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.