title: Effect of graft shape in lateral column lengthening on tarsal bone position and subtalar and talonavicular contact pressure in a cadaveric flatfoot model.
abstract: BACKGROUND
  Lateral column lengthening (LCL) has been used for correction of flatfoot deformity. The purpose of this study was to determine the effect of LCL graft shape on tarsal bone position and talonavicular and subtalar joint pressure.
  
  
  METHODS
  A flatfoot model was created in 6 cadaveric specimens. Corrective LCL was performed using a rectangular graft or a trapezoidal graft with the broad surface oriented dorsally, laterally, or plantarly. Bony surface markers were digitized to calculate angular parameters used in the evaluation of flatfoot deformity. Contact pressure and area in the subtalar and talonavicular joints were also recorded. All measurements were carried out under multiple axial loads in the intact and flatfoot conditions, and following LCL with each graft shape.
  
  
  RESULTS
  Flatfoot creation resulted in significant changes in arch collapse and forefoot abduction. LCL with a rectangular graft best corrected these parameters, while a laterally oriented trapezoidal graft provided some correction. Talonavicular contact pressure was unchanged after flatfoot creation, and was significantly less than intact after LCL. Subtalar contact pressure decreased in some conditions after flatfoot creation, and decreased further after LCL.
  
  
  CONCLUSIONS
  LCL with a rectangular graft best restored tarsal bone orientation in a cadaveric flatfoot model. The decreases in talonavicular pressure likely represent redistribution of force from the medial to lateral foot.
  
  
  CONCLUSIONS
  When performing LCL for flatfoot deformity, increased bone graft volume medially better restores tarsal bone position. One way of achieving this is through the use of a rectangular graft as opposed to a trapezoidal graft.
authors.affiliation: Orthopaedics Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach, CA, USA.
authors.forename: Sean T
authors.initials: ST
authors.lastname: Campbell
authors.affiliation: Orthopaedics Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach, CA, USA Department of Orhtopaedic Surgery, University of California, Irvine, Orange, CA, USA.
authors.forename: Keri A
authors.initials: KA
authors.lastname: Reese
authors.affiliation: Department of Orhtopaedic Surgery, University of California, Irvine, Orange, CA, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Ross
authors.affiliation: Orthopaedics Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach, CA, USA.
authors.forename: Michelle H
authors.initials: MH
authors.lastname: McGarry
authors.affiliation: Orthopaedics Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach, CA, USA.
authors.forename: Thu-Ba
authors.initials: TB
authors.lastname: Leba
authors.affiliation: Orthopaedics Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach, CA, USA Department of Orhtopaedic Surgery, University of California, Irvine, Orange, CA, USA tqlee@med.va.gov tqlee@uci.edu.
authors.forename: Thay Q
authors.initials: TQ
authors.lastname: Lee
mesh_terms: D001696:Biomechanical Phenomena; D001852:Bone Lengthening / Q000379:methods*; D016025:Bone Transplantation / Q000379:methods; D002102:Cadaver; D005260:Female; D005413:Flatfoot / Q000503:physiopathology / Q000601:surgery*; D005545:Forefoot, Human / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D010027:Osteotomy; D011312:Pressure; D013314:Stress, Mechanical; D013380:Subtalar Joint / Q000503:physiopathology / Q000601:surgery*; D013639:Tarsal Bones / Q000503:physiopathology / Q000601:surgery*
keywords: flatfoot; graft shape; lateral column lengthening; subtalar joint pressure; talonavicular joint pressure; tarsal bone position