Changes in bone density and geometry of the radius in chronic stroke and related factors: a one-year prospective study.

OBJECTIVES To describe the changes in bone density and geometry of the radius after chronic stroke and the associated clinical factors. METHODS Twenty stroke patients (12 men and 8 women, age=42-78 years, time post-stroke=12-166 months) and 23 control participants (14 men and 9 women, age=53-77 years) were assessed at the time of enrolment and one year later. Peripheral quantitative computed tomography was used to scan the radius epiphysis (4% site) and diaphysis (33% site). Grip strength, spasticity, paretic arm disuse, physical activity, and vascular health were also evaluated. RESULTS During the follow-up period, only the cortical thickness and cortical bone mineral content (BMC) in the paretic radius diaphysis showed a decline that exceeded the least significant change value (p=0.002). Paretic arm disuse, lower vascular elasticity and physical activity level at initial assessment were significantly related to more decline in cortical thickness at this site (p<0.01). CONCLUSIONS The paretic radius diaphysis sustained significant reduction in cortical thickness and cortical BMC over time in chronic stroke, but these changes were less pronounced than those previously reported in sub-acute stroke. Strategies to modify vascular health, disuse, and physical activity may be important in improving upper limb bone health but will need further investigations.