title: Radiographic morphometry and densitometry predict strength of cadaveric proximal humeri more reliably than age and DXA scan density.
abstract: Methods are needed for identifying poorer quality cadaver proximal humeri to ensure that they are not disproportionately segregated into experimental groups for fracture studies. We hypothesized that measurements made from radiographs of cadaveric proximal humeri are stronger predictors of fracture strength than chronological age or bone density values derived from dual-energy x-ray absorptiometry (DXA) scans. Thirty-three proximal humeri (range: 39-78 years) were analyzed for: (1) bone mineral density (BMD, g/cm(2)) using DXA, (2) bulk density (g/cm(3)) using DXA and volume displacement, (3) regional bone density in millimeters of aluminum (mmAl) using radiographs, and (4) regional mean (medial+lateral) cortical thickness and cortical index (CI) using radiographs. The bones were then fractured simulating a fall. Strongest correlations with ultimate fracture load (UFL) were: mean cortical thickness at two diaphyseal locations (r = 0.71; p < 0.001), and mean mmAl in the humeral head (r = 0.70; p < 0.001). Weaker correlations were found between UFL and DXA-BMD (r = 0.60), bulk density (r = 0.43), CI (r = 0.61), and age (r = -0.65) (p values <0.01). Analyses between UFL and the product of any two characteristics showed six combinations with r-values >0.80, but none included DXA-derived density, CI, or age. Radiographic morphometric and densitometric measurements from radiographs are therefore stronger predictors of UFL than age, CI, or DXA-derived density measurements.
authors.affiliation: Department of Orthopaedics, University of Utah, Salt Lake City, Utah.|Utah Orthopaedic Specialists, Salt lake City, Utah.
authors.forename: John G
authors.initials: JG
authors.lastname: Skedros
authors.affiliation: Utah Orthopaedic Specialists, Salt lake City, Utah.
authors.forename: Alex N
authors.initials: AN
authors.lastname: Knight
authors.affiliation: Utah Orthopaedic Specialists, Salt lake City, Utah.|Department of Orthopaedics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Pitts
authors.affiliation: Letterkenny General Hospital, Co Donegal, Ireland.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: O'Rourke
authors.affiliation: Department of Orthopaedics, University of Texas Southwestern Medical School and the W.B. Carrell Memorial Clinic, Dallas, Texas.
authors.forename: Wayne Z
authors.initials: WZ
authors.lastname: Burkhead
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology; D015519:Bone Density; D005260:Female; D050723:Fractures, Bone / Q000209:etiology*; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D033081:Shear Strength
keywords: DXA; densitometry; fracture; morphometry; proximal humerus