Differential Changes in Regional Bone Mineral Density in Healthy Chinese: Age-Related and Sex-Dependent

To investigate the pattern of age-related and sex-dependent bone mineral density (BMD) changes in the six skeletal regions in healthy Chinese, total-body and regional BMD were measured by dual-energy X-ray absorptiometry (DXA) in 310 women and 387 men aged 20-80 years. In women, a five-phase change was discernible in the axial bones: (1) gradual bone increase from 20-29 years old to maximal BMD at 35-39 years old; (2) maintenance of this level from 35-39 to 40-44; (3) a mild bone decrease from 40-44 to 45-49; (4) a rapid bone decrease from 45-49 to 55-59; and (5) a decelerated bone decrease after 55-59 years old. After validation of menopause status, the decrease of BMD in the late 40s became insignificant in premenopausal women. In appendicular bones, no obvious peak was observed, and significant bone decrease started at 50-54 years old. The overall bone decrease from 35-39 to 70-80 years old was 19.3% for the total body, 16.4% for the head, 29% for the spine, 23% for the pelvis, 18.2% for the ribs, 23.9% for the arms, and 20.4% for the legs. In men, the maximal bone mass was attained at 30-34 and 35-39 years old for axial and appendicular bones, respectively. The age-related bone decrease in the skeletal regions was small, except from 60-64 to 65-69 years old. The overall bone decrease in each region from maximal bone mass to 70-80 years old was 6.7% for the total body, 1.7% for the head, 7.6% for the spine, 11.3% for the pelvis, 9.5% for the ribs, 7.8% for the arms, and 10.4% for the legs. The overall magnitude of reduction in total-body BMD in women was about three times greater than that in men. The pattern of BMD changes differs in each region and is age-related as well as sex-dependent. There appeared to be no significant premenopausal bone decrease.     

Age-Related Cancellous Bone Loss in the Proximal Femur of Caucasian Females

The purpose of this investigation was to directly define the age-related intrafemoral variations in cancellous bone density, bone mineralization and rate of bone loss in a cadaveric population of Caucasian female femoral necks and trochanters. Forty-three Caucasian female femora were obtained and divided into premenopausal, postmenopausal and elderly age groups. The neck and trochanter were removed, and cores of cancellous bone were taken from the superior, middle and inferior regions; volume fraction and ash fraction were determined for each core. The cancellous bone volume fraction of the neck was significantly greater than that of the trochanter, as was that of the inferior region of the neck compared with the superior and middle regions at all age groups (p<0.05). The mean neck/trochanter and neck inferior/superior volume fraction ratios did not change with age; however, the variance increased with age (p<0.001). This increasing variability with age suggests that there may be a subpopulation of individuals within the elderly Caucasian population with a significantly different intrafemoral bone density distribution than was present prior to menopause. This study identified no mineralization changes with age in the cancellous bone of the proximal femur (p>0.05). The influence of increased neck/trochanter and neck inferior/superior ratios on femoral neck integrity and fracture prediction is of interest and requires further investigation. Received: 8 April 1999 / Accepted: 18 October 1999     

Ageing Effects on 3-Dimensional Femoral Neck Cross-Sectional Asymmetry: Implications for Age-Related Bone Fragility in Falling

This paper explores the effects of aging on femoral neck (FN) anatomy in a study of women aged 20–90years in relation to implications for FN fracture propensity in buckling. Five hundred and four participants were scanned by Quantitative Computed Tomography and analyzed using Quantitative Computed Tomography Pro BIT (Mindways). FN cross-section was split through geometric center into superior and inferior sectors. Bone mass, structural measurements, and bone mineral density were analyzed. Buckling ratio was calculated as ratio of buckling radius to cortical thickness. Between 2nd decade and 8th decade, age-related integral bone mass reduction in superior sector was substantially larger than in inferior sector (33% compared to 21%), especially in cortical bone superiorly compared to inferiorly (53% vs 21%; p < 0.001), principally due to reduction in cortical thickness, averaged cortical thickness (56%) with little difference in density. Superior and inferior sector trabecular bone mineral density reduction was similar at 41% and 43% respectively. Differential cortical bone loss in superior sector resulted in a 59% inferior displacement (δ) of center-of-mass from geometric center. Differences in δ and averaged cortical thickness with age accounted for a 151% increase in mean superior buckling ratio from 9 to 23. Analysis confirms significant progressive age-related superior cortical bone loss as the major age effect on FN structure with relative preservation of inferior cortex probably related to maintenance of inferior sector by regular loading as a result of standing and walking. Computation of buckling ratio may allow prediction of fracture propensity in a sideways fall.     

Age-Related Changes in Femoral Trabecular Bone in Arthrosis

Age-related changes in the cancellous bone in selected regions of the proximal femur and iliac crest were assessed. An arthrosis group and a control cadaver group, partitioned into subjects younger and older than aged 50 years, were compared. The control group comprised 69 heads of femur and iliac crest samples. The arthrosis group comprised 28 consecutive heads of femur affected by primary arthrosis and an iliac crest biopsy taken during hip arthroplasty.

Cancellous bone was sampled from four selected regions in the proximal femur. Histomorphometric estimates of percentage bone volume were determined using image analysis. In the young controls the bone volume was higher than that in the old controls for all the regions. In the arthrosis group the bone volume was higher than that of the old controls except for the subchondral principal tensile and medial to the greater trochanter regions.

The old controls had regression of bone volume on age for the subchondral and medial principal compressive regions and the iliac crest. The arthrosis group had a minimal dependence of bone volume on age.

Our study showed that primary arthrosis modulates the age dependence of bone volume in the proximal femur.     

Age-Related Changes in the Biochemical Properties of Human Cancellous Bone Collagen: Relationship to Bone Strength

The metabolism of bone collagen has received little attention in relation to age-related loss of bone mass and strength. The aim of the present study was to analyze bone collagen content and metabolism in human bone with respect to age. The material consisted of iliac crest bone biopsies from 94 individuals: 46 women (ages 18–96, mean age 60.8 years) and 48 men (ages 23–92, mean age 59.5 years). Excluded from the study were all individuals with known osteoporotic lumbar vertebral fractures and renal, hepatic, or malignant diseases. Prior to collagen analysis the biopsies were scanned in a pQCT scanner for density assessment and then tested biomechanically. The results showed a decline in apparent bone density with age (P < 0.0001), a decline in maximum stress, Young's modulus, and energy absorption with age (P < 0.001). Concomittantly, there was an age-related decline in the intrinsic collagen content with age (P < 0.001). However, there were no biochemical modifications of the bone collagen during aging. There were no significant differences between women and men in the slopes of the regressions-curves. When multiple regression analyses were performed, only apparent bone density came out as a significant contributor in the correlation to biomechanical properties. Nevertheless, the decrease in bone collagen content with age might indicate an increase in the mineralization degree (probably due to decreased bone turnover) and thereby a change in material properties of bone. In conclusion, the present study has shown that loss of bone mass plays the major role in loss of bone strength. However, there is also a change in bone composition during normal aging, leading to a decrease in collagen content and an increase in the degree of mineralization. At this skeletal site, in a normal population there was no change in the biochemical properties of bone collagen. Received: 3 November 1998 / Accepted: 12 March 1999     

Age-Related Changes in Collagen Properties and Mineralization in Cancellous and Cortical Bone in the Porcine Mandibular Condyle

Collagen is an important constituent of bone, and it has been suggested that changes in collagen and mineral properties of bone are interrelated during growth. The aim of this study was to quantify age-related changes in collagen properties and the degree of mineralization of bone (DMB). The DMB in cancellous and cortical bone samples from the mandibular condyle of 35 female pigs aged 0–100 weeks was determined using micro-computed tomography. Subsequently, the amount of collagen and the number of pentosidine (Pen), hydroxylysylpyridinoline (HP), and lysylpyridinoline (LP) cross-links were quantified by means of high-performance liquid chromatography. The amount of collagen increased with age in cancellous bone but remained unchanged in cortical bone. The number of Pen and LP cross-links decreased in both bone types. In contrast, the number of HP cross-links decreased only in cancellous bone. The sum of the number of HP and LP cross-links decreased with age in cancellous bone only. The DMB increased in cancellous and cortical bone. It was concluded that the largest changes in the number of mature collagen cross-links and the mineralization in porcine cancellous and cortical bone take place before the age of 40 weeks. The low number of mature cross-links after this age suggests that the bone turnover rate continues to be high and thereby prevents the development of mature cross-links.     

Mechanical Property Distributions in the Cancellous Bone of the Human Proximal Femur

Proximal femurs obtained at routine autopsy were sectioned into large numbers of 5 mm cubic specimens, in order to obtain detailed quantitative information about the spatial and directional variations of the material properties of the cancellous bone. Low strain rate compression tests were performed, evaluating the apparent elastic modulus and yield strength, in three perpendicular testing directions, for each cube. A computer contouring program was used to assemble the experimental data into smoothed distribution plots across sections of interest.

The results revealed stiffness and strength elevations/reductions which clearly correspond to roentgenographic features. Especially prominent stiffness elevations (160 to 400 percent above the overall cancellous bone average) were found in the regions traversed by the primary trabeculation system, although the modulus of the bone samples was substantially reduced when measured in directions other than those of habitual weight-bearing. Similar but less pronounced effects were observed for the arcuate trabeculation system. Conversely, Wards triangle and the intertrochanteric regions exhibited significant (as much as 40 to 90 percent below average) stiffness and strength reductions.

There was close qualitative agreement between the stiffness and yield strength distributions for all sections examined. This phenomenon was found to be a corollary of the remarkably linear proportionality between the modulus and yield strength values for individual compression tests.     

Quantitative Radiographic Assessment of Cancellous Bone Changes in the Proximal Tibia After Total Knee Arthroplasty: a 3-year Follow-up Study

The objective of this study was to determine whether fractal signature analysis (FSA) of digitized macroradiographs of knees with prosthetic implants quantifies alterations in tibial trabecular structure surrounding the implant over a 3-year period. Nineteen knees (16 patients) with arthroplasty had macroradiographs (×4) at baseline and annually for 3 years. The regions of interest (ROIs) were located in the medial and lateral plateau, midstem, and apical sites. FSA of horizontal and vertical trabecular organization was measured at each ROI, and the changes at the yearly visits were compared to the baseline values. Compared to the baseline values, FSA of the first-year radiographs detected a significant (P < 0.05) decrease in the number of vertical trabeculae in the medial compartment, and vertical, and horizontal trabeculae in the lateral compartment. During the second year, bone remodeling led to an increase in the number of horizontal trabeculae in the medial compartment, and vertical, and horizontal trabeculae in the lateral compartment. During the third year, there was a significant increase (P < 0.05) in the number of vertical and some horizontal trabeculae in both the medial and lateral compartments. Overall trabecular changes were significantly greater in the lateral than in the medial compartment. Following total knee arthroplasty, the response of bone showed that the first year was characterized by trabecular loss in response to posttraumatic osteopenia following surgery. By the third year, this process had reversed, with a significant increase in mainly vertical and some horizontal trabeculae in both the medial and lateral compartments, with only the lateral compartment showing an overall loss in small- and medium-sized trabeculae by the end of the study period.     

Stereologic Analysis of Tibial-Plateau Cartilage and Femoral Cancellous Bone in Guinea Pigs With Spontaneous Osteoarthritis

Background  

Two strains of guinea pig develop spontaneous osteoarthritis of the knee. Although the disease evolves at different rates in the two strains, it is not known whether these differences are reflected in the structure of the cartilage and cancellous bone.     

股骨近端解剖型钢板治疗股骨粗隆间骨折

目的探讨股骨近端解剖型钢板治疗股骨粗隆间骨折的临床疗效。方法自2000年1月至2005年1月，采用切开复位，股骨近端解剖型钢板治疗股骨粗隆间骨折36例，根据术前、术后X线片及术后髋关节功能恢复情况评价内固定效果。结果术后随访6个月～3年，平均18个月，所有病例均在术后3～5．5个月获得骨性愈合，髋关节功能根据Harris评分标准进行评定，优32例，良4例。结论股骨近端解剖型钢板适用于治疗大多数类型的股骨粗隆间骨折，能达到良好的骨折复位和坚强的固定，促进关节早期功能锻炼，骨折愈合率高，是治疗股骨粗隆间骨折的理想选择。     

椎体骨折及愈合的磁共振成像

目的：松质骨骨折及愈合用Ｘ线平片诊断较困难，本文探讨ＭＲＩ对松质骨骨折及愈合的诊断价值。材料与方法：创伤后不同时间的６３例７５个椎体骨折进行ＭＲＩ检查，对骨折区骨髓信号进行分类对照研究。结果：骨髓创伤后信号分为Ⅰ型（水肿型）、Ⅱ型（不均匀型）、Ⅲ型（复原型）和Ⅳ型（脂肪型）。Ⅰ型提示骨髓水肿和急性出血；Ⅱ型与骨折创伤区肉芽组织、小血肿或微骨痂混杂有关，提示骨折修复早期；Ⅲ型信号提示骨髓腔已复原，骨折修复；Ⅳ型骨髓内脂肪细胞增多，与创伤性缺血有关。结论：骨髓ＭＲＩ信号变化对松质骨骨折愈合判断有意义。     

Effect of Estrogen Deficiency on Cancellous and Cortical Bone Structure and Strength of the Femoral Neck in Rats

Eighty mature Sprague-Dawley rats were weight matched before ovariectomy (Ovx) or Sham surgery (Sham). Sham rats had free access to food and water throughout the experiment, whereas Ovx rats were kept on the pair-fed diet. Rats were euthanized at 4, 8, and 12 weeks after surgery, and had received fluorochrome bone markers at 9 and 2 days prior to euthanasia. In addition 10 rats were euthanized at the time of surgery serving as baseline controls. All rats were also scanned for body composition and bone mineral parameters by DEXA before surgery and euthanasia. Left proximal femurs (femoral necks) were used for bone histomorphometry, whereas right femurs were used for in vitro DEXA measurements and mechanical testing. Despite pair-feeding, ovariectomized rats had increased body weights and fat body mass, whereas the percent lean body mass steadily declined throughout the experiment. Mineral density of the whole femur and femoral neck was significantly higher in the Sham rats relative to Ovx animals. Ovariectomy reduced trabecular number and thickness, and increased trabecular separation and bone marrow space at the femoral midneck location. The structure of the remaining trabeculae was dramatically changed toward simpler struts as revealed by nodal analyses. Cortical thickness in Ovx rats was reduced because of the high endocortical resorption, which, in addition to cancellous bone resorption, resulted in fewer endocortico-trabecular connections. Femoral necks obtained from ovariectomized rats had reduced strength and were less stiff relative to controls. Because of the enormous clinical significance of the proximal femur for osteoporosis in humans, and the opportunity for studying bone BMD, mass, structure, and strength at the same skeletal location, the femoral neck appears superior to other skeletal sites routinely used for bone histomorphometry or mechanical testing in the Ovx rat model. Received: 25 September 1996 / Accepted: 24 March 1997     

小儿股骨近端骨折78例治疗及康复

目的 :探讨小儿股骨近端骨折治疗方法的选择、远期并发症的预防及早期功能康复问题。方法 :按Colonna分型 ,Ⅰ型 :骨折无移位者 ,行骨牵引治疗 ,牵引后 ,行髋人字石膏固定 ;骨折移位 >1/ 4者 ,先给予骨牵引治疗 ,然后行切开复位、Steinmann针固定术。Ⅱ型 :Pauwel角 <40°者 ,给予骨牵引治疗后 ,行髋人字石膏固定 ;Pauwel角 >40°者 ,先给予骨牵引治疗 ,然后行切开复位、Steinmann针固定术。Ⅲ型、Ⅳ型 :骨折无移位或移位较轻微者牵引治疗 ,牵引后 ,行髋人字石膏固定 ;骨折移位较重者 ,牵引治疗后行切开复位、Steinmann针固定术。对骨折后的患儿给与早期及全程的功能康复指导。结果 :本组 78例均获得愈合 ,其中有 5例发生缺血性坏死 (Ⅰ型 2例 ,Ⅱ型 3例 )。无一例发生髋内翻、骨不连接和骺板过早闭合。 78例患儿无一例发生肌肉萎缩和功能障碍。结论 :对于儿童股骨近端骨折 ,正确选择治疗方式、牵引治疗的常规应用以及在手术中选择Steinmann针作为内固定器材 ,早期及全程的功能康复指导 ,对减少其并发症的发生 ,肢体功能的全面康复 ,有着重要的作用。     

Calcitonin Provides Complete Protection Against Cancellous Bone Loss in the Femoral Neck of Ovariectomized Rats

Calcitonin (CT) has been found to partially prevent cancellous bone loss in the proximal tibia of ovariectomized (OVX) rats. The current study was designed to determine whether CT has similar bone protective effects in the femoral neck, a skeletal site with a slower rate of bone loss after ovariectomy than the proximal tibia. Female Sprague Dawley rats were sham-operated or ovariectomized at 3 months of age. Groups of OVX rats were injected s.c. with vehicle or CT at a dose of 16 U/kg body weight on alternate days for 30, 60, or 90 days. Sham-operated control rats were treated with vehicle alone on alternate days. The proximal femur from each rat was processed undecalcified for quantitative bone histomorphometry. Cancellous bone volume in the femoral neck of vehicle-treated OVX rats was significantly less than that of vehicle-treated control rats at all time points. This cancellous osteopenia induced by ovariectomy was associated with increased indices of bone turnover such as osteoclast surface, osteoblast surface, and bone formation rate (tissue level, total surface referent). In contrast, cancellous bone volume in the femoral neck of CT-treated OVX rats was nearly identical of that of vehicle-treated control rats throughout the study. In addition, CT treatment of OVX rats decreased all indices of bone turnover to near the level of vehicle-treated control rats. The results indicate that CT treatment depresses bone turnover and provides complete protection against moderate cancellous osteopenia in the femoral neck of OVX rats. Since previous studies have shown that CT only partially protects against more pronounced cancellous bone loss in the proximal tibia of OVX rats, our findings suggest that CT has a greater bone protective effect at a skeletal site with a slower rate of cancellous bone loss (femoral neck) than at a skeletal site with a rapid rate of cancellous bone loss (proximal tibia). Received: 21 August 1996 / Accepted: 10 December 1996     

骨质疏松症松质骨连接性参数改变与计算机辅助测量

目的 松质骨连接性参数主要指小梁骨的节点数和游离末端数,是反映松质骨显微构筑的重要参数,而松质骨的构筑情况可直接影响其力学性能。本研究旨在观察骨质疏松症小梁骨连接性参数的改变,并介绍一种计算机辅助测量方法。方法 对老年人和青年人股骨头负重区与非负重区、卵巢切除后７周大鼠椎体骨以及采用重组人生长激素治疗后的椎体标本,进行节点数和游离末端数的测量。并发展了小梁骨节九和游离末端数的计算机图像自动分析系统     

股骨头开瓣植骨治疗非创伤性股骨头坏死

目的报道成人非创伤性股骨头坏死的手术治疗。方法自1997年2月至1999年6月,采用经股骨头负重区开瓣死骨清除取髂骨植骨术治疗FicatⅡ～Ⅲ期非创伤性股骨头坏死10例,其中男8例,女2例;年龄30～47岁,平均39岁。Ficat分期Ⅱ～Ⅲ期,其中Ⅱa期3例,Ⅱb期5例,Ⅲ期2例。采用经股骨头负重区开瓣死骨清除,取髂骨植骨术。结果所有病人均获随访,平均随访10年,根据Harris临床评分,Ⅱa、Ⅱb期8例效果满意,优良率达85．5％。结论该手术对Ⅱa、Ⅱb期软骨面完好的病人效果优良。