Premium
Bisphosphonate treatment affects trabecular bone apparent modulus through micro‐architecture rather than matrix properties
Author(s) -
Day J. S.,
Ding M.,
Bednarz P.,
van der Linden J. C.,
Mashiba T.,
Hirano T.,
Johnston C. C.,
Burr D. B.,
Hvid I.,
Sumner D. R.,
Weinans H.
Publication year - 2004
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/j.orthres.2003.05.001
Subject(s) - osteoporosis , bisphosphonate , trabecular bone , matrix (chemical analysis) , x ray microtomography , modulus , medicine , bone density , lumbar vertebrae , lumbar , dentistry , materials science , anatomy , radiology , composite material
Bisphosphonates are emerging as an important treatment for osteoporosis. But whether the reduced fracture risk associated with bisphosphonate treatment is due to increased bone mass, improved trabecular architecture and/or increased secondary mineralization of the calcified matrix remains unclear. We examined the effects of bisphosphonates on both the trabecular architecture and matrix properties of canine trabecular bone. Thirty‐six beagles were divided into a control group and two treatment groups, one receiving risedronate and the other alendronate at 5–6 times the clinical dose for osteoporosis treatment. After one year, the dogs were killed, and samples from the first lumbar vertebrae were examined using a combination of micro‐computed tomography, finite element modeling, and mechanical testing. By combining these methods, we examined the treatment effects on the calcified matrix and trabecular architecture independently. Conventional histomorphometry and microdamage data were obtained from the second and third lumbar vertebrae of the same dogs [Bone 28 (2001) 524]. Bisphosphonate treatment resulted in an increased apparent Young's modulus, decreased bone turnover, increased calcified matrix density, and increased microdamage. We could not detect any change in the effective Young's modulus of the calcified matrix in the bisphosphonate treated groups. The observed increase in apparent Young's modulus was due to increased bone mass and altered trabecular architecture rather than changes in the calcified matrix modulus. We hypothesize that the expected increase in the Young's modulus of the calcified matrix due to the increased calcified matrix density was counteracted by the accumulation of microdamage. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.