title: Ankle joint pressure changes in a pes cavovarus model after lateralizing calcaneal osteotomies.
abstract: BACKGROUND
  Tendon transfers and calcaneal osteotomies are commonly used to treat symptoms related to medial ankle arthrosis in fixed pes cavovarus. However, the relative effect of these osteotomies in terms of lateralizing the ground contact point of the hindfoot and redistributing ankle joint contact stresses are unknown.
  
  
  METHODS
  Pes cavovarus with fixed hindfoot varus was simulated in eight cadaver specimens. The effect of three types of calcaneal osteotomies on the migration of the center of force and tibiotalar peak pressure at 300 N axial static load (half-body weight) were recorded using pressure sensors.
  
  
  RESULTS
  A significant lateral shift of the center of force was observed: 4.9 mm for the laterally closing Z-shaped osteotomy with additional lateralization of the tuberosity, 3.4 mm for the lateral sliding osteotomy of the calcaneal tuberosity, and 2.7 mm for the laterally closing Z-shaped osteotomy (all p < 0.001). A significant peak pressure reduction was recorded: -0.53 MPa for the Z-shaped osteotomy with lateralization, -0.58 MPa for the lateral sliding osteotomy of the calcaneal tuberosity, and -0.41 MPa for the Z-shaped osteotomy (all p < 0.01).
  
  
  CONCLUSIONS
  This cadaver study supports the hypothesis that lateralizing calcaneal osteotomies substantially help to normalize ankle contact stresses in pes cavovarus.
authors.affiliation: Department of Orthopaedic Surgery Inselspital, University of Berne, Freiburgstrasse, Berne, CH-3010, Switzerland. fabian.krause@insel.ch
authors.forename: Fabian G
authors.initials: FG
authors.lastname: Krause
authors.forename: Damian
authors.initials: D
authors.lastname: Sutter
authors.forename: Dirk
authors.initials: D
authors.lastname: Waehnert
authors.forename: Markus
authors.initials: M
authors.lastname: Windolf
authors.forename: Karsten
authors.initials: K
authors.lastname: Schwieger
authors.forename: Martin
authors.initials: M
authors.lastname: Weber
mesh_terms: D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002102:Cadaver; D002111:Calcaneus / Q000601:surgery*; D005530:Foot Deformities / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011312:Pressure