title: Precision of foot alignment measures in Charcot arthropathy.
abstract: BACKGROUND
  Foot deformity associated with diabetes mellitus (DM) and peripheral neuropathy (PN) contributes to joint instability, ulceration and amputation. This study reports the intrarater and inter-rater measurement precision and least significant change (LSC) of radiological measures of foot deformity in subjects with DM, PN, and foot related complications.
  
  
  METHODS
  Cuboid height, Meary's angle, calcaneal pitch and hindfoot-forefoot angle were measured from plain-film radiographs on 15 subjects with DM, PN, and foot-related complications. A foot and ankle fellowship-trained orthopedic surgeon with 23 years of experience (Rater 1) measured radiographs twice. A foot and ankle fellowship-trained orthopedic surgeon with 2 years of experience (Rater 2) and a radiologist in residency training (Rater 3) measured radiographs once. Root mean square standard deviation and LSC were calculated to determine measurement precision and the smallest change considered biologically real, not the result of chance.
  
  
  RESULTS
  Intrarater measurement precision was: 0.9 mm for cuboid height, 3 degrees for Meary's angle, and 2 degrees for calcaneal pitch and hindfoot-forefoot angle. Inter-rater measurement precision for rater 1 versus 2 and 1 versus 3 were: 1.7 and 1.6 mm for cuboid height, 4 degrees for Meary's angle, 2 degrees for calcaneal pitch, and 3 degrees for the hindfoot-forefoot angle. The LSC was less than or equal to: 4.7 mm for cuboid, 12 degrees for Meary's angle, 6 degrees for calcaneal pitch, and 8 degrees for hindfoot-forefoot angle.
  
  
  CONCLUSIONS
  Cuboid height, calcaneal pitch, and hindfoot-forefoot angle measures can be completed with relatively good measurement precision.
authors.affiliation: Washington University School of Medicine, Campus Box 8502, 4444 Forest Park Blvd., Room 1101, St. Louis, MO 63108-2212, USA. hastingsmk@wustl.edu
authors.forename: Mary K
authors.initials: MK
authors.lastname: Hastings
authors.forename: David R
authors.initials: DR
authors.lastname: Sinacore
authors.forename: Nicole
authors.initials: N
authors.lastname: Mercer-Bolton
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: McCormick
authors.forename: Charles F
authors.initials: CF
authors.lastname: Hildebolt
authors.forename: Fred W
authors.initials: FW
authors.lastname: Prior
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Johnson
mesh_terms: D000843:Ankle Joint / Q000000981:diagnostic imaging; D001177:Arthropathy, Neurogenic / Q000150:complications*; D003929:Diabetic Neuropathies / Q000150:complications*; D005260:Female; D005528:Foot / Q000000981:diagnostic imaging*; D005529:Foot Bones / Q000000981:diagnostic imaging*; D005531:Foot Deformities, Acquired / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D008875:Middle Aged; D011859:Radiography; D013639:Tarsal Bones / Q000000981:diagnostic imaging
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