Author: Ouyang, Huixi
Title: Using high-resolution peripheral quantitative computed tomography to study the long bone structural changes after stroke : a longitudinal study
Advisors: Pang, Marco (RS)
Degree: Ph.D.
Year: 2023
Subject: Bones -- Tomography
Cerebrovascular disease -- Patients
Hong Kong Polytechnic University -- Dissertations
Department: Department of Rehabilitation Sciences
Pages: xix, 263 pages : illustrations
Language: English
Abstract: Background (Chapter 1) and Study 1 (Chapter 2):
Secondary stroke-induced osteoporosis is often overlooked. Study 1 (systematic review and meta-analysis) revealed moderate evidence supporting that exercise was beneficial for hip bone health in post-stroke individuals. However, individualized effective interventions to alleviate post-stroke bone loss have not been well established, especially for the radius and tibia. Therefore, knowing how the long bone health changes measured by the High Resolution – peripheral Quantitative Computed Tomography (HR-pQCT) and their associated factors during different stages of stroke recovery were crucial. Thus, the overall aims of this thesis project were (1) to study the changes in long bone properties during different stages of stroke recovery using HR-­pQCT; (2) to identify the contributing factors to compromise bone strength during different stages of stroke recovery.
Study 2-3 (Chapter 3-4):
Methods: Forty-six people with chronic stroke and 45 age and gender-matched healthy controls were recruited. Bone properties and failure load of the bilateral distal radius and tibia were measured twice with a 24-month interval period using HR-pQCT.
Results: On the paretic side, the decline in trabecular bone density (1.18%-2.29%), cortical vBMD (0.53-1.28%), cortical thickness (1.95%-3.61%) exceeded precision error in both bones after two years of follow up. The decrease in the latter two bone variables contributed most to the decrease in failure load of the corresponding bone. The blood flow volume significantly improved the regression model to predict the change in failure load in both paretic limbs. In addition, hand sensory (ΔF =4.26, p =0.046) at baseline significantly improved the regression model to predict the change in failure load of the radius. As to lower limb, the change in walking speed (F change = 5.10, p = 0.029) and baseline factors (gait speed, physical activity level, and muscle strength) (F change = 6.47, p = 0.015) significantly improved the regression model.
Conclusions: Changes in cortical bone properties accounted most for the deterioration of the failure load of both bones in people with chronic stroke. More compromised vascular health and hand sensation at baseline were associated with a greater decline in failure load of the hemi-paretic distal radius. Individuals with lower levels of mobility and less physical activity tended to show a greater decline in the estimated tibial bone strength on the paretic side.
Study 4 (Chapter 5):
Methods: Bone properties and failure load of the bilateral distal radius and tibia were measured twice: within 2 weeks post-stroke onset with 6-month follow-up using HR­-pQCT. Results and conclusion: Due to the Covid pandemic, this pilot study only included six individuals with acute stroke in analysis. In the paretic distal radii and tibiae, the reduction in the trabecular vBMD (1.18%-1.25%), cortical vBMD (0.4%­-0.73%) and estimated failure (2.18%-3.96%) load was similar to the decline reported in Chapter 3 and 4. However, an increase was observed in the trabecular thickness (0.80%) of the distal radius and in the trabecular number (1.53%) of the distal tibia on the paretic side. During the follow-up period, the reduction in the failure load was related to wrist range of motion and hand grip strength in the paretic upper limb, whereas it was related to vascular health at baseline in the paretic lower limb.
Conclusion: In summary, the evidence obtained from the studies performed in this thesis reveals the key aspects of bone changes at different sites during different stages of stroke recovery (i.e., acute to subacute, chronic stage). They also reveal the modifiable clinical factors that contribute to compromised bone strength at different stages of stroke. These findings will guide the design of treatment protocols for future intervention trials.
Rights: All rights reserved
Access: open access

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