title: Comparison between amputation-induced demineralization and age-related bone loss using digital X-ray radiogrammetry.
abstract: Digital X-ray radiogrammetry (DXR) is a computer-assisted automatic osteodensitometric tool. This study was performed to compare DXR measurements between bone changes following amputation trauma and age-related bone loss. Thirty-five men, who had undergone finger amputations, received a baseline examination and 2--3 serial measurements. As a second group, 215 males older than 70yr were enrolled. All patients obtained standardized hand radiographs. The following DXR parameters evaluating metacarpals were considered: cortical bone mineral density (DXR-BMD), cortical thickness (DXR-CT), metacarpal index (DXR-MCI), outer bone diameter (width; DXR-W), and inner medullary diameter (DXR-MD). In the amputation group, the DXR parameters showed an accentuated initial decrease between first and second measurements (DRX-BMD--12.7%, DXR-CT--14.2%, DXR-W--8.6%, DXR-MCI--6.1%; p<0.001) followed by a less pronounced reduction between second and third radiographs (DRX-BMD--0.5%, DXR-CT--1.5%, DXR-W--0.1%, DXR-MCI--1.3%). DXR-MD revealed a reduction of--3.6% (p<0.05) between first and second estimates and a non-significant increase (+1.1%) between second and third measurements. When compared with the second and third estimates in the amputation group, men older than 70yr presented lower DXR-BMD, DXR-CT, and DXR-MCI values (p<0.001), but larger metacarpal outer and inner bone diameters (DXR-W and DXR-MD; p<0.001). DXR-MD of the elderly men group was also more extended when compared with the baseline measurements of the amputation cohort (p<0.001). The early accentuated cortical bone loss and particularly the pronounced decrease of the outer bone width seem to be characteristic for amputation-induced osteoporosis, suggesting that this might be a distinct secondary osteoporosis entity. When compared with amputation-associated osteoporosis, where the bone loss occurs to a higher extent in the outer bone diameter than in the medullary cavity, the age-related bone changes lead more to an increase of the medullary diameter than of the outer bone width.
authors.affiliation: Department of Radiology, Charité University Medicine Berlin, Campus Virchow Clinic, Berlin, Germany.
authors.forename: Max-Ludwig
authors.initials: ML
authors.lastname: Schäfer
authors.forename: Joachim
authors.initials: J
authors.lastname: Böttcher
authors.forename: Alexander
authors.initials: A
authors.lastname: Pfeil
authors.forename: Andreas
authors.initials: A
authors.lastname: Hansch
authors.forename: Ansgar
authors.initials: A
authors.lastname: Malich
authors.forename: Martin H
authors.initials: MH
authors.lastname: Maurer
authors.forename: Florian
authors.initials: F
authors.lastname: Streitparth
authors.forename: Rainer
authors.initials: R
authors.lastname: Röttgen
authors.forename: Diane M
authors.initials: DM
authors.lastname: Renz
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000671:Amputation, Surgical; D000674:Amputees; D018488:Bone Demineralization, Pathologic / Q000000981:diagnostic imaging*; D015519:Bone Density; D005383:Finger Injuries / Q000601:surgery*; D050278:Finger Phalanges / Q000000981:diagnostic imaging*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging*; D011795:Surveys and Questionnaires