CONTRIBUTING FACTORS TO DECREASED FAILURE LOAD OF RADIUS IN THE HEMI-PARETIC LIMB AFTER CHRONIC STROKE: A PROSPECTIVE COHORT STUDY

H. Ouyang¹, T. Miller¹, M. Pang¹

¹The Hong Kong Polytechnic University, Department of Rehabilitation Sciences, Kowloon, Hong Kong

Background: Secondary osteoporosis is common after stroke, particularly in the hemi-paretic limbs. Previous research found that bone failure load was a significant risk factor to facture post stroke.

Purpose: This prospective cohort study aimed to explore how bone density, macrostructure, and microstructure of the distal radius changed during chronic stage of stroke recovery and to identify the factors associated with change in failure load of the distal radius.

Methods: A total of 46 people with chronic stroke (21 women, mean age: 60 Years; mean post-stroke onset: 6 years). Bone properties and failure load of the bilateral distal radius were measured twice using high-resolution peripheral quantitative computed tomography (HR-pQCT), first at the time of study enrolment and again at 2-year follow-up. Blood flow volume of brachial artery was measured by Doppler Ultrasound. Multiple hierarchical regression analysis was applied to identify the predictors of failure load.

Results: On the paretic side, there was significant decline in trabecular bone density (-2.29%), cortical thickness (-3.61%), cortical area (-3.45%) and trabecular thickness (-0.09%), whereas the cortical perimeter (0.23%) and the trabecular area (1.06%) demonstrated significant increase after two years of follow up. Among these, the change of cortical thickness (Beta =0.46, p =0.005) and cortical bone density (Beta =0.51, p <0.001) contributed most to the decrease in failure load of the hemi-paretic radius. In addition, smaller blood flow volume of the brachial artery on the paretic side at baseline assessment (standardized Beta =-0.40, p =0.011) was a significant predictor of the decrease in failure load of the radius over the 2-year follow-up period.

Conclusions: Changes in cortical bone properties accounted most for the deterioration of failure load of the radius in people with chronic stroke. More compromised vascular health was associated with greater decline in failure load of the hemi-paretic distal radius.

Implications: Cortical bone properties continued to show deterioration during the chronic stage of stroke. Improving vascular health may be a potential target to mitigate secondary osteoporosis in individuals with chronic stroke.

Funding acknowledgements: General Research Fund (granted by Research Grants Council (General Research Fund; 151031/18M), PhD studentship granted by the Hong Kong Polytechnic University

Keywords:
Stroke
Bone
Peripheral quantitative computed tomography

Topics:
Neurology: stroke

Did this work require ethics approval? Yes

Institution: The Hong Kong Polytechnic University

Committee: Institutional Review Board

Ethics number: HSEARS20161229002-02