title: High Variability of Observed Weight Bearing During Standing Foot and Ankle Radiographs.
abstract: BACKGROUND
  Weight-bearing radiographs are a critical component of evaluating foot and ankle pathology. An underlying assumption is that patients are placing 50% of their body weight on the affected foot during image acquisition. The accuracy of weight bearing during radiographs is unknown and, presumably, variable, which may result in uncertain ability of the resultant radiographs to appropriately portray the pathology of interest.
  
  
  METHODS
  Fifty subjects were tested. The percentage body weight through the foot of interest was measured at the moment of radiographic image acquisition. The subject was then instructed to bear "half [their] weight" prior to the next radiograph. The percentage body weight was calculated and compared to ideal 50% weight bearing.
  
  
  RESULTS
  The mean percentage body weight in trial 1 and 2 was 45.7% ± 3.2% ( P = .012 compared to the 50% mark) and 49.2% ± 2.4%, respectively ( P = .428 compared to 50%). The mean absolute difference in percentage weight bearing compared to 50% in trials 1 and 2 was 9.3% ± 2.3% and 5.8% ± 1.8%, respectively ( P = .005). For trial 1, 18/50 subjects were within the "ideal" (45%-55%) range for weight bearing compared to 32/50 on trial 2 ( P = .005). In trial 1, 24/50 subjects had "appropriate" (>45%) weight bearing compared to 39/50 on trial 2 ( P = .002).
  
  
  CONCLUSIONS
  There was substantial variability in the weight applied during radiograph acquisition. This study raises questions regarding the assumptions, reliability, and interpretation when evaluating weight-bearing radiographs.
  
  
  METHODS
  Level III, comparative study.
authors.affiliation: 1 Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Miller
authors.affiliation: 1 Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghorbanhoseini
authors.affiliation: 2 Naval Hospital Beaufort, Beaufort, SC, USA.
authors.forename: Lauren K
authors.initials: LK
authors.lastname: Ehrlichman
authors.affiliation: 1 Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Kempland C
authors.initials: KC
authors.lastname: Walley
authors.affiliation: 3 Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Ghaheri
authors.affiliation: 1 Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: John Y
authors.initials: JY
authors.lastname: Kwon
mesh_terms: D000842:Ankle / Q000000981:diagnostic imaging* / Q000502:physiology*; D000843:Ankle Joint / Q000000981:diagnostic imaging* / Q000502:physiology*; D005528:Foot / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D011859:Radiography; D015203:Reproducibility of Results; D016474:Weight-Bearing / Q000502:physiology*
keywords: foot and ankle; radiographs; reliability; weight bearing