Compromised bone strength index in the hemiparetic distal tibia epiphysis among chronic stroke patients: the association with cardiovascular function, muscle atrophy, mobility, and spasticity

Elevated sclerostin levels contribute to reduced bone mineral density in non-ambulatory stroke patients

Osteoporosis following stroke is a significant impediment to patient recovery. Decreased mechanical loading and locomotion following the onset of paralysis in stroke patients, especially those who are non-ambulatory, contributes greatly to bone loss. Sclerostin, a protein encoded by the SOST gene, accumulates as a result of reduced mechanical loading and inhibits bone formation. This study explores the relationship between mechanical unloading, sclerostin levels, and bone mineral density (BMD) in stroke patients, utilizing three cohorts. Analysis of Cohort 1, consisting of patients with available sclerostin level measurements, found significantly elevated sclerostin levels in non-ambulatory patients compared to ambulatory patients, indicating the influence of ambulatory status on sclerostin regulation. Cohort 2, consisting of patients with BMD measurements, demonstrated that prolonged mechanical unloading in non-ambulatory patients resulted in a greater decline in BMD over time. Analysis in Cohort 3 patients, who had bilateral BMD measurements available, revealed that hemiplegic sides subjected to reduced mechanical loading exhibited lower BMD compared to non-hemiplegic sides. These findings collectively confirm the hypothesis that reduced mechanical loading elevates sclerostin levels and accelerates bone loss. By integrating data across the three cohorts, this study underscores the critical impact of mechanical unloading on bone health, particularly in chronic stroke patients with limited mobility. Our study provides clinical insights for treatments integrating ambulatory status, sclerostin levels, and BMD in chronic stroke patients and highlights an increased need for therapeutics targeting mechanical loading pathways and sclerostin accumulation which can be administered to treat chronic osteoporosis following stroke.

Establishment and validation of a nomogram for predicting the risk of hip fracture in patients with stroke: A multicenter retrospective study

PURPOSE

There are currently no models for predicting hip fractures after stroke. This study wanted to investigate the risk factors leading to hip fracture in stroke patients and to establish a risk prediction model to visualize this risk.

PATIENTS AND METHODS

We reviewed 439 stroke patients with or without hip fractures admitted to the Affiliated Hospital of Xuzhou Medical University from June 2014 to June 2017 as the training set, and collected 83 patients of the same type from the First Affiliated Hospital of Harbin Medical University and the Affiliated Hospital of Xuzhou Medical University from June 2020 to June 2023 as the testing set. Patients were divided into fracture group and non-fracture group based on the presence of hip fractures. Multivariate logistic regression analysis was used to screen for meaningful factors. Nomogram predicting the risk of hip fracture occurrence were created based on the multifactor analysis, and performance was evaluated using receiver operating characteristic curve (ROC), calibration curves, and decision curve analysis (DCA). A web calculator was created to facilitate a more convenient interactive experience for clinicians.

RESULTS

In training set, there were 35 cases (7.9 %) of hip fractures after stroke, while in testing set, this data was 13 cases (15.6 %). In training set, univariate analysis showed significant differences between the two groups in the number of falls, smoking, hypertension, glucocorticoids, number of strokes, Mini-Mental State Examination (MMSE), visual acuity level, National Institute of Health stroke scale (NIHSS), Berg Balance Scale (BBS), and Stop Walking When Talking (SWWT) (P<0.05). Multivariate analysis showed that number of falls [OR=17.104, 95 % CI (3.727-78.489), P = 0.000], NIHSS [OR=1.565, 95 % CI (1.193-2.052), P = 0.001], SWWT [OR=12.080, 95 % CI (2.398-60.851), P = 0.003] were independent risk factors positively associated with new fractures. BMD [OR = 0.155, 95 % CI (0.044-0.546), P = 0.012] and BBS [OR = 0.840, 95 % CI (0.739-0.954), P = 0.007] were negatively associated with new fractures. The area under the curve (AUC) of nomogram were 0.939 (95 % CI: 0.748-0.943) and 0.980 (95 % CI: 0.886-1.000) in training and testing sets, respectively, and the calibration curves showed a high agreement between predicted and actual status with an area under the decision curve of 0.034 and 0.109, respectively.

CONCLUSIONS

The number of falls, fracture history, low BBS score, high NIHSS score, and positive SWWT are risk factors for hip fracture after stroke. Based on this, a nomogram with high accuracy was developed and a web calculator (https://stroke.shinyapps.io/DynNomapp/) was created.

Robotized Knee-Ankle-Foot Orthosis-Assisted Gait Training on Genu Recurvatum during Gait in Patients with Chronic Stroke: A Feasibility Study and Case Report

Genu recurvatum (knee hyperextension) is a common problem after stroke. It is important to promote the coordination between knee and ankle movements during gait; however, no study has investigated how multi-joint assistance affects genu recurvatum. We are developing a gait training technique that uses robotized knee-ankle-foot orthosis (KAFO) to assists the knee and ankle joints simultaneously. This report aimed to investigate the safety of robotized KAFO-assisted gait training (Experiment 1) and a clinical trial to treat genu recurvatum in a patient with stroke (Experiment 2). Six healthy participants and eight patients with chronic stroke participated in Experiment 1. They received robotized KAFO-assisted gait training for one or 10 sessions. One patient with chronic stroke participated in Experiment 2 to investigate the effect of robotized KAFO-assisted gait training on genu recurvatum. The patient received the training for 30 min/day for nine days. The robot consisted of KAFO and an attached actuator of four pneumatic artificial muscles. The assistance parameters were adjusted by therapists to prevent genu recurvatum during gait. In Experiment 2, we evaluated the knee joint angle during overground gait, Fugl-Meyer Assessment of lower extremity (FMA-LE), modified Ashworth scale (MAS), Gait Assessment and Intervention Tool (G.A.I.T.), 10-m gait speed test, and 6-min walk test (6MWT) before and after the intervention without the robot. All participants completed the training in both experiments safely. In Experiment 2, genu recurvatum, FMA-LE, MAS, G.A.I.T., and 6MWT improved after robotized KAFO-assisted gait training. The results indicated that the multi-joint assistance robot may be effective for genu recurvatum after stroke.

Gait speed and spasticity are independently associated with estimated failure load in the distal tibia after stroke: an HR-pQCT study

This HR-pQCT study was conducted to examine bone properties of the distal tibia post-stroke and to identify clinical outcomes that were associated with these properties at this site. It was found that spasticity and gait speed were independently associated with estimated failure load in individuals with chronic stroke.

PURPOSE

(1) To examine the influence of stroke on distal tibia bone properties and (2) the association between these properties and clinical outcomes in people with chronic stroke.

METHODS

Sixty-four people with stroke (age, 60.8 ± 7.7 years; time since stroke, 5.7 ± 3.9 years) and 64 controls (age: 59.4 ± 7.8 years) participated in this study. High-resolution peripheral quantitative computed tomography (HR-pQCT) was used to scan the bilateral distal tibia, and estimated failure load was calculated by automated finite element analysis. Echo intensity of the medial gastrocnemius muscle and blood flow of the popliteal artery were assessed with ultrasound. The 10-m walk test (10MWT), Fugl-Meyer Motor Assessment (FMA), and Composite Spasticity Scale (CSS) were also administered.

RESULTS

The percent side-to-side difference (%SSD) in estimated failure load, cortical area, thickness, and volumetric bone mineral density (vBMD), and trabecular and total vBMD were significantly greater in the stroke group than their control counterparts (Cohen's d = 0.48-1.51). Isometric peak torque and echo intensity also showed significant within- and between-groups differences (p ≤ 0.01). Among HR-pQCT variables, the %SSD in estimated failure load was empirically chosen as one example of the strong discriminators between the stroke group and control group, after accounting for other relevant factors. The 10MWT and CSS subscale for ankle clonus remained significantly associated with the %SSD in estimated failure load after adjusting for other relevant factors (p ≤ 0.05).

CONCLUSION

The paretic distal tibia showed more compromised vBMD, cortical area, cortical thickness, and estimated failure load than the non-paretic tibia. Gait speed and spasticity were independently associated with estimated failure load. As treatment programs focusing on these potentially modifiable stroke-related impairments are feasible to administer, future studies are needed to determine the efficacy of such intervention strategies for improving bone strength in individuals with chronic stroke.

Relationship between bone strength index of the hemiparetic tibial diaphysis and muscle strength in people with chronic stroke: influence of muscle contraction type and speed

This study was conducted to examine the association between the tibial bone strength index and leg muscle strength of different contraction types and speeds among people with chronic stroke. We found that concentric muscle power at moderate speed was more associated with tibial bone strength index than other types.

INTRODUCTION

To compare the influence of muscle strength of different contraction types and speeds on the bone strength index of tibial diaphysis in people with chronic stroke.

METHODS

Eighty individuals with chronic stroke (age: 62.6 ± 8.0 years; men/women: 46/34; post-stroke duration: 9.0 ± 5.4 years) underwent scanning of the tibia at the 66% site on both sides using peripheral quantitative computed tomography. Each participant was also evaluated for isometric and dynamic (at 60°/s and 120°/s) strength of knee flexors/extensors and ankle dorsiflexors/plantarflexors using an isokinetic dynamometer. For a given contraction type and speed, the strength values of the four muscle groups were summed to yield a composite score. Multiple regression analysis was used to identify the association of the percent side-to-side difference (%SSD) in tibial polar-stress-strain index (p-SSI) with %SSD in muscle strength of different contraction types and speeds.

RESULTS

The p-SSI and all muscle strength parameters on the paretic side had lower values than the non-paretic side (p ≤ 0.001). The %SSD in concentric muscle power at angular speed of 60°/s (R² = 0.317, p = 0.006) and 120°/s (R² = 0.298, p = 0.020) remained independently associated with that in p-SSI, after controlling for age, sex, body mass index, post-stroke duration, motor impairment, spasticity, and physical activity level. The effect of isometric strength and eccentric muscle power was not significant in multivariate analysis.

CONCLUSIONS

Concentric muscle power was more predictive of %SSD in p-SSI at the tibial diaphysis than other contraction types and may be an important target for intervention to promote bone health in people with chronic stroke.

Determinants of estimated failure load in the distal radius after stroke: An HR-pQCT study

Bone health is often compromised after stroke and the distal radius is a common site of fragility fractures. The macro- and mircoproperties of bone tissue after stroke and their clinical correlates are understudied. The objectives of the study were to use High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) to investigate the bone properties at the distal radius, and to identify the correlates of estimated failure load for the distal radius in people with chronic stroke. This was a cross-sectional study of 64 people with stroke (age: 60.8 ± 7.7 years, stroke duration: 5.7 ± 3.9 years) and 64 age- and sex-matched controls. Bilateral bone structural, densitometric, geometric and strength parameters of the distal radius were measured using HR-pQCT. The architecture, stiffness and echo intensity of the bilateral biceps brachii muscle and brachial artery blood flow were evaluated using diagnostic ultrasound. Other outcomes included the Fugl-Meyer Motor Assessment (FMA), Motor Activity Log (MAL), and Composite Spasticity Scale (CSS). The results revealed a significant side (paretic vs non-paretic for the stroke group, non-dominant vs dominant for controls) by group (stroke vs control) interaction effect for estimated failure load, cortical area, cortical thickness, trabecular number and trabecular separation, and all volumetric density parameters. Post-hoc analysis showed percent side-to-side differences in bone outcomes were greater in the stroke group than the control group, with the exception of trabecular thickness and intracortical porosity. Among the HR-pQCT variables, percent side-to-side difference in trabecular volumetric bone mineral density contributed the most to the percent side-to-side difference in estimated failure load in the stroke group (R² change = 0.334, β = 1.106). Stroke-related impairments (FMA, MAL, CSS) were found to be significant determinants of the percent side-to-side difference in estimated failure load (R² change = 0.233, β = -0.480). This was the first study to examine bone microstructure post-stroke. We found that the paretic distal radius had compromised bone structural properties and lower estimated failure load compared to the non-paretic side. Motor impairment was a determinant of estimated bone strength at the distal radius and may be a potential intervention target for improving bone health post-stroke.

Effects of different vibration frequencies on muscle strength, bone turnover and walking endurance in chronic stroke

This randomized controlled trial aimed to evaluate the effects of different whole body vibration (WBV) frequencies on concentric and eccentric leg muscle strength, bone turnover and walking endurance after stroke. The study involved eighty-four individuals with chronic stroke (mean age = 59.7 years, SD = 6.5) with mild to moderate motor impairment (Fugl-Meyer Assessment lower limb motor score: mean = 24.0, SD = 3.5) randomly assigned to either a 20 Hz or 30 Hz WBV intervention program. Both programs involved 3 training sessions per week for 8 weeks. Isokinetic knee concentric and eccentric extension strength, serum level of cross-linked N-telopeptides of type I collagen (NTx), and walking endurance (6-min walk test; 6MWT) were assessed at baseline and post-intervention. An intention-to-treat analysis revealed a significant time effect for all muscle strength outcomes and NTx, but not for 6MWT. The time-by-group interaction was only significant for the paretic eccentric knee extensor work, with a medium effect size (0.44; 95% CI: 0.01, 0.87). Both WBV protocols were effective in improving leg muscle strength and reducing bone resorption. Comparatively greater improvement in paretic eccentric leg strength was observed for the 30 Hz protocol.

The impact of stroke on bone properties and muscle-bone relationship: a systematic review and meta-analysis

To systematically review available evidence related to the characteristics of bone changes post-stroke and the relationship between various aspects of muscle function (e.g., strength, spasticity) and bone properties after stroke onset. An extensive online database search was undertaken (last search in January 2019). Articles that examined the bone properties in stroke patients were included. The quality of the studies was evaluated with the National Institutes of Health (NIH) Study Quality Assessment Tools. Publication bias of meta-analyses was assessed using the Egger's regression asymmetry test. The selection and evaluation of the articles were conducted by two independent researchers. Fifty-nine studies were identified. In subacute and chronic stroke studies, the skeletal sites in the paretic limbs sustained a more pronounced decline in bone quality than did their counterparts in the non-paretic limbs. The rate of changes showed a decelerating trend as post-stroke duration increased, but the timing of achieving the steady rate differed across skeletal sites. The magnitude of bone changes in the paretic upper limb was more pronounced than the paretic lower limb. There was a strong relationship between muscle strength/mass and bone density/strength index. Muscle spasticity seemed to have a negative impact on bone integrity in the paretic upper limb, but its influence on bone properties in the paretic lower limb was uncertain. Substantial bone changes in the paretic limbs occurred particularly in the first few months after stroke onset. Early intervention, muscle strength training, and long-term management strategies may be important to enhance bone health post-stroke. This review has also revealed the knowledge gaps which should be addressed in future research.

Peripheral Quantitative Computed Tomography: Review of Evidence and Recommendations for Image Acquisition, Analysis, and Reporting, Among Individuals With Neurological Impairment

In 2015, the International Society for Clinical Densitometry (ISCD) position statement regarding peripheral quantitative computed tomography (pQCT) did not recommend routine use of pQCT, in clinical settings until consistency in image acquisition and analysis protocols are reached, normative studies conducted, and treatment thresholds identified. To date, the lack of consensus-derived recommendations regarding pQCT implementation remains a barrier to implementation of pQCT technology. Thus, based on description of available evidence and literature synthesis, this review recommends the most appropriate pQCT acquisition and analysis protocols for clinical care and research purposes, and recommends specific measures for diagnosis of osteoporosis, assigning fracture risk, and monitoring osteoporosis treatment effectiveness, among patients with neurological impairment. A systematic literature search of MEDLINE, EMBASE^©, CINAHL, and PubMed for available pQCT studies assessing bone health was carried out from inception to August 8th, 2017. The search was limited to individuals with neurological impairment (spinal cord injury, stroke, and multiple sclerosis) as these groups have rapid and severe regional declines in bone mass. Of 923 references, we identified 69 that met review inclusion criteria. The majority of studies (n = 60) used the Stratec XCT 2000/3000 pQCT scanners as reflected in our evaluation of acquisition and analysis protocols. Overall congruence with the ISCD Official Positions was poor. Only 11% (n = 6) studies met quality reporting criteria for image acquisition and 32% (n = 19) reported their data analysis in a format suitable for reproduction. Therefore, based on current literature synthesis, ISCD position statement standards and the authors' expertise, we propose acquisition and analysis protocols at the radius, tibia, and femur sites using Stratec XCT 2000/3000 pQCT scanners among patients with neurological impairment for clinical and research purposes in order to drive practice change, develop normative datasets and complete future meta-analysis to inform fracture risk and treatment efficacy evaluation.

Effects of Single or Multiple Sessions of Whole Body Vibration in Stroke: Is There Any Evidence to Support the Clinical Use in Rehabilitation?

Background and Purpose

Recently new technologies and new techniques, such as Whole Body Vibration (WBV), have been introduced by the health and fitness industry to pursue therapeutic or physical performance goals. The aim of this systematic review is to investigate the effectiveness of single or multiple WBV sessions alone or in association with traditional rehabilitation, compared to traditional rehabilitation therapy or with sham therapy in poststroke patients.

Methods

Randomized Control Trials and controlled clinical trials written in English between January 1st, 2003, and December 31st, 2017, were selected from PubMed, Cochrane-Central-Register-of-Controlled-Trials, and Physiotherapy-Evidence-Database (PEDro). The single WBV session and multiple sessions' effects were assessed. Study characteristics, study population, intervention protocols, effects of WBV sessions, and adverse events were investigated with a descriptive analysis.

Results

The search reported 365 articles and after screening and removal of duplicates, 11 manuscripts with PEDro score≥6/10 were selected (391 poststroke patients). Study characteristics, study population, intervention protocols (frequencies, amplitude of vibration, and peak acceleration), effects of a single or multiple WBV sessions, and adverse events were analyzed. They have been investigated with particular attention to bone turnover, structure and muscle functions, spasticity, postural control and risk of falls, functional mobility, somatosensory threshold, and activity and participation. Comparing WBV group with control group no significant benefits emerged.

Discussion

This systematic review included studies involving participants with non homogeneous characteristics, just considering the incorporation of studies on individuals with chronic and postacute stroke. Despite these limits, WBV treatment has no significant risks for patients and shows interesting effects of WBV treatment in Structure and muscle functions, Spasticity and Postural control.

Conclusions

Even though treatment with WBV appears safe and feasible, there is insufficient evidence to support its clinical use in poststroke rehabilitation at this point. More studies assessing other functional tests and with more specific treatment protocols are needed.

The Effect of Radial Extracorporeal Shock Wave Stimulation on Upper Limb Spasticity in Chronic Stroke Patients: A Single-Blind, Randomized, Placebo-Controlled Study

The main purpose of this study was to determine the clinical, electrophysiological and thermal effects of radial extracorporeal shock wave (rESW) stimulation on upper limb muscles affected by spasticity in patients with chronic stroke. Patients included in the study were randomly assigned into the following two groups: 30 patients stimulated with active rESW (A); and 30 patients stimulated with placebo rESW (B). All patients were analyzed using the Modified Ashworth Scale (MAS) to test the spasticity levels of the elbow (E), radio carpal (RC) and fingers (FF) joints; surface electromyography (sEMG) was performed for the resting bioelectrical activity registration of the flexor carpi radialis (FCR) and flexor carpi ulnaris (FCU) muscles; and infrared thermal imaging (IRT) was used to assess the temperature distributions of the carpal flexor muscles (CFM). All assessments were performed at baseline (t0), immediately after rESW (t1) as well as 1 and 24 h following its finalization (t2 and t3). Patients treated with active rESW showed a statistically significant reduction in the MAS score for the RC joint at t1 and for the FF joints at t1, t2 and t3 (p < 0.05). A significant decrease in sEMG activity was observed in the FCR and FCU muscles at t1, t2 and t3 (p < 0.05); significant increases in the mean and maximum values of the IRT detection was observed using inter-group comparisons in t2 and t3 (p < 0.05). No significant alterations were observed in patients after placebo rESW stimulation (p > 0.05). Applications of rESW demonstrating positive effects at reducing the level of spastic hypertonia of the upper limb muscles in patients with chronic stroke. ESW treatments should be considered as a potential anti-spastic effect to regulate vasculature.

Chronic effects of stroke on hip bone density and tibial morphology: a longitudinal study

The study aimed to quantify the long-term effects of stroke on tibial bone morphology and hip bone density. Only the trabecular bone mineral density and bone strength index in the hemiparetic tibial distal epiphysis showed a significant decline among individuals who had sustained a stroke 12-24 months ago.

INTRODUCTION

This study aims to determine the changes in bone density and morphology in lower limb long bones during a 1-year follow-up period and their relationship to muscle function in chronic stroke patients.

METHODS

Twenty-eight chronic stroke patients (12-166 months after the acute stroke event at initial assessment) and 27 controls underwent bilateral scanning of the hip and tibia using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. Each subject was re-assessed 1 year after the initial assessment.

RESULTS

Twenty stroke cases and 23 controls completed all assessments. At the end of the follow-up, the paretic tibial distal epiphysis suffered significant decline in trabecular bone density (-1.8 ± 0.6 %, p = 0.006) and bone strength index (-2.7 ± 0.6 %, p < 0.001). More severe decline in the former was associated with poorer leg muscle strength (ρ = 0.447, p = 0.048) and motor recovery (ρ = 0.489, p = 0.029) measured at initial assessment. The loss in trabecular bone density remained significant among those whose stroke onset was 12-24 months ago (p < 0.001), but not among those whose stroke onset was beyond 24 months ago (p > 0.05) at the time of initial assessment. The changes of outcomes in the tibial diaphysis, except for cortical bone mineral content on the non-paretic side (-1.3 ± 0.3 %, p = 0.003), and hip bone density were well within the margin of error for precision.

CONCLUSIONS

There is evidence of continuous trabecular bone loss in the paretic tibial distal epiphysis among chronic stroke patients, but it tends to plateau after 2 years of stroke onset. The steady state may have been reached earlier in the hip and tibial diaphysis.

Exercise stress testing after stroke or transient ischemic attack: a scoping review

OBJECTIVE

To provide insight into exercise stress testing after stroke or transient ischemic attack (TIA) in terms of feasibility, safety, and protocols used.

DATA SOURCES

PubMed, Embase, CINAHL, and Web of Science were searched for relevant studies published from inception to March 2014, and reference lists were hand searched.

STUDY SELECTION

To be included in the review, the articles needed to include participants diagnosed with stroke or TIA and have any form of test to assess exercise capacity.

DATA EXTRACTION

The scoping review methodology does not include critical appraisal of the literature but was chosen to reflect all aspects of exercise stress testing after stroke or TIA. Two reviewers performed screening for eligible studies independently, and 1 reviewer extracted the data.

DATA SYNTHESIS

We found a total of 112 studies involving 5008 participants describing symptom-limited (n=103), submaximal (n=9), and field (n=6) exercise stress test protocols. Some of the studies reported on data from >1 protocol. Metabolic analysis was included in 87% of the studies involving symptom-limited tests, 40% of submaximal studies, and 29% of field tests. Monitoring of blood pressure, perceived exertion, and electrocardiographic responses was done in 54%, 42%, and 95% of all studies, respectively. A mere 10% of all studies reported on electrocardiographic abnormalities detected during testing. No serious adverse events were reported.

CONCLUSIONS

Symptom-limited exercise stress testing appears to be safe in patients with stroke or TIA and provides a more valid measure of exercise capacity than submaximal and field tests. The level of disability may compromise feasibility, and test modality should be chosen carefully to optimize test results.

Influence of chronic stroke impairments on bone strength index of the tibial distal epiphysis and diaphysis

SUMMARY

The influence of various stroke impairments on bone health is poorly understood. This study showed that muscle function and small artery compliance were more strongly associated with the bone strength index at the tibial diaphyseal and epiphyseal regions, respectively. These impairments should be targeted in promoting bone health post-stroke.

INTRODUCTION

This study examined the bone structural properties of the tibial distal epiphysis and diaphysis after chronic stroke and identified the clinical correlates of the bone strength index measured at these sites.

METHODS

The tibial distal epiphysis (4% site) and diaphysis (66% site) were scanned on both sides in 66 chronic stroke patients and 23 control participants using peripheral quantitative computed tomography. Dynamic knee muscle strength, balance function, spasticity, arterial compliance, and endurance were also measured in the stroke group.

RESULTS

At the 4% site, multivariate analysis showed a significant side×group interaction effect (Wilk's lambda=3.977, p<0.001), with significant side-to-side differences in total volumetric bone mineral density (vBMD), trabecular vBMD, and bone strength index in the stroke group, but not in the control group. A significant side×group interaction was also found at the 66% site (Wilk's lambda=4.464, p<0.001), with significant side-to-side differences in cortical vBMD, cortical area, cortical thickness, and bone strength index in the stroke group only. Balance and endurance were independently associated with bone strength index at both tibial sites in the paretic leg (p<0.05) after adjusting for relevant factors in multivariate regression analysis. Small artery compliance and muscle strength were significantly associated with the bone strength index at the 4% site and 66% site, respectively.

CONCLUSIONS

The influence of various stroke impairments on bone was region-specific. While muscle function was more strongly associated with the bone strength index in the diaphyseal region, the effect of vascular health was more apparent in the tibial epiphysis in the paretic leg.

Predictors of low bone mineral density of the stroke-affected hip among ambulatory individuals with chronic stroke

Risk of hip fracture is greater poststroke than in an age-matched healthy population, in part because of declining hip BMD. We found that individuals may be at risk of loss of hip BMD from muscle atrophy, asymmetrical gait, and poor affected-side ankle dorsiflexor strength. These impairments may be targeted during rehabilitation.

INTRODUCTION

This study aimed to determine predictors of low hip BMD on the stroke-affected side in people living in the community.

METHODS

Forty-three participants (female; 27.9%), mean age 62.4 ± 13.5 and 17.9 ± 32.8 months, poststroke with motor impairments underwent dual energy X-ray absorptiometry scans. Gait characteristics, isometric strength, body composition, and fasting plasma lipids were measured.

RESULTS

At entry, 34.9% (15/43) of the participants had low total hip BMD on the stroke-affected side. Of those with low BMD, 93.3% (14/15) had a step length symmetry ratio >1, indicating greater reliance on the non-paretic leg for weight bearing. Logistic regression analysis revealed that lower affected-side ankle dorsiflexor strength (ß = 0.700, p = 0.02), lower total body fat-free mass index (ß = 0.437, p = 0.02), and greater step length symmetry ratio during walking (ß = 1.135 × 10(3), p = 0.03) were predictors of low hip BMD.

CONCLUSION

Low BMD of the stroke-affected side hip is prevalent in over a third of individuals with lower limb motor impairments. These individuals may be at particular risk of accelerated loss of BMD at the hip from asymmetrical gait pattern and poor affected-side ankle dorsiflexor strength. These impairments are intervention targets that may be addressed during rehabilitation which includes resistance training and addresses gait impairments.

Effects of whole-body vibration therapy on body functions and structures, activity, and participation poststroke: a systematic review

BACKGROUND

Whole-body vibration (WBV) has gained increasing popularity in rehabilitation. Recent studies have investigated the application of WBV in individuals with chronic illnesses, including stroke.

PURPOSE

The purpose of this study was to compare WBV exercise with the same exercise condition without WBV and with other types of physical exercise in enhancing body functions and structures, activity, and participation in individuals with stroke and examine its safety.

DATA SOURCE

Electronic searches were conducted on MEDLINE, CINAHL, PEDro, PubMed, PsycINFO, and Science Citation Index.

STUDY SELECTION

Randomized controlled trials (RCTs) that investigated the effects of WBV among individuals with stroke were identified by 2 independent researchers. Ten articles (9 studies, totaling 333 study participants) satisfied the selection criteria and were included in this review.

DATA EXTRACTION

The methodological quality was rated using the PEDro scale. The results were extracted by 2 independent researchers and confirmed with the principal investigator.

DATA SYNTHESIS

Only 2 RCTs were considered as demonstrating level 1 evidence (PEDro score ≥6 and sample size >50). Two RCTs examined the effects of a single WBV session, and 7 RCTs examined the effects of WBV programs spanning 3 to 12 weeks. No consistent benefits on bone turnover, leg motor function, balance, mobility, sensation, fall rate, activities of daily living, or societal participation were found, regardless of the nature of the comparison group. Adverse events were minor.

LIMITATIONS

A broad approach was used, with stroke as an inclusion criterion for review. No solid evidence was found concerning the effects of WBV on subgroups of people with specific stroke-related deficits due to the heterogeneity of patient groups.

CONCLUSIONS

Based on the review, there is insufficient evidence to support clinical use of WBV in enhancing body functions and structures, activity, and participation after stroke.

Vascular elasticity and grip strength are associated with bone health of the hemiparetic radius in people with chronic stroke: implications for rehabilitation

BACKGROUND

People with stroke often have increased bone loss and fracture rate. Increasing evidence has demonstrated a link between cardiovascular health and bone loss in other patient populations.

OBJECTIVE

The study objectives were: (1) to compare the bone density and geometry of the radius diaphysis on the left and right sides in people with chronic stroke and people who were matched for age (control participants) and (2) to examine the relationship between the bone strength index at the hemiparetic radius diaphysis and vascular health in people with chronic stroke.

DESIGN

This was a case-control study.

METHODS

The radius diaphysis on both sides was scanned with peripheral quantitative computed tomography in 65 participants with chronic stroke and 34 control participants. Large-artery and small-artery elasticity indexes were evaluated with a cardiovascular profiling system.

RESULTS

The paretic radius diaphysis had significantly lower values for cortical bone mineral density, cortical thickness, cortical area, and the bone strength index but a larger marrow cavity area than the nonparetic radius diaphysis in participants with chronic stroke, whereas no bone measurement showed a significant side-to-side difference in control participants. Multiple regression analyses showed that the large-artery elasticity index and grip strength remained significantly associated with the bone strength index at the hemiparetic radius diaphysis after controlling for age, sex, time since stroke diagnosis, body mass index, and physical activity (R(2)=.790).

LIMITATIONS

This study was cross-sectional and could not establish causality. The radius diaphysis is not the most common site of fracture after stroke.

CONCLUSIONS

Both the integrity of the vasculature and muscle strength were significantly associated with the bone strength index at the hemiparetic radius diaphysis in participants with chronic stroke. The results may be useful in guiding rehabilitative programs for enhancing bone health in the paretic arm after stroke.

Differences in tibia morphology between the sound and affected sides in ankle-foot orthosis-using survivors of stroke

OBJECTIVE

To examine differences in tibia and proximal femur morphology between the affected and sound limbs in ankle-foot orthosis (AFO)-using survivors of stroke.

DESIGN

Observational study.

SETTING

A university bone density laboratory.

PARTICIPANTS

Ambulatory, AFO-using survivors of stroke (N=9; age range, 55-74y; poststroke duration, 13.5±4.4y; AFO use, 6.5±1.4y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Total body and hip areal bone mineral density (aBMD) and bone mineral content (BMC) were assessed by dual-energy x-ray absorptiometry. The 4%, 38%, and 66% sites of both tibias were measured with peripheral quantitative computed tomography for total, cortical, and trabecular volumetric BMD (vBMD) and BMC. Bone geometry, bone strength index (BSI), strength strain index (SSI), and minimum and maximum rotated moments of inertia (Imin, Imax) were determined.

RESULTS

Total hip and trochanter BMC and aBMD were 7% to 19% greater on the sound side (P<.05). Total BMC and vBMD were 2% to 21% greater (P<.05) on the sound limb, depending on site. Trabecular BMC and vBMD and BSI values were 19%, 21%, and 31% higher (P<.05) on the sound limb at the 4% site. Cortical BMC and vBMD (P<.05), and cortical thickness (P<.01) were greater on the sound side at the 38% and 66% sites. Cortical area and bone strength (SSI, Imin) were greater (P<.05) at the 66% site. Endosteal circumferences were greater on the affected side (P<.01).

CONCLUSIONS

Interlimb differences in bone characteristics after a stroke persist despite returning to ambulatory status with AFO use.

Relative impact of neuromuscular and cardiovascular factors on bone strength index of the hemiparetic distal radius epiphysis among individuals with chronic stroke

The objective of this study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors. The results showed that grip strength is the most predominant predictor of the bone strength index.

INTRODUCTION

The purpose of the study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors.

METHODS

Sixty-five chronic stroke survivors and 34 healthy control subjects underwent scanning of the distal radius epiphyseal site on both sides using peripheral quantitative computed tomography to measure trabecular volumetric bone mineral density (vBMD) (mg/cm(3)), total vBMD (mg/cm(3)), total area (mm(2)), and compressive bone strength index (cBSI) (g(2)/cm(4)). Various indicators of neuromuscular (grip strength, spasticity) and cardiovascular function (vascular elasticity, oxygen consumption during 6-min walk test) were evaluated.

RESULTS

Analysis of variance revealed a significant main effect of side (p < 0.001) and group × side interaction (p < 0.05) for total BMC, total vBMD, trabecular vBMD, and cBSI (p < 0.05), with the stroke group showing greater side-to-side difference in these variables. However, no significant side-to-side difference in total area was detected in either group (p > 0.05). Sex-specific analysis yielded similar results. Multiple regression analyses revealed that the cBSI of the hemiparetic distal radius epiphysis had a stronger association with neuromuscular factors than cardiovascular factors. Overall, grip strength was the strongest determinant of the cBSI of the hemiparetic distal radius epiphysis (p < 0.01).

CONCLUSIONS

Muscle weakness is the most predominant determinant of cBSI in the hemiparetic distal radius epiphysis among chronic stroke patients. Future studies should investigate the efficacy of different muscle-strengthening strategies in enhancing bone strength of this skeletal site in the chronic stroke population.

Strontium ranelate prevents bone loss in a rat model of localized muscle paralysis

Twenty-one 3.5-month-old female Sprague-Dawley rats were randomly assigned to three groups: BTX group, in which each rat received a single intramuscular injection of 2 U of Clostridium botulinum toxin (BTX) in the quadriceps femoris muscle of the right hind limb; BTX + SR group, in which each rat received a BTX injection and a dose of strontium ranelate (dose level of 625 mg/kg/day); and the control group. All the rats were killed at 9 weeks post-treatment. It was showed that BTX-induced rats a rapid loss of body weight in the first 3 weeks, after which their body weight showed a slow increase similar to that observed in the control rats. The net body weight loss was mainly attributed to muscle atrophy. BTX caused remarkable bone degradation in either the trabecular bone or the cortical bone of the disuse femur. The deteriorations in the bone mass and bone microstructure were locally limited and could be prevented by strontium ranelate treatment. Biomechanical analysis showed that strontium ranelate treatment improved the mechanical performance of the tibia in BTX-treated rats. It was showed that a clinical-corresponding dose of strontium ranelate could prevent bone loss in long-term immobilized rats.