陕西地区股骨上段骨折风险阈值研究

目的 找出最佳的预测老年人群股骨上段骨折风险的方法.方法 利用双能X线吸收仪(DEXA)和其他工具,测量30具尸体骨右侧股骨上段的骨密度、几何形态以及股骨上段极限强度.然后,通过物理公式分析摔倒时股骨上段的受力情况.结果 (1)女性各项参数多数低于男性.(2)股骨颈骨密度与股骨上段载荷之间的相关性最佳(r2 =0.807),推导出预测股骨上段骨折风险回归方程.(3)股骨颈宽度与股骨上段极限强度的相关性较好.(4)推导出骨折风险阈值.结论 (1)陕西地区老年人股骨上段骨折发生率较低,与体型小导致摔倒时的暴力低有关.(2)股骨颈骨密度为较好的骨折风险预测指标.与几何形态结合可提高预测能力.(3)通过骨折风险阈值公式早期预防骨质疏松骨折的发生.     

Cortical and trabecular bone in the femoral neck both contribute to proximal femur failure load prediction

Summary  We examined the contributions of femoral neck cortical and trabecular bone to proximal femur failure load. We found that trabecular bone mineral density explained a significant proportion of variance in failure load after accounting for total bone size and cortical bone mineral content or cortical area. Introduction  The relative contribution of femoral neck trabecular and cortical bone to proximal femur failure load is unclear. Objectives  Our primary objective was to determine whether trabecular bone mineral density (TbBMD) contributes to proximal femur failure load after accounting for total bone size and cortical bone content. Our secondary objective was to describe regional differences in the relationship among cortical bone, trabecular bone, and failure load within a cross-section of the femoral neck. Materials and methods  We imaged 36 human cadaveric proximal femora using quantitative computed tomography (QCT). We report total bone area (ToA), cortical area (CoA), cortical bone mineral content (CoBMC), and TbBMD measured in the femoral neck cross-section and eight 45° regions. The femora were loaded to failure. Results and observations  Trabecular bone mineral density explained a significant proportion of variance in failure load after accounting for ToA and then either CoBMC or CoA respectively. CoBMC contributed significantly to failure load in all regions of the femoral neck except the posterior region. TbBMD contributed significantly to failure load in all regions of the femoral neck except the inferoanterior, superoposterior, and the posterior regions. Conclusion  Both cortical and trabecular bone make significant contributions to failure load in ex vivo measures of bone strength.

Cancellous bone microdamage in the proximal femur: influence of age and osteoarthritis on damage morphology and regional distribution

This study describes the in vivo distribution of cancellous bone microdamage in the proximal femur of an autopsy control sample. In addition, in vivo microdamage in the region medial to the greater trochanter of the proximal femur is compared between patients with severe osteoarthritis and controls. Taken at autopsy, the control group comprised normal right proximal femora that were then cut in the coronal plane with an Exakt saw (n = 12; aged 20–83 years). Cancellous bone samples were taken from the subchondral principal compressive region, the medial principal compressive region, and medial to the greater trochanter. A cancellous bone core biopsy was taken of the region medial to the greater trochanter (of the proximal femur) from patients with primary osteoarthritis undergoing total hip replacement surgery (n = 33; aged 37–85 years). Samples were embedded in resin, and in vivo microdamage identified in 70-μm-thick sections using the basic fuchsin en bloc staining technique. Microdamage was similar in all proximal femur sites in controls, except in the subchondral principal compressive region, where a significantly smaller crack length (μm) was identified (p < 0.05). In the region medial to the greater trochanter, osteoarthritic vs. control group comparisons showed that the crack density (#/mm²) and crack surface density (mm/mm²) were not significantly different, but crack length was significantly less (p < 0.03) and damage volume fraction was significantly increased for osteoarthritics (p < 0.005). The osteoarthritic and control data for crack density, and the osteoarthritic data for damage volume fraction, showed a nonlinear increase with age. Furthermore, crack length was not dependent on damage volume fraction or age for either the osteoarthritic or control group. This study identified differences in microdamage between osteoarthritic and autopsy control cases. We hypothesize that these results are consistent with the reported bone material property differences for osteoarthritis. In addition, the relatively uniform distribution of microdamage in the control group suggests that the principal components of the femoral cancellous bone network are equally exposed to deformations resulting in microdamage. Further study into the factors that influence the accumulation and skeletal distribution of microdamage is fundamental to understanding skeletal health.     

Feasibility of in vivo structural analysis of high-resolution magnetic resonance images of the proximal femur

Previously, high resolution MRI to assess bone structure of deep-seated regions of the skeleton such as the proximal femur was substantially limited by signal-to-noise ratio (SNR). With the advent of new optimized pulse sequences in MRI at 1.5 T and 3 T, it may now be possible to depict and quantify the trabecular microarchitecture in the proximal femur. The purpose of this study was to investigate the feasibility of assessing trabecular microstructure of the human proximal femur in vivo with MR imaging at 1.5 T and 3 T. MR images of six young, healthy male and female subjects were acquired using standard clinical 1.5-T and high-field 3-T whole-body MR scanners. Using a T2/T1-weighted 3D FIESTA sequence (and a 3D FIESTA-C sequence at 3 T to avoid susceptibility artifacts) a resolution of 0.234 × 0.234 × 1.5 mm³ was achieved in vivo. Structural parameters analogous to standard bone histomorphometry were determined in femoral head and trochanter regions of interest. Bone mineral density (BMD) measurements were also obtained using dual-energy X-ray absorptiometry (DXA) for the femoral trochanter in the same subjects. The bone structure of the proximal femur is substantially better depicted at 3 T than at 1.5 T. Correlation between the structural parameters obtained at both field strengths was up to R =0.86 for both the femoral head and the trochanteric region. However, the resolution of the images limits the application of 3D structural analysis, making the assessment more akin to 2D textural measures, which may be correlated to histomorphometric but are not identical measures. This feasibility study establishes the potential of MRI as a means of imaging proximal femur structure, and improvements in technique and resolution enhancements are warranted.     

股骨近端骨密度的测量

双能X线骨密度仪检测骨密度是诊断骨质疏松症和疗效随访的金标准,特别是髋部骨密度的测量对于骨折的预测尤其测定部位本身骨折的预测作用较大.由于脊柱部位的骨密度测量值易受到脊柱退行性疾病的病理改变如退行性侧凸、骨赘增生、腰椎间盘突出等影响,测量的准确性下降.因而近年来欧美国家临床试验也好或者骨质疏松诊疗也好,大都以股骨近端的BMD测定为标准.本文就股骨近端解剖特点、骨密度测量的意义、方法以及测量的注意点作一个综述,以期帮助临床医生或技术员全面评估股骨近端骨密度测定的意义.     

Differentiating between orchiectomized rats and controls using measurements of trabecular bone density: A comparison among DXA,Histomorphometry, and peripheral quantitative computerized tomography

In studies of rat bone metabolism, trabecular bone density should be measured. Three established methods of measuring trabecular bone include trabecular bone volume by histomorphometry (BV/TV%), trabecular bone density by peripheral quantitative computerized tomography (pQCT), and areal bone density of trabecular-rich regions by dual x-ray absorptiometry (DXA). We compared the ability of these three methods to discriminate between orchiectomized (orchidectomized) rats and controls. Sixteen male Sprague-Dawley rats (400–425 g) were orchiectomized, and 16 others were controls. In vivo spine bone mineral density (BMD) was measured at the beginning of the study and again after 11 weeks. Rats were sacrificed, and ex vivo BMDs of the right femur and tibia were measured by DXA, followed by trabecular bone density of the right proximal tibia by pQCT. BV/TV% of the left proximal tibia was measured by histomorphometry. Differences between groups were detected by all three methods, but both the magnitude of the difference between groups and the variance of the measurements was much greater for histomorphometry and pQCT than for DXA. Consequently, the statistical significance for the difference between groups was comparable for all three methods. Of the sites measured with DXA, the proximal tibia had the greatest statistical significance for the difference between groups. In summary, all three methods can demonstrate the effect of orchiectomy on trabecular bone. The large differences between groups seen by histomorphometry are also seen by pQCT but not by DXA. We conclude that trabecular bone density by pQCT may be a reasonable surrogate for measurements by histomorphometry.Portions of the data presented here were presented at the 16th Annual Meeting of the American Society for Bone and Mineral Research, Kansas City, Missouri, September 30-September 9–13, 1994.     

Epidemiology of fractures of the proximal femur in Geneva: Incidence,clinical and social aspects

Fracture of the proximal femur (hip fracture) as a consequence of osteoporosis is an important public health problem. Its incidence, which rises with age, varies according to geographical location and race. There is no information concerning hip fracture in Switzerland, which is a Western country with a particularly aged population. During 1987, 361 patients with hip fracture were recorded in the University of Geneva Hospital, which is the main referral center for a population of about 376000 inhabitants. This represented 94% of all hip fractures occurring in the region. A moderate trauma was reported in 329 cases (91.1%). The overall annual incidence was 96.1 per 100000 population (146.9 for women and 39.8 for men). When only hip fractures following moderate trauma were considered, the incidence was 87.6 per 100000 population (138.8 for women and 30.8 for men). Rare under the age of 65, hip fracture incidence increased exponentially in older subjects. The mean age of patients with hip fracture was 82.0 years in women and 75.7 years in men. The ratio of cervical to trochanteric fracture was 1.03 and 1.12 in women and men, respectively. The mean length of stay in the orthopaedic ward was 30.5 days, and the total costs amounted to 8.8 million Swiss francs for hip fracture associated with moderate trauma. Forty-seven percent of subjects were transferred to another hospital for recovery or rehabilitation. During the stay in the orthopaedic ward, the mortality rate was 8.2%. These results emphasize the high incidence and cost of hip fractures in a region of Switzerland where the population is particularly old. The problem could even worsen with the progressive aging of the population.     

A biomechanical study comparing proximal femur nail and proximal femur locking compression plate in fixation of reverse oblique proximal femur fractures

BackgroundThe reverse oblique trochanteric fractures are common fractures and its treatment poses a challenge. The purpose of this study was to compare the biomechanical parameters of the construct using proximal femoral nail (PFN) and proximal femoral locking compression plates (PFLCP) in these fractures using cadaveric specimens.Materials and MethodsTwenty freshly harvested cadaveric femoral specimens were randomly assigned to two groups after measuring bone mineral density, ten of which were implanted with PFN and the other ten with PFLCP. The constructs were made unstable to simulate reverse oblique trochanteric fracture (AO type 31A3.3) by removing a standard size posteromedial wedge. These constructs were tested in a computer controlled cyclic compressive loading with 200 kg at a frequency of 1 cycle/s (1 Hz) and test was observed for 50,000 cycles or until implant failure, whichever occurred earlier. Peak displacements were measured and analysis was done to determine axial stiffness and subsidence in axial loading.ResultsAll the specimens in PFN group completed 50,000 cycles and in PFLCP group, seven specimens completed 50,000 cycles. Average subsidence in PFN group was 1.24 ± 0.22 mm and in PFLCP group was 1.48 ± 0.38 mm. The average stiffness of PFN group (72.6 ± 6.8 N/mm) was significantly higher than of PFLCP group (62.4 ± 4.9 N/mm) (P = 0.04). The average number of cycles sustained by PFLCP was 46634 and for PFN group was 50,000 (P = 0.06).ConclusionThe PFN is biomechanically superior to PFLCP in terms of axial stiffness, subsidence and number of specimens failed for the fixation of reverse oblique trochanteric fractures of femur.     

Preferential low bone mineral density of the femoral neck in patients with a recent fracture of the proximal femur

Bone mass is an important determinant of resistance to fractures. Whether bone mineral density (BMD) in subjects with a fracture of the proximal femur (hip fracture) is different from that of age-matched controls is still debated. We measured BMD of the femoral neck (FN) on the opposite side to the fracture, as well as femoral shaft (FS) and lumbar spine (LS) BMD by dual-photon absorptiometry in 68 patients (57 women and 11 men, mean age 78.8±1.0) 12.4±0.8 days after hip fracture following a moderate trauma. These values were compared with BMD of 93 non-fractured elderly control subjects (82 women and 11 men), measured during the same period. As compared with the controls, FN BMD was significantly lower in fractured women (0.592±0.013 v. 0.728±0.014 g/cm²,P<0.001) and in fractured men (0.697±0.029 v. 0.840±0.052,P<0.05). Expressed as standard deviations above or below the mean BMD of age and sex-matched normal subjects (Z-score), the difference in FN BMD between fractured women and controls was highly significant (–0.6±0.1 v. +0.1±0.1,P<0.001). As compared with mean BMD of young normal subjects, BMD was decreased by 36.9±1.4 and 22.4±1.5% (P<0.001) in fractured and control women, respectively. There was no significant difference between FN BMD of 33 women with cervical and 24 with trochanteric hip fractures (0.603±0.017 v. 0.577±0.020). FN BMD was lower than 0.705 g/cm² in 90% of fractured women. The prevalence of fracture increased with decreasing FN BMD, reaching 100% with values below 0.500 g/cm². FS and LS BMD were significantly lower in women with hip fracture than in controls (1.388±0.036 v. 1.580±0.030,P<0.001, for FS, and 0.886±0.027 v. 0.985±0.023,P<0.01, for LS), but these differences were not significant when expressed as a Z-score. In men with a recent hip fracture, FS BMD was significantly lower than in controls (1.729±0.096 v. 2.069±0.062,P<0.01), but the difference at the LS level did not reach statistical significance. These results indicate that both women and men with a recent hip fracture had decreased bone mineral density of the femoral neck, femoral shaft and lumbar spine. However, the difference appeared to be of higher magnitude for the femoral neck suggesting a preferential bone loss at this site.     

Epidemiological study on the bone mineral density of inhabitants in Miyama Village, Wakayama prefecture (Part II) bone mineral density of the spine and proximal femur

Reference values of bone mineral density (BMD) have mainly been based on hospital volunteers in Japan. Consequently, these values may be inappropriate for the use as a standard in the osteoporotic study. In order to establish reference values, BMD was measured of 400 age-stratified inhabitants of Miyama Village, utilizing dual energy x-ray absorptiometry (DEXA). The mean BMD of L2–L4 in males in each age group was 1.19±0.16 g/cm² (mean±standard deviation) in 40's, 1.15±0.19 g/cm² in 50's, 1.03±0.18 g/cm² in 60's and 1.06±0.25 g/cm² in 70's. The difference of BMD was statistically significant between the 50 and 60 age groups. On the other hand, in females the mean BMD of L2–L4 was 1.18±0.16 g/cm² in 40's; 0.99±0.18 g/cm² in 50's, 0.84±0.19 g/cm² in 60's and 0.78±0.17 g/cm² in 70's. The BMD was significantly lower in the 50 age group than in the 40 age group and was similarly lower in the 60 age group than in the 50 age group.     

The discriminative ability of peripheral and axial bone measurements to identify proximal femoral, vertebral, distal forearm and proximal humeral fractures: a case control study

Previous studies evaluating peripheral bone measurement devices have often used discontinued technologies, compared single devices, only evaluated a single fracture syndrome or failed to make a comparison with central densitometry, which is currently the gold standard for fracture discrimination. We have used a case control study to evaluate the ability of different peripheral and central bone techniques to discriminate between fracture cases and controls, determine the impact of different measurement sites, evaluate the role of measuring the cortical or trabecular envelopes using quantitative computed tomography (QCT) and determine the impact of using combinations of sites and techniques on fracture discrimination. We recruited postmenopausal women with proximal femoral (n=53), vertebral (n=73), distal forearm (n=78) or proximal humeral (n=75) fractures, and 500 population-based women (age 55-80 years). All subjects had measurements of the spine, total hip and distal forearm with dual-energy X-ray absorptiometry (DXA), distal forearm QCT and quantitative ultrasound (QUS) of the heel (four devices), finger (two devices), radius and metatarsal. The association of each device with fracture was expressed as the age-adjusted standardized odds ratios (sOR) per 1-SD decrease of population variance. The association of bone measurements with fracture was site-specific. We found the hip (sOR up to 3.40) and vertebral (sOR up to 4.67) fractures were more closely associated with central bone measurements than upper limb fractures (sOR 1.96 and 2.05). The performance of heel broadband ultrasound attenuation (sOR 2.09-2.41), heel speed of sound (sOR 1.79-2.28) and peripheral BMD (sOR 2.07 and 2.24) was comparable with total hip (sOR 2.46) and lumbar spine DXA (sOR 2.31) in discriminating all types of osteoporotic fracture. In general, measuring cortical or trabecular envelopes did not increase sOR. However, combining different measurement sites or technologies provided additional information, which was independent of total hip BMD. The ability of different bone measurements to discriminate between fracture cases and controls is device- and site-specific, with additional information obtained by combining measurement sites and technologies.     

Relationships between T-scores at the hip and bone mineral density at the distal femur and proximal tibia in persons with spinal cord injury

Objective: To identify T-score values at the total hip (TH) and femoral neck (FN) that correspond to the cutoff value of <0.60?g/cm² for heightened risk of fracture at the distal femur (DF) and proximal tibia (PT).

Design: Retrospective analysis of data in a research center’s database.

Setting: Community-based individuals with spinal cord injury (SCI).

Participants: 105 unique individuals with SCI.

Outcome Measurements: DXA derived areal BMD (aBMD) and T-score of the DF, PT, TH, and FN.

Results: The aBMD at the DF and PT regions were predictors of T-scores at the TH (R ²?=?0.63, P?<?0.001 and R ²?=?0.65, P?<?0.001) and FN (R ²?=?0.55, P?<?0.001 and R ²?=?0.58, P?<?0.001). Using the DF and PT aBMD of 0.60?g/cm² as a value below which fractures were more likely to occur, the predicted T-score was ?3.1 and ?3.5 at the TH and ?2.6 and ?2.9 at the FN, respectively. However, when the predicted and observed T-score values disagree outside the 95% limit of agreement, the predicted T-score values are lower than the measured T-score values, overestimating the measured values between ?2.0 and ?4.0 SD.

Conclusion: The DF and PT cutoff value for aBMD of 0.60?g/cm² was a moderate predictor of T-score values at the TH and FN, with considerable inaccuracies outside the clinically acceptable limits of agreement. As such, the direct measurement of knee aBMD in persons with SCI should be performed, whenever possible, prior to prescribing weight bearing upright activities, such as robotic exoskeletal-assisted walking.     

容积性定量CT测量股骨近端骨密度准确性研究

目的通过分别对比容积性定量CT(vQCT)、双能X射线吸收法(DXA)与灰化法测量股骨近端骨密度结果,确定并对比相关性,进行指导临床骨质疏松诊断及治疗。方法选取20个尸体股骨近端标本,先使用DXA骨密度仪扫描,测得骨矿含量(BMC)及骨密度(BMD)。再对标本相同部位行64层螺旋CT扫描,数据导入OsteoCAD软件自动分析得出骨密度值。应用灰化法得出标本灰质量密度。所有资料进行统计分析分别确定并对比vQCT及DXA测量的骨密度值与灰密度之间的相关性。结果vQCT测量股骨颈骨密度与灰质量密度线性相关性较好(r=0.852,P0.01),DXA与灰质量密度的相关性略差(r=0.807,P0.01)。结论vQCT测得的骨密度较DXA与灰质量密度线性相关性更好,可靠性高,对于诊断骨质疏松,预测骨质疏松性骨折,评价、指导骨质疏松骨折手术更有应用价值。     

Mean wall thickness and formation periods of trabecular bone packets in idiopathic osteoporosis

Summary The mean wall thickness (MWT) and duration of formation periods (sigma_f) of trabecular bone packets have been measured in iliac crest biopsies following double tetracycline labeling from 9 women having primary osteoporosis, with vertebral crush fractures and reduced trabecular bone volume (TBV), and 9 age- and sex-matched controls. The MWT of the osteoporotic biopsies was significantly less than that of the controls and was negatively correlated with age in the latter. There was also a positive correlation between MWT and TBV in the controls but not in the osteoporotics. Sigma_f, in days, showed a tendency to decline with age in the control biopsies and was further decreased in the osteoporotic patients. These results suggest that a major contribution to the negative skeletal balance existing in both primary osteoporosis and physiological osteopenia is a decrease in bone formation, caused by a reduction in the life span of the osteoblastic population at the basic multicellular unit (BMU) level.     

绝经后女性股骨近端骨密度与骨质疏松性骨折相关性研究

目的：研究绝经后女性股骨近端骨密度的变化规律与骨质疏松症、骨质疏松性骨折间的关系。方法采用法国Medlink公司Osteocore 3型双能X线骨密度仪,对本地区417例绝经后女性股骨颈、大转子、粗隆间、全髋进行骨密度测定。结果骨折组各年龄段、各部位的BMD均比非骨折组低（ P＜0．05）。随着年龄的增长,股骨近端骨量逐渐丢失,除了45～50组,其余各年龄段骨折组的患病率明显高于非骨折组（ P＜0．05）,骨密度值越低,骨折危险性越大。结论绝经后女性股骨近端骨密度与发生骨质疏松性骨折的风险呈明显负相关性,应该注意预防。     

Reduced bone perfusion in proximal femur of subjects with decreased bone mineral density preferentially affects the femoral neck

Using dynamic contrast enhanced MR imaging, this study investigated perfusion of the proximal femur in subjects with normal BMD, low bone mass and osteoporosis. Study cohort comprised healthy elderly Hong Kong Chinese volunteers consisting of 107 males (74.4 ± 4.2 years, mean ± SD) and 135 females (73.9 ± 4.3 years). Right proximal femur BMD measurement by DXA and MR perfusion imaging (maximum enhancement, E^max and enhancement slope, E^slope) of the femoral head, neck, and proximal shaft were carried out within a one month interval. Normal BMD, low bone mass and osteoporotic subjects accounted for 46.7%, 44.9%, and 8.4% of males; and 32.6%, 43.7%, and 23.7% of females. Perfusion indices showed that femoral head perfusion was less perfused compared to the femoral shaft (E^max and E^slope indices of head region = 28% of shaft region). Compared with normal BMD subjects, E^max of femoral head, neck, and proximal femur shaft were reduced by 15 ± 5% (mean ± standard error); 40 ± 4%; 15 ± 5% respectively for low bone mass subjects, and 36 ± 4%; 50 ± 6%; 47 ± 6% respectively for osteoporotic subjects. E^slope of femoral head, neck, and proximal femur shaft were reduced by 17 ± 7%; 41 ± 5%; 4 ± 7% for low bone mass subjects and 50 ± 5%, 62 ± 5%, 34 ± 8% for osteoporotic subjects. In low bone mass and osteoporotic subjects there was a tendency for perfusion in the femoral neck to reduce to a greater degree relative to that in the femoral head and shaft.     

The hidden blood loss in proximal femur fractures is sizeable and significant

BackgroundPatients sustaining hip fractures experience blood loss as a direct result the fracture independent of surgery. The objective of this study was to quantify the expected non-surgical blood loss for proximal femur fractures using hemoglobin values.MethodsA retrospective chart review of patients at a level 1 trauma center sustaining proximal femur fractures between October 2015 and January 2018 was performed. Patients were ≥30 years of age, had sustained intertrochanteric, subtrochanteric, or femoral neck fractures and had hemoglobin values documented at admission and after 12 h but before surgery. Patients with concomitant fractures, other hemorrhagic injuries, or blood transfusions before their second hemoglobin result were excluded. A multivariate linear regression model was constructed to evaluate the predictive ability of age, sex, BMI, number of comorbidities, fracture type, anticoagulation/antiplatelet therapy, admission hemoglobin, timing of surgical intervention and changes in electrolyte levels on subsequent hemoglobin values. Hemoglobin changes were compared between intertrochanteric, subtrochanteric, and femoral neck fractures and anticoagulant therapy types with Welch’s tests.Results119 patients were included. The mean age was 80.9 ± 10.81 years. Nearly 53% of subjects were using anticoagulation therapy. The mean drop in hemoglobin was 1.4 ± 1.03 g/dL. The multivariate linear regression model had statistically significant predictive ability (R = 0.91, p < 0.001). Independent predictors of hemoglobin decrease were number of comorbid conditions (p = 0.02), admission hemoglobin reading (p < 0.001), fracture type (p = 0.02), and time from admission to surgery (p = 0.03). Intertrochanteric fractures demonstrated the largest hemoglobin drops. Anticoagulation therapy had no effect on subsequent hemoglobin.ConclusionProximal femur fractures cause a significant amount of blood loss prior to surgical intervention. Patients at particular risk include those with comorbidities, intertrochanteric fractures, low admission hemoglobin values, and increased time to surgery. The identification of demographic, fracture type, and treatment characteristics may help surgeons identify patients at the greatest risk for blood loss, and provide more effective perioperative care.     

Dual photon absorptiometry of the proximal tibia

Summary Bone mineral content (BMC) and bone mineral density (BMD) of the proximal tibia were determined by dual photon absorptiometry on 44 women, aged 23–87 years. The area of the tibia measured was a 2.01 cm region immediately distal to the medial and lateral tuberosities. Values of BMC ranged between 5.09 and 14.57 g and BMD between 0.380 and 1.180 g/cm². Both tibial BMC and BMD declined with age and tibial BMD was significantly correlated with lumbar spine (r=0.70), femoral neck (r=0.73), and femoral trochanter (r=0.74). However, the large standard errors of estimate (SEE) (0.08–0.14 g/cm²) do not allow for reliable prediction in an individual of other skeletal sites by the tibia. Repeated measurements demonstrated that dual photon absorptiometry of the proximal tibia is a reliable measurement and may be a useful tool in the monitoring of therapeutic or intervention modalities in those individuals with skeletal diseases in whom measurement of the lumbar spine or proximal femur may not be possible.     

The effects of menopause on longitudinal bone loss from the spine

Summary Two hundred and thirty women aged 45–66 years were divided into three groups according to their menopausal status and were followed to assess the changes in vertebral bone mineral density (BMD). These included 71 premenopausal, 42 perimenopausal, and 117 postmenopausal women. Menopausal status was assessed through menstrual history and plasma concentrations of 17 estradiol and luteinizing hormone. BMD was measured by dual photon absorptiometry between 2 and 5 times over an average period of 27 months, and annual rates of changes were calculated by linear regression. BMD decreased significantly (P<0.0001) in the three groups during the follow-up. Mean (±SD) annual rate of change was-0.79±1.5% for premenopausal,-2.35±1.5% for perimenopausal, and-1.24±1.5% for postmenopausal women. There was no difference in the rates of bone loss between the perimenopausal group and the postmenopausal group within 3 years after menopause (1–2 years:-2.34±2.1%; 2–3 years:-1.9±1.5%). Thereafter, rates decreased exponentially with time since menopause to fall out at the same level as the premenopausal level. These longitudinal data indicate that vertebral bone loss begins before menopause and accelerates sharply during menopause to decline exponentially with time after 3 years.     

绝经后骨质疏松症对股骨近端的生物学影响

骨质疏松症是一种以系统骨量、骨强度及骨微结构损害为特征常导致骨折风险增加的疾病,是绝经后妇女常见且严重的情况。骨质疏松症在骨折发生前大多是一种隐性疾病,存在着检测和治疗不足的情况。而骨质疏松性骨折的发生常导致疼痛、畸形、活动障碍,对患者的生活质量造成严重影响。绝经后骨质疏松症是一种好发于中老年女性的全身性骨骼系统疾病。众所周知,雌激素是一种维持正常骨量的重要保护因素。绝经后妇女体内雌激素水平的降低与骨量的迅速流失密切相关。在妇女绝经之后,骨重建增加,内在的不平衡加速了骨质流失,最终导致骨质疏松症的形成。干预绝经后骨质疏松症的最主要的目的是防止骨折。最常发生骨质疏松性骨折的部位是椎体(脊柱)、股骨近端(髋部)及前臂远端(腕部)。其中,髋部骨折是骨质疏松症最严重的后果,往往导致重大残疾和过早死亡。鉴于绝经后骨质疏松症的特殊性及髋部骨折的严重性,系统全面地了解绝经后骨质疏松症对股骨近端的影响显得尤为重要。