Fracture Risk Research Articles

2341 Qualitative assessment of introducing bone health assessment for Parkinson’s disease patients in a university hospital setting

Abstract Introduction Parkinson’s disease (PD) patients with or without psychosis are at higher risk of recurrent falls and fracture and, as a consequence, higher mortality and morbidity NICE (13) Henderson et al. (2019). We conducted a qualitative study to understand barriers and facilitators of introducing ‘bone health assessment’ for PD patients. Method We conducted a pilot study to identify and implement a bone health assessment tool to communicate falls and fracture risks to GPs. • SWOT and Stakeholder analysis was conducted to identify an appropriate bone health assessment tool. • PDSA cycles were completed to assess barriers and facilitators of bone health assessment in all PD clinical areas. • 4 Participants were identified from all possible PD clinical settings and trained on how to use the FRAX assessment tool. • Semi structured interviews were conducted to explore themes from 6-week pilot study. Results Bone health assessments were not conducted routinely in PD clinical settings in our Trust Literature review/SWOT and Stake holder analysis identified ‘FRAX’ score as an appropriate bone health assessment tool for PD patients. Interviews with participants identified time constraints during the clinical consultation as a major barrier to conducting bone health assessment using the FRAX assessment tool. All participants agreed that this improved communication with patients and GPs in understanding bone health and risk of falls and fractures. Face to face PD Nurse Clinics were deemed the most appropriate clinical settings for these assessments. Conclusion As a result of this service improvement project bone health is now assessed in all PD Nurse clinics. This has enabled GPs to start the most appropriate bone protection treatment for PD patients.

The Effects of Sarcopenia and Fracture Risk on Kinesiophobia, Fear of Falling, Fall Risk and Quality of Life in Geriatric Individuals

The Effects of Sarcopenia and Fracture Risk on Kinesiophobia, Fear of Falling, Fall Risk and Quality of Life in Geriatric Individuals

One versus 2years of alendronate following denosumab: the CARD extension.

When denosumab is discontinued, antiresorptive therapy is critical to attenuate high-turnover bone loss. The ideal choice and duration of antiresorptive therapy are not yet defined, however. In the Comparison of Alendronate or Raloxifene following Denosumab (CARD) study, we demonstrated that 12months of alendronate was better able to maintain the bone mineral density (BMD) gains achieved with 12months of denosumab versus 12months of raloxifene. In this extension, we wished to determine if 12months of alendronate would be sufficient in maintaining these denosumab-induced BMD gains. In the CARD study, postmenopausal osteoporotic women aged 60-79 at high fracture risk received 12months of denosumab 60-mg SC every 6months followed by 12months of either alendronate 70mg weekly (N = 26) or raloxifene (N = 25). All subjects in the alendronate arm were then offered participation in a 1-year extension in which they were randomized to continue alendronate for an additional 12months (N = 10) or to receive calcium and vitamin D alone (N = 8). The primary outcome was change in spine BMD between months 24 and 36. Exploratory endpoints included changes in areal BMD (aBMD) at other anatomic sites as well as changes in serum bone turnover markers. The CARD study demonstrated the effectiveness of 12months alendronate in preserving denosumab-induced BMD gains. In the extension, aBMD was maintained at the spine, total hip, and femoral neck in both those randomized to an additional year of alendronate and those randomized to calcium/vitamin D alone. We did, however, observe a transient comparative decrease between months 24-30 in the calcium/vitamin D group at the total hip (P = 0.008) and femoral neck (P = 0.040). At the end of 24months of the CARD study, bone turnover markers serum c-telopeptide (CTX) and procollagen N-propeptide of type I collagen (PINP) were suppressed in both groups and then increased more between months 24-36 in the calcium/vitamin D group than the alendronate group (P = 0.051 for CTX, P = 0.030 for P1NP). Both CTX and PINP remained below the month 0 baseline in both groups (P < 0.05 for all comparisons). With the limitations of our small sample size, these data suggest that both 1 and 2years of alendronate effectively maintain BMD gains achieved with 1year of denosumab and prevented any rebound in bone turnover marker levels above pre-denosumab baseline. This is the first randomized trial to assess minimum duration of bisphosphonate after short-term denosumab and may be helpful to guide clinical care. Similar studies performed after longer durations of denosumab would be helpful to further define optimal management. ClinicalTrials.gov registration number: NCT03623633.

Association of obesity with osteoporotic fracture risk in individuals with bone metabolism-related conditions: a cross sectional analysis.

This study aimed to investigate the individual and composite associations of different indices of obesity on osteoporotic fractures at three different sites among individuals affected by conditions influencing bone metabolism. Participants were included from the National Health and Nutrition Examination Survey (NHANES), a national cross-sectional survey. BMI and WC were used separately and in combination to evaluate the presence of obesity. Obesity was defined as BMI ≥ 30 kg/m2, WC ≥ 88 cm in females, and WC ≥ 102 cm in males. Associations between obesity and osteoporotic fractures were assessed using multivariable logistic regression and OR curves. Associations modified by age, sex, race, and alcohol consumption were also evaluated. A total of 5377 participants were included in this study. In multivariable logistic regression analyses, we found that BMI, WC, BMI defining obesity, and WC defining obesity were negatively associated with hip fracture (all p < 0.05). However, harmful associations between WC and BMI defining obesity and spine fracture were found (all p < 0.05). OR curves revealed that BMI and WC had a linear relationship with hip and spine fractures (all P for non-linearity >0.05). Further analyses showed that the highest WC quartile was harmfully associated with a higher risk of spine fractures (p < 0.05). Obese participants diagnosed by both BMI and WC were less likely to have hip fractures but more likely to have spine fractures (all P for trend <0.05). A significant interaction between age (Ref: age < 50 years) and BMI and WC was detected for hip fractures (all P for interaction <0.05). In people with conditions influencing bone metabolism, obesity diagnosed by BMI and WC was associated with a lower risk of hip fracture, while obesity diagnosed by BMI and the highest WC quartile were associated with a higher risk of spine fracture.

Type 2 Diabetes and Fracture Risk in Older Women

The reasons for the increased fracture risk in type 2 diabetes (T2D) are not fully understood. To determine if poorer skeletal characteristics or worse physical function explain the increased fracture risk in T2D. This prospective observational study is based on the population-based Sahlgrenska University Hospital Prospective Evaluation of Risk of Bone Fractures study cohort of older women, performed in the Gothenburg area between March 2013 and May 2016. Follow-up of incident fracture data was completed in March 2023. Data analysis was performed between June and December 2023. Data were collected from questionnaires and through examination of anthropometrics, physical function, and bone measurements using bone densitometry (dual-energy x-ray absorptiometry), and high-resolution peripheral computed tomography. A subsample underwent bone microindentation to assess bone material strength index (BMSi). Baseline assessment of bone characteristics and physical function and radiograph verified incident fractures. Of 3008 women aged 75 to 80 years, 294 women with T2D (mean [SD] age, 77.8 [1.7] years) were compared with 2714 women without diabetes (mean [SD] age, 77.8 [1.6] years). Women with T2D had higher bone mineral density (BMD) at all sites (total hip, 4.4% higher; femoral neck (FN), 4.9% higher; and lumbar spine, 5.2% higher) than women without. At the tibia, women with T2D had 7.4% greater cortical area and 1.3% greater density, as well as 8.7% higher trabecular bone volume fraction. There was no difference in BMSi (T2D mean [SD], 78.0 [8.3] vs controls, 78.1 [7.3]). Women with T2D had lower performance on all physical function tests. The study found 9.7% lower grip strength, 9.9% slower gait speed, and 13.9% slower timed up-and-go time than women without diabetes. During a median (IQR) follow-up of 7.3 (4.4-8.4) years, 1071 incident fractures, 853 major osteoporotic fractures (MOF), and 232 hip fractures occurred. In adjusted (for age, body mass index, clinical risk factors, and FN BMD) Cox regression models, T2D was associated with an increased risk of any fracture (HR, 1.26; 95% CI, 1.04-1.54) and MOF (HR, 1.25; 95% CI, 1.00-1.56). In this cohort study of older women, T2D was associated with higher BMD, better bone microarchitecture, and no different BMSi but poorer physical function, suggesting that poor physical function is the main reason for the increased fracture risk in T2D women.

Cemented Calcar-Guided Short-Stem Prostheses in Geriatric Patients: Short-Term Results from a Prospective Observational Study.

Both cementless and cemented stems have exhibited favorable long-term outcomes in total hip arthroplasty. Nonetheless, in elderly patients, cemented hips offer an advantage due to their reduced risk of periprosthetic fractures. This study aimed to assess the initial outcomes of 28 patients who underwent unilateral cemented total hip arthroplasty utilizing a calcar-guided A2 stem (ARTIQO GmbH, Lüdinghausen, Germany). Various types of antibiotic-loaded bone cement were employed. During follow-up, we recorded demographic data and comorbidities and employed standardized clinical assessment tools, including the Harris Hip Score. Radiographic assessments included preoperative, postoperative, and follow-up imaging to evaluate subsidence, osteolysis, and bone resorption. The results indicated that among the 28 patients, 5 withdrew consent and 2 patients passed away from unrelated causes. Additionally, one prosthesis was explanted due to the undersizing of the cement stopper, which resulted in an inadequate cement mantle. As a result, 20 patients underwent a 1-year follow-up, revealing noteworthy enhancements in clinical scores, with no instances of radiolucent lines or osteolysis. No infections were detected. In summary, our short-term experience with this particular cemented short-stem design yielded promising results, exhibiting excellent functional outcomes, no aseptic loosening attributable to the stem, and no infections. Further clinical studies and registry data are essential to corroborate these findings.

Sarcopenia definitions and their association with injurious falls in older Swedish women from the Sahlgrenska University Hospital Prospective Evaluation of Risk of Bone fractures (SUPERB) study.

To investigate the association between three commonly used sarcopenia definitions and the risk of injurious falls in a population of older Swedish women. A total of 2,883 75-80-year-old women with complete data on relevant sarcopenia definitions from the Swedish SUPERB cohort were studied. Sarcopenia was defined based on the Sarcopenia Definitions and Outcomes Consortium (SDOC: low handgrip strength and gait speed), revised European Working Group on Sarcopenia in Older People (EWGSOP2: low appendicular lean mass index (ALMI, dual-energy X-ray absorptiometry (DXA)-derived), appendicular lean mass (kg)/height (m2), hand grip strength (kg), or low chair stand time (s)), and Asian Working Group for Sarcopenia (AWGS: low ALMI and hand grip strength (kg) or low gait speed (m/s)). Questionnaires captured the occurrence of falls in the past 12months. Incident injurious falls were identified using national registers. Cox regression (hazard ratios (HR) and 95% confidence intervals (CI)) analyses were performed without adjustment and after adjustment for age, body mass index, previous falls, and the Charlson comorbidity index. During a median (IQR) follow-up time of 7.06 (6.2-7.9) years, there were 491 injurious falls without fracture and 962 injurious falls when also including falls resulting in a fracture. Sarcopenia according to EWGSOP2 and AWGS was not associated with an increased risk of injurious falls. Individuals with sarcopenia defined by SDOC had a higher risk of injurious falls with and without fracture (HR 2.11; 95% CI, 1.63-2.73 and HR, 2.16; 95% CI, 1.55-3.02, respectively). Sarcopenia definitions confined to muscle function and strength such as SDOC, rather than including DXA-determined ALMI (EWGSOP2 and AWGS), are associated with incident injurious falls with and without fractures in older women.

Analysis of Critical Instability Conditions for Solid-Phase Plugging of Natural Fractures during Temporary Plugging and Fracturing.

Hydraulic fracturing has become a key technology for the development of unconventional oil and gas resources, such as deep shale. Due to the development of natural fractures in deep shale reservoirs, the opening of natural fractures during the fracturing process can cause a significant loss of fracturing fluid, resulting in a reduction in the width of the main fracture and construction risks, such as sand plugging. It is important to improve the fracturing effect of deep shale reservoirs by plugging natural fractures with solid phases, reducing filtration, and improving the efficiency of the fracturing fluid. Ensuring the effectiveness of solid plugging is key to optimizing the fracturing design and improving the stimulation effect after fracturing. In this study, solid plugging technology is introduced into the filtration control process of natural fractures. By setting a plugging zone with a certain length and permeability inside the natural fracture, a stability prediction model for the plugging zone of natural fractures is established, and the instability conditions of the plugging zone are analyzed. The simulation results indicate that the instability of the plugging zone is related to permeability and there is a critical permeability. When the permeability of the plugging zone is greater than this value, expansion instability will occur, and when it is less than or equal to this value, shear slip instability may occur. The strength of shear slip instability is mainly determined by the length of the plugging zone, the friction angle of the natural fracture surface, the friction angle between the plugging particles, and the porosity of the plugging zone. The friction angle of natural fracture surfaces affects only the strength of slip instability, while the friction angle of plugging particles and porosity mainly affect the strength of shear instability. The research results provide a theoretical basis for the optimization of fracturing construction parameters in deep shale reservoirs.

Pro-Osteogenic Effect of the Nutraceutical BlastiMin Complex® in Women with Osteoporosis or Osteopenia: An Open Intervention Clinical Trial.

Osteoporosis is a chronic disease that affects millions of patients worldwide and is characterized by low bone mineral density (BMD) and increased risk of fractures. Notably, natural molecules can increase BMD and exert pro-osteogenic effects. Noteworthily, the nutraceutical BlastiMin Complex® (Mivell, Italy, European Patent Application EP4205733A1) can induce differentiation of human bone marrow mesenchymal stem cells (BM-MSCs) in osteoblasts and can exert in vitro pro-osteogenic and anti-inflammatory effects. Thus, the purpose of this study was to verify the effects of BlastiMin Complex® on bone turnover markers (BTMs) and BMD in patients with senile and postmenopausal osteopenia or osteoporosis. The efficacy of BlastiMin Complex® on BTMs in serum was evaluated through biochemical assays. BMD values were analyzed by dual-energy X-ray absorptiometry (DXA) and Radiofrequency Echographic Multi Spectrometry (R.E.M.S.) techniques, and the SNPs with a role in osteoporosis development were evaluated by PCR. Clinical data obtained after 12 months of treatment showed an increase in bone turnover index, a decrease in C-reactive protein levels, and a remarkable increase in P1NP levels, indicating the induction of osteoblast proliferation and activity in the cohort of 100% female patients recruited for the study. These findings show that the nutraceutical BlastiMin Complex® could be used as an adjuvant in combination with synthetic drugs for the treatment of osteoporosis pathology.

Subsequent fracture risk in Norwegians and immigrants with an index forearm fracture: a cohort study

SummaryThe current study investigated subsequent fracture risk following a forearm fracture in three country of birth categories: Norway, Europe and North America, and other countries. Subsequent fracture risk was modestly higher in Norwegian-born individuals compared to the two other groups. Secondary fracture prevention should be recommended regardless of country background.BackgroundFracture risk is higher in patients with a previous fracture, but whether subsequent fracture risk differs by origin of birth is unknown. This study explores subsequent fracture risk in patients with an index forearm fracture according to region of birth.MethodsNationwide data on forearm fractures in patients ≥ 18 years in 2008–2019 were obtained from the Norwegian Patient Registry and Statistics Norway. Index fractures were identified by ICD-10 code S52, whereas subsequent fractures included any ICD-10 fracture code. Data on country of birth were from Statistics Norway and included three regional categories: (1) Norway, (2) other Europe and North America and (3) other countries. Direct age standardization and Cox proportional hazard regression were used to analyse the data.ResultsAmong 143,476 individuals with an index forearm fracture, 35,361 sustained a subsequent fracture. Norwegian-born forearm fracture patients had the highest subsequent fracture rates (516/10,000 person-years in women and 380 in men). People born outside Europe and North America had the lowest rates (278/10,000 person-years in women and 286 in men). Compared to Norwegian-born individuals, the hazard ratios (HRs) of subsequent fracture in individuals from Europe and North American were 0.93 (95% CI 0.88–0.98) in women and 0.85 (95% CI 0.79–0.92) in men. The corresponding HRs in individuals from other countries were 0.76 (95% CI 0.70–0.84) in women and 0.82 (95% CI 0.74–0.92) in men.ConclusionIndividuals born outside Norway had a lower subsequent fracture risk than Norwegian-born individuals; however, subsequent fracture risk increased with age in all groups. Our results indicate that secondary fracture prevention should be recommended regardless of region of origin.

Bone Fragility in Diabetes and its Management: A Narrative Review.

Bone fragility is a serious yet under-recognised complication of diabetes mellitus (DM) that is associated with significant morbidity and mortality. Multiple complex pathophysiological mechanisms mediating bone fragility amongst DM patients have been proposed and identified. Fracture risk in both type 1 diabetes (T1D) and type 2 diabetes (T2D) continues to be understated and underestimated by conventional risk assessment tools, posing an additional challenge to the identification of at-risk patients who may benefit from earlier intervention or preventive strategies. Over the years, an increasing body of evidence has demonstrated the efficacy of osteo-pharmacological agents in managing skeletal fragility in DM. This review seeks to elaborate on the risk of bone fragility in DM, the underlying pathogenesis and skeletal alterations, the approach to fracture risk assessment in DM, management strategies and therapeutic options.

Mitigating calcar fracture risk with automated impaction during total hip arthroplasty

BackgroundAutomated broaching has recently been introduced for total hip arthroplasty (THA), with the goal of improving surgical efficiency and reducing surgeon workload. While studies have suggested that this technique may improve femoral sizing and alignment, little has been published regarding its safety, particularly with regard to calcar fractures. The purpose of our study was to evaluate the risk of calcar fracture during automated broaching, and to determine if this risk can be mitigated. MethodsWe queried our prospective institutional database and identified 1596 unilateral THAs performed by the senior author using automated impaction between 2019 and 2023. We identified the incidence of calcar fracture with automated impaction, and whether the fracture occurred during broaching or stem insertion. We additionally determined calcar fracture incidence within two consecutive subgroups of patients using different stem insertion techniques; subgroup (1): automated broaching with automated stem insertion for all patients; versus subgroup (2): automated broaching with automated stem insertion ONLY if a cushion of cancellous bone separated the broach from the calcar, otherwise the stem was placed manually. Continuous and categorical variables were analyzed with Student's t-test and Fisher's exact test, respectively. ResultsSeventeen calcar fractures occurred intraoperatively (1.1 %). Only two fractures occurred during automated broaching (0.1 %), while fifteen occurred during final stem impaction (0.9 %) (p = 0.007). Four calcar fractures (1.4 %) occurred in subgroup 1, compared to two in subgroup 2 (0.6 %) (p = 0.28). ConclusionsOur study found a calcar fracture incidence of 1.1 % using automated impaction, consistent with historically reported rates of 0.4–3.7 %. We found that calcar fractures are more likely to occur during stem insertion than during femoral broaching. We recommend that if any part of the final broach is in direct contact with the calcar, the final stem should be impacted manually to minimize fracture risk.

Tartrate-resistant acid phosphatase (TRAP/ACP5) promotes bone length, regulates cortical and trabecular bone mass, and maintains growth plate architecture and width in a sex- and site-specific manner in mice

Tartrate-resistant acid phosphatase (TRAP) serum levels reflect osteoclast number, bone remodeling activity, and fracture risk. Deletion or loss of function of TRAP results in short stature in mice and man. Yet, the impact and mechanisms of TRAP for the site- and sex-specific development of bone and cartilage is not well understood. Here, we use a global TRAP knockout (TRAPKO) and wildtype littermate control (WT) mice of both sexes to investigate TRAP as a possible sex- and site-specific regulator of bone and growth plate development. TRAPKO mice of both sexes weighed less and had shorter tibial length than their WT, features that were more accentuated in male than female TRAPKO mice. These changes were not associated with a general reduction in growth as not all organs displayed a proportionally lower mass, and serum IGF-1 was unchanged. Using μCT and site-specificity analysis of the cortical bone revealed wider proximal tibia, a higher trabecular thickness, and lower trabecular separation in male TRAPKO compared to WT mice, an effect not seen in female mice. Histomorphometric analysis revealed that the growth plate height as well as height of terminal hypertrophic chondrocytes were markedly increased, and the number of columns was decreased in TRAPKO mice of both sexes. These effects were more accentuated in female mice. Proliferation and differentiation of bone marrow derived macrophages into osteoclasts, as well as C-terminal cross links were normal in TRAPKO mice of both sexes. Collectively, our results show that TRAP regulates bone and cartilage development in a sex-and site-specific manner in mice.

Stem to prevent periprosthetic fracture after notching in total knee arthroplasty.

Improper osteotomy during total knee arthroplasty (TKA) can lead to anterior femoral notching, which increases the risk of periprosthetic fractures due to stress concentration. One potential solution is the addition of an intramedullary stem to the femoral component. However, the optimal stem length remains unclear. In this study, we aimed to determine the optimal stem length using finite element models. Finite element models of femurs were developed with unstemmed prostheses and prostheses with stem lengths of 50, 75, and 100 mm. Under squat loading conditions, the von Mises stress at the notch and stress distribution on four transversal sections of the femur were analyzed. Additionally, micromotion of the prosthesis-bone interface was evaluated to assess initial stability. The unstemmed prosthesis exhibited a von Mises stress of 191.8 MPa at the notch, which decreased to 43.1, 8.8, and 23.5 MPa for stem lengths of 50, 75, and 100 mm, respectively. The stress reduction on four selected femoral transversal sections compared with the unstemmed prosthesis was 40.0%, 84.4%, and 67.1% for stem lengths of 50, 75, and 100 mm, respectively. Micromotion analysis showed a maximum of 118.8 μm for the unstemmed prosthesis, which decreased significantly with the application of stems, particularly at the anterior flange. Intramedullary stems effectively reduced stress concentration at the femoral notch. The 50-mm stem length provided the optimal combination of reduced notch stress, minimized stress-shielding effect, and decreased micromotion at the anterior flange.

Iatrogenic Intraoperative Fracture in Patients With Osteogenesis Imperfecta.

Osteogenesis imperfecta (OI) is a genetic defect in collagen type I, phenotypically characterized by bony fragility and a propensity to high rates of childhood fracture. Fragility fractures in patients with OI have been reported with routine hospital care. In addition, there is a nonzero rate of iatrogenic fracture during orthopaedic surgery directly related to the technical steps of the procedure itself. The rate of this latter has never been explicitly investigated. A review of all patients at a single OI referral center was conducted, including all patients with a diagnosis of OI seen between 2013 and 2023, inclusive. All patients who underwent orthopaedic surgery of any kind were reviewed, and clinical and radiographic details of all procedures were extracted. Among the details examined were the OI subtype, surgery details, any implants used, intraoperative and hospital stay complications, modified Clavien-Dindo classification of complications, and ultimate outcome. Eleven of 60 patients experienced an unplanned, iatrogenic intraoperative fracture during orthopaedic surgery (11/60 = 18.3%). This comprised 15 fractures among 356 total orthopaedic surgical episodes (15/356 = 4.2%). All but one fracture occurred on the operative long bone segment, all were a direct result of surgical steps, and 11 of 15 fractures occurred in the femur. Most fractures were secondary to the removal, insertion, or exchange of intramedullary implants in the lower extremity (11 of 15 fractures), most often the femur. Thirteen of 15 injuries were classified as modified Clavien-Dindo II or III, requiring modification of postop rehabilitation, additional treatments, or surgical intervention (87%). Overall, iatrogenic fracture was the most common intraoperative complication experienced in the cohort. Iatrogenic fracture during orthopaedic surgery for patients with OI is not uncommon. A sizeable minority of patients with OI undergoing orthopaedic surgery will experience unplanned fractures, most commonly in the femur, and care is altered in most instances. The risk of intraoperative fracture can be discussed with families of children with OI as part of informed consent and shared decision-making. Level IV-retrospective cohort series.

Biomechanical Comparisons between One- and Two-Compartment Devices for Reconstructing Vertebrae by Kyphoplasty.

This biomechanical in vitro study compared two kyphoplasty devices for the extent of height reconstruction, load-bearing capacity, cement volume, and adjacent fracture under cyclic loading. Multisegmental (T11-L3) specimens were mounted into a testing machine and subjected to compression, creating an incomplete burst fracture of L1. Kyphoplasty was performed using a one- or two-compartment device. Then, the testing machine was used for a cyclic loading test of load-bearing capacity to compare the two groups for the amount of applied load until failure and subsequent adjacent fracture. Vertebral body height reconstruction was effective for both groups but not statistically significantly different. After cyclic loading, refracture of vertebrae that had undergone kyphoplasty was not observed in any specimen, but fractures were observed in adjacent vertebrae. The differences between the numbers of cycles and of loads were not statistically significant. An increase in cement volume was strongly correlated with increased risks of adjacent fractures. The two-compartment device was not substantially superior to the one-compartment device. The use of higher cement volume correlated with the occurrence of adjacent fractures.

Senescence of skeletal stem cells and their contribution to age-related bone loss

Human aging is linked to bone loss, resulting in bone fragility and an increased risk of fractures. This is primarily due to an age-related decline in the function of bone-forming osteoblastic cells and accelerated cellular senescence within the bone microenvironment. Here, we provide a detailed discussion of the hypothesis that age-related defective bone formation is caused by senescence of skeletal stem cells, as they are the main source of bone forming osteoblastic cells and influence the composition of bone microenvironment. Furthermore, this review discusses potential strategies to target cellular senescence as an emerging approach to treat age-related bone loss.

Assessment of differences in mechanical properties and thickness of temporal and occipital bones and correlation with age in Japanese forensic samples

The mechanical properties and thickness of adult temporal and occipital bones were examined in modern Japanese forensic samples. Cranial bones were obtained from 293 Japanese corpses (179 men and 114 women). During autopsy, left temporal (LT), right temporal (RT), and occipital (O) bone samples were extracted from each skull. Sample thickness (ST) was measured using multidetector computed tomographic imaging. The fracture load (FL) of each sample was measured by a bending test, in which the flexural strength (FS) was calculated. The FL and ST values for O were significantly greater compared with those of the LT and RT bones. The temporal bones were thinner compared with other parts of the skull and at greater risk for fracture. There is a need to take precautions to prevent temporal bone fractures. There were no significant differences in any of the values between LT and RT, indicating bilateral symmetry of the temporal bones. There were significant negative correlations between age and the FL and FS values for all sites in both sexes, except for O in the male samples, suggesting that older individuals are at increased risk for fractures. No significant correlations were observed between age and ST values in any of the samples. There were significantly positive correlations between FL and ST values at all sites regardless of sex.

Multi-site phantomless bone mineral density from clinical quantitative computed tomography in males.

Volumetric bone mineral density (vBMD) is commonly assessed using QCT. Although standard vBMD calculation methods require phantom rods that may not be available, internal-reference phantomless (IPL) and direct measurements of Hounsfield units (HU) can be used to calculate vBMD in their absence. Yet, neither approach has been systemically assessed across skeletal sites, and HU need further validation as a vBMD proxy. This study evaluated the accuracy of phantomless methods, including IPL and regression-based phantomless (RPL) calibration using HU to calculate vBMD, compared to phantom-based (PB) methods. vBMD from QCT scans of 100 male post-mortem human subjects (PMHS) was calculated using site-specific PB calibration at multiple skeletal sites throughout the body. A development sample of 50/100 PMHS was used to determine site-specific reference material density for IPL calibration and RPL equations. Reference densities and equations from the development sample were used to calculate IPL and RPL vBMD on the remaining 50/100 PMHS for method validation. PB and IPL/RPL vBMD were not significantly different (p > .05). Univariate regressions between PB and IPL/RPL vBMD were universally significant (p < 0.05), except for IPL Rad-30 (p = 0.078), with a percent difference across all sites of 6.97% ± 5.95% and 5.22% ± 4.59% between PB and IPL/RPL vBMD, respectively. As vBMD increased, there were weaker relationships and larger differences between PB vBMD and IPL/RPL vBMD. IPL and RPL vBMD had strong relationships with PB vBMD across sites (R2 = 97.99, R2 = 99.17%, respectively), but larger residual differences were found for IPL vBMD. As the accuracy of IPL/RPL vBMD varied between sites, phantomless methods should be site-specific to provide values more comparable to PB vBMD. Overall, this study suggests that RPL calibration may better represent PB vBMD compared to IPL calibration, increases the utility of opportunistic QCT, and provides insight into bone quality and fracture risk.

Fracture rate and risk factors associated with the fracture of narrow diameter implants: A long-term retrospective analysis.

The objective of this long-term retrospective study was to evaluate the fracture rate and the risk factors associated with the fracture of 3.3 mm narrow diameter implants (NDIs). A total of 524 records of patients rehabilitated with 3.3 mm NDIs between 1997 and 2015 were assessed. Data on patients, implants, and prostheses were collected, and descriptive analysis of the variables was performed. NDIs were separated into 2 groups: "fractured" and "non-fractured", and a multilevel logistic regression model was applied to identify the risk factors associated with NDI fracture. Eighty-four patients were removed from the analysis for interrupting follow-up or presenting failures other than fractures. Of the 440 patients included (64.66 ± 13.4 years), 272 were females (61.8%), and 168 males (38.2%), and mean follow-up time was 129 ± 47.1 months. Of the 1428 NDIs, 15 (1.05%) in 9 patients (2.04%) fractured during the studied period. Ten fractures (66.66%) happened in 6 patients (66.66%) showing signs of parafunction. NDI with modified sandblasted, large grit, acid-etched surface was the only implant variable to show a protective statistical significance (p = .0439). NDI fracture was a rare event in the studied sample. NDIs manufactured with modified sandblasted, large grit, acid-etched surface may provide extra protection against NDI fracture. Patient-specific factors and implant characteristics should be carefully considered to limit the risk of fracture of 3.3 mm NDIs.