Estimation of geometric properties of cortical bone in spinal cord injury

Objective: To evaluate structural and geometrical properties of the tibia s haft in subjects with spinal cord injury (SCI) and subjects without SCI and to estimate the potential usefulness of a multimodal approach to diagnosin g osteoporosis in SCI. Design: A cross-sectional study of randomly selected SCI and non-SCI subjec ts. Methods: Measurements of bone geometric indices by computed tomography, and calculated bending stiffness with a biomechanical testing method. Setting: An SCI center hospital. Subjects: Ten men without known orthopedic or neurologic impairments (contr ols), 10 men with SCI who bad a history of lower extremity pathologic fract ure since SCI, and 10 men with SCI who had never had lower extremity pathol ogic fracture. Results: Analysis of geometric and structural indices of subjects' tibias f ound a significant difference in all geometric indices between controls and the SCI subjects with pathologic fracture history. Between the controls an d the SCI subjects with no fracture history, however, differences were foun d only in cross-sectional area and calculated bending stiffness. Conclusion: Structural analysis of leg bone, combined with measurement of b one density, may improve the ability to assess fracture risk in patients wi th SCI.