title: Effect of foot orthoses on 3-dimensional kinematics of flatfoot: a cadaveric study.
abstract: OBJECTIVE
  To test in cadaveric feet the hypothesis that prefabricated foot orthoses will improve arch alignment in flatfoot deformity.
  
  
  METHODS
  Experimental, paired comparisons.
  
  
  METHODS
  Biomechanics laboratory.
  
  
  METHODS
  Nine cadaveric lower-extremity specimens with no abnormalities.
  
  
  METHODS
  To evaluate the performance of 2 orthoses specimens were tested in 4 combinations: intact, flatfoot, flatfoot with shoe and orthosis 1, and flatfoot with shoe and orthosis 2. To simulate the midstance phase of gait, loads were applied to 5 tendons and an axial load equivalent to two thirds of the standing load was applied to the foot's plantar surface.
  
  
  METHODS
  Arch height and tarsal bone positions before and after a flatfoot deformity created by ligament sectioning; tarsal bone positions determined with a magnetic tracking system.
  
  
  RESULTS
  After ligament sectioning, the average decrease in arch height with a shoe applied was 4.6+/-1.6mm (8%); with orthosis 1, mean arch height increased 0.7+/-0.6mm (P=.008); with orthosis 2, it increased 0.3+/-0.5mm (P=.05). With both orthoses, arch height after sectioning was significantly less than that of the normal arch. Compared with the flatfoot condition, metatarsal-talar alignment improved in plantar flexion and inversion with both orthoses but did not approximate normal with either orthosis. Calcaneal-tibial position did not improve with either orthosis and was markedly different from that in the intact foot with either orthosis. No difference was found between the 2 orthoses except for metatarsal-talar motion in external rotation (P=.014) and eversion (P=.026).
  
  
  CONCLUSIONS
  Arch alignment improved significantly but to a limited degree (<2%) in cadaveric feet with the use of orthoses. Hindfoot valgus malalignment did not consistently improve by the use of shoe inserts.
authors.affiliation: Department of Orthopedics, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Harold B
authors.initials: HB
authors.lastname: Kitaoka
authors.forename: Zong-Ping
authors.initials: ZP
authors.lastname: Luo
authors.forename: Hideji
authors.initials: H
authors.lastname: Kura
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: An
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D005413:Flatfoot / Q000503:physiopathology / Q000534:rehabilitation*; D005529:Foot Bones / Q000502:physiology; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D009989:Orthotic Devices