Structural determinants of hip fracture in elderly women: re-analysis of the data from the EPIDOS study

Association of osteoporotic fractures of femoral neck and femoral neck geometric parameters in native Chinese women

BACKGROUND

Although it is generally believed that the femoral neck fracture is related to the femoral neck geometric parameters (FNGPs), the association between the risk of osteoporotic fracture of the femoral neck and FNGPs in native Chinese women is still unclear.

METHODS

A total of 374 female patients (mean age 70.2 ± 9.32 years) with osteoporotic fracture of the femoral neck, and 374 non-fracture control groups were completely matched with the case group according to the age ratio of 1:1. Using DXA bone densitometer to measured eight FNGPs: the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compressive strength index (CSI) at the narrowest point of the femoral neck.

RESULTS

Compared with the control group, the average values of OD (2.9%), ED (4.5%), and BR (26.1%) in the patient group significantly increased (p = 0.015 to < 0.001), while CSA (‒15.3%), CT (‒18.2%), SM (‒10.3%), CSMI (‒6.4%), and CSI (‒10.8%) significantly decreased (all p < 0.001). The prevalence of osteoporosis in the lumbar spine, femoral neck, and total hip was, respectively, 82%, 81%, and 65% in fracture patients. Cox proportional hazard model analysis showed that in the age adjusted model, the fracture hazard ratio (HR) of CSA, CT, BR, SM, and CSI significantly increased (HRs = 1.60‒8.33; 95% CI = 1.08‒16.6; all p < 0.001). In the model adjusted for age and femoral neck BMD, HRs of CT (HRs = 3.90‒8.03; 95% CI = 2.45‒15.1; all p < 0.001) and BR (HRs = 1.62‒2.60; 95% CI = 1.20‒5.44; all p < 0.001) were still significantly increased.

CONCLUSION

These results suggest that the majority of osteoporotic fractures of the femoral neck of native Chinese women occur in patients with osteoporosis. CT thinning or BR increase of FNGPs may be independent predictors of fragility fracture of femoral neck in native Chinese women unrelated to BMD.

The increasing complexity of femoral fragility fractures: incidence, fracture patterns and management over a 10-year period

INTRODUCTION

The purpose of this study was to determine whether there have been changes in the numbers and complexity of femoral fragility fractures presenting to our department over a period of 10 years.

METHODS

Patients >60 years presenting with femoral fragility fractures to our institution in 2018-2019 (397 fractures) were compared with respect to demographic data, incidence rates, fracture classification and surgical management with a historical cohort from 2009-2010 (335 fractures). Pathological and high velocity fractures were excluded.

RESULTS

The gender proportion and average age (83.1 vs. 82.7 years) was unchanged. The number of femoral fractures increased by 19% but the overall incidence in people >60 years fell by 6% (p = 0.41). The proportion of unstable trochanteric fractures (31A2 and A3) increased from 22% to 55% (p < 0.001). The proportion of displaced intracapsular fractures increased from 53% to 72% (p < 0.001). The incidence of stable trochanteric fractures fell from 12.4 to 7.3/10,000 patients>60 years (p = 0.0006) while the incidence of unstable trochanteric fractures (31A2 and 31A3) increased from 3.5 to 8.9/10,000 patients >60 years (p < 0.0001). The proportion of trochanteric fractures treated with an intramedullary (IM) nail increased from 9% to 35% (p = 0.0001). The number of shaft and distal femoral fractures increased by 41% although the incidence did not change significantly. Periprosthetic fractures comprised 70% of femoral shaft fractures in both cohorts.

CONCLUSIONS

The increasing number and complexity of femoral fragility fractures, especially unstable trochanteric fractures and periprosthetic fractures, is likely to have an impact on implant use, theatre time and cost.

Is Regional Bone Mineral Density the Differentiating Factor Between Femoral Neck and Femoral Trochanteric Fractures?

Background Osteoporosis is globally recognized as a prevalent bone disease, and proximal femoral fractures constitute a serious complication associated with it. In recent years, the frequency of hip fractures has increased rapidly, with ramifications that extend into the social and economic aspects of both patients' lives and healthcare systems. The primary goal of this study is to discover whether bone mineral density (BMD) in specific regions of the hip could be related to femoral neck or trochanteric fractures. Methodology This prospective cohort study employed dual-energy X-ray absorptiometry (DEXA) measurements on 70 individuals with proximal femoral fractures. The participants sought treatment at the emergency department of our unit for hip fractures and adhered to our predefined eligibility criteria. These criteria primarily included (i) age exceeding 60 years and (ii) a diagnosis of either femoral neck or trochanteric fracture attributed to (iii) a low-energy lateral fall and (iv) a previously established state of complete ambulation before the occurrence of the fracture. In this context, we recorded the BMD of the hip, as well as the BMD values of the upper and lower halves of the neck, trochanteric region, and diaphysis. For the comparison of the categorical variables, Pearson's χ2 criterion was used, whereas Student's t-test was applied for the comparison of means of quantitative variables across fracture types. Results No statistical differences were identified when comparing regional BMDs and T-scores with the fracture type. This conclusion was also reconfirmed concerning age, gender, and Tonnis classification. Only a moderate correlation was observed, demonstrating lower values of regional BMDs in women compared to men. Conclusions The inability of our study to establish a direct correlation between BMD measurements across diverse areas of the proximal femur underlines the imperative need for subsequent investigations. These studies should not only integrate more precise techniques for measuring and mapping the BMD of different hip regions but should also encompass a comprehensive examination that would consider both intrinsic and extrinsic characteristics of the proximal femur.

Distinctive Geometrical Traits of Proximal Femur Fractures-Original Article and Review of Literature

Background and Objectives: The incidence of proximal femoral fractures is escalating rapidly, generating a significant challenge for healthcare systems globally and, carrying serious social and economic implications. The primarily object of this study was to discover potential distinguishing factors between fractures occurring in the femoral neck and trochanteric region. Materials and Methods: We performed a prospective cohort study of the radiographic images of 70 people over 65 years of age who were admitted to the orthopedic department with hip fracture and who fulfilled our eligibility criteria. Neck Length (NL), Offset Lenth (OL), Hip Axis Length (HAL), Neck Shaft Angle (NSA), Wiberg Angle (WA), Acetabular Angle (AA), Femoral Neck Diameter (FND), Femoral Head Diameter (FHD), Femoral Shaft Diameter (FSD), Femoral Canal Diameter (FCD) and Tonnis classification were recorded. For the comparison of the categorical variables, Pearson's χ2 criterion was used, while Student's t-test was applied for the comparison of means of quantitative variables across fracture types. Results: There were no statistically significant variances observed while comparing the selected geometric parameters of the proximal femur with the type of fracture. This finding was reaffirmed in relation to age, gender, and Tonnis classification. However, a moderate correlation was noted, revealing comparatively reduced values of HAL, FHD, and FND in women as opposed to men. Conclusions: The inability of our research to establish the differentiative geometric factors between femoral neck and trochanteric fractures underscores the need for further investigations, which would take into consideration the intrinsic characteristics of the proximal femur.

Subtype consideration in hip fracture research: patient variances in inter- and intra-classification levels highlight the need for future research deliberation. A 2-years follow-up prospective-historical cohort

Current research on elderly patients with hip fractures often neglects specific subtypes, either grouping all fracture types or overlooking them entirely. By categorizing elderly patients based on fracture subtypes, we observed diverse baseline characteristics but found no discrepancies in measured outcomes. This emphasizes the need for caution in future research dealing with different or broader measured outcomes that were not covered by the scope of this research.

PURPOSE/INTRODUCTION

Existing research in elderly patients with hip fractures often overlooks the distinct subtypes or lumps all fracture types together. We aim to examine the differences between hip fracture subtypes to assess if these differences are meaningful for clinical outcomes and should be considered in future research.

METHODS

Patients above 65 years who underwent hip fracture surgeries during a three-year period were retrospectively reviewed. Cases were grouped based on fracture subtype: non-displaced femoral neck (nDFN), displaced femoral neck (DFN), stable intertrochanteric (sIT), and unstable intertrochanteric (uIT).

RESULTS

Among the 1,285 included cases, the nDFN-group had lower ASA scores (p = 0.009) and younger patients (p < 0.001), followed by the DFN-group (p = 0.014). The uIT-group had a higher proportion of female patients (72.3%, p = 0.004). Differences in preoperative ambulation status were observed (p = 0.001). However, no significant associations were found between fracture type and postoperative outcomes, including ambulation, transfusions, complications, reoperations, or mortality. Gender and preoperative ambulation status were predictors of mortality across all time frames. ASA score predicted mortality only within the first year after surgery. Age and gender were predictors of postoperative blood transfusions, while age and preoperative ambulation status were predictors of postoperative complications.

CONCLUSIONS

Variations in baseline characteristics of hip fractures were observed, but no significant differences were found in measured outcomes. This indicates that the hip fracture group is not homogeneous, emphasizing the need for caution in research involving this population. While grouping all types of proximal femur fractures may be acceptable depending on the outcome being studied, it's essential not to extrapolate these results to outcomes beyond the study's scope. Therefore, we recommend consider hip fracture subtypes when researching different outcomes not covered by this study.

Site-Specific Differences in Bone Mineral Density of Proximal Femur Correlate with the Type of Hip Fracture

The aim of this study was to investigate whether site-specific differences in bone mineral density (BMD) of proximal femur correlate with the type of hip fracture using quantitative computed tomography. Femoral neck (FN) fractures were classified as nondisplaced or displaced subtypes. Intertrochanteric (IT) fractures were classified as A1, A2, or A3. The severe hip fractures were identified as displaced FN fractures or unstable IT fractures (A2 and A3). In total, 404 FN fractures (89 nondisplaced and 317 displaced) and 189 IT fractures (76 A1, 90 A2, and 23 A3) were enrolled. Areal BMD (aBMD) and volumetric BMD (vBMD) were measured in the regions of total hip (TH), trochanter (TR), FN, and IT of the contralateral unfractured femur. IT fractures exhibited lower BMD than FN fractures (all p ≤ 0.01). However, unstable IT fractures had higher BMD compared with stable ones (p < 0.01). After adjusting for covariates, higher BMD in TH and IT were associated with IT A2 (A1 vs. A2: odds ratios (ORs) from 1.47 to 1.69, all p < 0.01). Low bone measurements were risk factors for stable IT fractures (IT A1 vs. FN fracture subtypes: ORs from 0.40 to 0.65, all p < 0.01). There are substantial site-specific differences in BMD between IT fractures A1 and displaced FN fractures. Higher bone density was associated with unstable IT fracture when compared with stable ones. The understanding of biomechanics of various fracture types could help to improve the clinical management of these patients.

Associations Among Hip Structure, Bone Mineral Density, and Strength Vary With External Bone Size in White Women

Bone mineral density (BMD) is heavily relied upon to reflect structural changes affecting hip strength and fracture risk. Strong correlations between BMD and strength are needed to provide confidence that structural changes are reflected in BMD and, in turn, strength. This study investigated how variation in bone structure gives rise to variation in BMD and strength and tested whether these associations differ with external bone size. Cadaveric proximal femurs (n = 30, White women, 36-89+ years) were imaged using nanocomputed tomography (nano-CT) and loaded in a sideways fall configuration to assess bone strength and brittleness. Bone voxels within the nano-CT images were projected onto a plane to create pseudo dual-energy X-ray absorptiometry (pseudo-DXA) images consistent with a clinical DXA scan. A validation study using 19 samples confirmed pseudo-DXA measures correlated significantly with those measured from a commercially available DXA system, including bone mineral content (BMC) (R ²  = 0.95), area (R ²  = 0.58), and BMD (R ²  = 0.92). BMD-strength associations were conducted using multivariate linear regression analyses with the samples divided into narrow and wide groups by pseudo-DXA area. Nearly 80% of the variation in strength was explained by age, body weight, and pseudo-DXA BMD for the narrow subgroup. Including additional structural or density distribution information in regression models only modestly improved the correlations. In contrast, age, body weight, and pseudo-DXA BMD explained only half of the variation in strength for the wide subgroup. Including bone density distribution or structural details did not improve the correlations, but including post-yield deflection (PYD), a measure of bone material brittleness, did increase the coefficient of determination to more than 70% for the wide subgroup. This outcome suggested material level effects play an important role in the strength of wide femoral necks. Thus, the associations among structure, BMD, and strength differed with external bone size, providing evidence that structure-function relationships may be improved by judiciously sorting study cohorts into subgroups. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Age Related Trends in Structural Indices of Proximal Femur in Women Aged 20-70 in Southern Sri Lanka

Age related trends of the indices of hip structure help understanding how bone strength changes with age and the increased bone fragility in old age. Community-dwelling women aged 20-70years (n = 419) were selected by stratified random method and divided into age categories; 20-29years (n-69), 30-39years (n = 60), 40-49years (n = 69), 50-59years (n = 107) and 60-70years (n = 114). All subjects underwent dual energy x-ray absorptiometry (DXA) and hip structure analysis using Hologic Discovery scanner (Hologic Inc, Bedford, USA). Measured indices included hip axis length (HAL) and neck shaft angle (NSA) of the proximal femur. Cross sectional area (CSA), cross sectional moment of inertia (CSMI), section modulus (SM), cortical thickness (CT), buckling ration (BR) of three regions of interest; narrow neck, intertrochanteric region and femoral shaft, were also measured. Age related trends of all indices were studied with Locally Weighted Scatterplot Smoothing lines (LOESS) and ANOVA. Mean HAL and NSA values were not different between age categories. CSA, CSMI, SM and CT in three different regions showed curvilinear relationships with age. These indices gradually increased with age between 20-50 years and the maximum values were seen in the 40-49years age category and they declined afterwards. The decline of these indices was more rapid in the narrow neck and intertrochanter regions when compared with femoral shaft and the lowest mean CSA, CSMI, SM and CT in these two regions were seen in the 60-70 age category. BR showed a gradual decrease with age between 20-50 years and the lowest mean value was seen in the 40-49 age category. BR increased afterwards and the maximum mean value was seen in the 60-70 age category. This study demonstrates the dynamics of structural properties of proximal femur in the three selected cross sections of community-dwelling women aged 20-70 years and the increased bone fragility in old age.

Bending Resistance at Hip and Fractures Risk in Postmenopausal Women Independent of Bone Mineral Density

Several studies suggest that aging loss of bone mass is not necessarily associated with reduced mechanical proprieties as bending resistance. Since postmenopausal women with fracture and without osteoporosis might have an impairment in the bending mechanisms at hip, our aim was to assess if women with and without fractures differ in the femoral parameters of resistance to bending, independent of the bone loss. In this cross-sectional study we enrolled 192 postmenopausal women who underwent X-ray absorptiometry scan to measure bone mineral density as well as cross-sectional geometry parameters at the hip (Hip structure analysis). Among women with osteoporosis, a higher odds ratio for fracture was found in the first tertile of NN-D_max, a parameter linked to the resistance to bending forces in a cross-section (tertile I, OR = 6.7, p = 0.03; CI 1.19-38.01; reference tertile III). We also found a significantly higher risk for major fracture in the first tertile of NN-D_max (tertile I, OR = 6.0, p = 0.02; CI 1.26-28.4; reference tertile III). Among women without osteoporosis, a significantly higher odds ratio for fracture was found in the first tertile of IT-CSA, a parameter of resistance to axial load (tertile I, OR = 7.2, p = 0.002; CI 2.04-25.9; reference tertile III). We also found a significantly higher risk for major fracture in the first tertile of IT-CSA (OR = 18.4, p = 0.001; CI 1.52-221.8; tertile III reference). We demonstrate that some hip structural parameters are independently associated to the fracture risk in postmenopausal women.

Newly developed hip geometry parameters are associated with hip fracture

BACKGROUND

The conventional and newly developed geometry parameters at the femoral neck have formed a large geometry profile and their relationship with hip fracture was largely unknown. We aimed to evaluate the relationship between the geometry profile and hip fracture in Chinese.

METHODS

The hip geometry profile contains seven conventional geometry parameters at femoral neck (FN) and thirty newly developed parameters at three sub-regions (Narrow Neck, NN; Intertrochanter, IT; Femoral shaft, FS) of the total hip. Based on 6294 recruited Chinese (≥65 years), 97 subjects with osteoporotic fracture (OF) history and 388 matched controls were selected. The t test, Chi-square statistic, conditional logistic regression model were used.

RESULTS

Three geometric parameters (endocortical diameter, ED; cortical thickness, CT; buckling ratio, BR) have consistent differences at all the sites between the cases and controls (p < 0.01). Conventional geometry parameters (e.g., cross-sectional area, CSA; BR) and the newly developed parameters (e.g., NN_ED, NN_Outer Diameter, IT_ED) were identified as the risk factors of hip fracture independent of BMD. The additional predictive ability of the hip geometric parameters, over BMD alone, (receiver operating characteristic curve (ROC) analysis) was improved. Especially at NN, the area of ROC used single NN_BMD is only 0.596, but increased rapidly at 0.705 when combined with the hip geometric parameters.

CONCLUSIONS

This study found that three newly developed hip geometry parameters are associated with hip fracture. The results will increase our understanding of the determinants of fracture and provide potential clue for future prevention of fracture in Chinese Population.

The influence of androgen deprivation therapy on hip geometric properties and bone mineral density in Japanese men with prostate cancer and its relationship with the visceral fat accumulation

The influence of androgen deprivation therapy (ADT) for prostate cancer on the hip geometric properties evaluated by dual-energy X-ray absorptiometry (DXA) has not yet been demonstrated. This study aimed to investigate the changes in these properties after 1 year of ADT. A total of 65 Japanese men with prostate cancer who underwent ADT for the first time in our facility were included in the study. The hip geometric parameters and the bone mineral density (BMD) taken before and after 1 year of ADT were retrospectively examined. With ADT, we not only confirmed significant BMD annual changes in the lumbar spine, the femoral neck, and the total hip of -1.65%, -1.91%, and -2.20%, respectively, but we also confirmed significant annual changes in cross-sectional areas, cross-sectional moments of inertia, and section modulus in the narrow femoral neck of -2.55%, -3.50%, and -3.14%, respectively. The annual rate of decrease in the femoral neck BMD was significantly higher in patients with visceral fat obesity than in those without visceral obesity (-1.79% vs. -0.28%). One year of ADT for Japanese men with prostate cancer might decrease the strength of bending and the structural rigidity as well as BMD at the femoral neck.

Evaluation of Hip Geometry Parameters in Patients With a Distal Radius Fracture

BACKGROUND

Patients with a distal radius fracture (DRF) have an increased risk of subsequent fractures including hip fractures. The purpose of this study was to evaluate whether women with a DRF have certain hip geometry parameters known to indicate susceptibility to hip fractures.

METHODS

We compared bone mineral density (BMD) and hip geometry parameters (hip axis length, neck shaft angle, mean cortical thickness, femur neck width, cross-sectional area [CSA], cross-sectional moment of inertia, section modulus, and buckling ratio) in 181 women with a DRF (DRF group) and 362 propensity score-matched women without a fracture (control group). We evaluated the associations between DRF and hip geometry parameters using logistic regression analysis.

RESULTS

The DRF group had lower hip BMD; lower cortical thickness, CSA, and section modulus; and higher buckling ratio than the control group (all p < 0.05). The occurrence of a DRF was significantly associated with decreases in neck shaft angle (odds ratio [OR], 1.047; 95% confidence interval [CI], 1.008-1.088) and CSA (OR, 3.114; 95% CI, 1.820-5.326) after adjusting for age, BMI, and total hip BMD.

CONCLUSIONS

In this study, women with a DRF were more likely than women without a DRF to have hip geometry parameters known to indicate susceptibility to hip fractures. Our results suggest that not only low hip BMD but also a decreased CSA could account for the increased risk of subsequent hip fracture in patients with a DRF.

Sarcopenia negatively affects hip structure analysis variables in a group of Lebanese postmenopausal women

BACKGROUND

The current study's purpose is to compare hip structural analysis variables in a group of postmenopausal women with sarcopenia and another group of postmenopausal women with normal skeletal muscle mass index. To do so, the current study included 8 postmenopausal women (whose ages ranged between 65 and 84 years) with sarcopenia and 60 age-matched controls (with normal skeletal muscle mass index (SMI)). Body composition and bone parameters were evaluated by dual-energy X-ray absorptiometry (DXA).

RESULTS

Weight, lean mass, body mass index, femoral neck cross-sectional area (FN CSA), FN section modulus (Z), FN cross sectional moment of inertia (CSMI), intertrochanteric (IT) CSA, IT Z, IT CSMI, IT cortical thickness (CT), femoral shaft (FS) CSA, FS Z and FS CSMI were significantly greater (p < 0.05) in women with normal SMI compared to women with sarcopenia. In the whole population, SMI was positively associated with IT CSA, IT Z, IT CSMI, IT CT, FS CSA, FS Z, FS CSMI, FS CT but negatively correlated to IT buckling ratio (BR) and FS BR.

CONCLUSION

The current study suggests that sarcopenia has a negative effect on hip bone strength indices in postmenopausal women.

Hip Structure Analyses in Acromegaly: Decrease of Cortical Bone Thickness After Treatment: A Longitudinal Cohort Study

Long‐standing growth hormone (GH) excess causes the skeletal clinical signs of acromegaly with typical changes in bone geometry, including increased cortical bone thickness (CBT). However, a high prevalence and incidence of vertebral fractures has been reported. The aim of this study was to assess the course of cortical bone dimensions in the hip by comparing patients with acromegaly and clinically nonfunctioning pituitary adenomas (NFPAs) at baseline and 1 year after pituitary surgery (1‐year PO) in a longitudinal cohort study. DXA was performed in patients with acromegaly (n = 56) and NFPA (n = 47). CBT in the femoral neck (CBTneck), calcar (CBTcalcar), and shaft (CBTshaft) were determined by hip structural analysis (HSA). CBT at baseline and the change to 1‐year PO were compared. Test results were adjusted for differences in gender distribution, age, and gonadal status. Cortical thickness analyses showed higher values [mm] at baseline in patients with acromegaly compared with NFPA: CBTneck median [25th; 75th] 6.2 [4.7; 8.0] versus 5.1 [4.1; 6.4] (p = 0.006), CBTcalcar 4.8 [4.2, 5.7] versus 4.0 [3.2, 4.5] (p < 0.001), CBTshaft 6.2 [5.1, 7.2] versus 5.2 [4.6, 6.0], (p = 0.003). In acromegaly, GH was correlated with CBTneck (r = 0.31, p = 0.020), whereas IGF‐1 was correlated with CBTcalcar (r = 0.39, p = 0.003) at baseline. In acromegaly, CBTneck decreased by 11.2%, p = 0.002 during follow‐up. Finally, the decrease in CBTneck and CBTcalcar in acromegaly was significant compared with NFPA (p = 0.023 and p = 0.017, respectively). Previous observations of increased CBT in acromegaly were confirmed with DXA‐derived HSA in a large, well‐defined cohort. The decline in CBT in acromegaly could contribute to the increased fracture risk in acromegaly despite increased bone dimensions and disease control. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

The spatial differences in bone mineral density and hip structure between low-energy femoral neck and trochanteric fractures in elderly Chinese using quantitative computed tomography

The purpose of this study was to investigate the differences in bone mineral density (BMD) and hip structure between femoral neck and trochanteric fractures in elderly Chinese individuals using quantitative computed tomography (QCT). A total of 625 Chinese patients (mean age 75.8 years) who sustained low-energy hip fractures (female: 293 femoral neck, 175 trochanteric; male: 82 femoral neck, 75 trochanteric) were recruited. Each patient underwent a hip QCT scan. The areal BMD (aBMD) of the contralateral normal hip was obtained using a computed tomography X-ray absorptiometry module. Using the bone investigation toolkit (BIT) module, the femoral neck was divided into four quadrants: supero-anterior (SA), infero-anterior (IA), infero-posterior (IP), and supero-posterior (SP). Estimated cortical thickness, cortical BMD, and trabecular BMD were measured in each quadrant. Using the hip structure analysis (HSA) function, several parameters were calculated. Stratified by sex, covariance analyses were applied to compare the femoral neck fractures group with trochanteric fractures group after adjustments for age, height, and weight. In women, trochanteric fractures exhibited lower trabecular BMD and estimated cortical thickness at three quadrants of the femoral neck (IA: P = 0.02, P < 0.01; IP: P < 0.01, P = 0.01; SP: P = 0.01, P < 0.01), and lower aBMD at the trochanter area (P < 0.01); femoral neck fractures exhibited lower cortical BMD and estimated cortical thickness at the SA quadrant (P = 0.04, P = 0.01). Differences in HSA parameters were not statistically significant. Among all parameters, the most valuable ones to discrimination of hip fracture type are estimated cortical thickness of the SA quadrant of femoral neck and the aBMD of the trochanter area. In men, only lower cortical BMD at the SP quadrant and aBMD at the trochanter were found in the trochanteric fractures (P = 0.02, P < 0.01). QCT outcomes indicate that spatial differences are helpful to explore the pathogenesis of different type of hip fractures. In women, trochanteric fractures are related to severer osteoporosis, whereas cortical fragility in the SA region of the femoral neck predominates in cases of femoral neck fractures. In men, trochanteric fractures are related to more bone loss of trochanter.

Longitudinal changes in hip geometry in relation to the final menstrual period: Study of Women's Health Across the Nation (SWAN)

BACKGROUND

In SWAN, we showed that accelerated loss of bone mineral density (BMD) begins 1 year before the final menstrual period (FMP) to 2 years after the FMP and slows thereafter. However, the risk of fracture depends on both BMD and bone geometry. The hip structural analysis (HSA) measures important geometric properties of bone. Changes in HSA parameters across the menopausal transition have not been previously assessed.

METHODS

The current analysis uses data from SWAN, 5 years before to 5 years after FMP (N = 900, Age (mean(SD)) = 46.85(2.60), 44% White). HSA parameters at the femoral narrow neck were obtained from 2D DXA scans and normalized to baseline values. FMP was determined from annual interviews. Changes in HSA were assessed over 3 periods, 5 to 2 years before FMP (pre-transmenopausal), 2 years before to 1 years after FMP (transmenopausal), 1 to 5 years after FMP (postmenopausal). Mixed linear models with random slopes were used to estimate the rate of change in HSA parameters relative to FMP.

RESULTS

Loss of BMD, cross-sectional area (CSA), and section modulus (SM) and increases in outer diameter (OD) were greatest in the transmenopausal period (p for all<0.05). Changes continued in the postmenopausal period but were not statistically significant. The cumulative percentage changes over 10 years in BMD (-10.67%), CSA (-9.01), SM (-7.03) and OD (+1.95) were statistically significant.

CONCLUSION

Changes in hip geometry across the menopause transition parallel changes in BMD and provide insight into mechanisms that may increase risk of fragility fracture.

Is there a correlation between outcomes after hip arthroscopy for femoroacetabular impingement syndrome and patient cortical bone thickness?

 

In order to determine the associations between age, sex, cortical bone thickness (CBT), and outcomes following hip arthroscopy for FAIS, a retrospective study of patients undergoing hip arthroscopy for FAIS from a single institution from 2012 to 2014 was performed. Based on preoperative radiographs, femoral cortical index (FCI) and femoral canal-to-calcar ratio (FCC) were used as measures of CBT and used to classify patients using the Dorr classification. Linear and logistic regression was used to determine whether CBT was predictive of 2-year patient reported outoutcomes. Patients were stratified by sex and age (<45 or =45 years old) to determine whether variables were potential effect modifiers on the association between outcomes and CBT. A total of 108 patients were included in the study, with 27 patients in each of the following groups: females <45, females =45, males <45, and males =45 years. The results showed that at 2-year follow-up, all groups demonstrated significant improvements in reported outcomes (HOS-ADL, HOS-SS, and mHHS) (p<0.001). Females =45 scored significantly worse than other groups on all scores (p<0.05 for all). Chi-square test for trend showed a linear by linear association between Dorr classification type and gender/age group (p=0.018). Analysis of the whole study population showed a linear association between FCC and HOS-ADL and mHHS scores. However, CBT measures were not predictive of achieving MCID. In conclusion, patients undergoing hip arthroscopy for FAIS, older female patients had the worst patient-reported outcomes and lowest CBT measures. Furthermore, FCC is independently associated with the HOS-ADL and mHHS.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III

What is known about the subject

Among patients undergoing hip arthroscopy for FAIS, female patients over the age of 45 have been reported to be at risk for inferior post-operative outcomes. Meanwhile, this patient population is also the most at risk for deteriorating CBT.

What this study adds to existing knowledge

This study demonstrates that female patients with FAIS over the age of 45 have inferior CBT indices than their male and younger-aged counterparts. Furthermore, this study presents an association between the FCC and 2-year patient-reported outcome measures, suggesting that CBT characterization may withhold prognostic value.

Pelvis and femur geometry: Relationships with impact characteristics during sideways falls on the hip

While metrics of pelvis and femur geometry have been demonstrated to influence hip fracture risk, attempts at linking geometry to underlying mechanisms have focused on fracture strength. We investigated the potential effects of femur and pelvis geometry on applied loads during lateral falls on the hip. Fifteen female volunteers underwent DXA imaging to characterize two pelvis and six femur geometric features. Additionally, participants completed low-energy sideways falls on the hip; peak impact force and pressure, contact area, and moment of force applied to the proximal femur were extracted. No geometric feature was significantly associated with peak impact force. Peak moment of force was significantly associated with femur moment arm (p = 0.005). Peak pressure was positively correlated with pelvis width and femur moment arm (p < 0.05), while contact area was negatively correlated with metrics of pelvis width and femur neck length (p < 0.05). This is the first study to link experimental measures of impact loads during sideways falls with image-based skeletal geometry from human volunteers. The results suggest that while skeletal geometry has limited effects on overall peak impact force during sideways falls, it does influence how impact loads are distributed at the skin surface, in addition to the bending moment applied to the proximal femur. These findings have implications for the design of protective interventions (e.g. wearable hip protectors), and for models of fall-related lateral impacts that could incorporate the relationships between skeletal geometry, external load magnitude/distribution, and tissue-level femur loads.

Ex Vivo Evaluation of Hip Fracture Risk by Proximal Femur Geometry and Bone Mineral Density in Elderly Chinese Women

Background

The incidence of hip fracture is steadily increasing. We aimed to establish a creative approach to precisely estimate the risk of hip fracture by exploring the relationship between hip fracture and bone mineral density (BMD)/femur geometry.

Material/Methods

Sixteen samples of cadaveric female proximal femora were randomly selected. Experiments were performed experimental measurement of the femoral neck BMD and geometric parameters (including neck length, neck diameter, head diameter, and neck-shaft angle). In addition, the experimental measurements contain the failure load, which represents the mechanical strength of the femoral neck, and we calculated the correlation coefficient among BMD, geometric parameters, and failure load.

Results

Significant correlations were discovered between femoral mechanical properties and femoral neck BMD (r=0.792, r²=0.628, P<0.001), trochanteric BMD (r=0.749, r²=0.560, P=0.001), and head diameter (r=0.706, r²=0.499, P=0.002). Multiple linear regression analyses indicated that the best predictor of hip fracture was the combination of femoral neck BMD, head diameter, and neck diameter (r²=0.844, P<0.001).

Conclusions

The results confirmed that, compared with BMD alone, the combination of BMD and geometric parameters of proximal femur is a better estimation of hip fracture. The geometry of the proximal femur played an important role in assessing the biomechanical strength of femur. This method greatly assists in predicting the risk of hip fracture in clinical trials and will assist studies on why the incidence of hip fracture varies among races.

Structural Parameters of the Proximal Femur by 3-Dimensional Dual-Energy X-ray Absorptiometry Software: Comparison With Quantitative Computed Tomography

Structural parameters of the proximal femur evaluate the strength of the bone and its susceptibility to fracture. These parameters are computed from dual-energy X-ray absorptiometry (DXA) or from quantitative computed tomography (QCT). The 3-dimensional (3D)-DXA software solution provides 3D models of the proximal femur shape and bone density from anteroposterior DXA scans. In this paper, we present and evaluate a new approach to compute structural parameters using 3D-DXA software. A cohort of 60 study subjects (60.9 ± 14.7 yr) with DXA and QCT examinations was collected. 3D femoral models obtained by QCT and 3D-DXA software were aligned using rigid registration techniques for comparison purposes. Geometric, cross-sectional, and volumetric structural parameters were computed at the narrow neck, intertrochanteric, and lower shaft regions for both QCT and 3D-DXA models. The accuracy of 3D-DXA structural parameters was evaluated in comparison with QCT. Correlation coefficients (r) between geometric parameters computed by QCT and 3D-DXA software were 0.86 for the femoral neck axis length and 0.71 for the femoral neck shaft angle. Correlation coefficients ranged from 0.86 to 0.96 for the cross-sectional parameters and from 0.84 to 0.97 for the volumetric structural parameters. Our study demonstrated that accurate estimates of structural parameters for the femur can be obtained from 3D-DXA models. This provides clinicians with 3D indexes related to the femoral strength from routine anteroposterior DXA scans, which could potentially improve osteoporosis management and fracture prevention.

Two-year cortical and trabecular bone loss in CKD-5D: biochemical and clinical predictors

This prospective two-year study of patients on chronic dialysis measured changes in bone mineral density (BMD). Patients with higher baseline BMD and shorter dialysis vintage lost more bone. Treatment with anti-hypertensives acting on the central nervous system was protective against bone loss. Baseline serum levels of sclerostin and bone-specific alkaline phosphatase predicted bone loss.

INTRODUCTION

This prospective 2-year study of chronic kidney disease on dialysis (CKD-5D) patients assessed trabecular and cortical bone loss at the hip and spine and examined potential demographic, clinical, and serum biochemical predictors of bone loss.

METHODS

Eighty-nine CKD-5D patients had baseline, year 1, and year 2 bone mineral density (BMD) measurements using dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT); concurrent blood samples were drawn and clinical variables recorded. No study treatments occurred.

RESULTS

The 2-year total hip BMD change was - 5.9% by QCT and - 3.1% by DXA (p < 0.001). Spinal BMD was unchanged. QCT total hip cortical mass and volume decreased (- 7.3 and - 10.0%); trabecular volume increased by 5.9% (ps < 0.001). BMD changes did not vary with age, BMI, race, diabetes, smoking, or exercise. Patients with higher baseline BMD and shorter dialysis vintage lost more bone (p < 0.05). Vitamin D analogs and phosphate binders were not protective against bone loss; cinacalcet was protective by univariate but not by multivariable analysis. CNS-affecting antihypertensives were protective against loss of BMD, cortical mass, cortical volume (ps < 0.05) and trabecular mass (p = 0.007). These effects remained after adjustment. BSAP correlated with changes in BMD, cortical mass, and volume (p < 0.01) as did sclerostin (inversely).

CONCLUSIONS

There was severe cortical bone loss at the hip best recognized by QCT. Patients with shorter dialysis vintage and less pre-existing bone loss lost more bone, while treatment with CNS-acting antihypertensives was protective. BSAP and sclerostin were useful markers of bone loss.

New quantitative ultrasound techniques for bone analysis at the distal radius in hip fracture cases: differences between femoral neck and trochanteric fractures

BACKGROUND

Ample evidence on etiological and pathological differences between femoral neck and trochanteric fracture cases suggests the possibility of individualized treatment. There are many issues related to areal bone mineral density and other quantitative computed tomography parameters of the proximal femur. Although osteoporosis is a systemic problem, little has been reported regarding differences in bone structural parameters, including bone mineral density, between them in regions other than the proximal femur.

METHODS

Participants were consecutive female patients >50 years of age admitted to the Saiseikai Suita Hospital (Osaka prefecture, Japan) for their first hip fracture between January 2012 and September 2014. Cortical thickness (CoTh, mm), volumetric trabecular bone mineral density (TBD, mg/cm³), and elastic modulus of trabecular bone (EMTb, GPa) were obtained as the new QUS parameters using the LD-100 system (Oyo Electric, Kyoto, Japan). The mean values of these parameters were compared between femoral neck and trochanteric fracture cases. In addition, correlations between age and each QUS parameter were investigated for each fracture type. A receiver operating characteristic (ROC) curve analysis was performed to examine the degree of effect each parameter on the fracture types. The area under the curve (AUC) for each parameter was compared to the AUC for age.

RESULTS

There were 63 cases of femoral neck fracture (mean age, 78.2 years) and 37 cases of trochanteric fracture (mean age, 85.9 years). Mean TBD and EMTb were significantly higher for femoral neck fractures. There were significant negative correlations between QUS parameters and age for femoral neck fractures (P < 0.005). The regression lines for femoral neck fractures were above those for trochanteric fractures for TBD and EMTb. AUCs were 0.72 for age, and 0.61, 0.65, and 0.65 for CoTh, TBD, and EMTb, respectively.

CONCLUSIONS

The new QUS parameters indicated that TR fracture cases were more osteoporotic than were FN fracture cases, even at the distal radius. There might be systemic differences between them, in addition to localized factors at the proximal femur.

Site-Specific Difference of Bone Geometry Indices in Hypoparathyroid Patients

BACKGROUND

Hypoparathyroid patients often have a higher bone mineral density (BMD) than the general population. However, an increase in BMD does not necessarily correlate with a solid bone microstructure. This study aimed to evaluate the bone microstructure of hypoparathyroid patients by using hip structure analysis (HSA).

METHODS

Ninety-five hypoparathyroid patients >20 years old were enrolled and 31 of them had eligible data for analyzing bone geometry parameters using HSA. And among the control data, we extracted sex-, age-, and body mass index-matched three control subjects to each patient. The BMD data were reviewed retrospectively and the bone geometry parameters of the patients were analyzed by HSA.

RESULTS

The mean Z-scores of hypoparathyroid patients at the lumbar spine, femoral neck, and total hip were above zero (0.63±1.17, 0.48±1.13, and 0.62±1.10, respectively). The differences in bone geometric parameters were site specific. At the femoral neck and intertrochanter, the cross-sectional area (CSA) and cortical thickness (C.th) were higher, whereas the buckling ratio (BR) was lower than in controls. However, those trends were opposite at the femoral shaft; that is, the CSA and C.th were low and the BR was high.

CONCLUSION

Our study shows the site-specific effects of hypoparathyroidism on the bone. Differences in bone components, marrow composition, or modeling based bone formation may explain these findings. However, further studies are warranted to investigate the mechanism, and its relation to fracture risk.

Dual-Energy X-Ray Absorptiometry: Beyond Bone Mineral Density Determination

Significant improvements in dual-energy X-ray absorptiometry (DXA) concerning quality, image resolution and image acquisition time have allowed the development of various functions. DXA can evaluate bone quality by indirect analysis of micro- and macro-architecture of the bone, which and improve the prediction of fracture risk. DXA can also detect existing fractures, such as vertebral fractures or atypical femur fractures, without additional radiologic imaging and radiation exposure. Moreover, it can assess the metabolic status by the measurement of body composition parameters like muscle mass and visceral fat. Although more studies are required to validate and clinically use these parameters, it is clear that DXA is not just for bone mineral densitometry.

Associations of Body Mass Index With Incident Fractures and Hip Structural Parameters in a Large Canadian Cohort

CONTEXT

Fractures in obese individuals are of public health importance, but the relationship between obesity and fracture is complex and remains poorly understood.

OBJECTIVE

The study examined the association of body mass index (BMI) with bone structural and strength parameters and incident fracture.

DESIGN AND SETTING

We performed cross-sectional and longitudinal analyses using data from the Manitoba Bone Density Program.

PARTICIPANTS

We included 51 313 women and 4689 men aged 50 years or older referred for dual-energy X-ray absorptiometry scans. For 41 919 women and 4085 men, we were able to derive hip structural parameters.

MAIN OUTCOME MEASURE

Cross-sectional moment of inertia, cross-sectional area, and femoral strength index were derived from dual-energy X-ray absorptiometry. Health service records were assessed for incident major osteoporotic fractures (MOFs) (mean follow-up 6.2 y in women and 4.7 y in men).

RESULTS

Among individuals with a BMI of less than 30 kg/m(2), increasing BMI was associated with progressive increases in bone mineral density (BMD), cross-sectional moment of inertia, and cross-sectional area. The relationship reached a plateau around a BMI of 30 kg/m(2), with little additional increment with further increases in BMI (all P for interaction < .0001, obese vs nonobese). Increasing BMI was linearly associated with decreases in strength index in both women and men. MOFs were ascertained in 3721 women and 276 men (1027 female and 75 male hip fractures). Higher BMI was associated with a lower risk of MOF in women in multivariable models, but this association was largely explained by their higher BMD. Protective association of higher BMI with hip fracture were stronger and only partially explained by BMD (hazard ratio [95% confidence interval] 0.79 [0.73-0.99] for obese I and 0.67 [0.46-0.98] for obese II). Higher BMI was not significantly associated with a risk of MOF or hip fracture in men.

CONCLUSIONS

Despite structural and biomechanical disadvantages, obese women were at lower risk of fracture.

Comparison of morphological features in the femur between femoral neck fractures and femoral intertrochanteric fractures

PURPOSE

The purpose of this study is to make proximal femur fracture types more predictable by considering morphological features of an acetabulum as well as of a proximal femur in the Japanese population.

METHODS

A retrospective review of radiographs of the proximal femoral fractures was conducted in patients registered from 2010 to 2012, dividing into patients with femoral neck fractures; Group Neck (n = 101), and patients with femoral intertrochanteric fractures; Group IT (n = 99). Intergroup comparison was conducted: age, sex, height, weight, the ratios of femoral intertrochanteric length (IT Length), femoral neck length (Neck Length), femoral neck width (Neck Width), lateral offset length (Offset) to femoral head diameter, neck-shaft angle (N-S angle), and center-edge angle of the acetabulum (C-E angle), adjusting for age. Multiple logistic regression analysis was conducted among these parameters.

RESULTS

The Group IT showed significantly older age than the Group Neck. Greater C-E angle in Group IT was observed in the patients in their 80s and 90s years of age. The Group Neck showed greater N-S angle only in the patients in their 80s years of age. In multiple logistic regression analysis, the impact of the age and the C-E angle on the fracture types was similar (odds ratio 1.08, 1.09, respectively, p < 0.01 both).

CONCLUSIONS

Age, N-S angle, and C-E angle could be independent predictors for determining the proximal femur fracture types.

Evaluation of a simplified hip structure analysis method for the prediction of incident hip fracture events

Many attempts have been made to improve the predictive ability of areal bone mineral density (aBMD) which integrates bone mass and area. The addition of an extra variable derived from the hip dual-energy X-ray (DXA) image TR_σ, which describes distribution of mass within the scanned area of the trochanter, improved prediction of 15-year hip fracture probability in elderly women.

INTRODUCTION

Two-dimensional DXA imaging of the proximal femur to produce an aBMD is a clinically useful predictor of future fracture risk. Further analysis of the DXA image to produce an eight-variable hip structure analysis (Beck HSA) has been developed to improve understanding of structural factors determining hip bone strength at each of three proximal femur sites, the narrow femoral neck (NN), intertrochanter (TR) and shaft (S). Recently, data on four measurements derived from the currently used eight Beck HSA variables were used to capture population variation in bone structure at each site. These include two previously used variables, the localised aBMD and the sub-periosteal width (W) applying to 5-mm sections (at each sites), and two new variables, standard deviation of normalised mineral-mass projection profile distribution (σ), and displacement between centre-of-mineral mass and geometric centre-of-mineral mass of projection profile (δ).

METHODS

Using a cohort of 1159 women, mean baseline age 75, who sustained 139 hip fractures over 15 years, we determined whether these measures significantly improved 15-year hip fracture prediction compared to current approach utilising age and total hip aBMD. To describe the most parsimonious model for hip fracture risk prediction, the 12 base measures (4 from each site), total hip aBMD and age were evaluated in stepwise logistic regression models.

RESULTS

The final model included TR_σ, total hip aBMD and age and provided improved utility for hip fracture prediction compared to total hip aBMD and age alone (C-statistic 0.73 vs. 0.69, P = 0.009 and net reclassification improvement 0.164, P < 0.001, respectively).

CONCLUSIONS

Addition of TR_σ to total hip aBMD and age substantially improved prediction of 15-year hip fracture risk in this cohort of elderly women.

Trabecular bone strength is not an independent predictive factor for dynamic hip screw migration--A prospective multicenter cohort study

This study assessed whether mechanically measured trabecular bone strength is an independent predictor of dynamic hip screw (DHS) stability, i.e., DHS migration (DHSM) after the fixation of proximal femoral fractures. One-hundred and seven patients older than 50 years with proximal femoral fractures were included. During fracture fixation, a mechanical probe (DensiProbe™ Hip) was inserted at the site where the DHS tip would ultimately be positioned. Peak torque to breakaway the trabecular bone was measured. Fracture reduction, primary implant position and postoperative DHSM were assessed by radiographs taken postoperatively, at 6 and 12 weeks after surgery. Univariate regression analysis revealed no association between peak torque and DHSM (R(2) = 0.025, p = 0.135). DHSM correlated with the primary DHS position, i.e., the distance between the DHS and (i) the central femoral neck axis (CNFAD, R(2) = 0.230; p < 0.0001) and (ii) the apex of the femoral head (R(2) = 0.110; p = 0.001). DHSM did not correlate with areal BMD of the contralateral proximal femur. Multivariable regression modeling revealed the CFNAD as predictive factor for screw migration. The primary implant position measured by the CFNAD, rather than DensiProbe™ Hip measured bone strength, is an independent predictor of DHSM.

Fracture Risk Prediction by Non-BMD DXA Measures: the 2015 ISCD Official Positions Part 1: Hip Geometry

Bone mineral density (BMD) measured by dual-energy X-ray absorptiometry is the current imaging procedure of choice to assess fracture risk. However, BMD is only one of the factors that explain bone strength or resistance to fracture. Other factors include bone microarchitecture and macroarchitecture. We now have the ability to assess some of these non-BMD parameters from a dual-energy X-ray absorptiometry image. Available measurements include various measurements of hip geometry including hip structural analysis, hip axis length, and neck-shaft angle. At the 2015 Position Development Conference, the International Society of Clinical Densitometry established official positions for the clinical utility of measurements of hip geometry. We present the official positions approved by an expert panel after careful review of the recommendations and evidence prepared by an independent task force. Each question addressed by the task force is presented followed by the official position with the associated medical evidence and rationale.

Distribution of vertebral fractures varies among patients according to hip fracture type

This study explored the distribution of vertebral fractures in hip fracture patients. Unlike patients with intertrochanteric fractures, those with subcapital fractures were less likely to have vertebral fractures in the T4-T10 region of the spine. The dissimilar distribution of vertebral fractures among patients with intertrochanteric and subcapital fractures may indicate different underlying etiologies.

INTRODUCTION

There are two main types of hip fractures: intertrochanteric and subcapital. Both types can have associated vertebral fractures. In this study, we explored the distribution of vertebral fractures in the two hip fracture populations.

METHODS

This was a retrospective analysis of a convenience sample of 120 patients: 40 with subcapital fractures and vertebral fractures, 40 with intertrochanteric fractures and vertebral fractures, and 40 with vertebral fractures only. Based on Genant's semiquantitative assessment method of radiographic images, the distribution and severity of each patient's vertebral fractures were explored [1].

RESULTS

Patients with subcapital fractures had significantly fewer total vertebral fractures (93 vs. 144, p = 0.005; 93 vs. 127, p = 0.019), vertebral fractures from T4 to T10 (41 vs. 81, p = 0.005; 41 vs. 64, p = 0.042), and vertebral fractures at the T7-T8 peak (11 vs. 31, p = 0.002; 11 vs. 30, p = 0.003) than patients with intertrochanteric fractures and those with vertebral fractures alone, respectively, and they were more likely to have only one vertebral fracture (15 vs. 3, p < 0.001; 15 vs. 2, p < 0.001). The number of vertebral fractures from T11 to L4 and at the T12-L1 peak did not differ among the groups. The numbers of fractures at each vertebral level was significantly correlated only between those with intertrochanteric fractures and those with vertebral fractures alone (r = 0.65, p = 0.009).

CONCLUSION

The distribution of vertebral fractures among patients with subcapital fractures differed from the other fracture groups, which may indicate that subcapital fractures and some lumbar fractures have a different underlying etiology than intertrochanteric fractures and thoracic (T4-T10) fractures.

Comparison of hip geometry, strength, and estimated fracture risk in women with anorexia nervosa and overweight/obese women

CONTEXT

Data suggest that anorexia nervosa (AN) and obesity are complicated by elevated fracture risk, but skeletal site-specific data are lacking. Traditional bone mineral density (BMD) measurements are unsatisfactory at both weight extremes. Hip structural analysis (HSA) uses dual-energy X-ray absorptiometry data to estimate hip geometry and femoral strength. Factor of risk (φ) is the ratio of force applied to the hip from a fall with respect to femoral strength; higher values indicate higher hip fracture risk.

OBJECTIVE

The objective of the study was to investigate hip fracture risk in AN and overweight/obese women.

DESIGN

This was a cross-sectional study.

SETTING

The study was conducted at a Clinical Research Center.

PATIENTS

PATIENTS included 368 women (aged 19-45 y): 246 AN, 53 overweight/obese, and 69 lean controls.

MAIN OUTCOME MEASURES

HSA-derived femoral geometry, peak factor of risk for hip fracture, and factor of risk for hip fracture attenuated by trochanteric soft tissue (φ(attenuated)) were measured.

RESULTS

Most HSA-derived parameters were impaired in AN and superior in obese/overweight women vs controls at the narrow neck, intertrochanteric, and femoral shaft (P ≤ .03). The φ(attenuated) was highest in AN and lowest in overweight/obese women (P < .0001). Lean mass was associated with superior, and duration of amenorrhea with inferior, HSA-derived parameters and φ(attenuated) (P < .05). Mean φ(attenuated) (P = .036), but not femoral neck BMD or HSA-estimated geometry, was impaired in women who had experienced fragility fractures.

CONCLUSIONS

Femoral geometry by HSA, hip BMD, and factor of risk for hip fracture attenuated by soft tissue are impaired in AN and superior in obesity, suggesting higher and lower hip fracture risk, respectively. Only attenuated factor of risk was associated with fragility fracture prevalence, suggesting that variability in soft tissue padding may help explain site-specific fracture risk not captured by BMD.

Full-Field Strain Measurement During Mechanical Testing of the Human Femur at Physiologically Relevant Strain Rates

Understanding the mechanical properties of human femora is of great importance for the development of a reliable fracture criterion aimed at assessing fracture risk. Earlier ex vivo studies have been conducted by measuring strains on a limited set of locations using strain gauges (SGs). Digital image correlation (DIC) could instead be used to reconstruct the full-field strain pattern over the surface of the femur. The objective of this study was to measure the full-field strain response of cadaver femora tested at a physiological strain rate up to fracture in a configuration resembling single stance. The three cadaver femora were cleaned from soft tissues, and a white background paint was applied with a random black speckle pattern over the anterior surface. The mechanical tests were conducted up to fracture at a constant displacement rate of 15 mm/s, and two cameras recorded the event at 3000 frames per second. DIC was performed to retrieve the full-field displacement map, from which strains were derived. A low-pass filter was applied over the measured displacements before the crack opened in order to reduce the noise level. The noise levels were assessed using a dedicated control plate. Conversely, no filtering was applied at the frames close to fracture to get the maximum resolution. The specimens showed a linear behavior of the principal strains with respect to the applied force up to fracture. The strain rate was comparable to the values available in literature from in vivo measurements during daily activities. The cracks opened and fully propagated in less than 1 ms, and small regions with high values of the major principal strains could be spotted just a few frames before the crack opened. This corroborates the hypothesis of a strain-driven fracture mechanism in human bone. The data represent a comprehensive collection of full-field strains, both at physiological load levels and up to fracture. About 10,000 points were tracked on each bone, providing superior spatial resolution compared to ∼15 measurements typically collected using SGs. These experimental data collection can be further used for validation of numerical models, and for experimental verification of bone constitutive laws and fracture criteria.

Prevalence of acute diseases in the elderly assisted in emergency department of orthopedics

OBJECTIVE

To make an analysis of the care of elderly in an Emergency Department of Orthopedics with the primary objective to know the percentage of elderly treated, their conditions of origin and level of accidental conditions, and examine possible comorbidities, evolution and mortality rate.

METHODS

Retrospective observational epidemiological study based on survey records of a tertiary hospital during one year (January to December 2006).

RESULTS

In the year 2006 (January to December) 12,916 calls to patients older than 60 were performed.

CONCLUSION

Massive attendance of the elderly population was observed, however, the vast majority related to chronic problems that do not require urgent attention. Patients requiring urgent attention suffer from trauma related to falls and are between the seventh and ninth decades of life, mostly female and requiring hospitalization for longer periods. Level of Evidence VI, Cases Series.

Genetic influence on bone phenotypes and body composition: a Swedish twin study

Bone mineral density (BMD), bone size and bone turnover are independent determinants of fractures in elderly. Earlier twin studies of these phenotypes have revealed high heritability for BMD and bone area, and more moderate heritability for bone turnover markers. No previous Scandinavian study has evaluated the genetic and environmental contribution to the variance of these phenotypes, despite the fact that Scandinavian countries have the highest incidence of osteoporotic fractures worldwide. Participants were selected from the Swedish Twin Registry. All intact like-sexed twin pairs born in 1965 or earlier and living in the county of Uppsala were invited to participate. A total of 102 twin pairs (45 monozygotic and 57 dizygotic) accepted the invitation to participate. All twins underwent measurement of BMD and bone area using dual-energy X-ray absorptiometry. Hip geometry was also calculated. Markers for bone formation (osteocalcin) and bone resorption (CrossLaps) were measured in serum. We observed a substantial heritability for BMD at the lumbar spine (0.85; 95 % CI 0.54-0.90), the femoral neck (0.75; 95 % CI 0.62-0.83), and the proximal femur (0.84; 95 % CI 0.74-0.90). The values for bone area were approximately similar to those for BMD. Bone turnover markers had a slightly lower genetic influence with a value of 0.69 (0.53-0.80) for osteocalcin and 0.58 (95 % CI 0.33-0.75) for CrossLaps. As a comparison, the heritabilities of body height and weight were 0.95 and 0.82, respectively. The high heritability on bone phenotypes among Swedish middle-aged and older men and women should encourage further work on the identification of specific genetic pathways. Continuing research in this area could reveal the mechanisms behind the strong genetic susceptibility of bone-related phenotypes.

Changes in the pattern of fractures of the hip in patients 60 years of age and older between 2001 and 2010

The purpose of this study was to identify changing trends in the pattern of distribution of the type and demographics of fractures of the hip in the elderly between 2001 and 2010. A retrospective cross-sectional comparison was conducted between 179 fractures of the hip treated in 2001, 357 treated in 2006 and 454 treated in 2010. Patients aged < 60 years and those with pathological and peri-prosthetic fractures were excluded. Fractures were classified as stable extracapsular, unstable extracapsular or intracapsular fractures.

The mean age of the 179 patients (132 women (73.7%)) treated in 2001 was 80.8 years (60 to 96), 81.8 years (61 to 101) in the 357 patients (251 women (70.3%)) treated in 2006 and 82.0 years (61 to 102) in the 454 patients (321 women (70.1%)) treated in 2010 (p = 0.17). There was no difference in the gender distribution between the three study years (p = 0.68).

The main finding was a steep rise in the proportion of unstable peritrochanteric fractures. The proportion of unstable extracapsular fractures was 32% (n = 57) in 2001, 35% (n = 125) in 2006 and 45% (n = 204) in 2010 (p < 0.001). This increase was not significant in patients aged between 60 and 69 years (p = 0.84), marginally significant in those aged between 70 and 79 years (p = 0.04) and very significant in those aged > 80 years (p < 0.001). The proportion of intracapsular fractures did not change (p = 0.94).

At present, we face not only an increasing number of fractures of the hip, but more demanding and complex fractures in older patients than a decade ago. This study does not provide an explanation for this change.

Cite this article: Bone Joint J 2013;95-B:1250–4.

Missense polymorphisms of the WNT16 gene are associated with bone mass, hip geometry and fractures

Two missense polymorphisms of WNT16 were associated with hip bone mineral density (BMD), the buckling ratio of the femoral neck, calcaneal ultrasound and hip fractures in individuals under 80 years of age. These results confirm the association of the WNT16 gene with bone mass and osteoporotic fractures.

INTRODUCTION

Osteoporosis has a strong genetic component. Wnt ligands stimulate the differentiation of osteoblast precursors and play a major role in skeletal homeostasis. Therefore, the aim of this study was to explore the association of allelic variants of the WNT16 gene with BMD, other structural parameters of bone and osteoporotic hip fractures.

METHODS

Six single nucleotide polymorphisms were analysed in 1,083 Caucasian individuals over 49 years of age.

RESULTS

Two missense polymorphisms (rs2908004 and rs2707466) were associated with femoral neck BMD, with average differences across genotypes of 35 mg/cm(2) (p = 0.00037 and 0.0015, respectively). Likewise, the polymorphisms were associated with calcaneal quantitative ultrasound parameters (p = 0.00004 and 0.0014, respectively) and the buckling ratio, an index of cortical instability of the femoral neck (p = 0.0007 and 0.0029, respectively). Although there were no significant differences in the genotype frequency distributions between 294 patients with hip fractures and 670 controls, among the subgroup under 80 years of age, TT genotypes were underrepresented in patients with fractures (odds ratio 0.50; CI 0.27-0.94).

CONCLUSION

Common missense polymorphisms of the WNT16 gene are associated with BMD at the hip, calcaneal ultrasound and the buckling ratio of the femoral neck, as well as with hip fractures in individuals under 80 years of age. Overall, these results confirm the association of the WNT16 locus with BMD identified in genome-wide association studies and support its role in determining the risk of osteoporotic fractures.

Ethnic variability in bone geometry as assessed by hip structure analysis: findings from the hip strength across the menopausal transition study

Racial/ethnic origin plays an important role in fracture risk. Racial/ethnic differences in fracture rates cannot be fully explained by bone mineral density (BMD). Studies examining the influence of bone geometry and strength on fracture risk have focused primarily on older adults and have not included people from diverse racial/ethnic backgrounds. Our goal was to explore racial/ethnic differences in hip geometry and strength in a large sample of midlife women. We performed hip structure analysis (HSA) on hip dual-energy X-ray absorptiometry (DXA) scans from 1942 premenopausal and early perimenopausal women. The sample included white (50%), African American (27%), Chinese (11%), and Japanese (12%) women aged 42 to 52 years. HSA was performed using software developed at Johns Hopkins University. African American women had higher conventional (8.4% to 9.7%) and HSA BMD (5.4% to 19.8%) than other groups with the exception being Japanese women, who had the highest HSA BMD (9.7% to 31.4%). HSA indices associated with more favorable geometry and greater strength and resistance to fracture were more prevalent in African American and Japanese women. Femurs of African American women had a smaller outer diameter, a larger cross-sectional area and section modulus, and a lower buckling ratio. Japanese women presented a different pattern with a higher section modulus and lower buckling ratio, similar to African American women, but a wider outer diameter; this was offset by a greater cross-sectional area and a more centrally located centroid. Chinese women had similar conventional BMD as white women but a smaller neck region area and HSA BMD at both regions. They also had a smaller cross-sectional area and section modulus, a more medially located centroid, and a higher buckling ratio than white women. The observed biomechanical differences may help explain racial/ethnic variability in fracture rates. Future research should explore the contribution of hip geometry to fracture risk across all race/ethnicities.

A comparison of bone density and bone morphology between patients presenting with hip fractures, spinal fractures or a combination of the two

Background

Currently it is uncertain how to define osteoporosis and who to treat after a hip fracture. There is little to support the universal treatment of all such patients but how to select those most in need of treatment is not clear. In this study we have compared cortical and trabecular bone status between patients with spinal fractures and those with hip fracture with or without spinal fracture with the aim to begin to identify, by a simple clinical method (spine x-ray), a group of hip fracture patients likely to be more responsive to treatment with current antiresorptive agents.

Methods

Comparison of convenience samples of three groups of 50 patients, one with spinal fractures, one with a hip fracture, and one with both. Measurements consist of bone mineral density at the lumbar spine, at the four standard hip sites, number, distribution and severity of spinal fractures by the method of Genant, cortical bone thickness at the infero-medial femoral neck site, femoral neck and axis length and femoral neck width.

Results

Patients with spinal fractures alone have the most deficient bones at both trabecular and cortical sites: those with hip fracture and no spinal fractures the best at trabecular bone and most cortical bone sites: and those with both hip and spinal fractures intermediate in most measurements. Hip axis length and neck width did not differ between groups.

Conclusion

The presence of the spinal fracture indicates poor trabecular bone status in hip fracture patients. Hip fracture patients without spinal fractures have a bone mass similar to the reference range for their age and gender. Poor trabecular bone in hip fracture patients may point to a category of patient more likely to benefit from therapy and may be indicated by the presence of spinal fractures.

Femoral geometric parameters and BMD measurements by DXA in adult patients with different types of osteogenesis imperfecta

OBJECTIVES

Osteogenesis imperfecta (OI) is an inherited disorder characterized by increased bone fragility with recurrent fractures that leads to skeletal deformities in severe cases. Consequently, in most OI patients, the hip is the only reliable measuring site for estimating future fracture risk. The aim of the study was to assess the applicability of hip structure analysis (HSA) by DXA in adult patients with osteogenesis imperfecta.

MATERIALS AND METHODS

We evaluated bone mineral density (BMD) and hip structure analysis (HSA) by DXA, including cross-sectional area (CSA), cross-sectional moment of inertia (CSMI) and femoral strength index (FSI) in 30 adult patients with different types of OI and 30 age-matched healthy controls (CO). The OI total group (OI-tot) was divided into two subgroups: the mild OI I group (OI-I) and the more severe OI III and IV group (OI-III-IV).

RESULTS

The mean neck BMD of OI-I and OI-III-IV were significantly lower compared to CO (-15.9 %, p < 0.005 and -37.5 %, p < 0.001 respectively). Similar results were observed at trochanter and total hip. CSA and the CSMI value were significantly lower for OI-I (-23.2 %, p < 0.001) and OI-III-IV (-45.9 %, p < 0.001) in comparison to CO. In addition, significant differences were found between the mild OI-I and the severe OI-III-IV group (-29.6 %, p < 0.05). FSI was significantly decreased in the OI-III-IV (25.7 %, p < 0.05) in comparison to the CO. Furthermore, significant correlations between BMD and HSA and between HSA and height and weight were found in osteogenesis imperfecta and controls.

CONCLUSION

BMD measurement in osteogenesis imperfecta patients is very critical. The combination of BMD and geometric structural measurements at the hip in osteogenesis imperfecta patients may represent an additional helpful means in estimating bone strength and fracture risk.

Impact of Charcot neuroarthropathy on metatarsal bone mineral density and geometric strength indices

Charcot neuroarthropathy (CN), an inflammatory condition characterized by rapid and progressive destruction of pedal bones and joints, often leads to deformity and ulceration in individuals with diabetes mellitus (DM) and peripheral neuropathy (PN). Repetitive, unperceived joint trauma may trigger initial CN damage, causing a proinflammatory cascade that can result in osteolysis and contribute to subsequent neuropathic fracture. We aimed to characterize osteolytic changes related to development and progression of CN by measuring bone mineral density (BMD) and geometric strength indices using volumetric quantitative computed tomography. Twenty individuals with DM+PN were compared to twenty age-, sex-, and race-matched individuals with DM+PN and acute CN. We hypothesized that individuals with acute CN would have decreased BMD and decreased total area, cortical area, minimum section modulus, and cortical thickness in the diaphysis of the second and fifth metatarsals. Results showed BMD was lower in both involved and uninvolved feet of CN participants compared to DM+PN participants, with greater reductions in involved CN feet compared to uninvolved CN feet. There was a non-significant increase in total area and cortical area in the CN metatarsals, which helps explain the finding of similar minimum section modulus in DM+PN and CN subjects despite the CN group's significantly lower BMD. Larger cortical area and section modulus are typically considered signs of greater bone strength due to higher resistance to compressive and bending loads, respectively. In CN metatarsals, however, these findings may reflect periosteal woven bone apposition, i.e., a hypertrophic response to injury rather than increased fracture resistance. Future research using these techniques will aid further understanding of the inflammation-mediated bony changes associated with development and progression of CN and other diseases.

Predicting ex vivo failure loads in human metatarsals using bone strength indices derived from volumetric quantitative computed tomography

We investigated the capacity of bone quantity and bone geometric strength indices to predict ultimate force in the human second metatarsal (Met2) and third metatarsal (Met3). Intact lower extremity cadaver samples were measured using clinical, volumetric quantitative computed tomography (vQCT) with positioning and parameters applicable to in vivo scanning. During processing, raw voxel data (0.4mm isotropic voxels) were converted from Hounsfield units to apparent bone mineral density (BMD) using hydroxyapatite calibration phantoms to allow direct volumetric assessment of whole-bone and subregional metatarsal BMD. Voxel data were realigned to produce cross-sectional slices perpendicular to the longitudinal axes of the metatarsals. Average mid-diaphyseal BMD, bone thickness, and buckling ratio were measured using an optimized threshold to distinguish bone from non-bone material. Minimum and maximum moments of inertia and section moduli were measured in the mid-diaphysis region using both a binary threshold for areal, unit-density measures and a novel technique for density-weighted measures. BMD and geometric strength indices were strongly correlated to ultimate force measured by ex vivo 3-point bending. Geometric indices were more highly correlated to ultimate force than was BMD; bone thickness and density-weighted minimum section modulus had the highest individual correlations to ultimate force. Density-weighted geometric indices explained more variance than their binary analogs. Multiple regression analyses defined models that predicted 85-89% of variance in ultimate force in Met2 and Met3 using bone thickness and minimum section modulus in the mid-diaphysis. These results have implications for future in vivo imaging to non-invasively assess bone strength and metatarsal fracture risk.

Can Hip Fracture Prediction in Women be Estimated beyond Bone Mineral Density Measurement Alone?

The etiology of hip fractures is multifactorial and includes bone and fall-related factors. Low bone mineral density (BMD) and BMD-related and BMD-independent geometric components of bone strength, evaluated by hip strength analysis (HSA) and finite element analysis analyses on dual-energy X-ray absorptiometry (DXA) images, and ultrasound parameters are related to the presence and incidence of hip fracture. In addition, clinical risk factors contribute to the risk of hip fractures, independent of BMD. They are included in the fracture risk assessment tool (FRAX) case finding algorithm to estimate in the individual patient the 10-year risk of hip fracture, with and without BMD. Fall risks are not included in FRAX, but are included in other case finding tools, such as the Garvan algorithm, to predict the 5- and 10-year hip fracture risk. Hormones, cytokines, growth factors, markers of bone resorption and genetic background have been related to hip fracture risk. Vitamin D deficiency is endemic worldwide and low serum levels of 25-hydroxyvitamin D [25(OH)D] predict hip fracture risk. In the context of hip fracture prevention calculation of absolute fracture risk using clinical risks, BMD, bone geometry and fall-related risks is feasible, but needs further refinement by integrating bone and fall-related risk factors into a single case finding algorithm for clinical use.

Hip cortical thickness assessment in postmenopausal women with osteoporosis and strontium ranelate effect on hip geometry

The aims of this study were to assess the relationship between hip geometry and the 5-yr risk of hip fractures in postmenopausal osteoporotic women and the effects of strontium ranelate on these parameters. Using the 5-yr data of a randomized placebo-controlled trial of strontium ranelate (Treatment of Peripheral Osteoporosis Study [TROPOS]), we reanalyzed the hip dual-energy X-ray absorptiometry scans to determine the role of hip geometry in the risk of hip fractures (placebo group, n=636) and to analyze the effects of strontium ranelate (n=483). The outcomes included the hip structure analysis (HSA) parameters: cross-sectional area (CSA), section modulus, cortical thickness, and buckling ratio, measured at femoral neck, intertrochanteric (IT) region, and proximal shaft. The geometric parameters associated with an increased risk of hip fracture over 5yr were IT CSA and femoral shaft cortical thickness independent of age and total-hip bone mineral density (BMD). Using Bonferroni adjustment, IT cortical thickness was associated with the risk of hip fracture. Over 5yr, significant decreases in some femoral dimensions of the placebo group contrast with significant increases in strontium ranelate group after adjustment for age and BMD. Using Bonferroni adjustment, differences between placebo and strontium ranelate groups were no longer significant after adjustment on 5-yr BMD changes. Some HSA parameters have predictive value for hip fracture risk in postmenopausal osteoporotic women. Strontium ranelate improves some HSA parameters, through the BMD increase.

Clinical profiles and risk factors for outcomes in older patients with cervical and trochanteric hip fracture: similarities and differences

Background

Data on clinical characteristics and outcomes in regard to hip fracture (HF) type are controversial. This study aimed to evaluate whether clinical and laboratory predictors of poorer outcomes differ by HF type.

Methods

Prospective evaluation of 761 consecutively admitted patients (mean age 82.3 ± 8.8 years; 74.9% women) with low-trauma non-pathological HF. Clinical characteristics and short-term outcomes were recorded. Haematological, renal, liver and thyroid status, C-reactive protein, cardiac troponin I, serum 25(OH) vitamin D, PTH, leptin, adiponectin and resistin were determined.

Results

The cervical compared to the tronchanteric HF group was younger, have higher mean haemoglobin, albumin, adiponectin and resistin and lower PTH levels (all P < 0.05). In-hospital mortality, length of hospital stay (LOS), incidence of post-operative myocardial injury and need of institutionalisation were similar in both groups. Multivariate analysis revealed as independent predictors for in-hospital death in patient with cervical HF male sex, hyperparathyroidism and lower leptin levels, while in patients with trochanteric HF only hyperparathyroidism; for post-operative myocardial injury dementia, smoking and renal impairment in the former group and coronary artery disease (CAD), hyperparathyroidism and hypoleptinaemia in the latter; for LOS > 20 days CAD, and age > 75 years and hyperparathyroidism, respectively. Need of institutionalisation was predicted by age > 75 years and dementia in both groups and also by hypovitaminosis D in the cervical and by hyperparathyroidism in the trochanteric HF.

Conclusions

Clinical characteristics and incidence of poorer short-term outcomes in the two main HF types are rather similar but risk factors for certain outcomes are site-specific reflecting differences in underlying mechanisms.

Genetic polymorphisms of the Wnt receptor LRP5 are differentially associated with trochanteric and cervical hip fractures

Epidemiological studies suggest that cervical and trochanteric hip fractures have different pathogenesis. We tested the hypothesis that genetic factors have different influences on both types of fractures. Ten polymorphisms of genes known to play an important role in skeletal homeostasis [estrogen receptor alpha (ESR1), aromatase (CYP19A1), type I collagen (COL1A1), and lipoprotein receptor-related protein 5 (LRP5)] were analyzed in 471 Spanish patients with fragility hip fractures. Two polymorphisms of the LRP5 gene (rs7116604 and rs3781600) were associated with the type of fracture (P = 0.0085 and 0.0047, respectively). The presence of rare alleles at each locus was associated with trochanteric fractures over cervical fractures (OR = 1.7 in individuals with at least one rare allele at rs7116604 or rs3781600 loci in comparison with the common homozygotes). Considering individuals bearing the four common alleles as reference, the OR for trochanteric fractures was 1.6 in those with one or two rare alleles and 7.5 in those with three or four rare alleles (P for trend = 0.0074), which is consistent with an allele-dosage effect. There were no significant differences in the frequency distributions of the ESR1, CYP19A1, and COL1A1 genotypes between trochanteric and cervical fractures in either the original group or an extended group of 818 patients. These results suggest that LRP5 alleles influence the type of hip fractures. They support the view that different genetic factors are involved in cervical and trochanteric fractures, which should be taken into consideration in future genetic association studies.