title: Reliability of lateral distal femur dual-energy X-ray absorptiometry measures.
abstract: Dual-energy X-ray absorptiometry (DXA) of the lateral distal femur (LDF) has been suggested for patients with metal implants or joint contractures preventing DXA scanning at conventional anatomical sites. This study assessed variability in LDF DXA measures due to repeat scanning using data from 5 healthy young adults who had 3 unilateral scans with repositioning between scans. Variability due to image analysis was evaluated in 10 children who underwent bilateral LDF scans with each scan being analyzed 3 times by 2 raters. Regions of interest (ROIs) were defined in the anterior distal metaphysis (R1), metadiaphysis (R2), and diaphysis (R3) as described previously. An additional region (R4) was defined in the metaphysis similar to R1 but centered in the medullary canal. Variability was consistently lower for bone mineral density than for bone mineral content and bone area; R4 was more repeatable than R1; and variability because of repeat scanning was negligible. These results suggest that DXA measures of the LDF are reliable and may be useful when standard DXA measures cannot be obtained, but it is recommended that a central, rather than anterior, ROI be used in the metaphysis.
authors.affiliation: Motion Analysis Lab, Children's Orthopaedic Center, Children's Hospital Los Angeles, Los Angeles, CA, USA. Electronic address: nmueske@chla.usc.edu.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Mueske
authors.affiliation: Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Linda S
authors.initials: LS
authors.lastname: Chan
authors.affiliation: Motion Analysis Lab, Children's Orthopaedic Center, Children's Hospital Los Angeles, Los Angeles, CA, USA; Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA.
authors.forename: Tishya A L
authors.initials: TA
authors.lastname: Wren
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density; D002648:Child; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
keywords: Bone mineral density; DXA; lateral DXA; reliability
references.citation: Postgrad Med J. 2007 Aug;83(982):509-17
references.pmid: 17675543
references.citation: QJM. 2008 Aug;101(8):605-17
references.pmid: 18334497
references.citation: J Pediatr Orthop. 1991 May-Jun;11(3):314-7
references.pmid: 2056078
references.citation: Orthopedics. 2008 Nov;31(11):1093
references.pmid: 19226092
references.citation: Skeletal Radiol. 1997 Sep;26(9):544-7
references.pmid: 9342815
references.citation: Pediatr Radiol. 1998 Apr;28(4):241-6
references.pmid: 9545479
references.citation: J Pediatr Orthop. 2006 Sep-Oct;26(5):686-90
references.pmid: 16932112
references.citation: J Clin Densitom. 2009 Apr-Jun;12(2):207-18
references.pmid: 19321369
references.citation: AJR Am J Roentgenol. 2002 Feb;178(2):439-43
references.pmid: 11804914
references.citation: Clin Orthop Relat Res. 2011 May;469(5):1253-7
references.pmid: 21042897
references.citation: J Bone Miner Res. 1995 Jul;10(7):1004-14
references.pmid: 7484275
references.citation: J Bone Miner Res. 2010 Mar;25(3):520-6
references.pmid: 19821773