High-resolution in vivo imaging of bone and joints: a window to microarchitecture

Retrospective Characterization of Bone Histomorphometric Findings in Clinical Patient Specimens

BACKGROUND

Bone histomorphometry provides comprehensive information on bone metabolism and microstructure. In this retrospective study, we aimed to obtain an overview of the typical indications, referring hospitals, and histomorphometric quantification-based diagnoses of the bone tissue in our histomorphometry laboratory, the only laboratory in Finland carrying out histomorphometric examination of clinical bone biopsies.

METHODS

Between January 1, 2005 and December 31, 2020, 553 clinical bone biopsies were sent to our histomorphometry laboratory for histomorphometric examination. The median age of the patients was 55 years (range, 0.2-89.9 years), 51% of them were males, and 18% comprised pediatric patients. We received bone biopsy specimens from 23 hospitals or healthcare units. The majority of the samples we sent by nephrologists.

RESULTS

The most common bone biopsy indications were suspicion of renal osteodystrophy (ROD), unknown bone turnover status in osteoporosis, and several or untypical fractures. The most common quantitative bone histomorphometry-based diagnosis was ROD.

CONCLUSIONS

This study provides information on the clinical application of bone histomorphometry in Finland. Precise and quantitative ROD evaluation is the most common indication for bone histomorphometry, being crucial in clinical decision-making and targeted treatment of this patient group.

Deteriorated bone microarchitecture caused by sympathetic overstimulation in pheochromocytoma and paraganglioma

PURPOSE

Despite the potentially destructive effect of sympathetic activity on bone metabolism, its impact on bone microarchitecture, a key determinant of bone quality, has not been thoroughly investigated. This study aims to evaluate the impact of sympathetic activity on bone microarchitecture and bone strength in patients with pheochromocytoma and paraganglioma (PPGL).

METHODS

A cross-sectional study was conducted in 38 PPGL patients (15 males and 23 females). Bone turnover markers serum procollagen type 1 N-terminal propeptide (P1NP) and β-carboxy-terminal crosslinked telopeptide of type 1 collagen (β-CTX) were measured. 24-h urinary adrenaline (24hUE) and 24-h urinary norepinephrine levels (24hUNE) were measured to indicate sympathetic activity. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in PPGL patients and 76 age-, sex-matched healthy controls (30 males and 46 females). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously.

RESULTS

PPGL patients had a higher level of β-CTX. HR-pQCT assessment revealed that PPGL patients had notably thinner and more sparse trabecular bone (decreased trabecular number and thickness with increased trabecular separation), significantly decreased volume BMD (vBMD), and bone strength at both the radius and tibia compared with healthy controls. The deterioration of Tt.vBMD, Tb.Sp, and Tb.1/N.SD was more pronounced in postmenopausal patients compared with the premenopausal subjects. Moreover, subjects in the highest 24hUNE quartile (Q4) showed markedly lower Tb.N and higher Tb.Sp and Tb.1/N.SD at the tibia than those in the lowest quartile (Q1). Age-related bone loss was also exacerbated in PPGL patients to a certain extent.

CONCLUSIONS

PPGL patients had significantly deteriorated bone microarchitecture and strength, especially in the trabecular bone, with an increased bone resorption rate. Our findings provide clinical evidence that sympathetic overstimulation may serve as a secondary cause of osteoporosis, especially in subjects with increased sympathetic activity.

High-resolution peripheral quantitative computed tomography for the assessment of acro-osteolysis and calcinosis in patients with systemic sclerosis

OBJECTIVE

To assist the development of future treatments in systemic sclerosis (SSc), the development of reliable outcome measures is pivotal. We aimed to evaluate the use of high-resolution peripheral quantitative CT (HR-pQCT) for visualization and gradation of acro-osteolysis (AO) and calcinosis compared to conventional hand radiographs (CR) in patients with SSc.

METHODS

HR-pQCT scans of the 2nd to 4th fingers, CR, nail fold capillaroscopy, and a clinical examination were conducted. Images were reviewed for the presence and degree of AO and calcinosis according to semiquantitative grading scales.

RESULTS

Forty patients were included. Fourteen had AO according to CR, whereas HR-pQCT revealed AO in 18 patients. The sensitivity and specificity of classifying patients as having AO by HR-pQCT when CR was used as reference were 93% (95% CI: 66-99%) and 80% (95% CI: 59-93%), respectively. By CR and with HR-pQCT as reference, the sensitivity and specificity were 72% (95% CI: 47-90%) and 95% (95% CI: 76-99%). Patients with AO had more or larger calcifications than patients without AO according to the proposed HR-pQCT grading system, with a median grade of 2 (IQR: 1-3) versus 0 (IQR: 0-1) (P<0.01). Grade 3 changes were observed exclusively in patients with AO (n=6/14, 42.9%). Assessment of AO and calcinosis by HR-pQCT demonstrated moderate to excellent test-retest reliability.

CONCLUSION

HR-pQCT allowed precise and reliable classification and grading of acro-osteolysis and acral calcinosis. The modality could prove helpful for detecting and monitoring these lesions as well as facilitating early diagnosis and guide treatment of these patients.

Early bone loss in patients with obstructive sleep apnea: a cross-sectional study

BACKGROUND

Obstructive sleep apnea (OSA) and osteoporosis are both prevalent diseases with shared pathophysiological mechanisms and risk factors. However, the association between the two diseases is seldom studied. This study aimed to identify the link between OSA and bone metabolism.

METHODS

Male participants aged 30-59-years who visited the sleep clinic were continuously recruited. Polysomnography was used to evaluate sleep and respiratory conditions. Blood samples were collected to detect metabolic, inflammatory and bone turnover indicators. High-resolution peripheral quantitative computer tomography was used to measure the non-dominant lateral radius and tibia.

RESULTS

Ninety subjects were recruited. The cortical area (Ct.Ar) of tibia of the severe OSA group was significantly higher than that of the mild and moderate OSA groups (P = 0.06 and P = 0.048). There were significant differences between the four groups in terms of total volumetric bone mineral density (vBMD) (F = 2.990, P = 0.035), meta trabecular vBMD (F = 3.696, P = 0.015), trabecular thickness (Tb.Th) (F = 7.060, P = 0.000) and cortical thickness (Ct.Th) (F = 4.959, P = 0.003). The mean values of the OSA groups were lower than control group. Hypopnea index and percentage of total sleep time with SpO2 < 90% were both positively correlated with alkaline phosphatase (R = 0.213, P = 0.044; R = 0.212, P = 0.045). Sleep efficiency was correlated with multiple indicators of the radius.

CONCLUSIONS

In non-elderly male populations, OSA patients tended to have lower vBMD, Tb.Th and Ct.Th than non-OSA patients. The negative effect of OSA may mainly affect the osteogenesis process, and is presumed to be related to sleep-related hypoxemia and sleep efficiency.

Validity of self-reported height, weight and BMI as applied to trends in malnutrition in Davao City, Philippines

BACKGROUND

Self-reported height, weight and body mass index (BMI) data are widely used to monitor trends in malnutrition. However, several studies expressed concerns about its reliability-citing trends of over-reporting and underreporting anthropometric data. This study aims to: (1) identify the validity of self-reported height and weight and BMI as compared with measured values and (2) examine the potential recurrence of malnutrition in an urban-based population.

METHODS

Paired t-tests and Pearson's correlation coefficients were conducted to identify potential discrepancies between self-reported and measured anthropometric data. These values were collected among 255 male and 400 female participants in the Davao City.

RESULTS

Height overestimation in females and underestimation in males were observed to be statistically significant (P < 0.05). Researchers also note an alarming rise in malnutrition cases when the Asia-Pacific Index was applied to the BMI study data. A 40.79 and 22% increase in obese cases among male and female respondents were recorded.

CONCLUSION

Modifying participant-gathered height and weight values is likely to result in discrepancies between self-reported and measured values. Identifying a person's height and weight status is crucial to understanding who among the population experience malnutrition. Thus, policymakers are called to strengthen educational support that trains respondents to report reliable and valid health data.

Bone Microarchitecture and Volumetric Mineral Density Assessed by HR-pQCT in Patients with 21- and 17α-Hydroxylase Deficiency

Due to disturbances in hormones and long-term glucocorticoid replacement therapy (GRT), congenital adrenocortical hyperplasia (CAH) patients are at risk of impaired bone structure and metabolism. This cross-sectional, case-control study aims to investigate for the first time bone microarchitecture features in 21-hydroxylase deficiency (21OHD; N = 38) and 17α-hydroxylase deficiency (17OHD; N = 16) patients using high-resolution peripheral quantitative computed tomography (HR-pQCT) by matching the same sex and similar age [21OHD vs. control: 29.5 (24.0-34.3) vs. 29.6 (25.9-35.2) years; 17OHD vs. controls: 29.0 (21.5-35.0) vs. 29.7 (24.6-35.3) years] with healthy controls (1:3). All patients underwent HR-pQCT scans of the nondominant radius and tibia, and had received GRT. Compared with corresponding controls, 17OHD cases had higher height (P < 0.001), weight (P = 0.013) and similar body mass index (BMI), while 21OHD had lower height (P < 0.001), similar weight and higher BMI (P < 0.001). 17OHD and 21OHD patients demonstrated various significant bone differences in most HR-pQCT indices, suggesting abnormalities in bone microarchitectures from healthy people. Further correlation analyses revealed that some characteristics, such as height and hormones, may contribute to the bone differences in HR-pQCT indices between two diseases. However, treatment dosage and time were not correlated, indicating that the current glucocorticoid doses may be within safety limits for bone impairment. Overall, our study for the first time revealed changes of bone microarchitecture in CAH patients and their potential relations with clinical characteristics. Further longitudinal researches are required to confirm these findings.

Bone quality in endocrine diseases: determinants and clinical relevance

PURPOSE

Bone is one of the main targets of hormones and endocrine diseases are frequent causes of secondary osteoporosis and fractures in real-world clinical practice. However, diagnosis of skeletal fragility and prediction of fractures in this setting could be a challenge, since the skeletal alterations induced by endocrine disorders are not generally captured by dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD), that is the gold standard for diagnosis of osteoporosis in the general population. The aim of this paper is to review the existing evidence related to bone quality features in endocrine diseases, proposing assessment with new techniques in the future.

METHODS

A comprehensive search within electronic databases was performed to collect reports of bone quality in primary hyperparathyroidism, hypoparathyroidism, hyperthyroidism, hypercortisolism, growth hormone deficiency, acromegaly, male hypogonadism and diabetes mellitus.

RESULTS

Using invasive and non-invasive techniques, such as high-resolution peripheral quantitative computed tomography or DXA measurement of trabecular bone score (TBS), several studies consistently reported altered bone quality as predominant determinant of fragility fractures in subjects affected by chronic endocrine disorders.

CONCLUSIONS

Assessment of skeletal fragility in endocrine diseases might take advantage from the use of techniques to detect perturbation in bone architecture with the aim of best identifying patients at high risk of fractures.

Clinical value of quantitative parameters of MSCT in the diagnosis of occult femoral neck fractures

To explore the clinical value of quantitative parameters of multi-slice computer tomography (MSCT) in the diagnosis of occult femoral neck fractures.The clinical data of 94 patients with suspected occult femoral neck fractures admitted to our hospital from April 2021 to April 2022 were selected for retrospective analysis, and they were divided into group A (accurate diagnosis, n = 63) and group B (non-occult femoral neck fractures, n = 31) according to the results of pathological and surgical diagnosis as the gold standard. All patients received MSCT examination to obtain quantitative parameters related to imaging, and receiver operator characteristic (ROC) curves were used to comprehensively evaluate the clinical value of quantitative parameters of MSCT in the diagnosis of occult femoral neck fractures.The quantitative parameters of MSCT in group A were overtly lower than those in group B (P < 0.05). The AUC value, Youden index and sensitivity of the combined detection were higher than those of single detection.The use of quantitative parameters of MSCT effectively reduces the missed diagnosis rate of occult femoral neck fractures, which could make an accurate diagnosis of the fracture type, as a basis for the formulation of clinical treatment plans.

Associations between body composition, physical activity, and diet and radial bone microarchitecture in older adults: a 10-year population-based study

Bone strength is important to prevent osteoporotic fractures and determined by bone mass and microarchitecture. This study suggests that having higher lean mass and lower fat mass, avoiding western dietary patterns, and improving steps per day may all be important for maintaining bone mass and microarchitecture in aging.

PURPOSE

To describe associations between exposures of lean mass and fat mass, dietary patterns, serum 25-hydroxyvitamin D (25(OH)D), physical activity and grip strength, and bone outcome measures including bone mineral density and microarchitecture in older adults.

METHODS

Data on 201 older adults (mean age 72 years, female 46% at 10.7-year follow-up (phase 4) from a population-based cohort study collected at baseline and follow-up at 2.6 (phase 2), 5.1 (phase 3), and 10.7 years (phase 4) were analyzed. Exposures were lean and fat mass, dietary patterns, physical activity (steps per day), serum 25(OH)D concentrations, and grip strength during follow-ups. Bone measures at phase 4 including areal bone mineral density (aBMD) at the spine, hip, and whole body by dual-energy X-ray absorptiometry, and radial cortical and trabecular bone microarchitecture by high-resolution peripheral computed tomography (HRpQCT). The cumulative average values of exposures were calculated. Multivariable linear regression was used to analyze associations between exposures and bone measures.

RESULTS

Lean mass was beneficially associated with the hip, spine, and total body aBMD, radial cortical and trabecular bone area, and trabecular number and separation (β ranged from - 0.39/standard deviation (SD) to 0.73/SD). Fat mass was detrimentally associated with radial compact cortical and inner transitional zone bone area, vBMD, and porosity (β ranged from - 0.21 to 0.22/SD). Western dietary pattern scores were detrimentally associated with radial total and cortical bone vBMD and porosity (β ranged from - 0.20 to 0.20/SD). Steps per day were beneficially associated with inner transitional zone area and thickness (β = 0.12/SD and 0.19/SD), but no other measures. Grip strength and serum 25(OH)D were not associated with any radial bone measures.

CONCLUSIONS

Lean mass was beneficially associated with aBMD, radial bone area, and trabecular bone microarchitecture. Fat mass had detrimental associations with radial bone area, vBMD, and porosity. A western dietary pattern was detrimental for radial bone microarchitecture while more steps per day (but not grip strength or 25(OH)D) appeared beneficial.

Progressive Resistance Training for Concomitant Increases in Muscle Strength and Bone Mineral Density in Older Adults: A Systematic Review and Meta-Analysis

Background

Older adults experience considerable muscle and bone loss that are closely interconnected. The efficacy of progressive resistance training programs to concurrently reverse/slow the age-related decline in muscle strength and bone mineral density (BMD) in older adults remains unclear.

Objectives

We aimed to quantify concomitant changes in lower-body muscle strength and BMD in older adults following a progressive resistance training program and to determine how these changes are influenced by mode (resistance only vs. combined resistance and weight-bearing exercises), frequency, volume, load, and program length.

Methods

MEDLINE/PubMed and Embase databases were searched for articles published in English before 1 June, 2021. Randomized controlled trials reporting changes in leg press or knee extension one repetition maximum and femur/hip or lumbar spine BMD following progressive resistance training in men and/or women ≥ 65 years of age were included. A random-effects meta-analysis and meta-regression determined the effects of resistance training and the individual training characteristics on the percent change (∆%) in muscle strength (standardized mean difference) and BMD (mean difference). The quality of the evidence was assessed using the Cochrane risk-of-bias tool (version 2.0) and Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria.

Results

Seven hundred and eighty studies were identified and 14 were included. Progressive resistance training increased muscle strength (∆ standardized mean difference = 1.1%; 95% confidence interval 0.73, 1.47; p ≤ 0.001) and femur/hip BMD (∆ mean difference = 2.77%; 95% confidence interval 0.44, 5.10; p = 0.02), but not BMD of the lumbar spine (∆ mean difference = 1.60%; 95% confidence interval − 1.44, 4.63; p = 0.30). The certainty for improvement was greater for muscle strength compared with BMD, evidenced by less heterogeneity (I² = 78.1% vs 98.6%) and a higher overall quality of evidence. No training characteristic significantly affected both outcomes (p > 0.05), although concomitant increases in strength and BMD were favored by higher training frequencies, increases in strength were favored by resistance only and higher volumes, and increases in BMD were favored by combined resistance plus weight-bearing exercises, lower volumes, and higher loads.

Conclusions

Progressive resistance training programs concomitantly increase lower-limb muscle strength and femur/hip bone mineral density in older adults, with greater certainty for strength improvement. Thus, to maximize the efficacy of progressive resistance training programs to concurrently prevent muscle and bone loss in older adults, it is recommended to incorporate training characteristics more likely to improve BMD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-022-01675-2.

Adaptive local thresholding can enhance the accuracy of HR-pQCT-based trabecular bone morphology assessment

High-resolution peripheral quantitative computed tomography (HR-pQCT) devices can scan extremities at bone microstructural level in vivo and are used mainly in research of bone diseases. Two HR-pQCT scanners are commercially available to date: XtremeCT (first generation) and XtremeCT-II (second generation) from Scanco Medical AG (Switzerland). Recently, we have proposed an adaptive local thresholding (AT) technique and showed that it can improve quantification accuracy of bone microstructural parameters, with visually less sharp cone-beam CT (CBCT) images providing a similar accuracy than XtremeCT. The aim of this study was to evaluate whether the AT segmentation technique could enhance the accuracy of HR-pQCT in quantifying bone microstructural images and to assess whether the agreement between XtremeCT and XtremeCT-II could be improved. Nineteen radii were scanned with three scanners from Scanco Medical AG: (1) XtremeCT at 82 μm, (2) XtremeCT-II at 60.7 μm and (3) the small animal microCT scanner VivaCT40 at 19 μm voxel size. The scans were segmented applying two different methods, once following the manufacturer standard technique (ST), and once by means of AT. Three-dimensional (3D) morphological analysis was performed on the trabecular volume of the segmented images using the manufacturer's standard software to calculate bone volume fraction (BV/TV), trabecular thickness (Tb.Th), separation (Tb.Sp) and number (Tb.N). The average accuracy of XtremeCT improved from R² = 0.76 (ST) to 0.85 (AT) and reached the same level of accuracy as XtremeCT-II with ST (R² = 0.86). The largest improvements were obtained for BV/TV and Tb.Th. For XtremeCT-II, mean accuracy improved slightly from R² = 0.86 (ST) to 0.89 (AT). For both segmentations and both scanners, the standard section was quantified slightly more accurate than the subchondral section. The agreement between the scanners was enhanced from R² = 0.89 (ST) to 0.98 (AT). In conclusion, AT can enhance the accuracy of XtremeCT to quantify distal radius bone microstructural parameters close to XtremeCT-II level and increases the agreement between the two HR-pQCT scanners. High-resolution peripheral quantitative computed tomography, segmentation, bone microstructural parameters.

Advances in bone turnover markers

Bone fragility fractures remain an important worldwide health and economic problem due to increased morbidity and mortality. The current methods for predicting fractures are largely based on the measurement of bone mineral density and the utilization of mathematical risk calculators based on clinical risk factors for bone fragility. Despite these approaches, many bone fractures remain undiagnosed. Therefore, current research is focused on the identification of new factors such as bone turnover markers (BTM) for risk calculation. BTM are a group of proteins and peptides released during bone remodeling that can be found in serum or urine. They derive from bone resorptive and formative processes mediated by osteoclasts and osteoblasts, respectively. Potential use of BTM in monitoring these phenomenon and therefore bone fracture risk is limited by physiologic and pathophysiologic factors that influence BTM. These limitations in predicting fractures explain why their inclusion in clinical guidelines remains limited despite the large number of studies examining BTM.

Bone Biopsy for Histomorphometry in Chronic Kidney Disease (CKD): State-of-the-Art and New Perspectives

The use of bone biopsy for histomorphometric analysis is a quantitative histological examination aimed at obtaining quantitative information on bone remodeling, structure and microarchitecture. The labeling with tetracycline before the procedure also allows for a dynamic analysis of the osteoblastic activity and mineralization process. In the nephrological setting, bone biopsy is indicated to confirm the diagnosis of subclinical or focal osteomalacia and to characterize the different forms of renal osteodystrophy (ROD). Even if bone biopsy is the gold standard for the diagnosis and specific classification of ROD, the use of this approach is very limited. The main reasons for this are the lack of widespread expertise in performing or interpreting bone biopsy results and the cost, invasiveness and potential pain associated with the procedure. In this regard, the sedation, in addition to local anesthesia routinely applied in Italian protocol, significantly reduces pain and ameliorates the pain perception of patients. Concerning the lack of widespread expertise, in Italy a Hub/Spokes model is proposed to standardize the analyses, optimizing the approach to CKD patients and reducing the costs of the procedure. In addition, new tools offer the possibility to evaluate the osteogenic potential or the ability to form bone under normal and pathological conditions, analyzing mesenchymal stem cells and their ability to differentiate in the osteogenic lineage. In the same way, circulating microRNAs are suggested as a tool for exploring osteogenic potential. The combination of different diagnostic approaches and the optimization of the bioptic procedure represent a concrete solution to spread the use of bone biopsy and optimize CKD patient management.

Volumetric Bone Mineral Density Measured by HR-pQCT in Patients with Psoriasis or Psoriatic Arthritis: A Systematic Review and Meta-Analysis with Trial Sequential Analysis

Bone health in psoriasis and psoriatic arthritis has been emphasized in recent years. Novel imaging modalities allow investigations into volumetric bone mineral density (vBMD) and bone microstructure in psoriatic patients. However, literature regarding vBMD measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) is inconclusive. We conducted a systematic review and meta-analysis to evaluate vBMD in patients with psoriatic disease. We searched PubMed, EMBASE, Web of Science, and Cochrane Library for relevant observational studies. A random-effects meta-analysis with trial sequential analysis (TSA) was performed. The pooled mean difference (MD) and 95% confidence interval (CI) were calculated. Five studies with 780 patients were included. Patients with psoriatic disease showed a lower average vBMD than controls (MD -14.90; 95% CI -22.90 to -6.89; TSA-adjusted CI -23.77 to -6.03; I² = 41%). Trabecular vBMD and cortical vBMD results were inconclusive because of the small sample size. Patients recruited in Asia and those whose vBMD were measured at the distal radius exhibited a lower average vBMD than controls. Further research should clarify the association of psoriasis with bone microstructure and the underlying pathophysiology.

The clinical application of high-resolution peripheral computed tomography (HR-pQCT) in adults: state of the art and future directions

High-resolution peripheral computed tomography (HR-pQCT) was developed to image bone microarchitecture in vivo at peripheral skeletal sites. Since the introduction of HR-pQCT in 2005, clinical research to gain insight into pathophysiology of skeletal fragility and to improve prediction of fractures has grown. Meanwhile, the second-generation HR-pQCT device has been introduced, allowing novel applications such as hand joint imaging, assessment of subchondral bone and cartilage thickness in the knee, and distal radius fracture healing. This article provides an overview of the current clinical applications and guidance on interpretation of results, as well as future directions. Specifically, we provide an overview of (1) the differences and reference data for HR-pQCT variables by age, sex, and race/ethnicity; (2) fracture risk prediction using HR-pQCT; (3) the ability to monitor response of anti-osteoporosis therapy with HR-pQCT; (4) the use of HR-pQCT in patients with metabolic bone disorders and diseases leading to secondary osteoporosis; and (5) novel applications of HR-pQCT imaging. Finally, we summarize the status of the application of HR-pQCT in clinical practice and discuss future directions. From the clinical perspective, there are both challenges and opportunities for more widespread use of HR-pQCT. Assessment of bone microarchitecture by HR-pQCT improves fracture prediction in mostly normal or osteopenic elderly subjects beyond DXA of the hip, but the added value is marginal. The prospects of HR-pQCT in clinical practice need further study with respect to medication effects, metabolic bone disorders, rare bone diseases, and other applications such as hand joint imaging and fracture healing. The mostly unexplored potential may be the differentiation of patients with only moderately low BMD but severe microstructural deterioration, which would have important implications for the decision on therapeutical interventions.

Tibial Macrostructure and Microarchitecture Adaptations in Women During 44 Weeks of Arduous Military Training

Bone adapts to unaccustomed, high-impact loading but loses mechanosensitivity quickly. Short periods of military training (≤12 weeks) increase the density and size of the tibia in women. The effect of longer periods of military training, where the incidence of stress fracture is high, on tibial macrostructure and microarchitecture in women is unknown. This observational study recruited 51 women (age 19 to 30 years) at the start of 44 weeks of British Army Officer training. Tibial volumetric bone mineral density (vBMD), geometry, and microarchitecture were measured by high-resolution peripheral quantitative computed tomography (HRpQCT). Scans of the right tibial metaphysis (4% site) and diaphysis (30% site) were performed at weeks 1, 14, 28, and 44. Measures of whole-body areal bone mineral density (aBMD) were obtained using dual-energy X-ray absorptiometry (DXA). Blood samples were taken at weeks 1, 28, and 44, and were analyzed for markers of bone formation and resorption. Trabecular vBMD increased from week 1 to 44 at the 4% site (3.0%, p < .001). Cortical vBMD decreased from week 1 to 14 at the 30% site (-0.3%, p < .001). Trabecular area decreased at the 4% site (-0.4%); trabecular bone volume fraction (3.5%), cortical area (4.8%), and cortical thickness (4.0%) increased at the 4% site; and, cortical perimeter increased at the 30% site (0.5%) from week 1 to 44 (p ≤ .005). Trabecular number (3.5%) and thickness (2.1%) increased, and trabecular separation decreased (-3.1%), at the 4% site from week 1 to 44 (p < .001). Training increased failure load at the 30% site from week 1 to 44 (2.5%, p < .001). Training had no effect on aBMD or markers of bone formation or resorption. Tibial macrostructure and microarchitecture continued to adapt across 44 weeks of military training in young women. Temporal decreases in cortical density support a role of intracortical remodeling in the pathogenesis of stress fracture. © 2021 Crown copyright. Journal of Bone and Mineral Research © 2021 American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

Biomechanical Basis of Predicting and Preventing Lower Limb Stress Fractures During Arduous Training

PURPOSE OF REVIEW

Stress fractures at weight-bearing sites, particularly the tibia, are common in military recruits and athletes. This review presents recent findings from human imaging and biomechanics studies aimed at predicting and preventing stress fractures.

RECENT FINDINGS

Peripheral quantitative computed tomography (pQCT) provides evidence that cortical bone geometry (tibial width and area) is associated with tibial stress fracture risk during weight-bearing exercise. The contribution of bone trabecular microarchitecture, cortical porosity, and bone material properties in the pathophysiology of stress fractures is less clear, but high-resolution pQCT and new techniques such as impact microindentation may improve our understanding of the role of microarchitecture and material properties in stress fracture prediction. Military studies demonstrate osteogenic outcomes from high impact, repetitive tibial loading during training. Kinetic and kinematic characteristics may influence stress fracture risk, but there is no evidence that interventions to modify biomechanics can reduce the incidence of stress fracture. Strategies to promote adaptive bone formation, in combination with improved techniques to assess bone strength, present exciting opportunities for future research to prevent stress fractures.

Bone mineral density and microarchitecture among Chinese patients with rheumatoid arthritis: a cross-sectional study with HRpQCT

BACKGROUND

Patients with rheumatoid arthritis (RA) are at increased risk of fractures. Although their decline in bone mineral density (BMD) is well-established, data regarding the alterations in bone microarchitecture are limited. In this study, we aimed to evaluate bone microarchitecture, geometry, and volumetric BMD among patients with RA in mainland China using high-resolution peripheral quantitative computed tomography (HRpQCT).

METHODS

In this cross-sectional study, patients with RA were recruited from the Peking Union Medical College Hospital site of the Chinese Registry of rhEumatoiD arthrITis (CREDIT). Each participant underwent HRpQCT scanning (Scanco XtremeCT II), thoracolumbar X-ray and dual-energy X-ray absorptiometry. The primary outcomes were HRpQCT-related measures at distal radius and tibia. Data regarding demographic features, RA-related characteristics, and history of fragility fractures were collected. Correlation between HRpQCT parameters and potentially related factors were analyzed using linear regression analysis. A group of age- and sex-matched healthy controls was included for comparison.

RESULTS

A total of 81 patients with RA [69 women, aged 57.9 ± 8.7 years, disease duration 5.7 (IQR 1.4-11.2) years] and 81 matched healthy controls were included. Compared with controls, patients with RA had significantly larger bone area and lower total and trabecular vBMD at both the distal radius and tibia. Lower cortical bone thickness was also shown at the distal tibia. Among patients with RA, advanced age, low BMI, female sex, disease duration, and activity were associated with decreased vBMD and impaired bone microstructure. Female reproductive factors including menopause, late menarche, breast feeding, and early childbirth also showed negative correlation with these parameters. Compared to patients with RA without fractures, patients with fragility fractures (n = 11) showed lower trabecular and cortical vBMD, thinner cortical bone, impaired trabecular microstructure, and a trend of declined bone strength. Current glucocorticoid intake was related to decreased vBMD, trabecular number, increased trabecular separation, and inhomogeneity.

CONCLUSIONS

In this study, we observed alterations in bone mineral density, geometry, and microarchitecture among patients with RA compared to healthy individuals, which may impair bone strength and lead to increased risk of fractures. Both traditional risk factors for osteoporosis and RA-associated factors need to be considered in the assessment of the bone quality.

Heterogeneity in microstructural deterioration following spinal cord injury

BACKGROUND

Modelling and remodelling adapt bone morphology to accommodate strains commonly encountered during loading. If strains exceed a threshold threatening fracture, modelling-based bone formation increases bone volume reducing these strains. If unloading reduces strains below a threshold that inhibits resorption, increased remodelling-based bone resorption reduces bone volume restoring strains, but at the price of compromised bone volume and microstructure. As weight-bearing regions are adapted to greater strains, we hypothesized that microstructural deterioration will be more severe than at regions commonly adapted to low strains following spinal cord injury.

METHODS

We quantified distal tibial, fibula and radius volumetric bone mineral density (vBMD) using high-resolution peripheral quantitative computed tomography in 31 men, mean age 43.5 years (range 23.5-75.0), 12 with tetraplegia and 19 with paraplegia of 0.7 to 18.6 years duration, and 102 healthy age- and sex-matched controls. Differences in morphology relative to controls were expressed as standardized deviation (SD) scores (mean ± SD). Standardized between-region differences in vBMD were expressed as SDs (95% confidence intervals, CI).

RESULTS

Relative to controls, men with tetraplegia had deficits in total vBMD of -1.72 ± 1.38 SD at the distal tibia (p < 0.001) and - 0.68 ± 0.69 SD at distal fibula (p = 0.041), but not at the distal radius, despite paralysis. Deficits in men with paraplegia were -2.14 ± 1.50 SD (p < 0.001) at the distal tibia and -0.83 ± 0.98 SD (p = 0.005) at the distal fibula while distal radial total vBMD was 0.23 ± 1.02 (p = 0.371), not significantly increased, despite upper limb mobility. Comparing regions, in men with tetraplegia, distal tibial total vBMD was 1.04 SD (95%CI 0.07, 2.01) lower than at the distal fibula (p = 0.037) and 1.51 SD (95%CI 0.45, 2.57) lower than at the distal radius (p = 0.007); the latter two sites did not differ from each other. Results were similar in men with paraplegia, but total vBMD at the distal fibula was 1.06 SD (95%CI 0.35, 1.77) lower than at the distal radius (p = 0.004).

CONCLUSION

Microarchitectural deterioration following spinal cord injury is heterogeneous, perhaps partly because strain thresholds regulating the cellular activity of mechano-transduction are region specific.

Quantification of 3D microstructural parameters of trabecular bone is affected by the analysis software

Over the last decades, the use of high-resolution imaging systems to assess bone microstructural parameters has grown immensely. Yet, no standard defining the quantification of these parameters exists. It has been reported that different voxel size and/or segmentation techniques lead to different results. However, the effect of the evaluation software has not been investigated so far. Therefore, the aim of this study was to compare the bone microstructural parameters obtained with two commonly used commercial software packages, namely IPL (Scanco, Switzerland) and CTan (Bruker, Belgium). We hypothesized that even when starting from the same segmented scans, different software packages will report different results. Nineteen trapezia and nineteen distal radii were scanned at two resolutions (20 μm voxel size with microCT and HR-pQCT 60 μm). The scans were segmented using the scanners' default protocol. The segmented images were analyzed twice, once with IPL and once with CTan, to quantify bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N) and specific bone surface (BS/BV). Only small differences between IPL and CTan were found for BV/TV. For Tb.Th, Tb.Sp and BS/BV high correlations (R² ≥ 0.99) were observed between the two software packages, but important relative offsets were observed. For microCT scans, the offsets were relative constant, e.g., around 15% for Tb.Th. However, for the HR-pQCT scans the mean relative offsets ranged over the different bone samples (e.g., for Tb.Th from 14.5% to 19.8%). For Tb.N, poor correlations (0.43 ≤ R² ≤ 0.81) for all tested cases were observed. We conclude that trabecular bone microstructural parameters obtained with IPL and CTan cannot be directly compared except for BV/TV. For Tb.Th, Tb.Sp and BS/BV, correction factors can be determined, but these depend on both the image voxel size and specific anatomic location. The two software packages did not produce consistent data on Tb.N. The development of a universal standard seems desirable.

Performance of bone mineral density and trabecular bone score in assessment of bone quality in Egyptian male patients with ankylosing spondylitis

Background

Osteoporosis is a common complication of ankylosing spondylitis (AS) even in the early stages of disease; however, previously published studies have demonstrated large discrepancies in the reported incidence of osteoporosis, based on measurement of bone mineral density (BMD). The aim of the present study was to compare bone quality using trabecular bone score (TBS) between AS patients and healthy controls and to evaluate factors associated with TBS in patients with AS.

Results

Ankylosing spondylitis patients had significantly lower BMD and T score at the neck of femur and lower total hip BMD than controls (BMD p = 0.010 and 0.032 respectively), (T score p = 0.006 and p = 0.025 respectively). The mean TBS was significantly lower in AS patients than in controls (p < 0.001). Lumbar spine TBS was directly correlated with BMI (p = 0.029) and BMD at the neck of femur (p = 0.016) and BMD of total hip (p = 0.007) while inversely correlated with the Bath AS Metrology Index (BASMI) (p = 0.026), the modified Stoke AS Spinal Score (mSASS) (p = 0.029), ESR (p = 0.031), and CRP (p = 0.033).

Conclusion

TBS evaluation detected lower bone quality in the lumbar spine in patients with AS when compared with matched controls, while lumbar BMD failed to identify it. These findings encourage the use of TBS as a beneficial tool to recognize the risk of axial osteoporosis as early as possible in AS patients. Also, we recommend its use for regular follow up of drug treatment for those patients.

A Detailed Analysis of the Association between Urate Deposition and Erosions and Osteophytes in Gout

OBJECTIVE

To characterize in detail the structural bone changes associated with the deposition of monosodium urate crystals in the first metatarsophalangeal (MTP1) joint in patients with tophaceous gout.

METHODS

Twenty patients with tophaceous gout and involvement of the MTP1 joint received both dual-energy computed tomography (DECT) of the feet for the detection of tophi and high-resolution peripheral quantitative computed tomography (HR-pQCT) of the feet for the detection of bone erosions and osteophytes. Demographic and clinical data were collected. Tophi in DECT and erosions and osteophytes in HR-pQCT were overlayed to define their anatomical relation. In addition, the feet of 20 sex- and age-matched healthy controls were scanned to define the normal architecture of the MTP1 joint.

RESULTS

Patients with gout had an increased number and extent of bone erosions and osteophytes compared with their healthy counterparts (erosions: 5 [0-17] vs 1 [1-2], 45.32 mm³ [7.26-550.32] vs 0.82 mm³ [0.15-21.8]; osteophytes: 10.5 [0-26] vs 1 [0-10], 4.93 mm [0.77-7.19 mm] vs 0.93 mm [0.05-7.61 mm]; all P < 0.001). The median tophi volume detected by DECT (0.12 mm³ [0.01-2.53]) was highly associated with the total volume of erosions (r = 0.597, P = 0.005).

CONCLUSION

Gout patients show increased changes in their bone microarchitecture. The extent of uric acid deposition is positively correlated with the extent of bone loss at the MTP1 joint, highlighting the strong cohesion of inflammation and erosive changes.

HR-pQCT in vivo imaging of periarticular bone changes in chronic inflammatory diseases: Data from acquisition to impact on treatment indications

Imaging is essential for the assessment of bone and inflammatory joint diseases. There are several imaging techniques available that differ regarding resolution, radiation exposure, time expending, precision, cost, availability or ability to predict disease progression. High-resolution peripheral quantitative computed tomography (HR-pQCT) that was introduced in 2004 allows the in vivo evaluation of peripheral bone microarchitecture and demonstrated high precision in assessing bone changes in inflammatory musculoskeletal diseases. This review summarizes the use of HR-pQCT for the evaluation of the hand skeleton in inflammatory joint diseases. We conducted a review of the literature regarding the protocols that involve hand joints assessment and evaluation of bone changes as erosions and osteophytes in chronic inflammatory diseases. Apart from measuring bone density and structure of the radius and the tibia, HR-pQCT has contributed to assessment of bone erosions and osteophytes, considered the hallmark of diseases as rheumatoid arthritis and psoriatic arthritis, respectively. In this way, there are some conventions recently established by rheumatic study groups that we just summarized here in order to standardize HR-pQCT measurements.

Comparison of bone structure and microstructure in the metacarpal heads between patients with psoriatic arthritis and healthy controls: an HR-pQCT study

Human cadaveric study has indicated that the metacarpal head (MCH) is intracapsular in location. We hypothesized that exposure to the intra-articular inflammatory milieu in psoriatic arthritis (PsA) will lead to bone loss in the MCH.

INTRODUCTION

To compare the bone structure and microstructure in the MCH between patients with PsA and healthy controls by high-resolution peripheral quantitative CT (HR-pQCT), and to ascertain factors associated with bone loss in PsA patients.

METHODS

Sixty-two PsA patients without joint destruction and 62 age-, gender-, and body mass index-matched healthy subjects underwent HR-pQCT imaging of the second and third MCH (MCH 2&3). The number and volume of bone erosion and enthesiophytes, as well as volumetric bone mineral density (vBMD) and microstructure at the MCH 2&3, were recorded. Correlation analysis and multivariable linear regression models were used to determine the association of demographic and disease-specific variables with compromised bone structure and microstructure in PsA.

RESULTS

At the MCH 2&3, bone erosion (p = 0.003) and enthesiophyte (p = 0.000) volumes in PsA patients were significantly larger than healthy controls. In PsA patients, older age was associated with a larger erosion and enthesiophyte volume. Concerning the mean vBMD and microstructure at the MCH 2&3, PsA patients had significantly lower mean vBMD (average vBMD - 6.9%, trabecular vBMD - 8.8%, peri-trabecular vBMD - 7.7%, meta-trabecular vBMD - 9.8%), trabecular bone volume fraction (- 8.8%), and trabecular thickness (- 8.1%) compared with control subjects. Multivariable regression analysis revealed that older age and a higher C-reactive protein level were associated with trabecular bone loss.

CONCLUSIONS

PsA patients had a higher burden of bone damages (erosions and enthesiophytes) and trabecular bone loss compared with healthy control at the MCH. Inflammation contributed to the deterioration in trabecular microstructure in these patients.

Distal radius bone microarchitecture: what are the differences between age 25 and old age?

This study reported that the transitional zones in older adults were enlarged at the expense of the compact-appearing cortex with a greater porosity in all cortical sub-compartments. The magnitude of differences in areal and volumetric bone mineral density (aBMD, vBMD) between older and younger groups was similar.

INTRODUCTION

Aging is strongly associated with bone loss, but little is known about magnitudes of differences in bone microarchitectures, aBMD, and vBMD from peak bone mass (PBM) to senescence. We aimed to describe differences in aBMD, vBMD, and bone microarchitecture parameters at the distal radius between older and young adults.

METHODS

We compared 201 participants, aged 62-89 years (female 47%) and 196 participants, aged 24-28 years (female 38%). Bone microarchitecture parameters at distal radius were measured using high-resolution peripheral computed tomography (HRpQCT). aBMD was measured using dual-energy X-ray absorptiometry (DXA). Unpaired t tests and chi-square tests were used to compare differences in means and proportions as appropriate.

RESULTS

Older adults had thinner compact-appearing cortices with larger (cross-sectional area: outer 30.96 mm² vs. 28.38 mm², inner 36.34 mm² vs. 32.93 mm²) and thicker (outer 0.57 mm vs. 0.54 mm, inner 0.71 mm vs. 0.65 mm) transitional zones compared with young adults (all p < 0.05). Cortical porosity was modestly higher in older adults than in young adults (54% vs. 49%, p < 0.001). The magnitude of the difference in hip aBMD between older and young adults was slightly lower than of total radial vBMD (- 0.51 SD vs. - 0.78 SD).

CONCLUSION

Compared with young adults at the time of PBM, the transitional zones in older adults were enlarged at the expense of the compact-appearing cortex with a greater porosity in all cortical sub-compartments. The similar SD differences in aBMD and vBMD between older and younger groups suggest that the differences in bone area are not leading to major artefactual change in aBMD.

A High-Intensity Exercise Intervention Improves Older Women Lumbar Spine and Distal Tibia Bone Microstructure and Function: A 20-Week Randomized Controlled Trial

Introduction: The effects of ageing on bone can be mitigated with different types of physical training, such as power training. However, stimuli that combine increasing external and internal loads concomitantly may improve bone quality. The goal of this study was to assess the efficacy of a combined power and plyometric training on lumbar spine and distal tibia microstructure and function. Methods: 38 sedentary elderly women between 60 and 70 years were randomly allocated in experimental (N = 21) and control group (N = 17). The effects of the 20-week protocol on lumbar spine microstructure and tibia microstructure and function were assessed by trabecular bone score (TBS), high resolution peripheral quantitative computed tomography (HR-pQCT) and microfinite element analysis. Results: when compared to the effects found in the control group, the experimental group showed significant improvements in lumbar spine TBS (Hedges' g = 0.77); and in distal tibia trabecular thickness (g = 0.82) and trabecular bone mineral density (g=0.63). Conclusion: our findings underscore the effectiveness of the proposed intervention, suggesting it as a new strategy to slow down and even reverse the structural and functional losses in the skeletal system due to ageing.

Effects of 24 Weeks of Growth Hormone Treatment on Bone Microstructure and Volumetric Bone Density in Patients with Childhood-Onset Adult GH Deficiency

OBJECTIVE

Adults with childhood-onset growth hormone deficiency (CO AGHD) have prominently impaired volumetric bone density (vBMD) and bone microarchitecture. Effects of recombinant human growth hormone (rhGH) on bone microarchitecture in CO AGHD were insufficiently evaluated. The objective of this study is to assess the effects of rhGH on bone microarchitecture and vBMD in CO AGHD patients.

DESIGN

In this single-center prospective study, nine CO AGHD patients received rhGH treatment for 24 weeks. High-resolution peripheral quantitative computerized tomography (HR-pQCT) of distal tibia and radius was performed at baseline and at the end of treatment. Main outcomes were vBMD and morphometric parameters from HR-pQCT.

RESULTS

After 24-week treatment, IGF-1 SDS gradually increased from -3.31 ± 1.56 to -1.92 ± 1.65 (p=0.113). Serum phosphate (1.17 ± 0.17 vs. 1.35 ± 0.18 mmol/L, p=0.030), alkaline phosphatase (83.6 ± 38.6 vs. 120.5 ± 63.7, p=0.045), and β-CTX (0.67 ± 0.32 vs. 1.09 ± 0.58, p=0.022) were significantly elevated. In distal tibia, total vBMD (200.2 ± 41.7 vs 210.3 ± 40.9 mg HA/cm³, p=0.017), cortical area (89.9 ± 17.7 vs 95.5 ± 19.9 mm², p=0.032), and cortical thickness (0.891 ± 0.197 vs 0.944 ± 0.239 mm, p=0.028) were significantly improved. Trabecular area decreased from 795.3 ± 280.9 to 789.6 ± 211.4 mm² (p=0.029). Trabecular bone volume fraction increased from 0.193 ± 0.038 to 0.198 ± 0.036 (p=0.027). In radius, cortical perimeter (74.1 ± 10.0 vs 75.0 ± 10.9 mm, p=0.034), trabecular thickness (0.208 ± 0.013 vs 0.212 ± 0.013 mm, p=0.008), trabecular separation (0.743 ± 0.175 vs 0.796 ± 0.199 mm, p=0.019), and inhomogeneity of network (Tb.1/N.SD) (0.292 ± 0.087 vs 0.317 ± 0.096 mm, p=0.026) were significantly improved, while trabecular number (1.363 ± 0.294 vs 1.291 ± 0.325 1/mm, p=0.025) decreased significantly.

CONCLUSIONS

Our results provide evidence for improvement of vBMD and bone microarchitecture in AGHD patients at a relatively early stage of rhGH treatment.

Impaired bone microarchitecture in distal interphalangeal joints in patients with primary hypertrophic osteoarthropathy assessed by high-resolution peripheral quantitative computed tomography

This study aimed to investigate the bone impairment in finger joints in PHO patients by HR-pQCT. Results showed distinguished differences in bone architecture and biomechanics parameters at DIPs between PHO patients and healthy controls using HR-pQCT assessment. Besides, serum PGE2, hsCRP and ESR levels were found negatively correlated with total vBMD.

INTRODUCTION

This study aimed to investigate the bone impairment in finger joints in primary hypertrophic osteoarthropathy (PHO) patients firstly by high-resolution peripheral quantitative computed tomography (HR-pQCT).

METHODS

Fifteen PHO patients and 15 healthy controls were enrolled in this study. Bone erosions in hands at distal interphalangeal joints (DIPs) in both PHO patients and controls were evaluated by X-ray. Bone geometry, vBMD, microstructure parameters, and size of individual bone erosion were also measured at the 3rd DIP by HR-pQCT as well. Blood biochemistry levels between the two groups were also compared.

RESULTS

Compared to X-ray, HR-pQCT assessment were more sensitive for detection of bone erosions, with 14 PHO patients by HR-pQCT versus ten PHO patients by X-ray judged at the 3rd DIP. The average depth, width, and volume of erosions size in PHO patients were 1.38 ± 0.80 mm, 0.79 ± 0.27 mm, and 1.71 ± 0.52 mm³, respectively. The bone cross-areas including total area (+ 25.3%, p ≤ 0.05), trabecular area (+ 56.2%, p ≤ 0.05), and cortical perimeter (+ 10.7%, p ≤ 0.05) at the defined region of interest of 3rd DIP was significantly larger than controls. Total vBMD was 11.9% lower in PHO patients compared with the controls (p ≤ 0.05). Biochemical test results showed the increased levels of inflammatory cytokines, bone resorption markers, and joint degeneration markers in PHO patients. Serum prostaglandin PGE2, high-sensitive C-reactive protein (hsCRP) and erythrocyte sedimentation rate (ESR) levels were found negatively correlated with total vBMD.

CONCLUSIONS

This study demonstrated higher sensitivity of the HR-pQCT measurement at DIPs by showing the differences in architecture and biomechanics parameters at DIPs between the PHO patients and healthy controls, which would be of interest clinically to investigate bone deterioration in PHO patients.

Progressive structural bone changes and their relationship with treatment in patients with psoriatic arthritis: a longitudinal HR-pQCT study

Background

Although the short-term effects of tumor necrosis factor alpha (TNF-α) and interleukin-17A (IL-17A) inhibition on the structural changes in psoriatic arthritis (PsA) using high-resolution peripheral quantitative computed tomography (HR-pQCT) have been reported, no studies have investigated the long-term structural changes in PsA patients receiving routine care. We reported longitudinal changes of erosions and enthesiophytes using HR-pQCT and their relationship with treatments in PsA patients over a 5-year period.

Methods

HR-pQCT examination at the second and third metacarpal heads (MCH2 and MCH3) was performed in 60 PsA patients at baseline and after 5 years. The size of each individual lesion was quantified. Erosion and enthesiophyte progression were defined as change exceeding the smallest detectable change (SDC).

Results

A total of 108 bone erosions and 99 enthesiophytes were detected at baseline. Three new bone erosions but no new enthesiophytes were evident at 5 years. A significant increase in mean (±SD) erosion (0.58 ± 1.50 mm³, P < 0.001) and enthesiophyte (0.47 ± 0.76 mm³, P < 0.001) volume was observed. Erosion and enthesiophyte progression were found in 37/111 (33.3%) and 50/99 (50.5%) lesions, respectively. During this 5-year period, 26 (43%) out of the 60 patients achieved sustained Disease Activity index for PSoriatic Arthritis (DAPSA) low disease activity (LDA) (SDL group, defined as achieving DAPSA-LDA at both baseline and 5 years). Fourteen (23%) out of 60 patients received a TNF inhibitor throughout the 5-year period (TNFi group). Fewer erosions progressed (12/51 [23.5%] vs 25/60 [41.7%], P = 0.047) and the increased in enthesiophyte volume was significantly less (0.28 ± 0.67 vs 0.61 ± 0.80 mm³, P = 0.048) in the SDL group than in the non-SDL group. However, no significant difference between the TNFi and non-TNFi groups was detected in terms of the change in volume or progression of bone erosion and enthesiophyte.

Conclusion

Damage accrual in terms of bone erosion and enthesiophyte was observed in PsA patients over a period of 5 years despite receiving routine clinical care. Nonetheless, sustained control of disease activity may be able to prevent these bony damages.

Dimorphism in axial and appendicular dimensions, cortical and trabecular microstructure and matrix mineral density in Chinese and Caucasian women

INTRODUCTION

Appendicular fractures are less common in Chinese than Caucasian women. Bone mineral density (BMD) is lower, not higher than in Caucasians because Chinese have smaller appendicular dimensions than Caucasians. However, smaller bones may offset the liability to fracture by being assembled with a more robust microstructure. We hypothesized that Chinese assemble an appendicular skeleton with a thicker, less porous and more mineralized cortex that is less deteriorated in advanced age than in Caucasians.

METHODS

We compared anthropometry in 477 Chinese and 278 Caucasian women and compared bone microstructure using high-resolution peripheral quantitative computed tomography in another cohort of 186 Chinese and 381 Caucasian women aged 18 to 86 years, all living in Melbourne, Australia. Trabecular plate (p) and rod (r) bone volume/total volume (BV/TV) were quantified using individual trabecula segmentation (ITS). Bone strength was estimated using micro-finite element analysis (μFEA).

RESULTS

Premenopausal Chinese were shorter than Caucasian women, mainly due to shorter leg length. Distal radial total cross sectional area (CSA) was 14.8% smaller (p < 0.001). After adjusting for age and total CSA, Chinese had similar cortical and medullary areas but 0.30 SD lower cortical porosity and 0.27 SD higher matrix mineral density (both p < 0.05). Trabecular plate-to-rod ratio was 0.55 SD higher due to a 0.41 SD higher pBV/TV and 0.36 SD lower rBV/TV (p ranging 0.001 to 0.023). Chinese also had 0.36 SD greater whole bone stiffness and 0.36 SD greater failure load than Caucasians (both p < 0.05). After adjusting for age and total CSA, postmenopausal Chinese had 3.3% smaller cortical area, medullary area was 2.1% larger, cortical porosity was no lower, matrix mineral density and pBV/TV were no higher compared with Caucasians at the distal radius. Whole bone stiffness was 0.39 SD lower and failure load was 0.40 SD lower in Chinese (both p < 0.05).

CONCLUSION

Chinese build a more robust skeleton than Caucasians during growth, an advantage not observed in advanced age due to greater bone loss or race-specific secular trends in bone morphology.

Three-dimensional intravital imaging in bone research

Intravital imaging has emerged as a novel and efficient tool for visualization of in situ dynamics of cellular behaviors and cell-microenvironment interactions in live animals, based on desirable microscopy techniques featuring high resolutions, deep imaging and low phototoxicity. Intravital imaging, especially based on multi-photon microscopy, has been used in bone research for dynamics visualization of a variety of physiological and pathological events at the cellular level, such as bone remodeling, hematopoiesis, immune responses and cancer development, thus, providing guidance for elucidating novel cellular mechanisms in bone biology as well as guidance for new therapies. This review is aimed at interpreting development and advantages of intravital imaging in bone research, and related representative discoveries concerning bone matrices, vessels, and various cells types involved in bone physiologies and pathologies. Finally, current limitations, further refinement, and extended application of intravital imaging in bone research are concluded.

Skeletal macro- and microstructure adaptations in men undergoing arduous military training

PURPOSE

Short periods of basic military training increase the density and size of the tibia, but the adaptive response of bone microarchitecture, a key component of bone strength, is not fully understood.

METHODS

Tibial volumetric bone mineral density (vBMD), geometry, microarchitecture and mechanical properties were measured using high-resolution peripheral quantitative computed tomography in 43 male British Army infantry recruits (mean ± SD, age 21 ± 3 years, height 1.76 ± 0.06 m, body mass 76.5 ± 9.4 kg). Bilateral scans were performed at the distal tibia at the start (week 1) and end (week 13) of basic military training. Concurrent measures were obtained for whole-body areal bone mineral density (aBMD) using DXA, and markers of bone metabolism (βCTX, P1NP, PTH, total 25(OH)D and ACa) from venous blood.

RESULTS

Training increased areal BMD for total body (1.4%) and arms (5.2%) (P ≤ 0.031), but not legs and trunk (P ≥ 0.094). Training increased trabecular (1.3 to 1.9%) and cortical vBMD (0.6 to 0.9%), trabecular volume (1.3 to 1.9%), cortical thickness (3.2 to 5.2%) and cortical area (2.6 to 2.8%), and reduced trabecular area (-0.4 to -0.5%) in both legs (P < 0.001). No changes in trabecular number, thickness and separation, cortical porosity, stiffness or failure load were observed (P ≥ 0.188). βCTX decreased (-0.11 μg∙l^-1, P < 0.001) and total 25(OH)D increased (9.4 nmol∙l^-1, P = 0.029), but no differences in P1NP, PTH or ACa were observed between timepoints (P ≥ 0.233).

CONCLUSION

A short period of basic military training increased density and altered geometry of the distal tibia in male military recruits. The osteogenic effects of basic military training are likely due to an increase in unaccustomed, dynamic and high-impact loading.

The ageing joint-standard age- and sex-related values of bone erosions and osteophytes in the hand joints of healthy individuals

OBJECTIVE

To analyze the age-related changes of the physiological hand joint architecture.

METHOD

To address this concept, healthy individuals (each 10 women and 10 men in six different age decades spanning from 21 to 80 years) were recruited through a field campaign, investigated for the absence of rheumatic diseases and other comorbidities and received high-resolution quantitative computed tomography (HR-pQCT) examination of the hand joints. Number and extent of erosions and osteophytes were quantified across the ages and different sexes.

RESULTS

Bone erosions [median (Q1-Q3), 1 (0-2)] and osteophytes [2 (1-4)] were found in healthy women and men with no significant sex differences. Structural changes however accumulated with age: the overall incidence rate ratio (IRR) for the number of erosions and osteophytes per age were 1.04 (95% CI: erosions 1.03-1.06; osteophytes: 1.03-1.05). This means a 4% increase in the number of erosions and osteophytes per year. Using third decade as reference, healthy individuals in the age decades from 50 years had higher IRR for erosion numbers (sixth, seventh, eigth decade: 4.87 (2.20-11.75), 6.81 (3.08-16.46) and 6.92 (3.11-16.79)) compared to younger subjects (fourth, fifth decade: 1.80 (0.69-4.87), 1.53 (0.59-4.10)). The IRRs of osteophytes also indicate a gradual increase after the fifth decade, with IRRs of 2.32 (1.32-4.17), 4.17 (2.38-7.49) and 6.86 (3.97-12.20) for the sixth, seventh and eigth decades, respectively.

CONCLUSIONS

Structural changes in the hand joints of healthy individuals are age dependent. While being rare under 50 years of age, erosions and osteophytes accumulate above the age of 50, suggesting that the threshold between "normal" and "pathological" is shifted with the increase of age.

The Correction of Systematic Error due to Plaster and Fiberglass Casts on HR-pQCT Bone Parameters Measured In Vivo at the Distal Radius

Due to difficulty assessing healing of distal radius fractures using conventional radiography, there is interest in using high resolution peripheral quantitative computed tomography (HR-pQCT) to track healing at the microarchitectural level. Unfortunately, the plaster-of-Paris and fiberglass casts used to immobilize fractures affect HR-pQCT measurements due to beam hardening, and increased noise. The challenge is compounded because casts have variable thickness, and an individual patient will often have their cast changed 2-3 times during the course of treatment. This study quantifies the effect of casts within a clinically relevant range of thicknesses on measured bone parameters at the distal radius, and establishes conversion equations to correct for systematic error in due to cast presence. Eighteen nonfractured participants were scanned by HR-pQCT in three conditions: no cast, plaster-of-Paris cast, and fiberglass cast. Measured parameters were compared between the baseline scan (no cast) and each cast scan to evaluate if systematic error exists due to cast presence. A linear regression model was used to determine an appropriate conversion for parameters that were found to have systematic error. Plaster-of-Paris casts had a greater range of thicknesses (3.2-9.5 mm) than the fiberglass casts (3.0-5.4 mm), and induced a greater magnitude of systematic error overall. Key parameters of interest were bone mineral density (total, cortical, and trabecular) and trabecular bone volume fraction, all of which were found to have systematic error due to presence of either cast type. Linear correlations between baseline and cast scans for these parameters were excellent (R² > 0.98), and appropriate conversions could be determined within a margin of error less than a ±6% for the plaster-of-Paris cast, and ±4% for the fiberglass cast. We have demonstrated the effects of cast presence on bone microarchitecture measurements, and presented a method to correct for systematic error, in support of future use of HR-pQCT to study fracture healing.

Retracted: Downregulation of microRNA-367 promotes osteoblasts growth and proliferation of mice during fracture by activating the PANX3-mediated Wnt/β-catenin pathway

A majority of people suffering from bone fractures fail to heal and develop a nonunion, which is a challenging orthopedic complication requiring complex and expensive treatment. Previous data showed the inhibition of some microRNAs (miRNAs or miRs) can enhance fracture healing. The objective of the present study is to explore effects of miR-367 on the osteoblasts growth and proliferation of mouse during fracture via the Wnt/β-catenin pathway by targeting PANX3. Primarily, the femur fracture model was successfully established in 66 (C57BL/6) 6-week-old male mice. To verify whether miR-367 target PANX3, we used the target prediction program and performed luciferase activity determination. Subsequently, to figure out the underlying regulatory roles of miR-367 in fracture, osteoblasts were elucidated by treatment with miR-367 mimic, miR-367 inhibitor, or siRNA against PANX3 to determine the expression of miR-367, siPANX3, β-catenin, and Wnt5b as well as cell proliferation and apoptosis. The results demonstrated that PANX3 was verified as a target gene of miR-367. MiR-367 was found to highly expressed but PANX3, β-catenin, and Wnt5b were observed poorly expressed in fracture mice. downregulated miR-367 increased the mRNA and protein expression of PANX3, β-catenin, and Wnt5b, increased cell growth, proliferation, and migration, while decreased cell apoptosis in osteoblasts. Altogether, our study demonstrates that the downregulation of miR-367 may promote osteoblasts growth and proliferation in fracture through the activation of the PANX3-dependent Wnt/β-catenin pathway.

Assessing bone impairment in ankylosing spondylitis (AS) using the trabecular bone score (TBS) and high-resolution peripheral quantitative computed tomography (HR-pQCT)

OBJECTIVES

To compare bone quality using the trabecular bone score (TBS) and bone microarchitecture in the distal tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT) in ankylosing spondylitis (AS) patients and healthy controls (HC).

METHODS

Areal bone mineral density (aBMD) and TBS (TBS iNsight software) were evaluated using DXA (Hologic, QDR 4500); while volumetric bone mineral density (vBMD) and bone microarchitecture were analyzed in the distal tibia using HR-pQCT (Scanco) in 73 male patients with AS and 52 age-matched HC.

RESULTS

AS patients were a mean 41.6 ± 7.9 years old and had a mean disease duration of 16.4 ± 8.6 y, with a mean mSASSS 25.6 ± 16.4. No difference was observed in lumbar spine aBMD in AS patients and HC (p = 0.112), but total hip BMD (p = 0.011) and TBS (p < 0.001) were lower in AS patients. In the distal tibia, reduced trabecular volumetric density [Tb.vBMD (p < 0.006)] and structural alterations - trabecular thickness (Tb.Th), p = 0.044 and trabecular separation (Tb.Sp), p = 0.039 - were observed in AS patients relative to controls. Further analysis comparing TBS < 1.310 and TBS ≥ 1.310 in AS patients revealed a higher mean body mass index [BMI] (p = 0.010), lower tibia cortical vBMD [Ct.vBMD] (p = 0.007), lower tibia cortical thickness [Ct.Th]: (p = 0.048) in the former group. On logistic regression analysis, BMI (OR = 1.27; 95%IC = 1.08-1.50, p = 0.005), (VF 4.65; 1.13-19.1, p = 0.033) and tibial Ct.vBMD (0.98; 0.97-1.00, p = 0.007) were associated with a lower TBS (<1.310).

CONCLUSIONS

The present study demonstrates that TBS and HR-pQCT imaging are important technologies evaluating bone impairment in AS patients. Moreover, in these patients vertebral fractures were associated with lower TBS.

Characterising variability and regional correlations of microstructure and mechanical competence of human tibial trabecular bone: An in-vivo HR-pQCT study

OBJECTIVE

Quantifying spatial distribution of trabecular bone mechanical competence and microstructure is important for early diagnosis of skeletal disorders and potential risk of fracture. The objective of this study was to determine a spatial distribution of trabecular mechanical and morphological properties in human distal tibia and examine the contribution of regional variability of trabecular microarchitecture to mechanical competence.

METHODS

A total of 340 representative volume elements at five anatomic regions of trabecular bone - anterior, posterior, lateral, medial and centre - from ten white European-origin postmenopausal women were studied. Region-specific trabecular parameters such as trabecular volume fraction, trabecular thickness, trabecular number, trabecular surface area, trabecular separation, plate-like structure fraction and finite element analysis of trabecular stiffness were determined based on in-vivo high resolution peripheral quantitative computed tomographic (HR-pQCT) images of distal tibiae from ten postmenopausal women. Mean values were compared using analysis of variance. The correlations between morphological parameters and stiffness were calculated.

RESULTS

Significant regional variation in trabecular microarchitecture of the human distal tibia was observed (p < 0.05), with up to 106% differences between lowest (central and anterior) and highest (medial and posterior) regions. Higher proportion of plate-like trabecular morphology (63% and 53%) was found in medial and posterior regions in the distal tibia. Stiffness estimated from finite element models also differed significantly (p < 0.05), with stiffness being 4.5 times higher in the highest (medial) than lowest (central) regions. The bone volume fraction was the strongest correlate of stiffness in all regions.

CONCLUSION

A novel finding of this study is the fact that significant regional variation of stiffness derived from two-phased FEA model with individual trabecula representation correlated highly to regional morphology obtained from in-vivo HR-pQCT images at the distal tibia. The correlations between regional morphological parameters and mechanical competence of trabecular bone were consistent at all regions studied, with regional BV/TV showing the highest correlation. The method developed for regional analysis of trabecular mechanical competence may offer a better insight into the relationship between mechanical behaviour and microstructure of bone. The findings provide evidence needed to further justify a larger-cohort feasibility study for early detection of bone degenerative diseases: examining regional variations in mechanical competence and trabecular specifications may allow better understanding of fracture risks in addition to others contributing factors.

Bone microarchitecture and volumetric bone density impairment in young male adults with childhood-onset growth hormone deficiency

Context Adult growth hormone deficiency (AGHD) is characterized by low bone density and increased risk of fracture. Bone microarchitecture is insufficiently evaluated in patients with childhood-onset AGHD (CO AGHD). Objective To assess volumetric bone density (vBMD) and bone microarchitecture in CO AGHD in early adulthood after cessation of recombinant growth hormone (rhGH) treatment. Design and subjects Case-control study in a major academic medical center in Beijing, including 20 young male adults with CO AGHD and 30 age- and weight-matched non-athletic healthy men. High-resolution peripheral quantitative computerized tomography (HR-pQCT) of distal radius and tibia was performed. Outcomes The main outcomes were vBMD and morphometry parameters from HR-pQCT. Results Compared with healthy controls, CO AGHD group had significantly decreased insulin-like growth factor 1 (IGF-1) level and IGF-1 SDS (P < 0.001). β-CTX and alkaline phosphatase levels in CO AGHD group were significantly increased (P < 0.001). CO AGHD group had significantly decreased total vBMD, cortical vBMD, trabecular vBMD, cortical area, cortical thickness as well as trabecular thickness and trabecular bone volume fraction of both tibia and radius (P < 0.001). CO AGHD patients had an 8.4 kg decrease in grip strength and a significant decrease in creatinine levels (P = 0.001). At both tibia and radius, by finite element analysis, bone stiffness and failure load of the CO AGHD patients were significantly decreased (P < 0.001). After adjusting for age, BMI and serum levels of testosterone and free thyroxin, serum IGF-1 level was a positive predictor for total vBMD, cortical vBMD, cortical area, trabecular vBMD, bone stiffness and failure load of both tibia and distal radius in all subjects. Conclusions Young adult male patients with childhood-onset adult growth hormone deficiency who are no longer receiving growth hormone replacement have prominently impaired volumetric bone density and bone microarchitecture and lower estimated bone strength.

The effect of running on foot muscles and bones: A systematic review

Despite the widespread evidence of running as a health-preserving exercise, little is known concerning its effect on the foot musculature and bones. While running may influence anatomical foot adaptation, it remains unclear to what extent these adaptations occur. The aim of this paper is to provide a systematic review of the studies that investigated the effects of running and the adaptations that occur in foot muscles and bones. The search was performed following the PRISMA guidelines. Relevant keywords were used for the search through PubMed/MEDLINE, Scopus and SPORTDiscus. The methodological quality of intervention studies was assessed using the Downs and Black checklist. For cross-sectional studies, the Newcastle-Ottawa scale was used. Sixteen studies were found meeting the inclusion criteria. In general, the included studies were deemed to be of moderate methodological quality. Although results of relevant literature are limited and somewhat contradictory, the outcome suggests that running may increase foot muscle volume, muscle cross-sectional area and bone density, but this seems to depend on training volume and experience. Future studies conducted in this area should aim for a standard way of reporting foot muscle/bone characteristics. Also, herein, suggestions for future research are provided.

Use of Micro-Computed Tomography for Bone Evaluation in Dentistry

Micro computed tomography (µCT) follows the same principle of computed-tomography used for patients, however providing higher-resolution. Using a non-destructive approach, samples can be scanned, and each section obtained is used to build a volume using tridimensional reconstruction. For bone analysis, it is possible to obtain information about the tissue's microarchitecture and composition. According to the characteristics of the bone sample (e.g. human or animal origin, long or irregular shape, epiphysis or diaphysis region) the pre-scanning parameters must be defined. The resolution (i.e. voxel size) should be chosen taking into account the features that will be evaluated, and the necessity to identify inner structures (e.g. bone channels and osteocyte lacunae). The region of interest should be delimited, and the threshold that defines the bone tissue set in order to proceed with binarization to separate the voxels representing bone from the other structures (channels, resorption areas, and medullary space). Cancellous bone is evaluated by means of the trabeculae characteristics and their connectivity. The cortex is evaluated in relation to the thickness and porosity. Bone mineral density can also be measured, by the amount of hydroxyapatite. Other parameters such as structure-model-index, anisotropy, and fractal dimension can be assessed. In conclusion, intrinsic and extrinsic determinants of bone quality can be assessed by µCT. In dentistry, this method can be used for evaluating bone loss, alterations in bone metabolism, or the effects of using drugs that impair bone remodeling, and also to assess the success rate of bone repair or surgical procedures.

Normative Standards for HRpQCT Parameters in Chinese Men and Women

Assessing bone architecture using high-resolution peripheral quantitative computed tomography (HRpQCT) has the potential to improve fracture risk assessment. The Normal Reference Study aimed to establish sex-specific reference centile curves for HRpQCT parameters. This was an age-stratified cross-sectional study and 1072 ambulatory Chinese men (n = 544) and women (n = 528) aged 20 to 79 years, who were free from conditions and medications that could affect bone metabolism and had no history of fragility fracture. They were recruited from local communities of Hong Kong. Reference centile curves for each HRpQCT parameter were constructed using generalized additive models for location, scale, and shape with age as the only explanatory variable. Patterns of reference centile curves reflected age-related changes of bone density, microarchitecture, and estimated bone strength. In both sexes, loss of cortical bone was only evident in mid-adulthood, particularly in women with a more rapid fashion probably concurrent with the onset of menopause. In contrast, loss of trabecular bone was subtle or gradual or occurred at an earlier age. Expected values of HRpQCT parameters for a defined sex and age and a defined percentile or Z-score were obtained from these curves. T-scores were calculated using the population with the peak values as the reference and reflected age- or menopause-related bone loss in an older individual or the room to reach the peak potential in a younger individual. These reference centile curves produced a standard describing a norm or desirable target that enables value clinical judgements. Percentiles, Z-scores, and T-scores would be helpful in detecting abnormalities in bone density and microarchitecture arising from various conditions and establishing entry criteria for clinical trials. They also hold the potential to refine the diagnosis of osteoporosis and assessment of fracture risk. © 2018 American Society for Bone and Mineral Research.

Trabecular bone microarchitecture predicts fragility fractures in postmenopausal women on denosumab treatment

BACKGROUND

High-resolution peripheral quantitative computed tomography (HR-pQCT) represents a three-dimensional tool for the screening of osteoporosis patients i.e., regarding fracture risk. The purpose of this study was to determine the baseline and follow-up bone microarchitecture in relation to incident fracture risk in postmenopausal women on denosumab treatment.

METHODS

We have retrospectively evaluated data from 182 postmenopausal women treated with denosumab that underwent an initial HR-pQCT scan before the initiation of the treatment; and at least one second HR-pQCT after 12 months. Women were assigned to two groups based on documented fragility fractures for the following 2.9 ± 1.1 years: fracture (n = 22) and no fracture (n = 160). Baseline parameters from DXA, HR-pQCT and bone turnover were compared between the two groups. Furthermore, ROC and multiple regression analyses of the baseline and follow-up data were performed to evaluate the predictive value regarding incident fractures.

RESULTS

At baseline, trabecular parameters were significantly reduced in the fracture group and showed the best predictive value for new fractures, while DXA results could not predict fractures. A multiple regression model identified BV/TV and age as the best baseline parameters for incident fracture risk. At 12 months, cortical and trabecular parameters increased in the non-fracture group, while no significant increase was noted in the fracture group. However, no significant differences regarding the changes of these parameters could be detected between the non-fracture and fracture cohort.

CONCLUSIONS

Trabecular bone microstructure at baseline is crucial for incident fracture risk in postmenopausal women on denosumab treatment, especially in comparison to DXA values. In this context, the microstructural follow-up results seemed to be of lesser importance regarding fracture risk. The results of this exploratory study should be validated in independent populations.

Low Muscle Strength and Mass Is Associated With the Accelerated Decline of Bone Microarchitecture at the Distal Radius in Older Men: the Prospective STRAMBO Study

Low muscle mass and strength are associated with poor bone microarchitecture. We studied the association of muscle mass and strength with changes in bone microarchitecture of distal radius in 821 older men during an 8-year prospective follow-up. Bone microarchitecture was assessed by high resolution peripheral quantitative computed tomography (XtremeCT-1, Scanco) at baseline, then after 4 and 8 years. Relative appendicular lean mass of the upper limbs (RALM-u.l.) was calculated as DXA-measured lean mass of upper limbs divided by (height)² . Relative grip strength was calculated as grip strength divided by height. Decrease in bone mineral content (BMC), total volumetric bone mineral density (Tt.vBMD), cortical thickness (Ct.Th), cortical area (Ct.Ar) and cortical vBMD (Ct.vBMD) accelerated with age. Trabecular area (Tb.Ar) expansion and trabecular bone deterioration accelerated with age. Men in the first RALM-u.l. quartile had more rapid loss of BMC, Tt.vBMD, Ct.Th, Ct.vBMD and Ct.Ar vs. the highest quartile. They had more rapid increase in Tb.Ar. Men in the lowest quartile of grip strength had greater decrease in BMC, Tt.vBMD, Ct.Th, Ct.vBMD, Ct.Ar, and greater increase in Tb.Ar vs. the highest quartile. In the models including ALM-u.l. and grip strength (not corrected for height), both muscle-related variables were associated with more rapid bone microarchitectural deterioration (slightly more so for grip strength). Trabecular vBMD (Tb.vBMD) and Central.Tb.vBMD increased in men having higher muscle mass and strength. Trends in trabecular number and thickness did not differ across the groups in all the analyses. Thus, in men, aging-related deterioration of bone microarchitecture was most rapid after the age of 80. Low grip strength (and slightly more weakly low RALM-u.l.) is associated with the more rapid decrease in Tt.vBMD and cortical variables, and with greater Tb.Ar expansion. In conclusion, dynapenia and sarcopenia contribute to the deterioration of bone microarchitecture in older men. © 2018 American Society for Bone and Mineral Research.

Assessment of Cortical Interruptions in the Finger Joints of Patients With Rheumatoid Arthritis Using HR-pQCT, Radiography, and MRI

Small cortical interruptions may be the first sign of an erosion, and more interruptions can be found in patients with rheumatoid arthritis (RA) compared with healthy subjects. First, we compared the number and size of interruptions in patients with RA with healthy subjects using high-resolution peripheral quantitative CT (HR-pQCT). Second, we investigated the association between structural damage and inflammatory markers on conventional radiography (CR) and MRI with interruptions on HR-pQCT. Third, the added value of HR-pQCT over CR and MRI was investigated. The finger joints of 39 patients with RA and 38 healthy subjects were examined through CR, MRI, and HR-pQCT. CRs were scored using the Sharp/Van der Heijde method. MRI images were analyzed for the presence of erosions, bone marrow edema, and synovitis. HR-pQCT images were analyzed for the number, surface area, and volume of interruptions using a semiautomated algorithm. Descriptives were calculated and associations were tested using generalized estimating equations. Significantly more interruptions and both a larger surface area and the volume of interruptions were detected in the metacarpophalangeal joints of patients with RA compared with healthy subjects (median, 2.0, 1.42 mm² , and 0.48 mm³ versus 1.0, 0.69 mm² , and 0.23 mm³ , respectively; all p < 0.01). Findings on CR and MRI were significantly associated with more and larger interruptions on HR-pQCT (prevalence ratios [PRs] ranging from 1.03 to 7.74; all p < 0.01) in all subjects, and were consistent in patients with RA alone. Having RA was significantly associated with more and larger interruptions on HR-pQCT (PRs, 2.33 to 5.39; all p < 0.01), also after adjustment for findings on CR or MRI. More and larger cortical interruptions were found in the finger joints of patients with RA versus healthy subjects, also after adjustment for findings on CR or MRI, implying that HR-pQCT imaging may be of value in addition to CR and MRI for the evaluation of structural damage in patients with RA. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Association of Decreased Handgrip Strength with Reduced Cortical Thickness in Japanese Female Patients with Type 2 Diabetes Mellitus

LD-100, a quantitative ultrasonic device, allows us to measure cortical thickness (CoTh). Patients with type 2 diabetes mellitus (T2DM) show high prevalence of sarcopenia. This study aimed to clarify the association of handgrip strength (HGS) with cortical porosis, a major risk for fracture of DM. CoTh and trabecular bone mineral density (TrBMD) at the 5.5% distal radius were assessed in T2DM female patients (n = 122) and non-DM female controls (n = 704) by LD-100. T2DM patients aged older 40 years showed significantly lower HGS and CoTh, but not TrBMD, than non-DM counterparts. Although HGS was significantly and positively correlated with CoTh and TrBMD in T2DM patients, multivariate analysis revealed HGS as an independent factor positively associated with CoTh, but not TrBMD, in T2DM patients, suggesting the preferential association of HGS with cortical, but not trabecular, bone component in T2DM female patients. In conclusion, the present study demonstrated an early decline of HGS in T2DM female patients as compared with non-DM healthy controls after the age of 40 years, which is independently associated with thinner CoTh, but not TrBMD in T2DM patients, and thus suggested that reduced muscle strength associated with DM might be a major factor for cortical porosis development in DM patients.

The role of imaging in early diagnosis and prevention of joint damage in inflammatory arthritis

INTRODUCTION

Inflammatory arthritis is characterized by chronic inflammation in the synovium, associated with degradation of cartilage and erosion of juxta-articular bone. The bone loss and joint destruction mediated by aberrant immunological responses resulting in proinflammatory cytokine release and various immune cell activation are known as osteoimmunology. Areas covered: A structured literature search including Medline and PubMed, Cochrane meta-analyses and abstracts of international congresses was performed to review joint damage in inflammatory arthritis in terms of pathogenesis, novel imaging assessment, and prevention. Expert commentary: Deeper understanding of the integration of the skeletal and immune as well as inflammatory system is paving the way to prevent bone loss and bone destruction in inflammatory arthritis. With the availability of various imaging modalities such as ultrasound, magnetic resonance imaging (MRI) and high-resolution peripheral quantitative computed tomography (HR-pQCT), we are now able to detect early joint damage, early diagnosis of inflammatory arthritis, monitor the progression or even ascertain whether the inflammatory process is effectively suppressed to allow repair of joint damage by novel therapeutic agents.

Deterioration of Cortical Bone Microarchitecture: Critical Component of Renal Osteodystrophy Evaluation

BACKGROUND

Cortical bone is a significant determinant of bone strength and its deterioration contributes to bone fragility. Thin cortices and increased cortical porosity have been noted in patients with chronic kidney disease (CKD), but the "Turnover Mineralization Volume" classification of renal osteodystrophy does not emphasize cortical bone as a key parameter. We aimed to assess trabecular and cortical bone microarchitecture by histomorphometry and micro-CT in patients with CKD G5 and 5D (dialysis).

METHODS

Transiliac bone biopsies were performed in 14 patients undergoing kidney transplantation (n = 12) and parathyroidectomy (n = 2). Structural parameters were analysed by histomorphometry and micro-CT including trabecular bone volume, thickness (TbTh), number (TbN) and separation and cortical thickness (CtTh) and porosity (CtPo). Indices of bone remodelling and mineralisation were obtained and relationships to bone biomarkers examined. Associations were determined by Spearman's or Pearson's rank correlation coefficients.

RESULTS

By micro-CT, trabecular parameters were within normal ranges in most patients, but all patients showed very low CtTh (127 ± 44 µm) and high CtPo (60.3 ± 22.5%). CtPo was inversely related to TbN (r = -0.56; p = 0.03) by micro-CT and to TbTh (r = -0.60; p = 0.024) by histomorphometry and correlated to parathyroid hormone values (r = 0.62; p = 0.021). By histomorphometry, bone turnover was high in 50%, low in 21% and normal in 29%, while 36% showed abnormal patterns of mineralization. Significant positive associations were observed between osteoblast surface, osteoclast surface, mineralization surface and bone turnover markers.

CONCLUSIONS

Deterioration of cortical -microarchitecture despite predominantly normal trabecular parameters reinforces the importance of comprehensive cortical evaluation in patients with CKD.

An automated algorithm for the detection of cortical interruptions and its underlying loss of trabecular bone; a reproducibility study

Background

We developed a semi-automated algorithm that detects cortical interruptions in finger joints using high-resolution peripheral quantitative computed tomography (HR-pQCT), and extended it with trabecular void volume measurement. In this study we tested the reproducibility of the algorithm using scan/re-scan data.

Methods

Second and third metacarpophalangeal joints of 21 subjects (mean age 49 (SD 11) years, 17 early rheumatoid arthritis and 4 undifferentiated arthritis, all diagnosed < 1 year ago) were imaged twice by HR-pQCT on the same day with repositioning between scans. The images were analyzed twice by one operator (OP1) and once by an additional operator (OP2), who independently corrected the bone contours when necessary. The number, surface and volume of interruptions per joint were obtained. Intra- and inter-operator reliability and intra-operator reproducibility were determined by intra-class correlation coefficients (ICC). Intra-operator reproducibility errors were determined as the least significant change (LSC_SD).

Results

Per joint, the mean number of interruptions was 3.1 (SD 3.6), mean interruption surface 4.2 (SD 7.2) mm², and mean interruption volume 3.5 (SD 10.6) mm³ for OP1. Intra- and inter-operator reliability was excellent for the cortical interruption parameters (ICC ≥0.91), except good for the inter-operator reliability of the interruption surface (ICC = 0.70). The LSC_SD per joint was 4.2 for the number of interruptions, 5.8 mm² for interruption surface, and 3.2 mm³ for interruption volume.

Conclusions

The algorithm was highly reproducible in the detection of cortical interruptions and their volume. Based on the LSC findings, the potential value of this algorithm for monitoring structural damage in the joints in early arthritis patients needs to be tested in clinical studies.

Electronic supplementary material

The online version of this article (10.1186/s12880-018-0255-7) contains supplementary material, which is available to authorized users.