Bone density and cortical thickness in normal, osteopenic, and osteoporotic sacra.
It is unclear if a decrease in cancellous bone density or cortical bone thickness is related to sacral insufficiency fractures. We hypothesized that reduction in overall bone density leads to local reductions in bone density and cortical thickness in cadaveric sacra that match clinically observed fracture patterns in patients with sacral insufficiency fractures. We used quantitative computed tomography to measure cancellous density and cortical thickness in multiple areas of normal, osteopenic, and osteoporotic sacra. Cancellous bone density was significantly lower in osteoporotic specimens in the central and anterior regions of the sacral ala compared with other regions of these specimens. Cortical thickness decreased uniformly in all regions of osteopenic and osteoporotic specimens. These results support our hypothesis that areas of the sacrum where sacral insufficiency fractures often occur have significantly larger decreases in cancellous bone density; however, they do not support the hypothesis that these areas have local reduction of cortical bone thickness.
International Center for Orthopaedic Advancement, Department of Orthopaedic Surgery, The Johns Hopkins Bayview Medical Center, 3rd Floor, Alpha Center, 5210 Eastern Avenue, Baltimore, MD 21224-2780, USA.
Andrew M
AM
Richards
Nathan W
NW
Coleman
Trevor A
TA
Knight
Stephen M
SM
Belkoff
Simon C
SC
Mears