Investigation of differences between hip fracture types: a worthy strategy for improved risk assessment and fracture prevention

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.

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.

Urban versus rural differences of hip fractures among the elderly in Kyoto, Japan: a 10-year study

Secular changes in the incidence rate of hip fractures were estimated to vary by fracture type, i.e., femoral neck or trochanteric fractures, age, and sex, in urban or rural areas in Kyoto Prefecture, Japan from 2008 to 2017.

PURPOSE

Our survey in Kyoto Prefecture from 2008 to 2017 showed that the incidence rate of femoral neck fractures is generally increasing. We investigated the differences between urban and rural areas in the changes of the incidence rate over time of femoral neck and trochanteric fractures during the same period.

METHODS

Patients aged 65 years and above who sustained hip fractures between 2008 and 2017 and were treated at one of the participating 11 hospitals were included. The ratio of sick beds for acute-term care at the investigated hospitals to total number of beds in the urban area was 16.5% (1863/11,158) and 30.6% (1863/5623) in the rural area. The change in incidence rate was estimated utilizing the population according to the national census conducted in 2010 and 2015.

RESULTS

There were 3559 and 6474 hip fractures in the urban and rural areas, respectively. Femoral neck fractures were 1936 (54.4%) and 2813 (43.5%) in each area. The increase of the population-adjusted numbers was marked by neck fractures in males, in both areas. In women, there was a significant increase in femoral neck fractures in the urban area in those aged 85 years and over. For trochanteric fractures, a significant increase was only found in women aged 65 to 74 years in the rural area.

CONCLUSION

A regional difference in the secular changes in incidence rate of hip fractures was found in women, not in men, mostly because neck fractures in women increased in the over 85 group in the urban area.

Sarcopenia, osteoporosis and the burden of prevalent vertebral fractures: a cross-sectional study of 350 women with hip fracture

BACKGROUND

The concurrent presence of sarcopenia and osteoporosis may enhance fracture risk.

AIM

The aim of this study was to evaluate the association between sarcopenia, osteoporosis, or the concurrent presence of both the conditions (osteosarcopenia) and the burden (number and severity) of vertebral fractures in women with hip fracture.

DESIGN

Cross-sectional study.

SETTING

Division of Physical and Rehabilitation Medicine.

POPULATION

We studied 350 women with subacute hip fracture.

METHODS

Lateral radiographs of the spine were taken 18.2±4.5 days after fracture occurrence and the Spine Deformity Index (SDI) was calculated. Body composition was assessed by dual-energy X-ray absorptiometry. Low muscle mass was identified with appendicular lean mass <15.02 kg and low bone mineral density with a femoral T-Score <-2.5.

RESULTS

The presence of sarcopenia (P=0.033) and osteoporosis (P=0.032) was associated with the SDI scores independently of each other and independently of age, percentage of body fat and hip-fracture type. The 350 women were categorized into 3 groups according to the absence of both osteoporosis and sarcopenia (N.=25), presence of either osteoporosis or sarcopenia (N.=95) or presence of osteosarcopenia (N.=230). We found a significant difference in SDI scores across the 3 groups: χ2 (2, N.=350) = 15.29; P<0.001. The categorization of the 350 women into the 3 groups was associated with the SDI scores (P=0.001) independently of age, percentage of body fat and hip-fracture type.

CONCLUSIONS

Both osteoporosis and sarcopenia were independently associated with the burden of prevalent vertebral fractures in women with hip fracture. The concurrent presence of sarcopenia and osteoporosis was associated with a higher SDI Score than the presence of only one of the 2 conditions.

CLINICAL REHABILITATION IMPACT

Subjects with both low bone mass and low muscle mass should be considered at particularly high risk for vertebral fractures. Interventions targeting both the components of the muscle-bone unit, including exercise, nutrition, and possibly new medications, should be investigated to optimize fracture prevention.

Differences in Bone Mineral Density and Hip Geometry in Trochanteric and Cervical Hip Fractures in Elderly Chinese Patients

OBJECTIVE

To assess the differences in bone mineral density (BMD) and hip geometry in trochanteric and cervical hip fractures in elderly Chinese patients.

METHODS

A consecutive series of 196 hip fracture patients aged over 50 years was recruited from November 2013 to October 2015, including 109 cases of cervical fractures (36 males and 73 females) and 87 cases of trochanteric fractures (34 males and 53 females). All patients were evaluated through dual-energy X-ray absorptiometry, and baseline characteristics, BMD and structural parameters were collected and reviewed.

RESULTS

There were statistically significant differences in age, height, and body mass index between patients with each type of fracture, and patients with trochanteric fractures were older than those with cervical fractures, especially in women. The BMD in trochanteric fractures was markedly lower than in cervical fractures in all five sites of the hip by an approximate reduction of 10%, in both men and women. The cross-sectional area, cross-sectional moment of inertia, and the cortical thickness in the cervical fracture group were significantly higher than in the trochanteric fracture group. However, the buckling ratio of both the femoral neck and trochanteric region were significantly lower in the cervical fracture group. Age (/10 years), cross-sectional moment of inertia in femoral neck and buckling ratio in trochanteric region were significant risk factors for trochanteric fractures compared with cervical fractures.

CONCLUSIONS

Compared with cervical hip fractures, patients with trochanteric fractures were older, had a lower BMD, and had less bone mechanical strength, especially in female patients. Age, femoral neck cross-sectional moment of inertia (FNCSMI), and trochanteric region buckling ratio (ITBR) were stronger risk factors for trochanteric hip fractures than for cervical fractures.

Structural risk factors for low-energy acetabular fractures

In this study, we aimed to clarify proximal femur and acetabular structural risk factors associated with low-energy acetabular fractures in the elderly using three-dimensional (3D) computed tomography (CT). Pelvic bones and femurs were segmented and modeled in 3D from abdominopelvic CT images of 121 acetabular fracture patients (mean age 72 ± 12 years, range 50-98 years, 31 females and 90 males) and 121 age-gender matched controls with no fracture. A set of geometric parameters of the proximal femur and the acetabulum was measured. An independent-samples t-test or a Mann-Whitney U test was used for statistical analyses. The fractured side was used for proximal femur geometry, while the contralateral side was used for acetabular geometry. The neck shaft angle (NSA) was significantly smaller (mean 122.1° [95% CI 121.1°-123.2°] vs. 124.6° [123.6°-125.6°], p = 0.001) and the femoral neck axis length (FNALb) was significantly longer (78.1 mm [77.0-79.2 mm] vs. 76.0 mm [74.8-77.2 mm], p = 0.026) in the fracture group than in the controls when genders were combined. The NSA was significantly smaller both for females (120.2° [117.8°-122.6°] vs. 124.7° [122.5°-127.0°], p = 0.007) and for males (122.7° [121.5°-123.8°] vs. 124.6° [123.4°-125.7°], p = 0.006) in the fracture group. However, only males showed a significantly longer FNALb (80.0 mm [78.9-81.1 mm] vs. 77.8 mm [76.6-79.0 mm], p = 0.025). No statistically significant associations of acetabular geometry with fractures were found. However, the mean values of the acetabular angle of Sharp (34°), the lateral center-edge angle (40°), the anterior center-edge angle (62°), and the posterior center-edge angle (105°) indicated possible over-coverage. In conclusion, our findings suggest that proximal femur geometry is associated with low-energy acetabular fractures. Especially elderly subjects with an NSA smaller than normal have an increased risk of acetabular fractures.

The role of parathyroid hormone (PTH) and vitamin D in falls and hip fracture type

BACKGROUND

Fragility fractures of the hip are associated with high morbidity and mortality, and represent a rather devastating consequence of osteoporosis. Hip fractures are traditionally investigated as a whole, although it has been recently implied that distinct pathogenic mechanisms may lead either to trochanteric or subcapital fractures.

AIMS

To investigate whether differences exist by hip fracture type with respect to serum 25(OH)D (vitamin D) and parathyroid hormone (PTH) levels, in addition to epidemiological and demographic data, including history of falls.

METHODS

The inclusion criteria were met by 116 patients [48 men and 68 women; mean age 80.8 ± 8.5 (range 62-94) years]. Patients were analyzed according to hip fracture type, history of falls, and vitamin D and PTH status.

RESULTS

Older age, recurrent falls, serum levels of PTH > 65 pg/ml, and severe vitamin D deficiency were found to be associated with trochanteric fractures. Additionally, older age, female gender, PTH > 65 pg/ml, and severe vitamin D deficiency were related to recurrent falls. Meanwhile, patients with absence of PTH response to low vitamin D levels, were not repeated fallers and suffered mostly from subcapital fractures.

DISCUSSION AND CONCLUSION

Elevated PTH levels predispose both to falls and trochanteric fractures, while vitamin D-deficient patients with normal PTH levels are mostly related to subcapital fractures. It is thereby indicated that different pathophysiological processes lie behind subcapital and trochanteric fractures. A better understanding of these mechanisms may assist in the development of prevention strategies for individuals recognized at risk for falls and either type of hip fracture.

Risk factors for trochanteric and femoral neck fracture

INTRODUCTION AND OBJECTIVES

The differences between the two main types of fracture of proximal end of the femur, trochanteric and cervical fractures, are still a subject of study, and could be the key to a better understanding of its pathophysiology and prevention. The aim of this study is to determine whether epidemiological differences in the distribution of risk factors associated with hip fracture exist between these two entities.

PATIENTS AND METHOD

A descriptive cross-sectional study of 428 patients over the age of 65 admitted for trochanteric or cervical fractures in 2015, in which gender, age, previous diagnosis, external causes associated with fracture and place of the event were recorded.

RESULTS

There were 220 patients with a cervical fracture (51.4%) and 208 patients with a trochanteric fracture (48.6%). The average age was higher in the trochanteric fracture, observing a constant increase with age only in women with trochanteric fractures. Cervical fracture showed a significant association with cerebrovascular disease (p=0.039) and trochanteric fracture with accidental falls (p=0.047) and presence of 5-9 previous diseases (p=0.014). A regression analysis maintained this association in the case of a cerebrovascular disease (OR 2.6, 95%CI 1.1-6.4) and the presence of 5-9 diseases (OR 1.5, 95%CI 1.1-2.3).

CONCLUSIONS

Trochanteric fractures are associated with women patients of more advanced ages, 5-9 previous diseases and accidental falls. Cerebrovascular disease shows a higher prevalence in cervical fractures.

Hip osteoarthritis as a predictor of the fracture pattern in proximal femur fractures

INTRODUCTION

Several authors have suggested a correlation between the fracture patterns of proximal femur fractures and the degree of hip osteoarthritis (HOA), but the current evidence to support this are insufficient. The aim of our study was to demonstrate whether there is an association between the grade of HOA and fracture pattern observed, in patients presenting with a fragility fracture of the proximal femur.

MATERIALS AND METHODS

We contacted a retrospective review of all patients presenting to our institution with fragility fractures involving the proximal femur, between March 2012 and October 2013. Pathological fractures, high-energy injuries and patients with less than one year of follow-up were excluded from further analysis. Admission radiographs and severity of HOA were assessed according to Kellgren and Lawrence scale (minimal: Grades 1-2; severe: Grades 3-4). Fractures were classified according to AO/OTA classification.

RESULTS

A total of 1003 patients (725 females; 1003 fractures) met the inclusion criteria, having a mean age of 81.5 (46-106 years). With regards to fracture classification, 417 (41.6%) fractures were classified as extracapsular and 586 (58.4%) as intracapsular. A total of 939 (93.9%) patients presented with minimal HOA, whilst 61 (6.1%) of the patients presented with severe HOA. Of the 61 patients presenting with severe HOA, 42 patients (68.9%) sustained a 31A-interthrocanteric fracture and 19 patients (31.1%) sustained a 31B-intracapsular fracture. Regarding the patients presenting with minimal HOA (832 patients in total), 323 patients (38.8%) sustained 31A-intertrochanteric fracture and 509 patients (61.2%) sustained a 31B-intracapsular fracture. Patients presenting with severe HOA were found to have a statistically significant chance to present with an extracapsular fracture (p<0.01).

CONCLUSIONS

The degree of HOA is related to the fracture pattern in patients presenting following simple mechanical falls. More specifically, higher grades of HOA are associated with extracapsular fracture patterns, whereas lower grades of HOA are associated with intracapsular fracture patterns.

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.

Focal osteoporosis defects play a key role in hip fracture

BACKGROUND

Hip fractures are mainly caused by accidental falls and trips, which magnify forces in well-defined areas of the proximal femur. Unfortunately, the same areas are at risk of rapid bone loss with ageing, since they are relatively stress-shielded during walking and sitting. Focal osteoporosis in those areas may contribute to fracture, and targeted 3D measurements might enhance hip fracture prediction. In the FEMCO case-control clinical study, Cortical Bone Mapping (CBM) was applied to clinical computed tomography (CT) scans to define 3D cortical and trabecular bone defects in patients with acute hip fracture compared to controls. Direct measurements of trabecular bone volume were then made in biopsies of target regions removed at operation.

METHODS

The sample consisted of CT scans from 313 female and 40 male volunteers (158 with proximal femoral fracture, 145 age-matched controls and 50 fallers without hip fracture). Detailed Cortical Bone Maps (c.5580 measurement points on the unfractured hip) were created before registering each hip to an average femur shape to facilitate statistical parametric mapping (SPM). Areas where cortical and trabecular bone differed from controls were visualised in 3D for location, magnitude and statistical significance. Measures from the novel regions created by the SPM process were then tested for their ability to classify fracture versus control by comparison with traditional CT measures of areal Bone Mineral Density (aBMD). In women we used the surgical classification of fracture location ('femoral neck' or 'trochanteric') to discover whether focal osteoporosis was specific to fracture type. To explore whether the focal areas were osteoporotic by histological criteria, we used micro CT to measure trabecular bone parameters in targeted biopsies taken from the femoral heads of 14 cases.

RESULTS

Hip fracture patients had distinct patterns of focal osteoporosis that determined fracture type, and CBM measures classified fracture type better than aBMD parameters. CBM measures however improved only minimally on aBMD for predicting any hip fracture and depended on the inclusion of trabecular bone measures alongside cortical regions. Focal osteoporosis was confirmed on biopsy as reduced sub-cortical trabecular bone volume.

CONCLUSION

Using 3D imaging methods and targeted bone biopsy, we discovered focal osteoporosis affecting trabecular and cortical bone of the proximal femur, among men and women with hip fracture.

Association of 3D Geometric Measures Derived From Quantitative Computed Tomography With Hip Fracture Risk in Older Men

We investigated the associations of 3D geometric measures and volumetric bone mineral density (vBMD) of the proximal femur assessed by quantitative computed tomography (QCT) with hip fracture risk among elderly men. This study was a prospective case-cohort design nested within the Osteoporotic Fractures in Men Study (MrOS) cohort. QCT scans of 230 men (65 with confirmed hip fractures) were evaluated with Mindways' QCTPRO-BIT software. Measures that are indicative of bone strength for the femoral neck (FN) and for the trochanteric region (TR) were defined. Bending strength measures were estimated by minimum section modulus, buckling strength by buckling ratio, and a local thinning index (LTI). Integral and trabecular vBMD measures were also derived. Areal BMD (aBMD) of the total proximal femur from dual-energy X-ray absorptiometry (DXA) is presented for comparison. Associations of skeletal measures with incident hip fracture were estimated with hazard ratios (HR) per standard deviation and their 95% confidence intervals (CI) from Cox proportional hazard regression models with adjustment for age, body mass index (BMI), site, and aBMD. Men with hip fractures were older than men without fracture (77.1 ± 6.0 years versus 73.3 ± 5.7 years, p < 0.01). Age, BMI, and site-adjusted HRs were significant for all measures except TR_LTI. Total femural BMD by DXA (HR = 4.9, 95% CI 2.5-9.9) and QCT (HR = 5.5, 95% CI 2.5-11.7) showed the strongest association followed by QCT FN integral vBMD (HR = 3.6, 95% CI 1.8-6.9). In models that additionally included aBMD, FN buckling ratio (HR = 1.9, 95% CI 1.1-3.2) and trabecular vBMD of the TR (HR = 2.0, 95% CI 1.2-3.4) remained associated with hip fracture risk, independent of aBMD. QCT-derived 3D geometric indices of instability of the proximal femur were significantly associated with incident hip fractures, independent of DXA aBMD. Buckling of the FN is a relevant failure mode not entirely captured by DXA. Further research to study these relationships in women is warranted. © 2016 American Society for Bone and Mineral Research.

Risk factors for hip fracture in very old people: a population-based study

SUMMARY

Knowledge of risk factors for hip fracture among very old people is limited. Walking indoors with help from ≤1 person, Parkinson's disease, currently smoking, delirium in the previous month, underweight, and age were associated with increased risk of hip fracture and could be important for preventive strategy development.

INTRODUCTION

The purpose of this study is to investigate risk factors for hip fracture among a representative sample of very old people.

METHODS

In total, 953 participants from the Umeå 85+/Gerontological Regional Database population-based cohort study were interviewed and assessed during home visits. Associations of baseline characteristics with hip fracture during the maximum 5-year follow-up period were analyzed using Cox proportional hazards regression.

RESULTS

Participants had a mean age of 89.3 ± 4.7 years; 65.8% were women, 36.8% lived in residential care facilities, 33.6% had dementia, and 20.4% had histories of hip fracture. During a mean follow-up period of 2.7 years, 96 (10.1%) individuals sustained hip fracture. Walking indoors with help from no more than one person (hazard ratio [HR] = 8.57; 95% confidence interval [CI], 1.90-38.71), Parkinson's disease (HR = 5.12; 95% CI, 1.82-14.44), currently smoking (HR = 4.38; 95% CI 2.06-9.33), delirium in the previous month (HR = 2.01; 95% CI, 1.15-3.49), underweight (body mass index <22; HR = 1.74, 95% CI, 1.09-2.77), and age (HR = 1.09; 95% CI, 1.04-1.14) were associated independently with an increased risk of hip fracture. Hip prosthesis at baseline decreased the risk of hip fracture (HR = 0.37; 95% CI, 0.15-0.91), but only for those with bilateral hip prostheses.

CONCLUSIONS

Seven factors were associated independently with incident hip fracture during follow-up in this sample of very old people. These factors could have important clinical implications in identifying persons at high risk of hip fracture, as well as in the development of effective preventive strategies.

Anemia on Admission Is an Independent Predictor of Long-Term Mortality in Hip Fracture Population: A Prospective Study With 2-Year Follow-Up

Anemia is a disputable factor for long-term mortality in hip fracture population in previous studies. Previous studies indicated that the level of hemoglobin (Hb) might fluctuate due to various factors, such as comorbidities and in-hospital interventions, and the changing level of Hb, may lead to discordance diagnosis of anemia and thus to the conflicting conclusions on prognostic value of anemia. So in this study, we aim to compare factors affecting the diagnosis of anemia at different time-points, admission, postoperation, and discharge, and to determine which the time point is most suitable for mortality prediction.This prospective cohort study included 1330 hip fracture patients from 1 January 2000 to 18 November 2012. Hb levels at 3 different time points, such as admission, postoperation, and discharge, were collected and used to stratify the cohort into anemia and nonanemia groups. Candidate factors including commodities, perioperative factors, blood transfusion, and other in-hospital interventions were collected before discharge. Logistic regression analyses were performed to detect risk factors for anemia for the 3 time points separately. Kaplan-Meier and multivariate Cox regression analyses were used to evaluate the association between anemia and 2-year mortality.Factors affecting the diagnosis of anemia were different for the 3 time points. Age, female sex, American Society of Anesthesiologists score (ASA), and intertrochanteric fracture were associated with admission anemia, while surgical procedure, surgical duration, blood transfusion, blood loss during the operation, and drainage volume were major risk factors for postoperation anemia. Cox proportional-hazards regression analysis suggested that the risk of all-cause mortality was higher in the anemia group on admission (1.680, 95%CI: 1.201-2.350, P < 0.01), but not postoperation or on discharge, after adjustment for confounding factors.Our study showed that risk factors for anemia varied at different time points, and therapy interventions would greatly affect the status of postoperation and discharge anemia in hip fracture patients. The take-home message is when anemia is used for mortality prediction in these patients, a specific time point should be chosen. We suggest that only admission anemia should be used for mortality prediction, but not postoperation nor discharge anemia.

The Trochanteric Localization is a Mediator of Slower Short-Term Functional Recovery in Overweight and Obese Elderly Women with Recent Hip Fracture: The BREAK Study

The hypothesis tested in this study, carried out on elderly Italian women with recent hip fracture, was to assess the extent to which the effect of a condition of being overweight/obese on short-term functional recovery as evaluated by the "time to permitted load" could be explained by a mediator variable (type of hip fracture). We studied 727 women aged 60 years or over with a recent low trauma surgically treated hip fracture and for whom an information on post-surgery complications and on the time to permitted load was available. To assess for mediation, the statistical analyses were carried out following the procedure described by Baron and Kenny. In this study, 46 % of women with hip fracture presented a time to permitted load of ≥ 10 days. The women with a post-surgery time to permitted load of ≥ 10 days showed a significantly higher proportion of trochanteric fracture localization (72.1 vs 42 %), of total overweight/obesity (46.5 vs 36.8 %) and of post-surgery complications (38.8 vs 18.8 %). The mediating effect of hip fracture localization on the association between overweight/obesity and the time of permitted load was demonstrated and confirmed in a multivariate logistic regression model. This study, carried out using a "mediator" statistical analysis, suggests that in elderly women with hip fracture being overweight/obese is associated with a slower short-term functional recovery as evaluated by the time to permitted load and that this association is mediated by the trochanteric localization of hip fracture.

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.

Older male physicians have lower risk of trochanteric but not cervical hip fractures

Background: Osteoporosis is pathophysiologically related to trochanteric fractures, and this condition is more preventable by lifestyle modifications than cervical fractures. We investigated whether older physicians, who are health-conscious people, are at a lower risk of hip fractures because of fewer trochanteric fractures. Methods: Data regarding older (≥65 years) physicians (n= 4303) and matched non-medical persons (control) were retrieved from Taiwan’s National Health Insurance claims. All of the subjects were obtained from NHIRD with index dates from 1 January 2000 to 31 December 2008. Cox proportional hazard and competing risk regression models were established to estimate the hazard ratio (HR) of hip fracture associated with older physicians. Results: The incidence rates of trochanteric fractures were lower in older physicians than in controls (1.73 and 3.07 per 1000 person-years, respectively), whereas the rates of cervical fractures were similar between the two groups (2.45 and 2.12 per 1000 person-years, respectively). Older physicians yielded 46% lower hazard of trochanteric fractures than controls (adjusted HR 0.54, 95% confidence interval 0.37–0.79); by contrast, hazards of cervical fractures were comparable between the two groups. The HRs estimated from the competing risk models remained unchanged. Conclusions: Our findings indicated that health risk awareness may pose a significant preventive effect on trochanteric hip fractures.

Differential impact of some risk factors on trochanteric and cervical hip fractures

AIM

To investigate the potential distinct risk factors associated with trochanteric and cervical hip fractures.

METHODS

Elderly patients aged 65 years and older (n = 1161) were admitted to the orthopedic department with hip fractures during the years 2006-2011. Demographic and clinical data, as well as routine blood tests, were retrieved from the patient electronic medical records.

RESULTS

Approximately 58% of patients had trochanteric fractures and 42% had cervical fractures. Women were more likely to have trochanteric fractures than men (P = 0.002). Female sex, frailty, falls, diabetes and subnormal calcium, as well as subnormal hemoglobin levels, were significant risk factors for trochanteric fractures (OR 1.39, P = 0.0202, OR 1.36, P = 0.0166, OR 1.49, P = 0.0015, OR 1.33, P = 0.0343, OR 0.68, P = 0.0054, OR 0.70, P = 0.0036, respectively). Patients with Parkinson's disease were at a lower risk for trochanteric fractures (OR 0.6, P = 0.007).

CONCLUSION

As there are some differences between risk factors for trochanteric and cervical hip fractures, there is a need for further studies in order to understand the etiology of fractures and to be able to carry out effective preventive efforts.

A holistic hip fracture approach: individualized diagnosis and treatment after surgery

Secondary fracture prevention is of paramount importance in the clinical management of patients with hip fractures. However, in contrast to the excellent surgical care provided to these patients in the Western hemisphere and despite good medical options, causative treatment of the underlying osteopathy causing skeletal fragility remains an unmet medical need that urgently needs to be improved. This calls for a concerted action between orthopedic/trauma surgeons and osteologists, as outstanding hospitals not only treat fragility fractures, but also prevent fractures from recurring. Aiming for a holistic hip fracture approach, in this work we highlight aspects of (a) improved risk assessment and differential diagnosis, (b) optimized basic medical care, and

The fragile elderly hip: mechanisms associated with age-related loss of strength and toughness

Every hip fracture begins with a microscopic crack, which enlarges explosively over microseconds. Most hip fractures in the elderly occur on falling from standing height, usually sideways or backwards. The typically moderate level of trauma very rarely causes fracture in younger people. Here, this paradox is traced to the decline of multiple protective mechanisms at many length scales from nanometres to that of the whole femur. With normal ageing, the femoral neck asymmetrically and progressively loses bone tissue precisely where the cortex is already thinnest and is also compressed in a sideways fall. At the microscopic scale of the basic remodelling unit (BMU) that renews bone tissue, increased numbers of actively remodelling BMUs associated with the reduced mechanical loading in a typically inactive old age augments the numbers of mechanical flaws in the structure potentially capable of initiating cracking. Menopause and over-deep osteoclastic resorption are associated with incomplete BMU refilling leading to excessive porosity, cortical thinning and disconnection of trabeculae. In the femoral cortex, replacement of damaged bone or bone containing dead osteocytes is inefficient, impeding the homeostatic mechanisms that match strength to habitual mechanical usage. In consequence the participation of healthy osteocytes in crack-impeding mechanisms is impaired. Observational studies demonstrate that protective crack deflection in the elderly is reduced. At the most microscopic levels attention now centres on the role of tissue ageing, which may alter the relationship between mineral and matrix that optimises the inhibition of crack progression and on the role of osteocyte ageing and death that impedes tissue maintenance and repair. This review examines recent developments in the understanding of why the elderly hip becomes fragile. This growing understanding is suggesting novel testable approaches for reducing risk of hip fracture that might translate into control of the growing worldwide impact of hip fractures on our ageing populations.

Cortical bone assessed with clinical computed tomography at the proximal femur

Hip fractures are the most serious of all fragility fractures in older people of both sexes. Trips, stumbles, and falls result in fractures of the femoral neck or trochanter, and the incidence of these two common fractures is increasing worldwide as populations age. Although clinical risk factors and chance are important in causation, the ability of a femur to resist fracture also depends on the size and spatial distribution of the bone, its intrinsic material properties, and the loads applied. Over the past two decades, clinical quantitative computed tomography (QCT) studies of living volunteers have provided insight into how the femur changes with advancing age to leave older men and women at increased risk of hip fractures. In this review, we focus on patterns of cortical bone loss associated with hip fracture, age-related changes in cortical bone, and the effects of drugs used to treat osteoporosis. There are several methodologies available to measure cortical bone in vivo using QCT. Most techniques quantify bone density (g/cm(3)), mass (g), and thickness (mm) in selected, predefined or “traditional” regions of interest such as the “femoral neck” or “total hip” region. A recent alternative approach termed “computational anatomy,” uses parametric methods to identify systematic differences, before displaying statistically significant regions as color-scaled maps of density, mass, or thickness on or within a representative femur model. This review will highlight discoveries made using both traditional and computational anatomy methods, focusing on cortical bone of the proximal femur.

Association between estrogen receptor α gene (ESR1) PvuII (C/T) and XbaI (A/G) polymorphisms and hip fracture risk: evidence from a meta-analysis

Background and Objective

Genetic factors are important in the pathogenesis of fractures. Notably, estrogen receptor α (ESR1) has been suggested as a possible candidate gene for hip fractures; however, published studies of ESR1 gene polymorphisms have been hampered by small sample sizes and inconclusive or ambiguous results. The aim of this meta-analysis is to investigate the associations between two novel common ESR1 polymorphisms (intron 1 polymorphisms PvuII-rs2234693: C>T and XbaI-rs9340799: A>G) and hip fracture.

Methods

Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the association.

Results

Five case-control and three cohort studies were assessed, including a total of 1,838 hip fracture cases and 14,972 healthy controls. This meta-analysis revealed that the PvuII T allele is a highly significant risk factor for hip fracture susceptibility, with an effect magnitude similar in male and pre-menopausal and post-menopausal female patients. In stratified analysis based on ethnicity, the PvuII T allele remained significantly correlated with increased risk of hip fracture in Caucasian populations; this correlation, however, was not found in Asian populations. Unlike the PvuII polymorphism, we did not find significant differences in the XbaI (A>G) polymorphism allele or genotype distributions of hip fracture patients and controls. We also found no obvious association between the XbaI polymorphism and hip fracture in any of the racial or gender subgroups.

Conclusion

Our findings show that the ESR1 PvuII T allele may increase the risk of hip fracture and that the XbaI polymorphism is not associated with hip fracture.

Temporal trends in the incidence of osteoporotic fractures

Osteoporotic fractures are associated with excess mortality and decreased functional capacity and quality of life. Age-standardized incidence rates of fragility fractures, particularly of the hip and forearm, have been noted to be decreasing in the last decade across many countries with the notable exception of Asia. The causes for the observed changes in fracture risk have not been fully identified but are likely the result of multiple factors, including birth cohort and period effects, increasing obesity, and greater use of anti-osteoporosis medications. Changing rates of fragility fractures would be expected to have an important impact on the burden of osteoporosis.

The assessment of vertebral fractures in elderly women with recent hip fractures: the BREAK Study

This study aimed to evaluate the prevalence of vertebral fractures in elderly women with a recent hip fracture. The burden of vertebral fractures expressed by the Spinal Deformity Index (SDI) is more strictly associated with the trochanteric than the cervical localization of hip fracture and may influence short-term functional outcomes.

INTRODUCTION

This study aimed to determine the prevalence and severity of vertebral fractures in elderly women with recent hip fracture and to assess whether the burden of vertebral fractures may be differently associated with trochanteric hip fractures with respect to cervical hip fractures.

METHODS

We studied 689 Italian women aged 60 years or over with a recent low trauma hip fracture and for whom an adequate X-ray evaluation of spine was available. All radiographs were examined centrally for the presence of any vertebral deformities and radiological morphometry was performed. The SDI, which integrates both the number and the severity of fractures, was also calculated.

RESULTS

Prevalent vertebral fractures were present in 55.7% of subjects and 95 women (13.7%) had at least one severe fracture. The women with trochanteric hip fracture showed higher SDI and higher prevalence of diabetes with respect to those with cervical hip fracture, p=0.017 and p=0.001, respectively. SDI, surgical menopause, family history of fragility fracture, and type2 diabetes mellitus were independently associated with the risk of trochanteric hip fracture. Moreover, a higher SDI was associated with a higher percentage of post-surgery complications (p=0.05) and slower recovery (p<0.05).

CONCLUSIONS

Our study suggests that the burden of prevalent vertebral fractures is more strictly associated with the trochanteric than the cervical localisation of hip fracture and that elevated values of SDI negatively influence short term functional outcomes in women with hip fracture.

Quantitative ultrasound of cortical bone in the femoral neck predicts femur strength: results of a pilot study

A significant risk of femoral neck (FN) fracture exists for men and women with an areal bone mineral density (aBMD) higher than the osteoporotic range, as measured with dual-energy X-ray absorptiometry (DXA). Separately measuring the cortical and trabecular FN compartments and combining the results would likely be a critical aspect of enhancing the diagnostic capabilities of a new technique. Because the cortical shell determines a large part of FN strength a novel quantitative ultrasound (QUS) technique that probes the FN cortical compartment was implemented. The sensitivity of the method to variations of FN cortical properties and FN strength was tested. Nine femurs (women, mean age 83 years) were subjected to QUS to measure the through transmission time-of-flight (TOF) at the FN and mechanical tests to assess strength. Quantitative computed tomography (QCT) scans were performed to enable analysis of the dependence of TOF on bone parameters. DXA was also performed for reference. An ultrasound wave propagating circumferentially in the cortical shell was measured in all specimens. Its TOF was not influenced by the properties of the trabecular compartment. Averaged TOF for nine FN measurement positions/orientations was significantly correlated to strength (R2  = 0.79) and FN cortical QCT variables: total BMD (R(2)  = 0.54); regional BMD in the inferoanterior (R2  = 0.90) and superoanterior (R2  = 0.57) quadrants; and moment of inertia (R2  = 0.71). The results of this study demonstrate that QUS can perform a targeted measurement of the FN cortical compartment. Because the method involves mechanical guided waves, the QUS variable is related to the geometric and material properties of the cortical shell (cortical thickness, tissue elasticity, and porosity). This work opens the way to a multimodal QUS assessment of the proximal femur, combining our approach targeting the cortical shell with the existing modality sensitive to the trabecular compartment. In vivo feasibility of our approach has to be confirmed with experimental data in patients.

Lifestyle factors and site-specific risk of hip fracture in community dwelling older women--a 13-year prospective population-based cohort study

BACKGROUND

Several risk factors are associated to hip fractures. It seems that different hip fracture types have different etiologies. In this study, we evaluated the lifestyle-related risk factors for cervical and trochanteric hip fractures in older women over a 13-year follow-up period.

METHODS

The study design was a prospective, population-based study consisting of 1681 women (mean age 72 years). Seventy-three percent (n = 1222) participated in the baseline measurements, including medical history, leisure-time physical activity, smoking, and nutrition, along with body anthropometrics and functional mobility. Cox regression was used to identify the independent predictors of cervical and trochanteric hip fractures.

RESULTS

During the follow-up, 49 cervical and 31 trochanteric fractures were recorded. The women with hip fractures were older, taller, and thinner than the women with no fractures (p < 0.05). Low functional mobility was an independent predictor of both cervical and trochanteric fractures (HR = 3.4, 95% CI 1.8-6.6, and HR = 5.3, 95% CI 2.5-11.4, respectively). Low baseline physical activity was associated with an increased risk of hip fracture, especially in the cervical region (HR = 2.5, 95% CI 1.3-4.9). A decrease in cervical fracture risk (p = 0.002) was observed with physically active individuals compared to their less active peers (categories: very low or low, moderate, and high). Moderate coffee consumption and hypertension decreased the risk of cervical fractures (HR = 0.4, 95% CI 0.2-0.8, for both), while smoking was a predisposing factor for trochanteric fractures (HR = 3.2, 95% CI 1.1-9.3).

CONCLUSIONS

Impaired functional mobility, physical inactivity, and low body mass may increase the risk for hip fractures with different effects at the cervical and trochanteric levels.

The interindividual variation in femoral neck width is associated with the acquisition of predictable sets of morphological and tissue-quality traits and differential bone loss patterns

A better understanding of femoral neck structure and age-related bone loss will benefit research aimed at reducing fracture risk. We used the natural variation in robustness (bone width relative to length) to analyze how adaptive processes covary traits in association with robustness, and whether the variation in robustness affects age-related bone loss patterns. Femoral necks from 49 female cadavers (29-93 years of age) were evaluated for morphological and tissue-level traits using radiography, peripheral quantitative computed tomography, micro-computed tomography, and ash-content analysis. Femoral neck robustness was normally distributed and varied widely with a coefficient of variation of 14.9%. Age-adjusted partial regression analysis revealed significant negative correlations (p < 0.05) between robustness and relative cortical area, cortical tissue-mineral density (Ct.TMD), and trabecular bone mineral density (Ma.BMD). Path analysis confirmed these results showing that a one standard deviation (SD) increase in robustness was associated with a 0.70 SD decrease in RCA, 0.47 SD decrease in Ct.TMD, and 0.43 SD decrease in Ma.BMD. Significantly different bone loss patterns were observed when comparing the most slender and most robust tertiles. Robust femora showed significant negative correlations with age for cortical area (R(2) = 0.29, p < 0.03), Ma.BMD (R(2) = 0.34, p < 0.01), and Ct.TMD (R(2) = 0.4, p < 0.003). However, slender femora did not show these age-related changes (R(2) < 0.09, p > 0.2). The results indicated that slender femora were constructed with a different set of traits compared to robust femora, and that the natural variation in robustness was a determinant of age-related bone loss patterns. Clinical diagnoses and treatments may benefit from a better understanding of these robustness-specific structural and aging patterns.

Cortical thickness mapping to identify focal osteoporosis in patients with hip fracture

Background

Individuals with osteoporosis are predisposed to hip fracture during trips, stumbles or falls, but half of all hip fractures occur in those without generalised osteoporosis. By analysing ordinary clinical CT scans using a novel cortical thickness mapping technique, we discovered patches of markedly thinner bone at fracture-prone regions in the femurs of women with acute hip fracture compared with controls.

Methods

We analysed CT scans from 75 female volunteers with acute fracture and 75 age- and sex-matched controls. We classified the fracture location as femoral neck or trochanteric before creating bone thickness maps of the outer ‘cortical’ shell of the intact contra-lateral hip. After registration of each bone to an average femur shape and statistical parametric mapping, we were able to visualise and quantify statistically significant foci of thinner cortical bone associated with each fracture type, assuming good symmetry of bone structure between the intact and fractured hip. The technique allowed us to pinpoint systematic differences and display the results on a 3D average femur shape model.

Findings

The cortex was generally thinner in femoral neck fracture cases than controls. More striking were several discrete patches of statistically significant thinner bone of up to 30%, which coincided with common sites of fracture initiation (femoral neck or trochanteric).

Interpretation

Femoral neck fracture patients had a thumbnail-sized patch of focal osteoporosis at the upper head-neck junction. This region coincided with a weak part of the femur, prone to both spontaneous ‘tensile’ fractures of the femoral neck, and as a site of crack initiation when falling sideways. Current hip fracture prevention strategies are based on case finding: they involve clinical risk factor estimation to determine the need for single-plane bone density measurement within a standard region of interest (ROI) of the femoral neck. The precise sites of focal osteoporosis that we have identified are overlooked by current 2D bone densitometry methods.