Effect of nonweight bearing on tibial bone density measured by QCT in patients with hip surgery

Tibial bone mineral density (BMD) was measured in 11 patients who had undergone hip joint surgery, including 10 women (22–61 years old; mean ± SD = 42.6 ± 10.3) and 1 man (61 years old). Four patients received total hip replacement (THR), while the others underwent rotational acetabular osteotomy (RAO). In one case, the start of rehabilitation was delayed until 4 months after the surgery because of infection at the surgical site. Nine patients underwent hip surgery for osteoarthritis and 2 patients for avascular necrosis. These 2 patients had a history of medication with corticosteroid. BMD of the tibia on the surgically treated side was measured by a peripheral quantitative CT (pQCT) system, which provided three different BMD values of trabecular BMD in the distal portion, total BMD in the distal portion, and total BMD in the diaphysis. The measurements were obtained preoperatively, and at several time points postoperatively, at 2, 4, 6, and 8 weeks and 3, 4, 5, 8, 12, 18, and 24 months after surgery. Brief periods of nonweightbearing lead to significant bone loss, and 1–1.5 years was required to recover to the baseline BMD. Accelerated bone loss was seen in patients in the perimenopausal state, with prolonged bed rest, and in patients receiving corticosteroid. Both trabecular and cortical components were influenced by nonweightbearing and restoration of weightbearing. The decrease in the cortical region occurs after the decrease in the trabecular and endosteal regions. Received: June 5, 1998 / Accepted: Aug. 25, 1998     

Impact of Weight Loss With Intragastric Balloon on Bone Density and Microstructure in Obese Adults

The historical concept that obesity protects against bone fractures has been questioned. Weight loss appears to reduce bone mineral density (BMD); however, the results in young adults are inconsistent, and data on the effects of weight loss on bone microstructure are limited. This study aimed to evaluate the impact of weight loss using an intragastric balloon (IGB) on bone density and microstructure. Forty obese patients with metabolic syndrome (mean age 35.1?±?7.3 yr) used an IGB continuously for 6 mo. Laboratory tests, areal BMD, and body composition measurements via dual-energy X-ray absorptiometry, and volumetric BMD and bone microstructure measurements via high-resolution peripheral quantitative computed tomography were conducted before IGB placement and after IGB removal. The mean weight loss was 11.5%. After 6 mo, there were significant increases in vitamin D and carboxyterminal telopeptide of type 1 collagen levels. After IGB use, areal BMD increased in the spine but decreased in the total femur and the 33% radius. Cortical BMD increased in the distal radius but tended to decrease in the distal tibia. The observed trabecular bone loss in the distal tibia contributed to the decline in the total volumetric BMD at this site. There was a negative correlation between the changes in leptin levels and the measures of trabecular quality in the tibia on high-resolutionperipheral quantitative computed tomography. Weight loss may negatively impact bone microstructure in young patients, especially for weight-bearing bones, in which obesity has a more prominent effect.     

Correlations of calcaneal QUS with pQCT measurements at distal tibia and non-weight-bearing distal radius

Quantitative ultrasound (QUS) is used for prediction for risks of osteoporotic fractures at various skeletal sites, irrespective of weight-bearing or non-weight-bearing skeletons. In the current study, we investigated the correlation between calcaneal QUS measurements (BUA, VOS, and Soundness) and volumetric trabecular, cortical, and its integral bone mineral density (tBMD, cBMD, and iBMD) using peripheral quantitative computed tomography (pQCT) of the weight-bearing distal tibia and non-weight-bearing distal radius in 198 healthy Chinese women between 40 and 62 years of age. Results showed that BUA, VOS, and Soundness measured by calcaneal QUS were significantly correlated with tBMD, cBMD, and iBMD of both distal tibia and distal radius (r = 0.210–0.447; all P < 0.01). The correlation coefficients of all the individual parameters between calcaneus and distal tibia were correspondingly higher (r = 0.214–0.447; all P < 0.01) than that of distal radius (r = 0.210–0.368; all P < 0.01). QUS Soundness showed the highest correlation (r = 0.447; P < 0.01) with tBMD of distal tibia when comparing with all other parameters between these two measurement devices. Stronger within-device correlations (r = 0.640–0.764; all P < 0.01) were found in pQCT measurements between distal tibia and radius. In addition, the largest and significant age-related decline was found in tBMD of the distal radius measured by pQCT and Soundness of the QUS measurement in the postmenopausal group. In conclusion, heel QUS measurement demonstrated slightly better correlation with trabecular bone of the weight-bearing skeleton than that of the non-weight-bearing skeleton measured by pQCT.     

Influence of bone adaptation on tendon‐to‐bone healing in bone tunnel after anterior cruciate ligament reconstruction in a rabbit model

Anterior cruciate ligament (ACL) reconstruction with placement of grafted tendon in bone tunnel is a common surgical procedure. Bone tunnel creation may result in stress shielding of postero‐lateral regions of tibial tunnel. The present study was designed to characterize the changes of peri‐graft bone and compare with tendon‐to‐bone (T‐B) healing in spatial and temporal manners after ACL reconstruction in rabbit. Surgical reconstruction using digital extensor tendon in bone tunnel was performed on 48 rabbits. Twelve rabbits were sacrificed at 0, 2, 6, and 12 weeks postoperatively for radiological and histological examinations. Bone mass and microarchitecture at the anterior, posterior, medial, and lateral regions of tunnel wall at distal femur and proximal tibia were evaluated. Using peripheral quantitative computed tomography, a 26, 22, and 42% decrease in bone mineral density (BMD) relative to baseline was present in the medial region of the femoral tunnel and the posterior and lateral regions of the tibial tunnel, respectively, at week 12 postoperatively (p < 0.05). It was accompanied by a decrease in trabecular number and increase in trabecular spacing, the shift of platelike to rodlike trabeculae, and loss of anisotropy under micro‐computed tomography evaluation. This finding was echoed by histology showing increased osteoclastic activities and poor T‐B healing in these regions. In conclusion, the postoperative bone loss and associated poor T‐B healing was region‐dependent, which may result from adaptive changes after tunnel creation. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1447–1456, 2009     

Quantitative Computed Tomography Reveals the Effects of Race and Sex on Bone Size and Trabecular and Cortical Bone Density

To examine the effects of race and sex on bone density and geometry at specific sites within the proximal femur and lumbar spine, we used quantitative computed tomography to image 30 Caucasian American (CA) men, 25 African American (AA) men, 30 CA women, and 17 AA women aged 35–45 yr. Volumetric integral bone mineral density (BMD), trabecular BMD (tBMD), and cross sectional area were measured in the femoral neck, trochanter, total femur, and L1/L2 vertebrae. Volumetric cortical BMD (cBMD) was also measured in the femur regions of interest. Differences were ascertained using a multivariate regression model. Overall, AA subjects had denser bones than CA subjects, but there were no racial differences in bone size. Men had larger femoral necks but not larger vertebrae than women. The AA men had higher tBMD and cBMD in the femur than CA men, whereas AA women had higher femoral tBMD but not higher femoral cBMD than CA women. These data support the idea that higher hip fracture rates in women compared with men are associated with smaller bone size. Lower fracture rates in AA elderly compared with CA elderly are consistent with higher peak bone density, particularly in the trabecular compartment, and potentially lower rates of age-related bone loss rather than larger bone size.     

Patient-specific microarchitecture of vertebral cancellous bone: a peripheral quantitative computed tomographic and histological study

This study directly compares peripheral quantitative computed tomography (pQCT) and histology for the assessment of 11 morphological parameters. Sixty-eight cylindrical cancellous bone samples were cored from the thoracic (T-9) thoracolumbar (T-12 or L-1), and lumbar (L-4) vertebral bodies of nine autopsy subjects (aged 44–88 years). Four transverse slices were acquired by pQCT from the bottom to the top of each cylinder. Slice thickness was 300 μm and pixel size was 70 × 70 μm. Thin sections (5 μm) were obtained at the same location in the samples, stained with Von Kossa, and photographed. Classical morphological parameters and strut analysis parameters were measured on all images (272 pQCT and 272 matched histological sections). Because of the partial volume effect and specific thresholding procedure, pQCT overestimated the absolute value of the bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) by a factor 2. The trabecular number (Tb.N), trabecular spacing (Tb.Sp), and total strut length (TSL) were correctly estimated. However, the direct correlation between pQCT and histology was excellent (r² > 0.85, p < 0.001) for BV/TV, Tb.N, Tb.Sp, TSL, and star surface. For Tb.Th, number of nodes, and number of free ends, the correlation was also good (r² > 0.6, p < 0.001). Using a random regression model, we also explored the ability of these parameters to add structural information to the readily available BV/TV or apparent density. The model identified significant (p < 0.001) differences between subjects. For a given BV/TV, some patients had more trabeculae (Tb.N) that were thinner (Tb.Th) and more disconnected (higher free ends and star). This was observed for both histology and pQCT morphometrical data. Our analysis demonstrates the capacity of both histology and pQCT to detect subjects with specific structural patterns in vertebral cancellous bone.     

Measuring Marrow Density and Area Using Peripheral Quantitative Computed Tomography at the Tibia: Precision in Young and Older Adults and Individuals With Spinal Cord Injury

The objective of this study was to compare the test-retest precision error for peripheral quantitative computed tomography (pQCT)-derived marrow density and marrow area segmentation at the tibia using 3 software packages. A secondary analysis of pQCT data in young adults (n?=?18, mean?±?standard deviation 25.4?±?3.2?yr), older adults (n?=?47, 71.8?±?8.2?yr), and individuals with spinal cord injury (C1–T12 American Spinal Injury Association Impairment Scale, classes A–C; n?=?19, 43.5?±?8.6?yr) was conducted. Repeat scans of the tibial shaft (66%) were performed using pQCT (Stratec XCT2000). Test-retest precision errors (root mean square standard deviation and root mean square coefficient of variation [RMSCV%]) for marrow density (mg/cm³) and marrow area (mm²) were reported for the watershed-guided manual segmentation method (SliceOmatic version 4.3 [Sliceo-WS]) and the 2 threshold-based edge detection methods (Stratec version 6.0 [Stratec-TB] and BoneJ version 1.3.14 [BoneJ-TB]). Bland-Altman plots and 95% limits of agreement were computed to evaluate test-retest discrepancies within and between methods of analysis and subgroups. RMSCV% for marrow density segmentation was >5% for all methods across subgroups (Stratec-TB: 12.2%–28.5%, BoneJ-TB: 14.5%–25.2%, and Sliceo-WS: 10.9%–23.0%). RMSCV% for marrow area segmentation was within 5% for all methods across subgroups (Stratec-TB: 1.9%–4.4%, BoneJ-TB: 2.6%–5.1%, and Sliceo-WS: 2.4%–4.5%), except using BoneJ-TB in older adults. Intermethod discrepancies in marrow density appeared to be present across the range of marrow density values and did not differ by subgroup. Intermethod discrepancies varied to a greater extent for marrow area and were found to be more frequently at mid- to higher-range values for those with spinal cord injury. Precision error for pQCT-derived marrow density segmentation exceeded 5% for all methods of analysis across a range of bone mineral densities and fat infiltration, whereas precision error for marrow area segmentation ranged from 2% to 5%. Further investigation is necessary to determine alternative acquisition and analysis methods for pQCT-derived marrow segmentation.     

Bone Mineral Density of the Radius Predicts All-Cause Mortality in Patients With Type 2 Diabetes: Diabetes Heart Study

This study aimed to determine the association between areal and volumetric bone mineral density (BMD) with all-cause mortality in patients with type 2 diabetes (T2D). Associations between BMD and all-cause mortality were examined in 576 women and 517 men with T2D in the Diabetes Heart Study. Volumetric BMD in the thoracic and lumbar spine was measured with quantitative computed tomography. Areal BMD (aBMD) in the lumbar spine, total hip, femoral neck, ultradistal radius, mid radius, and whole body was measured using dual X-ray absorptiometry. Association of BMD with all-cause mortality was determined using sequential models, stratified by sex: (1) unadjusted; (2) adjusted for age, race, smoking, alcohol, estrogen use; (3) model 2 plus history of cardiovascular disease, hypertension, and coronary artery calcification; (4) model 3 plus lean mass; and (5) model 3 plus fat mass. At baseline, mean age was 61.2 years for women and 62.7 years for men. At mean 11.0?±?3.7 years' follow-up, 221 (36.4%) women and 238 (43.6%) men were deceased. In women, BMD at all skeletal sites (except spine aBMD and whole body aBMD) was inversely associated with all-cause mortality in the unadjusted model. These associations remained significant in the mid radius (hazard ratio per standard deviation ?=?0.79; p?=?0.0057) and distal radius (hazard ratio per standard deviation ?=?0.76; p?=?0.0056) after adjusting for all covariates, including lean mass. In men, volumetric BMD measurements but not aBMD were inversely associated with mortality and only in the unadjusted model. In this longitudinal study, lower baseline aBMD in the radius was associated with increased all-cause mortality in women with T2D, but not men, independent of other risk factors for death.     

Estimation of distal radius failure load with micro-finite element analysis models based on three-dimensional peripheral quantitative computed tomography images

There is increasing evidence that, in addition to bone mass, bone microarchitecture and its mechanical load distribution are important factors for the determination of bone strength. Recently, it has been shown that new high-resolution imaging techniques in combination with new modeling algorithms based on the finite element (FE) method can account for these additional factors. Such models thus could provide more relevant information for the estimation of bone failure load. The purpose of the present study was to determine whether results of whole-bone micro-FE (μFE) analyses with models based on three-dimensional peripheral quantitative computer tomography (3D-pQCT) images (isotropic voxel resolution of 165 μm) could predict the failure load of the human radius more accurately than results with dual-energy X-ray absorptiometry (DXA) or bone morphology measurements. For this purpose, μFE models were created using 54 embalmed cadaver arms. It was assumed that bone failure would be initiated if a certain percentage of the bone tissue (varied from 1% to 7%) would be strained beyond the tissue yield strain. The external force that produced this tissue strain was calculated from the FE analyses. These predictions were correlated with results of real compression testing on the same cadaver arms. The results of these compression tests were also correlated with results of DXA and structural measurements of these arms. The compression tests produced Colles-type fractures in the distal 4 cm of the radius. The predicted failure loads calculated from the FE analysis agreed well with those measured in the experiments (R² = 0.75 p < 0.001). Lower correlations were found with bone mass (R² = 0.48, p < 0.001) and bone structural parameters (R² = 0.57 p < 0.001). We conclude that application of the techniques investigated here can lead to a better prediction of the bone failure load for bone in vivo than is possible from DXA measurements, structural parameters, or a combination thereof.     

Bone geometry and density in the skeleton of pre-pubertal gymnasts and school children

We have studied the differences between the peripheral and axial skeleton of pre-pubertal gymnasts and controls. We hypothesised that compared to controls, gymnasts would have larger and stronger radius and tibia diaphyses with greater bone mineral content and larger cross-sectional muscle area. At the distal metaphyseal sites of the radius and tibia, gymnasts would have greater bone cross-sectional area and total and trabecular volumetric bone mineral density (vBMD). Differences between the lumbar spine, total body and body composition in gymnasts versus controls were also studied. Peripheral quantitative computed tomography (pQCT) was used to measure bone geometry, density and muscle of the peripheral skeleton; dual energy X-ray absorptiometry (DXA) for total body and axial measurements.

Eighty-six pre-pubertal children, 44 gymnasts (mean age 9.0 years, range 5.4–11.9 years) and 42 controls (mean age 8.8 years, range 5.6–11.9 years) were studied. Eighty-four children were Caucasian, one child was mixed race, one Chinese. Data were adjusted for age, sex and height. Differences in the effect size between sexes were also tested.

At the 50% radius diaphysis gymnasts had larger bones (9.2%, p = 0.0054) with greater cortical area (8.2%, p = 0.022) and stress strain index (surrogate measure of bone strength) than controls (13.6%, p = 0.015). The effect size was different between males and females for cortical thickness (p = 0.03). At the 65% tibia diaphysis, gymnasts had greater cortical area (5.3%, p = 0.057) and thickness (6.2%, p = 0.068) than controls; consequently, bone strength was 5.4% higher (p = 0.14). There were no significant differences in cortical volumetric bone mineral density (vBMD) at the radius or tibia diaphysis between the groups. There was a difference in effect size for tibia muscle cross-sectional area between the sexes (p = 0.035). At the distal radius and tibia total and trabecular vBMD was greater (Total: radius 17%, p < 0.0001, tibia: 5.7%, p = 0.0053; trabecular: radius 21%, p < 0.0001, tibia 4.5%, p = 0.11). Bone size was not different in gymnasts compared to controls

Lumbar spine BMC (12.3%, p = 0.0007), areal bone mineral density (aBMD) (9.1%, p = 0.0006) and bone mineral apparent density (BMAD) (7.6%, p = 0.0047) were greater in gymnasts but vertebral size was not significantly different. Likewise, total body BMD (3.5%, p = 0.0057) and BMC (4.78%, p = 0.085) were greater in gymnasts but there were no differences in skeletal size.

These data suggest site-specific differences in how the pre-pubertal skeleton develops in response to the repetitive loading it experiences when participating in regular gymnastics. At diaphyseal sites these differences are predominantly in the bone and muscle geometry and not density. Conversely, at trabecular sites, the differences are increased density rather than geometry.

In conclusion, the present study has demonstrated skeletal differences between gymnasts and controls. These differences appear to be site and sex specific.     

Effects of sciatic neurectomy on the femur in growing rats: Application of peripheral quantitative computed tomography and Fourier transform infrared spectroscopy

The effects of unilateral sciatic neurectomy (USN) on the development of the femur were studied in 15 growing Wistar-derived rats (age, 5 weeks). The rats were divided into four groups: USN-operated group (right femur), USN-nonoperated group (left femur), sham-operated group (right femur), and sham-nonoperated group (left femur). Bone mineral density (BMD), bone mineral content (BMC), bone area, periosteal circumference, and endosteal circumference were measured by peripheral quantitative computed tomography (pQCT) and the mineral/matrix ratio was evaluated by Fourier transform infrared spectroscopy (FTIR). The USN-operated group showed a significant decrease in cortical BMC, bone area, and periosteal circumference compared with the other groups (P < 0.05). The cortical BMD did not vary significantly between the groups. In the cancellous bone, the USN-operated group showed a significant decrease in BMD and BMC at the metaphysis compared with the other groups (P < 0.05). The mineral/matrix ratio of the cortical bone did not differ significantly between the USN-operated and USN-nonoperated groups. These results suggest that in cortical bone, USN inhibits periosteal bone formation but has no significant effect on the mineral/matrix ratio of cortical bone in femurs. In cancellous bone, USN induces bone loss at the metaphysis. Received: Nov. 19, 1998 / Accepted: Feb. 12, 1999     

Peripheral computed tomography (pQCT) detected short-term effect of AAACa (heated oyster shell with heated algal ingredient HAI): A double-blind comparison with CaCO3 and placebo

Trabecular bone density at the distal radius and cortical bone density at the midradius were measured in four randomized groups of women before and after 4 months administration of AAACa, oyster shell heated under reduced pressure with addition of heated algal ingredient (HAI) (group A); AACa, the same preparation without HAI (group B); CaCO₃ (group C); and placebo (group D) in a double-blind system using peripheral quantitative computed tomography (pQCT) with lumbar spine density measurement by dual-energy X-ray absorptiometry (DXA). Groups A, B, and C received 900 mg/day elemental calcium and D received none. In subjects of group A, but not B, C, and D, radial trabecular bone density increased significantly, to 106.2% ± 2.1% of the initial value (mean ± SEM). The increase of trabecular bone density was significantly different from the placebo group (D) only in AAACa (group A) and not in AACa (group B) and the calcium carbonate (group C). Cortical bone density increase was also greater in group A (but not in B and C) than in D. Lumbar spine density did not change significantly. AAACa was apparently more effective, increasing trabecular bone density more than AACa and CaCO₃ containing the same amount of elemental calcium. Received: July 17, 1999 / Accepted: Dec. 27, 1999     

The Effects of Geometric and Threshold Definitions on Cortical Bone Metrics Assessed by In Vivo High-Resolution Peripheral Quantitative Computed Tomography

This study evaluates in vivo methods for calculating cortical thickness (Ct.Th) with respect to sensitivity to tissue-level changes in mineralization and the ability to predict whole-bone mechanical properties. Distal radial and tibial images obtained from normal volunteers using high-resolution peripheral quantitative computed tomography (HR-pQCT) were segmented using three thresholds including the manufacturer default and ±5% in terms of equivalent mineral density. Ct.Th was determined in two ways: using a direct three-dimensional (3D) method and using an annular method, where cortical bone volume is divided by periosteal surface area. D _comp (mg HA/cm³) was calculated based on the mean density-calibrated linear attenuation values of the cortical compartment. Finite element analysis was performed to evaluate the predictive ability of the annular and direct Ct.Th methods. Using the direct 3D method, a ±5% change in threshold resulted in a 2% mean difference in Ct.Th for both the radius and tibia. An average difference of 5% was found using the annular method. The change in threshold produced changes in D _comp ranging 0.50-1.56% for both the tibia and radius. Annular Ct.Th correlated more strongly with whole-bone apparent modulus (R ² = 0.64 vs. R ² = 0.41). Both thickness calculation methods and threshold selection have a direct impact on cortical parameters derived from HR-pQCT images. Indirectly, these results suggest that moderate changes in tissue-level mineralization can affect cortical measures. Furthermore, while the direct 3D Ct.Th method is less sensitive to threshold effects, both methods are moderate predictors of mechanical strength, with the annular method being the stronger correlate.     

Effects of Gender and Age on the Association of Apolipoprotein E ε4 with Bone Mineral Density,Bone Turnover and the Risk of Fractures in Older People*

The aim of this study was to examine whether the presence of apolipoprotein E ε4 (ApoE ε4) is associated with a lower bone mineral density (BMD), lower quantitative ultrasound (QUS) measurements, higher bone turnover and fracture risk, and whether these relations are modified by gender and age. A total of 1406 elderly men and women (≥65 years) of the Longitudinal Aging Study Amsterdam (LASA) participated in this study. In all participants, QUS measurements were assessed, as well as serum osteocalcin (OC) and urine deoxypyridinolin (DPD/Cr urine). Follow-up of fractures was done each three months. In a subsample (n = 604), total body bone mineral content (BMC) and BMD of the hip and lumbar spine were measured. In addition, prevalent vertebral deformities were identified on radiographs. In women, the presence of ApoE ε4 was associated with significantly lower femoral neck BMD (g/cm²; mean ± SEM; ε4+, 0.64 ± 0.01 vs. ε4−, 0.67 ± 0.01; p= 0.04), lower trochanter BMD (g/cm²; mean ± SEM; ε4+, 0.58 ± 0.01 vs. ε4–, 0.61 ± 0.01; p= 0.01) and lower total body BMC (g; mean ± SEM; ε4+, 1787 ± 40.0 vs. ε4–, 1863 ± 23.8; p= 0.04). Women with ApoE ε4 also had a higher risk of severe vertebral deformities (OR=2.78; 95%CI: 1.21–6.34). In men, the associations between ApoE status and both hip BMD and QUS depended on age. Only among the younger men (65–69 years) was the presence of ApoE ε4 associated with lower BMD values. Bone markers and fractures were not associated with ApoE ε4 in either women, or men. In conclusion, this large community-based study confirms the importance of ApoE ε4 as a possible genetic risk factor related to BMD and vertebral deformities and demonstrates that its effect is gender related, and depends on age in men only. Received: 6 July 2001 / Accepted: 2 April 2002     

Postmenopausal Women With Colles'' Fracture Have Lower Values of Bone Mineral Density Than Controls as Measured by Quantitative Ultrasound and Densitometry

Measurement of ultrasonographic parameters provides information concerning not only bone density but also bone architecture. We investigated the usefulness of ultrasonographic parameters and bone mineral density (BMD) to evaluate the probability of Colles' fracture. Two-hundred eighty-nine postmenopausal women (62.3 +/- 8.7 yr) with (n = 76) and without (n = 213) Colles' fracture were studied. BMD of lumbar spine and proximal femur was evaluated in all women by dual-energy X-ray absorptiometry (DXA) and speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness in the calcaneus were measured by a Sahara ultrasonometer (Hologic). Patients suffering from Colles' fracture had lower values of BMD adjusted by height at the lumbar spine, L2-L4 (0.797 g/cm2 vs 0.860 g/cm2), femoral neck (0.685 g/cm2 vs 0.712 g/cm2 ), SOS (1518 m/sg vs 1525 m/sg), and stiffness (74.6 vs 77.7) (p < 0.05). Nevertheless, BUA values were similar in both groups. After stepwise logistic regression analysis, the area found under receiver operating characteristic (ROC) curves was 0.60 for L2L4 and 0.63 for a formula combining L2L4 and height. Our data suggest that patients suffering from Colles' fracture have lower values of BMD by DXA, SOS, and stiffness. However, the ability of these techniques to discriminate is low because the values for the area under ROC curve are 0.60 for L2-L4 and 0.63 for a formula derived of the combination of L2-L4 and height.     

Quantitative Bone Mineral Assessment at the Forearm: A Review

Bone mineral density and geometric properties of the human forearm can be measured to determine the amount of bone or bone loss at the scanning site and to predict the risk of forearm fractures. These forearm mesurements are also used to estimate bone mass at remote anatomical locations and thereby estimate the risk for spine, hip and other fractures. The peripheral location of the human forearm, with its relatively small amount of surrounding soft tissue, improves the accuracy and the precision of bone mass measurement and has made this site an early choice for the assessment of a subject's bone mineral status. Furthermore, the anatomy of the human radius enables the examination of both cortical and cancellous bone. This review describes the procedures for non-invasive bone assessment at peripheral sites including some of the more recently developed systems dedicated to assessment of the distal radius. The accuracy, precision and normative values they provide are presented. Responses to different forms of therapies as well as the ability to discriminate or predict osteoporotic fractures are also assessed. Low radiation dose, comfortable and fast handling, moderate cost, and a strong association with the risk of non-spine fractures, promote the use of forearm scanning as a widely applied screening procedure for the detection of generalised osteoporotic bone loss. However, a higher accuracy of fracture risk prediction at the spine or at the hip can be achieved by a direct bone density measurement at these sites. The monitoring of treatment at the distal forearm appears to require a longer follow-up time due to its decreased responsiveness compared with such highly trabecular load-bearing sites as the spine and the proximal femur. Received: 4 August 1997 / Accepted: 13 November 1997     

Factors Associated with Cortical and Trabecular Bone Loss as Quantified by Peripheral Computed Tomography (pQCT) at the Ultradistal Radius in Aging Women

Peripheral quantitative computed tomography (pQCT) allows the separate determination of cortical and trabecular bone mineral density in the peripheral skeleton. This cross-sectional study was designed to examine the effects of healthy aging on pQCT measurements at the ultradistal radius. In a well-defined sample of 129 community-based women, aged 70–87 years, the differences in cortical and trabecular density over the age range were equivalent to losses of −0.41% and −0.65% per year, respectively. To investigate the mechanism of this age-related decline, we assessed relationships between both parameters and height, weight, body mass index, dietary calcium intake, grip strength, and serum concentrations of insulin-like growth factor-I (IGF-I), calcidiol (25(OH)D₃), calcitriol (1,25(OH)₂D₃), parathyroid hormone (PTH), and sex hormone binding globulin (SHBG). Multiple regression was used to adjust for potential confounders. Age was not significant after controlling for other covariables. Body mass index, grip strength, serum IGF-I, 25(OH)D₃, and PTH (1–84) were found to be independent predictors of total bone density. Including (total or free) 1,25(OH)₂D₃ did not improve the model precision. These findings provide evidence that, among other factors, the activity of the growth hormone-IGF-I-axis is of importance for skeletal integrity. Grip strength, serum IGF-I, and PTH (1–84) were discovered to be significantly related to cortical but not to trabecular density, suggesting that different mechanisms may be involved in compact and cancellous bone loss. Received: 2 May 1996 / Accepted: 18 June 1996     

Dynamic Effects of the Third Generation Bisphosphonate of Risedronate on Rat Osteoporotic Fractures for Clinical Usage Guidance

ObjectiveTo better understand the risks of bisphosphonates in order to develop guidance for appropriate clinical usage, to compared femoral fracture healing at different time points and to explore the effects of Residronate on fracture healing.MethodsOsteoporosis model was achieved by ovariectomy surgery, followed by surgical incision of left femoral shaft 4 weeks after ovariectomy surgery. Three days after fracture surgery, risedronateor saline was fed by intragastric administration. X ray examination was used to check the callus formation, Bone Mineral Density (BMD), Bone Mineral Content (BMC), biomechanical, imaging and micromorphological of bone tissue as well as the trabecular bone parameters were all examined. The femoral pathology tissue of each rat was used to analyze trabecular bone parameters, including trabecular bone volume/tissue volume (Tb. BV/TV), bone surface to tissue volume ratio (BS/TV), trabecular bone mineral density (Tb. BMD), trabecular bone number (Tb. N), trabecular bone thickness (Tb. Th) and small bone Trabecular bone space (Tb. Sp).Results Via X‐ray and pathologically, risedronate treatment promoted the callus forming at the fracture site during the following 6 weeks after osteoporotic fracture by X‐ray (P < 0.01), increased the local bone mineral density (P < 0.01), and accelerated the fracture healing during the first 3 weeks (P <0.01), but delayed facture healing in the later 3 weeks (P < 0.01). Risedronate increased the bone continuity of fracture at 7th week, but this phenomenon was not found at the 10th week (P < 0.01). Delayed fracture healing occurred locally at the fracture site. At 7th week, Risedronate may promote cartilage cells proliferating at fracture site, increase the dense of bone trabeculae and the connection of bone trabeculae, thicken the bone cortex showing better fracture healing than OPF‐Saline groups (P < 0.01). However, these parameter did not continue during the 7th and 10th weeks. Comparing the first and the later 3 weeks, the rats in group Osteoporotic Fracture‐Risedronate (OPF‐RD) accelerated the local fracture healing in the first 3 weeks but not in the last 3 weeks, which is consistent for the BMD and BMC among each group (P < 0.05). Through evaluation of bone mineral density and bone mineral content, risedronate dramatically increased the BMD at the fracture site and resulted in reduction of BMC by risedronate at the fracture site (P < 0.05) among each group still exist, indicating dramatic (P < 0.05). Through load testing, Risedronate increased the structural strength and mechanical indexes of the new callus (P < 0.01).ConclusionRisedronate can improve the structural strength and mechanical index of newborn callus. Longer than 7 weeks usage of third generation bisphosphonate of risedronate does not contribute to osteoporotic fracture.     

Relative Influence of Physical Activity, Muscle Mass and Strength on Bone Density

In a population-based sample of 348 men (age 22–90 years) and 351 women (age 21–93 years), we evaluated the relationship of bone density assessed at a variety of skeletal sites by dual-energy X-ray absorptiometry (DXA) with various muscle mass estimates obtained also from the DXA scan and with physical activity by interview and strength assessed both subjectively and objectively. All these parameters declined with age as judged from these cross-sectional data. All estimates of total skeletal muscle mass were strongly correlated with bone density at different skeletal sites. Muscle mass, in turn, was correlated with physical activity and hand strength. In multivariate models including these variables, muscle mass was the strongest determinant of bone density, accounting for 6–53% (mean 27%) of the variance at the different skeletal sites. Physical activity (and/or a physical activity × age interaction) was an independent predictor of bone mass in 48% of the site-specific models and accounted for 0.03–39% (mean 10%) of the variance, while hand strength (and/or a hand strength × age interaction) accounted for up to 4% (mean 1%) of the variance as an independent predictor of bone density in a third of the models. Although these variables together accounted for a large proportion of the variance in bone density, other potential predictors were not assessed in these analyses. The dramatic decline in physical activity over life seemed unable to completely explain the age-related loss of bone mass, and additional research is needed to determine whether the relationship of muscle mass with bone density is a direct one or due instead to other factors such as circulating hormone levels. Received: 2 December 1999 / Accepted: 12 May 2000