title: Dual-energy X-ray absorptiometry of human metatarsals: precision, least significant change and association to ex vivo fracture force.
abstract: BACKGROUND
  Fractures are common in foot bones, but clinicians lack adequate indices of bone strength.
  
  
  OBJECTIVE
  We used dual-energy X-ray absorptiometry (DXA) to measure bone mineral density (BMD) and content (BMC) of excised human metatarsals, determined intra- and inter-rater measurement precision, and assessed associations between BMD/BMC and ex vivo bone fracture strength.
  
  
  METHODS
  Two raters each made two measurements of whole-bone and sub-regional BMD and BMC in both second and third metatarsals from 10 cadavers. Variance components analysis was used to assess variability attributable to repeat measurements, raters, sub-regions, bones, sides, and cadavers. Root-mean-square standard deviation (RMS-SD) and least-significant change (LSC) were used to assess rater precision and ultimate forces during 3-point bending were tested for correlations with BMD and BMC.
  
  
  RESULTS
  Variation due to repeat measurements and rater was low (<1% combined) for BMD and BMC. RMS-SD for whole metatarsal BMD of both metatarsals ranged from 0.004 to 0.010 g/cm(2) and 0.062 to 0.086 g for BMC. Whole metatarsal and sub-region BMD and BMC were strongly correlated to ex vivo fracture force (r(2)=0.67-0.93).
  
  
  CONCLUSIONS
  DXA measurements of BMD and BMC have high intra- and inter-rater precision and are strongly correlated to ex vivo bone strength.
authors.affiliation: Applied Kinesiology Laboratory, Program in Physical Therapy, Washington University School of Medicine, Campus Box 8502, 4444 Forest Park Blvd, St. Louis, MO 63108-2212, USA. Electronic address: bohnertk@wustl.edu.
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Bohnert
authors.forename: David J
authors.initials: DJ
authors.lastname: Gutekunst
authors.forename: Charles F
authors.initials: CF
authors.lastname: Hildebolt
authors.forename: David R
authors.initials: DR
authors.lastname: Sinacore
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology*; D002102:Cadaver; D005260:Female; D050723:Fractures, Bone / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008682:Metatarsal Bones / Q000000981:diagnostic imaging* / Q000502:physiology*; D008875:Middle Aged; D012044:Regression Analysis
keywords: DXA; Metatarsal bone density; Metatarsal fracture; Rater precision