title: Dynamic footprint measurement collection technique and intrarater reliability: ink mat, paper pedography, and electronic pedography.
abstract: BACKGROUND
  Identifying the variability of footprint measurement collection techniques and the reliability of footprint measurements would assist with appropriate clinical foot posture appraisal. We sought to identify relationships between these measures in a healthy population.
  
  
  METHODS
  On 30 healthy participants, midgait dynamic footprint measurements were collected using an ink mat, paper pedography, and electronic pedography. The footprints were then digitized, and the following footprint indices were calculated with photo digital planimetry software: footprint index, arch index, truncated arch index, Chippaux-Smirak Index, and Staheli Index. Differences between techniques were identified with repeated-measures analysis of variance with post hoc test of Scheffe. In addition, to assess practical similarities between the different methods, intraclass correlation coefficients (ICCs) were calculated. To assess intrarater reliability, footprint indices were calculated twice on 10 randomly selected ink mat footprint measurements, and the ICC was calculated.
  
  
  RESULTS
  Dynamic footprint measurements collected with an ink mat significantly differed from those collected with paper pedography (ICC, 0.85-0.96) and electronic pedography (ICC, 0.29-0.79), regardless of the practical similarities noted with ICC values (P = .00). Intrarater reliability for dynamic ink mat footprint measurements was high for the footprint index, arch index, truncated arch index, Chippaux-Smirak Index, and Staheli Index (ICC, 0.74-0.99).
  
  
  CONCLUSIONS
  Footprint measurements collected with various techniques demonstrate differences. Interchangeable use of exact values without adjustment is not advised. Intrarater reliability of a single method (ink mat) was found to be high.
authors.affiliation: Scholl College of Podiatric Medicine, Rosalind Franklin University of Medicine and Science, Center for Lower Extremity Ambulatory Research, North Chicago, IL, USA. jeanna.fascione@gmail.com
authors.forename: Jeanna M
authors.initials: JM
authors.lastname: Fascione
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Crews
authors.forename: James S
authors.initials: JS
authors.lastname: Wrobel
mesh_terms: D000328:Adult; D000886:Anthropometry / Q000295:instrumentation* / Q000379:methods; D003878:Dermatoglyphics; D005260:Female; D005528:Foot / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007281:Ink; D008297:Male; D010209:Paper; D015203:Reproducibility of Results