Hollow-Bone-Graft Dynamic Hip Screw Can Fix and Promote Bone Union after Femoral Neck Fracture: an Experimental Research

Background: Delayed bone union, nonunion or osteonecrosis often occur after femoral neck fractures in young adults. Secondary bone healing requires strong internal fixation, intramedullary pressure reduction and early functional exercise.Objective: To compare bone healing of femoral neck fractures treated with hollow-bone-graft dynamic hip screws (Hb-DHS) and standard dynamic hip screws (DHS) in an animal model.Design: Testing of specifically designed fixation devices in a pig animal model.Interventions/Methods: We designed Hb-DHS and DHS devices appropriate to the femoral neck and head of experimental animals and used them in eight pigs (4-month-old, male or female, 30-40 kg/each). Under anesthesia, we induced medium neck type, Garden III type femoral neck fractures in each pig with fracture gaps of 0.5 mm and then fixed each left femur with Hb-DHS and each right femur with DHS. We assessed the animals radiographically and by postmortem visual appraisal of evidence of bone healing 8 and 16 weeks postoperatively.Results: There were significant differences in radiographic and general findings between the Hb-DHS and DHS groups at weeks 8 and 16 postoperatively. We found statistically significant differences between the Hb-DHS and DHS groups in bone healing scores, trabecular bone volume percentage and bone mineral density as assessed on plain radiographs and computed tomography images (P < 0.05). There were also significant differences between the Hb-DHS and DHS groups in postmortem visually assessed indicators of bone healing at both 8 and 16 weeks postoperatively.Conclusions: The Hb-DHS device promotes femoral neck bone union, stimulates trabecular bone formation, increases BMD and has advantages over DHS for internal fixation of femoral neck fractures. This animal experiment will contribute to developing optimal treatment for femoral neck fractures in young adults.     

Characterization of bone quality using computer-extracted radiographic features.

Both bone mineral density (BMD) and trabecular structure are important determinates of bone mechanical properties. However, neither BMD or trabecular structural features can completely explain the variations in bone mechanical properties. In this study, we combine BMD and bone structural features to characterize bone mechanical behavior. Radiographs were obtained from 34 femoral neck specimens excised during total hip arthroplasties. Each neck radiograph was digitized and a region of interest (ROI) was selected from the medial side of the femoral neck. Textural features, the global Minkoswski dimension and trabecular orientation, were extracted from each ROI image using Minkowski dimension analysis. The BMD of each specimen was measured using dual-energy x-ray absorptiometry (DXA) and subsequently normalized by bone size as measured from a standard pelvis radiograph. Mechanical testing was performed on the trabecular bone cubes machined from each femoral neck to yield bone mechanical properties. Multiple regression was performed to select the best features to predict bone mechanical properties. The results suggest that, using multiple predictors including normalized BMD structural features, and patient age, the coefficients of determination (R2) improved over the use of BMD alone. For bone strength, the R2 was improved from 0.24 using conventional BMD to 0.48 using a four-predictor model. Similar results were obtained in the prediction of Young's modulus, i.e., the R2 was improved from 0.25 to 0.55 in going from the model using conventional BMD to a four-predictor model. This study demonstrates the contributions of normalized BMD, structural features, and age to bone mechanical properties, and suggests a potential method for the noninvasive evaluation of bone mechanical properties.     

Influence of Ovariectomy on Bone Turnover and Trabecular Bone Mass in Mature Cynomolgus Monkeys

Purpose

To examine the influence of ovariectomy (OVX) on bone turnover and trabecular bone mass at the 3 clinically important skeletal sites in mature cynomolgus monkeys.

Materials and Methods

Six female cynomolgus monkeys, aged 17-21 years, were randomized into 2 groups by the stratified weight: the OVX and sham-operation groups (n = 3 in each group). The experimental period was 16 months. Lumbar bone mineral density (BMD) in vivo and serum and urinary bone turnover markers were longitudinally measured, and peripheral quantitative computed tomographic and bone histomorphometric analyses were performed on trabecular bone of the lumbar vertebra, femoral neck, and distal radius at the end of the experiment.

Results

OVX induced in a reduction in lumbar BMD compared with the sham controls and the baseline, as a result of increased serum levels of bone-specific alkaline phosphatase and urinary levels of cross-lined N- and C-terminal telopeptides of type I collagen. Furthermore, OVX induced reductions in trabecular volumetric BMD and trabecular bone mass compared with the sham controls, with increased bone formation rate at the lumbar vertebra, femoral neck, and distal radius.

Conclusion

The results indicated that OVX in mature cynomolgus monkeys (17-21 years of age) increased bone turnover and induced trabecular bone loss at the three skeletal sites compared with the sham controls. Thus, mature cynomolgus monkeys could be utilized for preclinical studies to examine the effects of interventions on bone turnover and trabecular bone mass at the 3 clinically important skeletal sites.     

A review of magnetic resonance (MR) imaging of trabecular bone micro-architecture: contribution to the prediction of biomechanical properties and fracture prevalence.

Bone mineral density and three-dimensional trabecular structure play a significant role in predicting bone strength and biomechanical properties. MR is a non-invasive technique for determining trabecular architecture both in vivo and in vitro. In this paper we review the use of magnetic resonance imaging to obtain high resolution images of trabecular bone structure and quantify the three-dimensional architecture of the trabecular bone network. Studies assessing the anisotropy of the trabecular architecture in human cadaveric specimens from the distal and proximal femur, and the thoracic and lumbar vertebrae, are reviewed. The contributions of the MR derived measures of 3D trabecular bone structure to the biomechanical strength of the specimen are presented. In vivo, the relationship between the high resolution MR derived trabecular bone structure parameters in the distal radius and calcaneus in patients with hip fractures, are compared to age matched normal controls. MR derived measures are compared to measures of trabecular bone mineral density (BMD) in the hip using dual X-ray absorptiometry (DXA).     

Avoiding the under-diagnosis of low bone mineral density in Egyptian children with chronic medical conditions affecting bone health

Introduction

The International Society for Clinical Densitometry recommended that the lumbar spine and total body less head (TBLH) are the most accurate and reproducible skeletal sites for performing areal bone mineral density (BMD) measurements. Our objective is to evaluate the role of measurement of femoral neck BMD in avoiding the under-diagnosis of low BMD being a risk for fractures in subjects with chronic medical conditions that might affect bone health.

Material and methods

Subjects with chronic medical conditions that might affect bone health were studied (n = 468) and 36 healthy children were recruited as control subjects. Physical examinations, height, weight measurements and BMI were calculated. Dual-energy radiographic absorptiometry of the lumbar spine and femoral neck were measured.

Results

Bone mineral density z scores in both sites were significantly reduced in chronic patients, compared with control subjects. Prevalence of very low BMD z scores (–2 or more) using lumbar DXA, femoral DXA, and either of the sites were 1.38%, 3.37%, and 3.96%, respectively, while low BMD Z scores (–1 to less than –2) were 9.52%, 18.05% and 21.14% respectively.

Conclusions

We identified a significant decrease in both lumbar and femoral BMDs in studied children. Sometimes femoral BMD is decreased while lumbar BMD is still within the normal range. For this reason we recommend that, when technically feasible and there is no facility to measure TBLH, all those patients should have lumbar spine and femoral neck bone mineral density measurements to avoid under-diagnosis of low BMD being a risk for fractures.     

Effect of physical activity on bone turnover in young boys

AIMS: To evaluate the effect of the physical activity on bone turnover in young male soccer players at the Tanner's stage of 1-2. MATERIAL AND METHODS: 61 young soccer players (13,4 +/- 0,3 years old) who actively participated in soccer since 3,7 +/- 0,7 years were compared to 60 age and sex- matched non active subjects. Bone mineral density (BMD) of whole body, and in specific skeleton sites, fatty body mass (FBM) and lean body mass (LBM) were determined by a dual energy X-ray absorptiometry (DXA). Total plasma alkaline phosphatase (ALP) and plasma bone alkaline phosphatase (BALP), plasma osteocalcin (OC) and plasma collagen type I cross-linked C-telopeptide (CTX) were measured. RESULTS: BMD of the whole body and at the lumbar spine (L2-L4), femoral, lower limbs and LBM were significantly higher in young soccer players than in controls. The biochemical markers of bone turnover: ALP (6,7%), BALP (8,9%), OC (3%) and CTX (3,1%) were not significantly higher in sportsmen than in controls. The calcium was significantly higher in sportsmen than in controls. CONCLUSION: These results suggest that soccer practice induced an increase of bone mass in boys. The increase in the level of bone turnover evaluated by the new biochemical markers was not significant in the sportsmen.     

Effect of ovariectomy on BMD, micro-architecture and biomechanics of cortical and cancellous bones in a sheep model

Osteoporotic/osteopenia fractures occur most frequently in trabeculae-rich skeletal sites. The purpose of this study was to use a high-resolution micro-computed tomography (micro-CT) and dual energy X-ray absorptionmeter (DEXA) to investigate the changes in micro-architecture and bone mineral density (BMD) in a sheep model resulted from ovariectomy (OVX). Biomechanical tests were performed to evaluate the strength of the trabecular bone. Twenty adult sheeps were randomly divided into three groups: sham group (n=8), group 1 (n=4) and group 2 (n=8). In groups 1 and 2, all sheep were ovariectomized (OVX); in the sham group, the ovaries were located and the oviducts were ligated. In all animals, BMD for lumbar spine was obtained during the surgical procedure. BMD at the spine, femoral neck and femoral condyle was determined 6 months (group 1) and 12 months (group 2) post-OVX. Lumbar spines and femora were obtained and underwent BMD scan, micro-CT analysis. Compressive mechanical properties were determined from biopsies of vertebral bodies and femoral condyles. BMD, micro-architectural parameters and mechanical properties of cancellous bone did not decrease significantly at 6 months post-OVX. Twelve months after OVX, BMD, micro-architectural parameters and mechanical properties decreased significantly. The results of linear regression analyses showed that trabecular thickness (Tb.Th) (r=0.945, R2=0.886) and bone volume fraction (BV/TV) (r=0.783, R2=0.586) had strong (R2>0.5) correlation to compression stress. In OVX sheep, changes in the structural parameters of trabecular bone are comparable to the human situation during osteoporosis was induced. The sheep model presented seems to meet the criteria for an osteopenia model for fracture treatment with respect to morphometric and mechanical properties. But the duration of OVX must be longer than 12 months to ensure the animal model can be established successfully.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

PRIMARY OBJECTIVE: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition. RESEARCH DESIGN: Cross-sectional. SUBJECTS: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm(-2)) of <30. METHODS: BMD (gcm(-2)) of the spine (L2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA. RESULTS: There was no difference in age (NHC, 69.5+/-0.7; MA 69.5+/-0.9 years; mean +/- SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, gcm(-3)), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women. CONCLUSIONS: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Accuracy of high-resolution peripheral quantitative computed tomography for measurement of bone quality

The introduction of three-dimensional high-resolution peripheral in vivo quantitative computed tomography (HR-pQCT) (XtremeCT, Scanco Medical, Switzerland; voxel size 82 μm) provides a new approach to monitor micro-architectural bone changes longitudinally. The accuracy of HR-pQCT for three important determinants of bone quality, including bone mineral density (BMD), architectural measurements and bone mechanics, was determined through a comparison with micro-computed tomography (μCT) and dual energy X-ray absorptiometry (DXA). Forty measurements from 10 cadaver radii with low bone mass were scanned using the three modalities, and image registration was used for 3D data to ensure identical regions were analyzed.

The areal BMD of DXA correlated well with volumetric BMD by HR-pQCT despite differences in dimensionality (R² = 0.69), and the correlation improved when non-dimensional bone mineral content was assessed (R² = 0.80). Morphological parameters measured by HR-pQCT in a standard patient analysis, including bone volume ratio, trabecular number, derived trabecular thickness, derived trabecular separation, and cortical thickness correlated well with μCT measures (R² = 0.59–0.96). Additionally, some non-metric parameters such as connectivity density (R² = 0.90) performed well. The mechanical stiffness assessed by finite element analysis of HR-pQCT images was generally higher than for μCT data due to resolution differences, and correlated well at the continuum level (R² = 0.73).

The validation here of HR-pQCT against gold-standards μCT and DXA provides insight into the accuracy of the system, and suggests that in addition to the standard patient protocol, additional indices of bone quality including connectivity density and mechanical stiffness may be appropriate to include as part of a standard patient analysis for clinical monitoring of bone quality.     

Microstructural trabecular bone from patients with osteoporotic hip fracture or osteoarthritis: Its relationship with bone mineral density and bone remodelling markers

Osteoporosis (OP) and osteoarthritis (OA) are the most prevalent musculoskeletal disorders in the elderly but the relationship between them is unclear. The purposes of this study are to analyze the bone turnover markers (BTM), bone mineral density (BMD) and the structural and mechanical properties of trabecular bone in patients with OP and OA, and to explore the relationship between these two diseases. We studied 12 OP patients and 13 OA patients. We analyzed BTM (β-CrossLaps and PINP), BMD and microstructural and biomechanical parameters (micro-CT). Our results were: OP group has higher levels of β-CrossLaps and lower BMD at the femoral neck. Also, OP patients have a decreased volume of trabecular bone and less trabecular number, with architecture showing prevalence of rod-like trabeculae and worse connectivity than OA patients. The biomechanical parameters were worse in OP patients. BMD was correlated with almost all the structural and biomechanical parameters. Moreover, β-CrossLaps was negatively correlated with hip BMD and with bone surface density and positively with trabecular separation. BTM, BMD and bone microstructural changes in osteoporosis are opposite to those of OA. These findings justify a less resistant bone with higher risk of fragility fractures in OP patients. These histomorphometric and biomechanical changes may be suspected by measuring of BMD and β-CrossLaps levels.     

Can intraoperative measurement of bone quality help in decision making for cementless unicompartmental knee arthroplasty?

Background

In uncemented total hip arthroplasty (THA), low bone mineral density (BMD) is associated with aseptic loosening. BMD is usually assessed via dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography, which takes time and exposes patients to radiation. Due to its low risk profile, intraoperative measurement of the trabecular stability might be a useful alternative to DXA.

Early postmenopausal bone loss in hyperthyroidism.

OBJECTIVES: To evaluate the effect of hyperthyroidism on bone in relation to the menopausal state. METHODS: Fifty-nine hyperthyroid (HYPER), 40 hypothyroid (HYPO), and 51 control euthyroid (EUTH) women were studied. Bone mineral density (BMD) was assessed by dual X-rays absorptiometry (DXA) at the lumbar spine, and at the femoral neck. A multi-site QUS device evaluated speed of sound (SOS) at the radius (RAD), tibia (TIB), metatarsus (MTR), and phalanx (PLX). Bone markers used were serum bone specific alkaline phosphatase (BSAP) and urinary deoxypyridinoline (DPD). RESULTS: At all sites, SOS was lower in HYPER than in EUTH (RAD P<0.05, TIB P<0.01, MTR P<0.05, PLX P=0.01). The low SOS was only noted at the early postmenopausal period. BMD at the femoral neck but not at the lumbar spine was lower in HYPER as compared to EUTH (P<0.05). Both femoral neck and tibia were the sites with the highest odds ratio for being hyperthyroid (2.3 and 2.04, respectively). There was no correlation between BMD or SOS and FT(4), TT(3) or duration of hyperthyroidism. BSAP and DPD positively correlated with FT(4) and TT(3) (P<0.05). CONCLUSIONS: This study suggests that hyperthyroidism affects bone mineralization especially during the early postmenopausal period, and the effect is mainly at the cortical bone.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

Primary objective: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition.

Research design: Cross-sectional.

Subjects: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm^-2) of &lt; 30.

Methods: BMD (gcm^-2) of the spine (L_2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA.

Results: There was no difference in age (NHC, 69.5 ± 0.7; MA 69.5 ± 0.9 years; mean ± SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, g cm^?3), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women.

Conclusions: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Nonhuman anthropoid primate femoral neck trabecular architecture and its relationship to locomotor mode

Functional analyses of human and nonhuman anthropoid primate femoral neck structure have largely ignored the trabecular bone. We tested hypotheses regarding differences in the relative distribution and structural anisotropy of trabecular bone in the femoral neck of quadrupedal and climbing/suspensory anthropoids. We used high‐resolution X‐ray computed tomography to analyze quantitatively the femoral neck trabecular structure of Ateles geoffroyi, Symphalangus syndactylus, Alouatta seniculus, Colobus guereza, Macaca fascicularis, and Papio cynocephalus (n = 46). We analyzed a size‐scaled superior and inferior volume of interest (VOI) in the femoral neck. The ratio of the superior to inferior VOI bone volume fraction indicated that the distribution of trabecular bone was inferiorly skewed in most (but not all) quadrupeds and evenly distributed the climbing/suspensory species, but interspecific comparisons indicated that all taxa overlapped in these measurements. Degree of anisotropy values were generally higher in the inferior VOI of all species and the results for the two climbing/suspensory taxa, A. geoffroyi (1.71 ± 0.30) and S. syndactylus (1.55 ± 0.04), were similar to the results for the quadrupedal anthropoids, C. guereza (male = 1.64 ± 0.13; female = 1.68 ± 0.07) and P. cynocephalus (1.47 ± 0.13). These results suggest strong trabecular architecture similarity across body sizes, anthropoid phylogenetic backgrounds, and locomotor mode. This structural similarity might be explained by greater similarity in anthropoid hip joint loading mechanics than previously considered. It is likely that our current models of anthropoid hip joint mechanics are overly simplistic. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Body fat distribution is associated with lumbar spine bone density independently of body weight in postmenopausal women

Objective

To assess the association between the body fat distribution and axial bone mineral density (BMD) in postmenopausal women with or without hormone replacement therapy (HRT).

Design

Cross-sectional population-based study.

Setting

University of Eastern Finland, Bone and Cartilage Research Unit, Kuopio, Finland.

Population

198 postmenopausal women, mean age 67.5 (1.9 SD), mean BMI 27.1 (3.9 SD).

Methods

Regional body composition and BMD assessed by dual X-ray absorptiometry (DXA, Prodigy).

Main outcome measures

Spinal and Femoral BMD.

Results

Out of the body composition parameters, FM was the main determinant of postmenopausal bone mass. Only the lumbar spine (L2–L4) BMD, not the femoral neck BMD, was positively associated with the trunk FM. Positive trends for association were revealed between the spinal BMD and the trunk FM regardless of the use of HRT. Adjustments did not change the results.

Conclusions

Higher trunk fat mass was associated with the spinal BMD, but not with the hip BMD in postmenopausal women, irrespective of the HRT use. In addition to biological factors, uncertainties related to DXA measurements in patients with varying body mass may contribute to this phenomenon.     

Relationship between estrogen use and musculoskeletal function in postmenopausal women

OBJECTIVES: The purpose of this study was to examine the relationship between estrogen use and muscle strength, bone mineral density (BMD), and body composition variables in postmenopausal women. Forty healthy, untrained women participated in this study. Subjects (53-65 years) were > or =5 years postmenopausal and were categorized into either estrogen replacement therapy (ERT n=20) or non-estrogen replacement therapy (Non-ERT n=20) groups. METHODS: Muscular strength was measured by 1-RM testing using Cybex isotonic weight machines. Handgrip strength was measured using a handgrip dynamometer. Diagnostic Ultrasound was used to determine cross-sectional areas of the biceps brachii and rectus femoris muscle groups. BMD of the lumbar spine, proximal femur, and total body was assessed by Dual Energy X-Ray Absorptiometry (Lunar DPX-IQ). Body composition variables were obtained from the total body scan. Serum osteocalcin was measured as an indicator of bone remodeling. RESULTS: There were no significant differences (P>0.05) for isotonic muscular strength, muscle cross-sectional areas, handgrip strength, or percent fat between ERT and Non-ERT groups. ERT had significantly higher (P<0.05) BMD for the total body, femoral neck and Ward's Area. There were moderate positive relationships between lean body mass and the hip sites (r=0.61-0.70, P<0.05). Regression analyses determined that lean body mass was the strongest predictor of the hip BMD sites. Estrogen use also was a significant predictor for the femoral neck and Ward's Area sites. CONCLUSION: Women taking estrogen exhibited similar muscular strength, muscle size, and body composition as their estrogen-deficient counterparts. Estrogen use was also associated with higher BMD for the total body and hip sites. Generally, body composition, specifically lean body mass, influenced hip BMD more than muscular strength or estrogen use.     

Decreased bone mineral density in Costello syndrome

IntroductionCostello syndrome (CS) is a multisystemic disorder characterized by postnatal reduced growth, facial dysmorphism, cardiac defects, cognitive impairment, skin and musculo-skeletal anomalies, and predisposition to certain cancers. CS is caused by activating germline mutations in the HRAS proto-oncogene. Similar to what is observed in other RASopathies, CS causative HRAS mutations promote enhanced signal flow through the RAF–MEK–ERK and PI3K–AKT signaling cascades. While decreased bone mineralization has been documented in other RASopathies, such as neurofibromatosis type 1 and Noonan syndrome, systematic studies investigating bone mineral density (BMD) are lacking in CS.Materials and methodsDual-energy X-ray absorptiometry (DXA) was utilized to assess BMD and body composition (fat and fat-free mass) in a cohort of subjects with molecularly confirmed diagnosis of CS (n = 9) and age-matched control individuals (n = 29). Using general linear regression, subtotal body (total body less head), lumbar, femoral neck and femur BMD parameters were compared considering age, sex, body mass index (BMI) and Tanner stage. Blood and urine biomarkers of bone metabolism were also assessed.ResultsAll individuals with CS showed significantly lower mean values of subtotal, lumbar and femoral neck BMD compared to the control group (p ≤ 0.01). Similarly, mean total body mass and fat-free mass parameters were lower among the CS patients than in controls (p < 0.01). Low 25-OH vitamin D concentration was documented in all individuals with CS, with values below the reference range in two patients. No significant correlation between vitamin D levels and BMD parameters was observed.DiscussionCS belongs to a family of developmental disorders, the RASopathies, that share skeletal defects as a common feature. The present data provide evidence that, similar to what is recently seen in NF1 and NS, bone homeostasis is impaired in CS. The significant decrease in BMD and low levels of vitamin D documented in the present cohort, along with the risk for pathologic fractures reported in adult individuals with CS, testifies the requirement for a preventive treatment to alleviate evolutive complications resulting from dysregulated bone metabolism.     

伊班膦酸钠间断静脉输注治疗北京绝经后骨质疏松症的疗效

 目的 评价新一代双膦酸盐类药物伊班膦酸钠间断静脉输注对北京绝经后骨质疏松症的疗效及安全性。方法 研究纳入绝经后骨质疏松女性60例,年龄48~74岁,绝经年限3~32年,随机分为2组,治疗组每3个月静脉输注伊班膦酸钠2mg,对照组每周口服阿仑膦酸钠70mg,疗程12个月。疗效指标为腰椎及髋部骨密度（采用双能X线骨密度仪测量）、骨吸收指标血I型胶原羧基末端肽（酶联免疫吸附法测量）及骨形成指标碱性磷酸酶（自动分析仪酶法检测）。安全性指标包括血尿生化指标、心电图及不良反应。结果 59例患者完成研究。治疗12个月后,伊班膦酸钠组腰椎2-4、股骨颈及大转子骨密度增幅达6.3%,2.5%和0.1% (腰椎P <0.001,股骨颈P <0.01)。阿仑膦酸钠组腰椎、股骨颈及大转子骨密度改变率为 3.7%,4.9和-0.5% (腰椎和股骨颈P <0.001)。两组间治疗前后骨密度均无明显差别。伊班膦酸钠和阿仑膦酸钠治疗后ALP及CTX浓度均快速、显著下降,ALP降低15.8%和17.2%,CTX降低78.1%及43.2%（均P <0.001）。两组血钙磷水平、肝肾功能在正常范围内,伊班膦酸钠组常见的不良反应是首次输液后肌肉疼痛和低热,占26.7%,反酸、上腹不适是阿仑膦酸钠组主要的不良反应,占13.3%,患者可以耐受这些轻度的不良反应。结论 新一代双膦酸类药物伊班膦酸钠对于治疗绝经后骨质疏松症是安全而有效的。     

The association of proximal femur geometry with hip fracture risk

We aimed to discuss the risk assessments of patients with hip fractures due to the fall-related moderate or minimal trauma and compare them with non-fractured control patients by bone mineral density (BMD) and proximal femur geometric measurements to assess whether geometric measurements of femoral dimensions were associated with femoral strength and hip fracture risk. Forty-two osteoporotic patients with proximal femur fracture and 40 osteoporotic non-fractured age and gender-matched controls were included in the study. Lunar DXA was used for BMD measurements and proximal femur geometric measurements were performed manually on direct X-rays as hip axial length (HAL), femoral length (FL), and femoral neck width (FW). The trochanteric and total BMD values of the fracture group were significantly lower than the control group. There was a significant increase in FW/FL ratio in the fracture group that would be of specific importance for guidance: if FL values did not increase as did FW, it would point out a risk for fracture. The trochanteric BMD values were correlated with all increased measurements in the control group. There are genetically determined adaptive differences among individuals concerning bone morphology and bone mineral distribution. These different adaptations result in different bone strengths and fracture formation risk.