Fat Infiltration in the Leg is Associated with Bone Geometry and Physical Function in Healthy Older Women.

The objective of this study was to estimate the associations between muscular fat infiltration, tibia bone mineral quantity and distribution, and physical function in healthy older women. Thirty-five women (aged 60-75 years, mean 70 years) were recruited from the community. Percent intramuscular fat (%IntraMF) within the right leg tibialis anterior, soleus, and gastrocnemius muscles and total intermuscular fat (IMF) were segmented from magnetic resonance imaging scans at the mid-calf. Intramyocellular lipid (IMCL) content in the right tibialis anterior was measured with proton magnetic resonance spectroscopy. Right tibia bone content, area, and strength were measured at the 4, 14, and 66% sites using peripheral quantitative computed tomography. Physical function was assessed by gait speed on the 20 m walking test. After adjusting for age, body size, and activity level, %IntraMF had a negative association with bone content and area at all tibia sites (r = -0.31 to -0.03). Conversely, greater IMF was associated with increased bone content and area (r = 0.04-0.32). Correlation coefficients for the association between IMCL and bone were negative (r = -0.44 to -0.03). All measures of fat infiltration had a negative association with observed physical function (r = -0.42 to -0.04). Our findings suggest that muscular fat infiltration in the leg of healthy postmenopausal women has a compartment-specific relationship with bone status and physical function. Minimizing fat accumulation within and between muscle compartments may prevent bone fragility and functional decline in women.

Age-related differences in the response of leg muscle cross-sectional area and water diffusivity measures to a period of supine rest.

OBJECT: The object was to assess whether cross-sectional area (CSA) and water diffusion properties of leg muscles in young and older women change with increased time spent in supine rest. MATERIALS AND METHODS: Healthy young (n = 9, aged 20-30 years) and older (n = 9, aged 65-75 years) women underwent MRI scanning of the right leg at baseline, 30 and 60 min of supine rest. Muscle CSA was derived from proton density images. Water diffusion properties [apparent diffusion coefficient (ADC) and fractional anisotropy (FA)] of the tibialis anterior and posterior, soleus, and medial and lateral heads of the gastrocnemius were derived from diffusion tensor imaging (DTI). Repeated measures ANOVAs and Bonferroni post hoc tests determined the effects of time and group on each muscle outcome. RESULTS: In both groups, muscle CSA and FA did not significantly change over time, whereas ADC significantly decreased. A greater decline at 30 min for young women was only observed for ADC in the medial gastrocnemius. CONCLUSION: Regardless of age, ADC values decreased with fluid shift associated with time spent supine, whereas CSA and FA were not affected. For leg muscle assessment in young and older women, DTI scanning protocols should consider the amount of time spent in a recumbent position.

Higher Hand Grip Strength Is Associated With Greater Radius Bone Size and Strength in Older Men and Women: The Framingham Osteoporosis Study.

Mechanical loading by muscles elicits anabolic responses from bone, thus age-related declines in muscle strength may contribute to bone fragility in older adults. We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to determine the association between grip strength and distal radius bone density, size, morphology, and microarchitecture, as well as bone strength estimated by micro-finite element analysis (µFEA), among older men and women. Participants included 508 men and 651 women participating in the Framingham Offspring Study with grip strength measured in 2011-2014 and HR-pQCT scanning in 2012-2015. Separately for men and women, analysis of covariance was used to compare HR-pQCT measures among grip strength quartiles and to test for linear trends, adjusting for age, height, weight, smoking, and physical activity. Mean age was 70 years (range, 50-95 years), and men had higher mean grip strength than the women (37 kg vs. 21 kg). Bone strength estimated by µFEA-calculated failure load was higher with greater grip strength in both men (p < 0.01) and women (p = 0.04). Higher grip strength was associated with larger cross-sectional area in both men and women (p < 0.01), with differences in area of 6% and 11% between the lowest to highest grip strength quartiles in men and women, respectively. Cortical thickness was positively associated with grip strength among men only (p = 0.03). Grip strength was not associated with volumetric BMD (vBMD) in men. Conversely, there was a trend for lower total vBMD with higher grip strength among women (p = 0.02), though pairwise comparisons did not reveal any statistically significant differences in total vBMD among grip strength quartiles. Bone microarchitecture (cortical porosity, trabecular thickness, trabecular number) was not associated with grip strength in either men or women. Our findings suggest that the positive association between hand grip strength and distal radius bone strength may be driven primarily by bone size. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Improved Methods to Measure Outcomes After High Tibial Osteotomy.

Observational studies suggest high tibial osteotomy produces substantial improvements in knee loading and stability that can limit the progression of joint damage; decrease pain; improve function and quality of life; and delay the need for knee replacement surgery. It can be cost-effective in knee osteoarthritis. However, systematic reviews and clinical practice guidelines are unable to provide strong recommendations, because limited high-level evidence supports its therapeutic value versus other treatments. We describe findings suggesting it can improve outcomes important to knee joint structure and function, patient quality of life, and health care systems. Future clinical trials are warranted and required.

A Longitudinal Study of Trunk Muscle Properties and Severity of Thoracic Kyphosis in Women and Men: The Framingham Study.

BACKGROUND: Cross-sectional studies suggest that trunk muscle morphology in the lumbar spine is an important determinant of kyphosis severity in older adults. The contribution of age-related changes in muscle morphology in the thoracic and lumbar spine to progression of kyphosis is not known. Our objective was to determine cross-sectional and longitudinal associations of thoracic and lumbar muscle size and density with kyphosis. METHODS: Participants were 1,087 women and men (mean age: 61 years) of the Framingham Heart Study who underwent baseline and follow-up quantitative computed tomography (QCT) scanning 6 years apart. We used QCT scans to measure trunk muscle cross-sectional area (CSA, cm2) and density (HU) at the thoracic and lumbar spine and Cobb angle (degrees) from T4 to T12. Linear regression models estimated the association between muscle morphology and kyphosis. RESULTS: At baseline, smaller muscle CSA and lower density of thoracic (but not lumbar) spine muscles were associated with a larger (worse) Cobb angle in women and men. For example, each standard deviation decrease in baseline thoracic paraspinal muscle CSA was associated with a larger baseline Cobb angle in women (3.7 degrees, 95% CI: 2.9, 4.5) and men (2.5 degrees, 95% CI: 1.6, 3.3). Longitudinal analyses showed that loss of muscle CSA and density at the thoracic and lumbar spine was not associated with progression of kyphosis. CONCLUSIONS: Our findings suggest that kyphosis severity is related to smaller and lower density trunk muscles at the thoracic spine. Future studies are needed to determine how strengthening mid-back musculature alters muscle properties and contributes to preventing kyphosis progression.

Association Between Knee Load and Pain: Within-Patient, Between-Knees, Case-Control Study in Patients With Knee Osteoarthritis.

OBJECTIVE: The association between knee loading and pain in patients with knee osteoarthritis is reported to be low and of questionable importance, but may be confounded by several factors that differ between patients. We aimed to elucidate the association between dynamic knee load and pain by minimizing confounding using a study design that was within the same patient, with knees discordant for pain. METHODS: A total of 265 patients with knees discordant for pain (530 knees) rated the pain in each knee before and after walking for 6 minutes, and then underwent 3-dimensional gait analysis. RESULTS: The peak knee adduction moment and knee adduction impulse (proxies for medial knee loading) were associated with increased pain (odds ratio [OR] 2.43 [95% confidence interval (95% CI) 1.77-3.33] and OR 6.62 [95% CI 3.46-12.7], respectively) and remained significant after controlling for radiographic disease severity. When split into quartiles, ORs indicated knees in the highest loading quartile had greater odds of experiencing increased pain with walking (OR 4.7 95% CI 2.3-9.5] for peak adduction moment; OR 9.0 [95% CI 4.0-20.1] for adduction impulse) compared to knees in the lowest loading quartile. CONCLUSION: When between-patient confounding is minimized, there is a strong association between medial knee load and increased knee pain during walking.

A longitudinal study of disc height narrowing and facet joint osteoarthritis at the thoracic and lumbar spine, evaluated by computed tomography: the Framingham Study.

BACKGROUND CONTEXT: Prevalence and progression of disc height narrowing (DHN) and facet joint osteoarthritis (FJOA) in the thoracic and lumbar regions in non-clinical populations are not well established. PURPOSE: The present study aimed to use computed tomography (CT) images to determine the prevalence and progression of DHN and FJOA according to age, sex, and spinal region. STUDY DESIGN: This is a 6-year longitudinal study. SAMPLE: A total of 1,195 members of the Framingham Study (mean baseline age 61±9 years) were included in the study. OUTCOME MEASURES: We compared the prevalence and progression (new or worsening) of moderate-to-severe DHN and FJOA by age, sex, and spinal region. METHODS: A musculoskeletal radiologist evaluated DHN and FJOA from T4/T5 to L4/L5 on baseline and follow-up CT images using a semi-quantitative scale: 0=normal, 1=mild, 2=moderate, and 3=severe. RESULTS: One-third or more of women and men ages 40-59 years at baseline had imaged-based evidence of prevalent DHN, more than half had prevalent FJOA, and DHN and FJOA prevalence increased approximately two- to fourfold in those age 60-69 and 70-89 years at baseline, respectively (p<.01). Progression of DHN and FJOA occurred more frequently at the lumbar than at the thoracic spine and more in women than in men (DHN: odds ratio [OR]=1.42, 95% confidence interval [CI]=1.07, 1.88; FJOA: OR=1.70, CI=1.33, 2.17). CONCLUSIONS: Prevalence and progression of moderate-to-severe DHN and FJOA are common in non-clinical populations of older adults. The high frequency of spinal degeneration observed on CTs in this community-based study may contribute to challenges in interpreting the clinical significance of imaging evidence of DHN and FJOA. Future studies investigating the association of CT-based spinal degenerative features with pain and functional impairments in population-based samples are needed to help determine the clinical significance of imaged-based findings of DHN and FJOA.

Magnetic Resonance Imaging and Spectroscopy to Assess Leg Muscle Macrostructure and Microstructure in Healthy Older Women: A Feasibility Assessment.

BACKGROUND: Advanced magnetic resonance (MR) scanning techniques, such as diffusion tensor imaging (DTI) and proton MR spectroscopy (1H-MRS) permit microstructural evaluation of water diffusivity and intramyocellular lipid content, respectively. We aimed to determine the feasibility of performing advanced MR scanning (proton density [PD] weighted imaging, DTI, and 1H-MRS) to evaluate properties of leg muscles in older women with respect to: (1) participant recruitment using three community-based strategies; (2) participant tolerance to the MRI scan acquisition protocol; and (3) scan acquisition and analyses protocols. METHODS: Recruitment feasibility was evaluated based on the number of participants enrolled using various strategies. Participant tolerance was feasible if the scanning session was uninterrupted and image artifacts were absent. Optimal PD imaging, DTI, and 1H-MRS acquisition and analyses protocols were established. RESULTS: Nine women (mean age = 71 years) were recruited over four months. The acquisition protocol was well tolerated by all participants. Adaptations were required for women with short stature and vertebral fracture risk. PD-weighted image analyses were improved by using the phased array uniformity enhancement filter to increase tissue contrast. CONCLUSIONS: It is feasible to use a combination of MR scanning methods to evaluate muscle macrostructure and microstructure in the leg of older women. Our findings suggest that advanced MR scanning methods can be used for future studies interested in quantifying components of muscle structure in older women, but prospective studies are needed to confirm whether change in microstructure can be detected in response to an intervention.

Severity of Kyphosis and Decline in Lung Function: The Framingham Study.

BACKGROUND: Hyperkyphosis reduces the amount of space in the chest, mobility of the rib cage, and expansion of the lungs. Decline in pulmonary function may be greater in persons with more severe kyphosis; however, no prospective studies have assessed this association. We conducted a longitudinal study to quantify the impact of kyphosis severity on decline in pulmonary function over 16 years in women and men. METHODS: Participants included a convenience sample of 193 women and 82 men in the Framingham Study original cohort (mean age: 63 years; range: 50-79 years), who had measurements of kyphosis angle from lateral spine radiographs obtained in 1972-1976 and forced expiratory volume in 1 second (FEV1) from spirometry taken four times over 16 (±1.87) years from 1972 through 1988. RESULTS: Kyphosis severity was associated with greater decline in FEV1 in women but not in men. Adjusted mean change in FEV1 over 16 years was -162, -245, and -261mL (trend, p = .02) with increasing tertile of kyphosis angle in women and -372, -297, and -257mL (trend, p = .20) in men, respectively. CONCLUSIONS: This longitudinal study found that kyphosis severity increased subsequent decline in pulmonary function in women but not in men. Reasons for an association between kyphosis and pulmonary function in women but in not men may be due, at least in part, to the small number of men in our study. Nevertheless, our findings suggest that preventing or slowing kyphosis progression may reduce the burden of pulmonary decline in older adults.

Thoracic Kyphosis and Physical Function: The Framingham Study.

OBJECTIVE: To evaluate the association between thoracic kyphosis and physical function. DESIGN: Prospective cohort. SETTING: Framingham, Massachusetts. PARTICIPANTS: Framingham Heart Study Offspring and Third Generation cohort members who had computed tomography (CT) performed between 2002 and 2005 and physical function assessed a mean 3.4 years later (N = 1,100; mean age 61 ± 8, range 50-85). MEASUREMENTS: Thoracic kyphosis (Cobb angle, T4-T12) was measured in degrees using supine CT scout images. Participants were categorized according to Cobb angle to compare those in the highest quartile (Q4, most-severe kyphosis) with those in the lowest quartiles (Q1-Q3). Quick walking speed (m/s), chair-stand time (seconds), grip strength (kg), and self-reported impairments were assessed using standardized procedures. Analyses were adjusted for age, height, weight, smoking, follow-up time, vertebral fractures, and prevalent spinal degeneration. RESULTS: Thoracic kyphosis was not associated with physical function in women or men, and these results were consistent in those younger than 65 and those aged 65 and older. For example, walking speed was similar in adults younger than 65 with and without severe kyphosis (women, Q4: 1.38 m/s, Q1-Q3: 1.40 m/s, P = .69; men, Q4: 1.65 m/s, Q1-Q3: 1.60 m/s; P = .39). CONCLUSION: In healthy relatively high-functioning women and men, kyphosis severity was not associated with subsequent physical function. Individuals at risk of functional decline cannot be targeted based on supine CT thoracic curvature measures alone.

Heritability of Thoracic Spine Curvature and Genetic Correlations With Other Spine Traits: The Framingham Study.

Hyperkyphosis is a common spinal disorder in older adults, characterized by excessive forward curvature of the thoracic spine and adverse health outcomes. The etiology of hyperkyphosis has not been firmly established, but may be related to changes that occur with aging in the vertebrae, discs, joints, and muscles, which function as a unit to support the spine. Determining the contribution of genetics to thoracic spine curvature and the degree of genetic sharing among co-occurring measures of spine health may provide insight into the etiology of hyperkyphosis. The purpose of our study was to estimate heritability of thoracic spine curvature using T4 -T12 kyphosis (Cobb) angle and genetic correlations between thoracic spine curvature and vertebral fracture, intervertebral disc height narrowing, facet joint osteoarthritis (OA), lumbar spine volumetric bone mineral density (vBMD), and paraspinal muscle area and density, which were all assessed from computed tomography (CT) images. Participants included 2063 women and men in the second and third generation offspring of the original cohort of the Framingham Study. Heritability of kyphosis angle, adjusted for age, sex, and weight, was 54% (95% confidence interval [CI], 43% to 64%). We found moderate genetic correlations between kyphosis angle and paraspinal muscle area (ρˆG , -0.46; 95% CI, -0.67 to -0.26), vertebral fracture (ρˆG , 0.39; 95% CI, 0.18 to 0.61), vBMD (ρˆG , -0.23; 95% CI, -0.41 to -0.04), and paraspinal muscle density (ρˆG , -0.22; 95% CI, -0.48 to 0.03). Genetic correlations between kyphosis angle and disc height narrowing (ρˆG , 0.17; 95% CI, -0.05 to 0.38) and facet joint OA (ρˆG , 0.05; 95% CI, -0.15 to 0.24) were low. Thoracic spine curvature may be heritable and share genetic factors with other age-related spine traits including trunk muscle size, vertebral fracture, and bone mineral density. © 2016 American Society for Bone and Mineral Research.

The International Classification of Functioning, Disability and Health (ICF) Core Sets: application to a postmenopausal woman with rheumatoid arthritis and osteoporosis of the spine.

The International Classification of Functioning, Disability and Health (ICF) framework facilitates systematic assessment of functioning across four components. ICF Core Sets are proposed to be beneficial for clinicians in multidisciplinary care settings because they provide a common language for communication. A clinical vignette of a postmenopausal woman with rheumatoid arthritis (RA) and a non-traumatic vertebral fracture is presented to discuss how the ICF Core Sets for RA and osteoporosis (OP) can be helpful in structuring clinical decisions. To demonstrate how condition-specific ICF Core Sets can be used to evaluate and treat women with two comorbidities, each component of the ICF Core Sets is compared across conditions and integrated into clinical decision-making. Topics covered include: exercise tolerance, urinary continence, bone mass, fear of falling, and environmental factors. The benefits of thorough communication with the client and a common language across healthcare disciplines are highlighted as the potential benefits of the ICF framework; however, limitations to uptake of the ICF in clinical practice are also addressed.

Imaging-Based Methods for Non-invasive Assessment of Bone Properties Influenced by Mechanical Loading.

PURPOSE: To describe the most common in vivo imaging-based research tools used to assess bone properties that are influenced by mechanical loading associated with exercise, habitual physical activity, or disease states. Bone is a complex metabolically active tissue that adapts to changes in mechanical loading by altering the amount and spatial organization of mineral. METHOD: Using a narrative review design, the authors provide an overview of bone biology and biomechanics to emphasize the importance of bone size scale, porosity, and degree of mineralization when interpreting measures acquired using quantitative ultrasound (QUS), dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), and finite element analysis (FEA). For each imaging modality, basic imaging principles, typical outcome measures associated with changes in mechanical loading, and salient features for physiotherapists are described. MAIN RESULTS: While each imaging modality has strengths and limitations, currently CT-based methods are best suited for determining the effects of mechanical loading on bone properties-particularly in the peripheral skeleton. CONCLUSIONS: Regardless of the imaging technology used, the physiotherapist must carefully consider the assumptions of the imaging-based method, the clinical context, the nature of the change in mechanical loading, and the expected time course for change in bone properties.Purpose: To describe the most common in vivo imaging-based research tools used to assess bone properties that are influenced by mechanical loading associated with exercise, habitual physical activity, or disease states. Bone is a complex metabolically active tissue that adapts to changes in mechanical loading by altering the amount and spatial organization of mineral. Method: Using a narrative review design, the authors provide an overview of bone biology and biomechanics to emphasize the importance of bone size scale, porosity, and degree of mineralization when interpreting measures acquired using quantitative ultrasound (QUS), dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), and finite element analysis (FEA). For each imaging modality, basic imaging principles, typical outcome measures associated with changes in mechanical loading, and salient features for physiotherapists are described. Main Results: While each imaging modality has strengths and limitations, currently CT-based methods are best suited for determining the effects of mechanical loading on bone properties­particularly in the peripheral skeleton. Conclusions: Regardless of the imaging technology used, the physiotherapist must carefully consider the assumptions of the imaging-based method, the clinical context, the nature of the change in mechanical loading, and the expected time course for change in bone properties.

RÉSUMÉ Objectif : Décrire les outils de recherche en imagerie in vivo les plus couramment utilisés pour l'évaluation des propriétés des os qui sont influencés par la charge mécanique associée à l'exercice, à l'activité physique habituelle ou aux problèmes de santé. Les os sont des tissus actifs complexes sur le plan métabolique, qui s'adaptent aux changements de la charge mécanique en modifiant la quantité et l'organisation spatiale des minéraux. Méthode : À l'aide d'un modèle de revue narrative, un aperçu de la biologie et de la biomécanique osseuse est produit en vue de mettre l'accent sur l'importance de l'échelle de la dimension des os, de la porosité et du degré de minéralisation au moment d'interpréter les mesures recueillies à l'aide d'ultrasons quantitatifs (QUS), d'absorptiométrie à rayons X biphotonique (DXA), de tomographie informatisée (CT), d'imagerie par résonance magnétique (IRM) et d'analyse par éléments finis (FEA). Pour chaque modalité d'imagerie, les principes d'imagerie de base, les mesures typiques de résultats associés aux changements de charge mécanique et les caractéristiques principales pour les physiothérapeutes ont été décrits. Principaux résultats : Bien que chaque modalité d'imagerie ait ses forces et ses limites, les méthodes à base de tomographie informatisée sont les mieux adaptées pour déterminer les effets de la charge mécanique sur les propriétés osseuses ­ particulièrement dans le squelette périphérique. Conclusions : Sans égard à la technologie d'imagerie utilisée, le physiothérapeute doit analyser soigneusement les hypothèses de la méthode fondée sur l'imagerie, le contexte clinique, la nature du changement de charge mécanique et le délai attendu de changement des propriétés osseuses.

Forearm muscle size, strength, force, and power in relation to pQCT-derived bone strength at the radius in adults.

We aimed to examine the relationship between forearm muscle cross-sectional area (MCSA), muscle force, or rate of torque development (RTD) and 2 estimated radius bone strength indices - compressive bone strength index (BSI) at the wrist and strength strain index in torsion (SSI(p)) at the shaft - in healthy middle-aged males and females. Distal (4%) and shaft (65%) sites of nondominant forearms were scanned using peripheral quantitative computed tomography (pQCT) in a sample of 48 adults (mean age ± SD, 49.4 ± 2.4 y) to obtain estimated bone strength indices and MCSA. Muscle force, measured by grip dynamometry and wrist flexion RTD, was obtained using an isokinetic dynamometer. Hierarchical linear regressions, adjusted for weight, explained 27% and 36% of the BSI variance at the 4% site in males and premenopausal females, respectively (p < 0.05). At the radius shaft, weight explained 26% (p < 0.05) and 83% (p < 0.01) of SSI(p) variance. The unique variance of BSI explained by MCSA was 16% in males (p < 0.05) and 31% in females (p < 0.01). Grip force predicted variance in SSI(p) in males (p < 0.01) and BSI in females (p < 0.05). RTD did not explain any variance in BSI or SSI(p). Body weight was the only significant predictor (p < 0.05) of SSI(p) in females. Although forearm muscle size and grip strength are associated with estimates of radius bone strength at midlife, this relationship appears to be sex dependent. The differences observed between muscle size and strength properties and bone strength at distal and shaft sites of the radius suggest a property-, sex-, and site-specific relationship between muscle and bone in the forearm.