsal (group A) or lateral (group B) plating using a 1.5mm non-locking plate, or lateral plating with a novel 1.3mm locking plate with bicortical (group C) or unicortical (group D) screws. The specimens were loaded in axial, dorsovolar and mediolateral direction to assess fixation stiffness followed by a cyclic destructive test in dorsovolar loading direction.
  
  
  RESULTS
  Axial stiffness was highest in group D (mean 321.02, SEM 21.47N/mm) with a significant difference between groups D and B (P=0.033). Locking plates (groups C and D) were stiffer than non-locking plates under mediolateral loading (P=0.007), no significant differences were noted under dorsovolar loading. Furthermore, no significant differences were observed under cyclic loading to failure between any of the study groups.
  
  
  CONCLUSIONS
  No considerable biomechanical advantage of using a conventional 1.5mm dorsal non-locking plate was identified over the novel 1.3mm lateral locking plate in the treatment of proximal phalanx fractures. Since the novel low-profile plate is less disruptive to the extensor mechanism, it should be considered as a valid alternative.
authors.affiliation: AO Research Institute Davos, Davos, Switzerland; Orthopaedic Department, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: R
authors.initials: R
authors.lastname: Shanmugam
authors.affiliation: AO Research Institute Davos, Davos, Switzerland. Electronic address: manuela.ernst@aofoundation.org.
authors.forename: M
authors.initials: M
authors.lastname: Ernst
authors.affiliation: Cantonal Hospital Baselland, Liestal, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Stoffel
authors.affiliation: AO Research Institute Davos, Davos, Switzerland.
authors.forename: M F
authors.initials: MF
authors.lastname: Fischer
authors.affiliation: AO Research Institute Davos, Davos, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Wahl
authors.affiliation: AO Research Institute Davos, Davos, Switzerland.
authors.forename: R G
authors.initials: RG
authors.lastname: Richards
authors.affiliation: AO Research Institute Davos, Davos, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Gueorguiev
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D050278:Finger Phalanges / Q000293:injuries / Q000502:physiology / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans
keywords: Fracture fixation; Lateral plating; Proximal phalanx