Peripheral quantitative computed tomography: measurement sensitivity in persons with and without spinal cord injury

OBJECTIVES: To determine (1) the error attributable to external tibia-length measurements by using peripheral quantitative computed tomography (pQCT) and (2) the effect these errors have on scan location and tibia trabecular bone mineral density (BMD) after spinal cord injury (SCI). DESIGN: Blinded comparison and criterion standard in matched cohorts. SETTING: Primary care university hospital. PARTICIPANTS: Eight able-bodied subjects underwent tibia length measurement. A separate cohort of 7 men with SCI and 7 able-bodied age-matched male controls underwent pQCT analysis. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The projected worst-case tibia-length-measurement error translated into a pQCT slice placement error of +/-3 mm. We collected pQCT slices at the distal 4% tibia site, 3 mm proximal and 3 mm distal to that site, and then quantified BMD error attributable to slice placement. RESULTS: Absolute BMD error was greater for able-bodied than for SCI subjects (5.87 mg/cm(3) vs 4.5 mg/cm(3)). However, the percentage error in BMD was larger for SCI than able-bodied subjects (4.56% vs 2.23%). CONCLUSIONS: During cross-sectional studies of various populations, BMD differences up to 5% may be attributable to variation in limb-length-measurement error.     

Regular Tai Chi Chuan exercise may retard bone loss in postmenopausal women: A case-control study

OBJECTIVE: To evaluate the potential benefits of regular Tai Chi Chuan exercise on the weight-bearing bones of postmenopausal women. DESIGN: Case-control study. SETTING: University medical school in Hong Kong. PARTICIPANTS: Postmenopausal women (age range, 50-59y), including 17 self-selected regular Tai Chi Chuan exercisers (TCE) with over 4 years of regular exercise, and 17 age- and gender-matched nonexercising controls (CON). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Bone mineral density (BMD) in the lumbar spine and proximal femur was measured at baseline and at follow-up 12 months later by using dual-energy x-ray absorptiometry (DXA) and in the distal tibia using multislice peripheral quantitative computed tomography (pQCT). RESULTS: Baseline results showed that the TCE group had significantly higher BMD (10.1%-14.8%, all P<.05) than the CON group in the lumbar spine, proximal femur, and the ultradistal tibia. The follow-up measurements showed generalized bone loss in both groups. Although both DXA and pQCT measurements revealed decelerated rates of bone loss in the TCE group, only the more sensitive pQCT showed significantly reduced rate of bone loss in trabecular BMD of the ultradistal tibia (TCE vs CON: -1.10%+/-1.26% vs -2.18%+/-1.60%, P<.05) and of cortical BMD of the distal tibial diaphysis (TCE vs CON: -0.90%+/-1.36% vs -1.86%+/-0.93%, P<.05). CONCLUSION: This is the first case-control study to show that regular Tai Chi Chuan exercise may help retard bone loss in the weight-bearing bones of postmenopausal women.     

A randomized, prospective study of the effects of Tai Chi Chun exercise on bone mineral density in postmenopausal women

OBJECTIVE: To evaluate the potential benefits of programmed Tai Chi Chun (TCC) exercise on the weight-bearing bones of early postmenopausal women. DESIGN: Age-matched and randomized prospective intervention. SETTING: University medical school. PARTICIPANTS: One hundred thirty-two healthy postmenopausal women (mean age, 54.0+/-3.5y) within 10 years of menopause onset were recruited and randomized into the TCC exercise group (n=67) or the sedentary control group (n=65). INTERVENTION: Supervised TCC exercise was performed by the TCC group for 45 minutes a day, 5 days a week, for 12 months; control subjects retained a sedentary life style.Main outcome measures Bone mineral density (BMD) was measured in the lumbar spine and proximal femur by using dual-energy x-ray absorptiometry and in the distal tibia by using multislice peripheral quantitative computed tomography (pQCT). All BMD measurements were repeated after 12 months in both groups. Fracture rate was also documented. RESULTS: Baseline measurements showed homogeneity in age, anthropometric variables, and menstruation status between the TCC and control groups. Exactly 81.6% of the subjects in the TCC group and 83.1% of subjects in the control group completed the 12-month follow-up study. BMD measurements revealed a general bone loss in both TCC and sedentary control subjects at all measured skeletal sites, but with a reportedly slower rate in the TCC group. A significant 2.6- to 3.6-fold retardation of bone loss (P<.01) was found in both trabecular and cortical compartments of the distal tibia in the TCC group as compared with the controls, as measured by pQCT. A total of 4 fracture cases were documented during follow-up, including 3 subjects in the control group and 1 in the TCC group. CONCLUSIONS: This is the first prospective and randomized study to show that a programmed TCC exercise intervention is beneficial for retarding bone loss in weight-bearing bones in early postmenopausal women. Long-term follow-up is needed to substantiate the role of TCC exercise in the prevention of osteoporosis and its related fracture.     

Bone mineral density after spinal cord injury: a reliable method for knee measurement

OBJECTIVES: To test the interrater reliability of a standardized method to analyze knee bone mineral density (BMD) using dual-energy x-ray absorptiometry (DXA); to compare spine, hip, and knee BMD of people with spinal cord injury (SCI) with able-bodied controls; and to determine the relation between hip BMD and knee BMD in SCI and able-bodied subjects. DESIGN: Criterion standard and masked comparison. SETTING: Primary care university hospital. PARTICIPANTS: A convenience sample of 11 subjects with complete SCI was age and sex matched with 11 able-bodied control subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Four raters analyzed regions of interest according to operational definitions recently developed to standardize the analysis of BMD of the knee. Subjects with chronic SCI and matched controls underwent conventional DXA scans of the spine and hips and "less conventional" scans of the distal femurs and proximal tibias. The relation between hip and knee BMD was analyzed. RESULTS: The knee measurements were highly reliable (femur intraclass correlation coefficient model 2,1 [ICC(2,1)]=.98; tibia ICC(2,1)=.89). Subjects with SCI had lower BMD values than controls at all hip and knee sites (P<.05). Lumbar spine BMD did not differ between groups. Hip BMD was moderately predictive of distal femur BMD (R2=.67), but less correlated with the proximal tibia (R2=.38). CONCLUSIONS: Knee BMD can be reliably analyzed using DXA with this protocol. Subjects with SCI have diminished knee and hip BMD. Low hip BMD is associated with low distal femur BMD.     

Electrical stimulation: can it increase muscle strength and reverse osteopenia in spinal cord injured individuals?

OBJECTIVE: To study the extent to which atrophy of muscle and progressive weakening of the long bones after spinal cord injury (SCI) can be reversed by functional electrical stimulation (FES) and resistance training. DESIGN: A within-subject, contralateral limb, and matching design. SETTING: Research laboratories in university settings. PARTICIPANTS: Fourteen patients with SCI (C5 to T5) and 14 control subjects volunteered for this study. INTERVENTIONS: The left quadriceps were stimulated to contract against an isokinetic load (resisted) while the right quadriceps contracted against gravity (unresisted) for 1 hour a day, 5 days a week, for 24 weeks. MAIN OUTCOME MEASURES: Bone mineral density (BMD) of the distal femur, proximal tibia, and mid-tibia obtained by dual energy x-ray absorptiometry, and torque (strength). RESULTS: Initially, the BMD of SCI subjects was lower than that of controls. After training, the distal femur and proximal tibia had recovered nearly 30% of the bone lost, compared with the controls. There was no difference in the mid-tibia or between the sides at any level. There was a large strength gain, with the rate of increase being substantially greater on the resisted side. CONCLUSION: Osteopenia of the distal femur and proximal tibia and the loss of strength of the quadriceps can be partly reversed by regular FES-assisted training.     

脉冲电磁场及阿仑膦酸钠对脊髓损伤大鼠骨质量的影响

目的探讨早期应用脉冲电磁场（PEMFs）和／或阿仑膦酸钠（ALN）对脊髓损伤（SCI）后大鼠骨质量的影响。方法将62只3月龄雌性sD大鼠随机分为5组，其中假手术组仅行椎板切除术，SCI组、SCI＋ALN组、SCI＋PEMFs组及SCI＋PEMFs＋ALN组行脊髓完全横断术，后3组于术后1周时分别给予ALN和／或PEMFs治疗；于术后8周时取材，检测各组大鼠股骨骨密度值、生物力学指标以及胫骨近端骨组织形态计量学等指标。实验所得数据比较采用单因素方差分析及析因分析。结果早期应用ALN和／或PEMFs均可使股骨骨密度、股骨弹性载荷、最大载荷等生物力学指标增高，胫骨近端骨小梁面积百分比也同时增大，骨小梁宽度增加。结论早期应用ALN和／或PEMFs均可抑制SCI后骨量丢失，增强抗骨折能力，阻止胫骨近端微观结构的退变，提示早期应用ALN及PEMFs有助于防治SCI后骨质疏松，但其具体治疗机制还有待进一步研究。     

脊髓损伤继发骨质疏松大鼠后肢骨质量变化

目的：探讨脊髓损伤对大鼠后肢骨质量的影响，揭示SCI继发骨质疏松特点。方法：60只SD大鼠按体重随机分为6组．对20只采用脊髓横断法在第10胸椎处横断脊髓制作完全性SCI模型，分为SCI6周和12周组；20只在同水平处切断棘突、椎板制作似手术对照组（sham），分为Sham6周和12周组；另20只分为正常6周和12周对照组。分别在脊髓损伤后6周和12周时取材，进行股骨生物力学性能和胫骨上端骨形态计量学测试。结果：脊髓损伤6周时，大鼠胫骨E端骨小梁厚度、骨小梁面积百分比明显降低（P〈0.01、P〈0．05），单位面积破骨细胞数明显增加（P〈0．05）：股骨中段最大载荷明显降低（P＜0．05）。脊髓损伤12周时，除上述改变外，胫骨上端骨体积百分比也明显降低（P〈0．05）：股骨最大载荷进一步降低（P＜0．001），结构刚度也明显下降（P〈0．05）。其他指标无明显改变（P〉0．05）。结论：脊髓损伤6周时，大鼠后肢骨已出现损害，12周时，其损害进一步加重。     

Predicting patient-specific rates of bone loss at fracture-prone sites after spinal cord injury

Purpose: People with spinal cord injury (SCI) experience bone loss and have an elevated rate of fracture in the paralysed limbs. The literature suggests an exponential time course of bone loss after SCI, but true rates may vary between patients. We propose systematic evaluation of bone status in the early stages of SCI to identify fast bone losers. Method: A case series of six patients with complete SCI were scanned using peripheral quantitative computed tomography within 5 weeks and at 4, 8 and 12 months post-injury. Bone mineral density (BMD) and bone mineral content (BMC) were measured at fracture-prone sites in the tibia and femur. Patient-specific-predictions (PSP) of expected rates of bone loss were produced by individualising published model equations according to each patient’s measured values at baseline. Wilcoxon Signed-Rank tests were used to identify changes between time-points; chi-squared tests for differences between measured and PSP values. Results: In the lower limbs, mean values decreased significantly between baseline and 8 months post-injury, by 19–31% for trabecular BMD, 21–32% for total BMD, and 9–29% for BMC. Most subjects showed no significant differences between PSP and measured values, but individuals with significantly faster rates of bone loss than predicted should be investigated further. Conclusions: There was considerable intersubject variability in rates of bone loss after SCI. Patients showing the fastest bone loss could benefit from continued follow-up and possibly treatment.

Implications for Rehabilitation

• Spinal cord injury (SCI) leads to extensive muscle paralysis, and is often accompanied by significant bone loss and increased fracture risk.

• Repeat bone scans within months of injury can be used to “red-flag” patients who are losing bone faster than predicted.

• A patient-specific approach to osteoporosis management will facilitate targeted treatment aimed at those who need it most, in SCI and other patient groups.

     

Increases in bone mineral density after functional electrical stimulation cycling exercises in spinal cord injured patients

Purpose. To assess the change in bone mineral density (BMD) after spinal cord injury (SCI) and to evaluate whether BMD loss can be reversed with the intervention of functional electric stimulation cycling exercises (FESCE).

Methods. Fifteen males with SCI were included. Fifteen able-bodied males were also tested to compare BMD. In the SCI group, the FESCE was performed for six months, and then was discontinued in the subsequent six months. BMD was performed before the FESCE, immediately after six months of the FESCE, and at the end of the subsequent six months.

Results. Before the FESCE, the BMD of the SCI subjects in every site, except the lumbar spine, was lower than that of the able-bodied subjects. After six months of FESCE, BMD of the distal femur (DF) and proximal tibia (PT) increased significantly, and BMD of the calcaneus (heel) showed a trend of increase. However, the BMD in the DF, PT, and heel decreased significantly after the subsequent six months without FESCE. The BMD of the femoral neck (FN) decreased progressively throughout the programme.

Conclusions. Our study showed site-specific BMD changes after FESCE. The BMD loss in the DF and PT was partially reversed after six months of FESCE, but the effect faded once the exercise was discontinued.     

超早期高压氧应用对脊髓完全横断损伤大鼠后肢骨密度的影响

摘要 目的：探讨超早期高压氧应用对脊髓完全横断损伤大鼠后肢骨密度（BMD）的影响。 方法：①55只3月龄健康雌性SD大鼠随机分为假手术组（Sham组,15只）、模型组（CSCT组,20只）及高压氧组（HBO组,20只）。Sham组仅行T10椎板切除术,其余两组均行T10椎板水平脊髓完全横向切断术。②HBO组于术后第3小时置于动物舱内开始高压氧处理,10d为1疗程,共3疗程,其中第一疗程每日2次,第二、三疗程均每日1次,每疗程间休息6d。③术后6周末取材,采用Delphi A型扇形束DEXA骨密度仪检测各组离体股骨、胫骨整体及其不同区域BMD。 结果：CSCT组与Sham组比较,前者股骨整体、股骨远端(FR1,FR2)、近端(FR6,FR7)及胫骨近端(TR1,TR2)BMD均明显下降,差异有显著性意义（P＜0.05—0.01);HBO组与CSCT组比较,前者股骨整体BMD明显增加（P＜0.05),而胫骨整体、股骨及胫骨其他各区域BMD均略呈上升趋势,但差异无显著性意义。 结论：超早期高压氧应用可减缓脊髓完全横断损伤大鼠后肢骨丢失。     

Increases in bone mineral density after functional electrical stimulation cycling exercises in spinal cord injured patients

Purpose.?To assess the change in bone mineral density (BMD) after spinal cord injury (SCI) and to evaluate whether BMD loss can be reversed with the intervention of functional electric stimulation cycling exercises (FESCE).

Methods.?Fifteen males with SCI were included. Fifteen able-bodied males were also tested to compare BMD. In the SCI group, the FESCE was performed for six months, and then was discontinued in the subsequent six months. BMD was performed before the FESCE, immediately after six months of the FESCE, and at the end of the subsequent six months.

Results.?Before the FESCE, the BMD of the SCI subjects in every site, except the lumbar spine, was lower than that of the able-bodied subjects. After six months of FESCE, BMD of the distal femur (DF) and proximal tibia (PT) increased significantly, and BMD of the calcaneus (heel) showed a trend of increase. However, the BMD in the DF, PT, and heel decreased significantly after the subsequent six months without FESCE. The BMD of the femoral neck (FN) decreased progressively throughout the programme.

Conclusions.?Our study showed site-specific BMD changes after FESCE. The BMD loss in the DF and PT was partially reversed after six months of FESCE, but the effect faded once the exercise was discontinued.     

Changes of tibia bone properties after spinal cord injury: effects of early intervention

OBJECTIVE: To evaluate the effectiveness of an early intervention program for attenuating bone mineral density loss after acute spinal cord injury (SCI) and to estimate the usefulness of a multimodality approach in diagnosing osteoporosis in SCI. DESIGN: A single-case, experimental, multiple-baseline design. SETTING: An SCI center in a university hospital. METHODS: Early loading intervention with weight-bearing by standing and treadmill walking. PATIENTS: Nineteen patients with acute SCI. OUTCOME MEASURES: (1) Bone density by peripheral computed tomography and (2) flexural wave propagation velocity with a biomechanical testing method. RESULTS: Analysis of the bone density data revealed a marked decrease of trabecular bone in the nonintervention subjects, whereas early mobilized subjects showed no or insignificant loss of trabecular bone. A significant change was observed in 3 of 10 subjects for maximal and minimal area moment of inertia. Measurements in 19 subjects 5 weeks postinjury revealed a significant correlation between the calculated bending stiffness of the tibia and the maximal and minimal area moment of inertia, respectively. CONCLUSION: A controlled, single-case, experimental design can contribute to an efficient tracing of the natural history of bone mineral density and can provide relevant information concerning the efficacy of early loading intervention in SCI. The combination of bone density and structural analysis could, in the long term, provide improved fracture risk prediction in patients with SCI and a refined understanding of the bone remodeling processes during initial immobilization after injury.     

脊髓损伤后大鼠骨代谢和骨密度变化

目的:了解脊髓损伤后不同时期大鼠骨代谢和骨密度的变化。方法:60只SD大鼠按体重随机分为6组,对20只大鼠采用脊髓横断法在第10胸椎段横断脊髓制作完全性脊髓损伤模型,分为脊髓损伤6周和12周组;20只在同水平处切断棘突、椎板制作假手术对照组,分为假手术6周和12周组;另20只分为正常6周和12周对照组。分别在脊髓损伤后6周和12周时处死动物。结果:脊髓损伤6周、12周时,脊髓损伤组血Ca较对照组明显升高(P<0.05),碱性磷酸酶和骨钙素则较对照组无明显变化(P>0.05)。脊髓损伤6周时,股骨近端、远端骨密度(BMD)均较对照组显著降低(P<0.001),损伤12周时,除股骨近端、远端外,中段BM D也明显降低(P<0.05)。L5BMD在SCI6周和SCI12周与对照组比较差异无显著性意义(P>0.05)。结论:脊髓损伤6周时,大鼠骨代谢已发生明显改变,骨量出现明显丢失,12周时骨代谢稍有改善,但股骨骨量丢失持续存在。     

脊髓损伤对大鼠股骨骨密度与生物力学特性的影响

目的探讨脊髓损伤(spinal cord injury, SCI)对大鼠股骨生物力学和骨密度(bone mineral density, BMD)的影响. 方法将40只3月龄大鼠随机分为SCI组和对照组,SCI组于T10椎体处完全切断脊髓,对照组仅行椎板切除术.于术后3,6周分2批处死动物进行股骨骨密度和生物力学测定. 结果术后3周时SCI组大鼠股骨远端BMD较对照组显著下降(P<0.05);术后6周时SCI组股骨近端BMD与对照组比较,下降差异显著(P<0.05);股骨远端BMD较对照组下降差异非常显著(P<0.01);股骨干BMD与对照组相比有降低趋势,但无统计学意义.术后3周时股骨颈最大载荷、最大变形、结构刚度及能量吸收在2组间差异均无统计学意义.术后6周时最大变形、结构刚度和能量吸收均低于对照组(P均<0.05),最大载荷低于对照组,差异具有极显著性意义(P<0.01). 结论脊髓损伤后松质骨骨密度和生物力学性能的降低先于密质骨.脊髓损伤后6周时SCI组股骨松质骨的骨密度及生物力学参数均显著低于对照组,脊髓损伤后6周的大鼠可作为骨质疏松动物模型.     

双能量CT虚拟去钙技术对膝关节隐匿性骨折的诊断价值

目的 探讨双能量CT(DECT)虚拟去钙技术(VNCa)对膝关节隐匿性骨折的诊断价值。方法 前瞻性收集有明确外伤史及膝关节活动障碍等症状、且临床诊断为膝关节隐匿性骨折的病例40例,同一天行膝关节DECT和MRI平扫检查。将每个膝关节分成12个区域(胫骨近端及股骨远端分别被分成6个区域),由两名独立的放射科医师评估膝关节VNCa图像是否存在骨髓损伤,在冠状位图像上测量正常区域和损伤区域VNCa图的CT值,并计算出两种CT值的差值。以MR图像作为“金标准”,评估主观评价和CT差值对膝关节隐匿性骨折的检测能力。通过ROC曲线观察两种方法对膝关节骨髓损伤评价的敏感度和特异度。使用Kappa值来检验两位放射医师对膝关节骨髓损伤诊断的一致性。结果 40个膝关节共480个区域,MRI显示股骨远端和胫骨近端分别有74个和166个区域出现骨髓损伤。虚拟去钙图显示股骨远端和胫骨近端分别有77和171个区域出现骨髓损伤。VNCa图CT差值显示股骨远端和胫骨近端分别有76和174个区域出现骨髓损伤。VNCa图对膝关节骨髓损伤主观评价及CT差值客观客观评价分别与MRI成像的一致性较高(Kappa值分别为0.829和0.867)。主观评价及CT差值客观评价的曲线下面积(AUC)、敏感度、特异度、准确度分别为0.876和0.885、92.0%和95.6%、92.2%和95.2%、84.2%和90.8%。结论双能量CT虚拟去钙技术对于膝关节隐匿性骨折具有良好的诊断性能,与MRI有较高的一致性,为临床诊断隐匿性骨折提供了参考依据。     

The relationship between basal metabolic rate and femur bone mineral density in men with traumatic spinal cord injury

OBJECTIVES: To investigate the relationship between basal metabolic rate (BMR) and hip bone mineral density (BMD) in people with spinal cord injury (SCI) and to determine whether neurologic factors contribute to this relationship. DESIGN: Cross-sectional study. SETTING: Inpatient SCI unit in a rehabilitation hospital. PARTICIPANTS: Thirty men with chronic (time since injury, >1 y) traumatic SCI with an American Spinal Injury Association Impairment Scale grade A or B. Subjects' mean age was 32 years (range, 20-45 y). INTERVENTIONS: All participants were evaluated with neurologic examination to define the level and severity of injury. BMR was determined by indirect calorimetry, and BMD was determined by dual-energy x-ray absorptiometry (DXA). Patients were allocated to osteoporotic, osteopenic, and normal bone density groups according to World Health Organization criteria. DXA was used also to estimate lean- and fat-tissue mass (in kilograms) by standard methods. DXA measurements were performed on the same day as BMR analysis. MAIN OUTCOME MEASURES: DXA and indirect calorimetry. RESULTS: BMR correlated significantly with BMD of the total femur, femur neck, trochanter, and shaft. However, there was no correlation between BMR and femur Ward's triangle. These correlations were stronger in patients with tetraplegia. There was a moderate correlation between BMR and lean tissue mass (r = .66, P < .001), although femur BMD values did not correlate with lean tissue mass in our study group (P > .05). CONCLUSIONS: BMR is closely associated with BMD in men with SCI.     

仙灵骨葆对尾悬吊拟失重大鼠骨量丢失的抑制

背景:以淫羊藿苷为主要成分的中药制剂仙灵骨葆具有促进骨形成的作用。目的:观察仙灵骨葆对尾悬吊拟失重大鼠骨量丢失的抑制作用及机制。方法:将SD大鼠随机分为正常对照组、拟失重组、仙灵骨葆组,后两组大鼠采用尾悬吊法模拟失重,仙灵骨葆组悬吊同时灌胃给予仙灵骨葆250mg/(kgd),拟失重组悬吊同时灌胃给予双蒸水,4周后取右侧股骨行骨密度、三点弯曲生物力学及骨组织形态计量学检测。结果与结论:正常对照组骨密度、胫骨近端骨小梁相对体积、骨小梁厚度、骨小梁数量、生物力学最大载荷显著高于拟失重组、仙灵骨葆组(P<0.05)。仙灵骨葆组胫骨远端1/4骨密度、胫骨近端骨小梁相对体积显著高于拟失重组(P<0.05),生物力学最大载荷也高于拟失重组,但差异无显著性意义。说明仙灵骨葆灌胃干预可促进松质骨的骨形成,部分阻止拟失重大鼠骨量的丢失。     

Decreased trabecular bone biomechanical competence, apparent density, IGF-II and IGFBP-5 content in acromegaly

BACKGROUND: Earlier studies on the effect of excess growth hormone (GH) on trabecular bone have been conflicting. Since insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) in part mediate the effects of GH, the present study aimed to investigate trabecular bone composition of these growth factors in relation to biomechanical properties in acromegaly. MATERIALS AND METHODS: Trabecular bone biomechanical competence (compression test), apparent density (peripheral quantitative computed tomography, pQCT), and bone matrix contents of calcium (HCl hydrolysis) and IGFs (guanidinium-HCl extraction) were measured in iliac crest biopsies from 13 patients with active acromegaly (two women and 11 men, aged 21-61 years) and 21 age- and sex-matched controls (four women and 17 men, aged 23-64 years). RESULTS: Trabecular bone pQCT was reduced in acromegalic patients compared with controls (P = 0.005), as was biomechanical competence (P < 0.05 for all measures). These parameters were significantly positively correlated in both acromegalic patients and controls. The calcium content of trabecular bone was significantly increased in patients compared with controls. No significant differences were found in trabecular bone content of IGF-I, IGFBP-3, or osteocalcin. However, IGF-II and IGFBP-5 content was decreased (P < 0.001 and P < 0.05, respectively). CONCLUSIONS: The present study demonstrates reduced trabecular biomechanical competence and apparent density in acromegaly, supporting previous observations of an unfavourable effect of chronic excess GH on the axial skeleton. Furthermore, we demonstrate decreased trabecular bone content of IGF-II and IGFBP-5 in these patients. However, we found no direct causal relationship between trabecular bone density and bone content of IGF-system components.     

老年骨质疏松性骨折骨量与骨质量关系的探讨

目的:探讨老年股骨颈骨折患者的骨量与骨质量两者的关系与规律。方法:取老年股骨颈骨折患者股骨头和正常青年股骨头,行骨密度测量后,进行扫描电镜观察和形态计量学检测。结果:86.5%病例符合WHO骨质疏松症诊断标准,43.2%病例股骨颈骨密度在骨折阈值之上。扫描电镜下观察发现:骨折患者骨小梁发生明显变化。形态计量学显示:老年组骨小梁游离末端数(FET)、平均骨小梁间距(MTPS)较青年组明显升高(P<0.01),小梁间连接点数(Tb.n)、松质骨体积(TBV)、平均骨小梁密度(MTPD)、平均骨小梁厚度(MTPT)明显减少(P<0.01)。结论:术后股骨头标本行扫描电镜观察和形态计量学分析是一种简便而准确的诊断骨量与骨质量下降的方法。     

实验性骨质疏松性骨折愈合中的骨密度及组织学观察

目的：观察骨质疏松性骨折愈合过程中骨折端骨密度及组织学变化特征，阐明骨质疏松性骨折愈合的特点。方法：60只3月龄，雌性SD大鼠，手术建立骨质疏松性骨折模型组和一般骨折模型组各30只。于骨折模型建立后2、6、12周截取股骨，用双能X线吸收法作骨折端骨密度测定。并同时对骨折端骨痂组织作光镜观察。结果：（1）骨折端骨密度：骨折后2周，两组动物骨折端的骨密度差异不明显（P＞0．05）；而在骨折后6周及12周，骨质疏松性骨折组的骨密度较一般骨折组明显低（P＜0．05，P＜0．01）。（2）光镜观察：术后2周，骨质疏松性骨折组骨折端结缔组织数量多，小梁骨较细小；术后6周，一般骨折组骨折端软骨痂为编织骨取代，而骨质疏松性骨折组骨折端则仍有透明样软骨存在，其软骨痂向骨性骨痂转化缓慢；术后12周，骨质疏性松骨折组原始小梁状骨向成熟小梁状骨转化亦较慢，且原已形成的成熟小梁状骨多吸收、消失。结论：（1）骨质疏松不仅使全身骨密度减少，也使骨折愈合中骨折端的骨密度升高减慢。（2）骨质疏松性骨折愈合质量降低是骨折端骨密度值低的重要原因。