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PubMed2001

Age, sex, and grip strength determine architectural bone parameters assessed by peripheral quantitative computed tomography (pQCT) at the human radius.

The purpose of this study was to estimate the relation of some noninvasively derived mechanical characteristics of radial bone including architectural parameters for bone strength to grip strength and muscle cross-section. Sixty-three males between 21 and 78yr of age and 101 females between 18 and 80yr of age were measured at the nondominant forearm using peripheral quantitative computed tomography (pQCT). We assessed the integral bone mineral density (BMD(I)) and content (BMC(I)) by pQCT at the distal and at the mid-shaft radius. Integral bone area (Area(I)), cortical thickness (C-th), and a newly proposed index for bone strength; the stress-strain index (SSI) were also calculated. The dynamometrically measured maximum grip strength was taken as a mechanical loading parameter and muscle cross-section as a substitute for it. Sex, grip strength, BMC(I) and BMD(I) (distal radius) were identified in a multiple regression analysis to significantly predict bone strength as expressed by SSI, after adjusting for all other independent variables, including age and sex (p<0.0001). Grip strength was closest related to age, sex, BMD(I) and SSI(p) of the distal radius. The cross-sectional area of muscle was not significantly determining the grip strength within the analysis model. In conclusion, our results suggested that architectural parameters at the distal radius were better related to grip strength than to cross-sectional muscle area in both males and females. Maximum muscle strength as estimated by grip strength might be a stronger determinant of mechanical characteristics of bones as compared with cross-sectional muscle area.

Adult↗
PubMed2002

The bone behind a low areal bone mineral density: peripheral quantitative computed tomographic analysis in a woman with osteogenesis imperfecta.

Areal bone mineral density (BMD) is the most widely used densitometric parameter. However, this approach makes it difficult to understand the structural basis of bone diseases, because a large number of bone properties are integrated into a single number. This is exemplified in the present case of a 27-year-old woman with osteogenesis imperfecta type I. Peripheral quantitative computed tomographic analysis at the radial metaphysis and at the radial diaphysis revealed a decreased areal BMD at both sites (z score -3.9 and -3.4, respectively). Yet, the structural basis for this decrease was different for the two locations: At the distal radius areal BMD was decreased because volumetric BMD was very low, whereas bone size was above the mean of the reference range. At the proximal radius areal BMD was decreased, because bone size was very low but volumetric BMD was above average. Bone mineral content of the radial diaphysis was very low for forearm muscle size, a finding which is compatible with Frost's hypothesis that the mechanostat setpoint is increased in osteogenesis imperfecta.

Journal Article↗
PubMed2000

Bone mineral density in upper and lower extremities during 12 months after spinal cord injury measured by peripheral quantitative computed tomography.

OBJECTIVE: To evaluate the loss of trabecular and cortical bone mineral density in radius, ulna and tibia of spinal cord injured persons with different levels of neurologic lesion after 6, 12 and 24 months of spinal cord injury (SCI). DESIGN: Prospective study in a Paraplegic Centre of the University Hospital Balgrist, Zurich. SUBJECTS AND METHODS: Twenty-nine patients (27 males, two females) were examined by the highly precise peripheral quantitative computed tomography (pQCT) soon after injury and subsequently at 6, 12 and in some cases 24 months after SCI. Using analysis of the bone mineral density (BMD), various degrees of trabecular and cortical bone loss were recognised. A rehabilitation program was started as soon as possible (1-4 weeks) after SCI. The influence of the level of neurological lesion was determined by analysis of variance (ANOVA). Spasticity was assessed by the Ashworth Scale. RESULTS: The trabecular bone mineral density of radius and ulna was significantly reduced in subjects with tetraplegia 6 months (radius 19% less, P<0.01; ulna 6% less, P>0.05) and 12 months after SCI (radius 28% less, P<0.01; ulna 15% less, P<0.05). The cortical bone density was significantly reduced 12 months after SCI (radius 3% less, P<0.05; ulna 4% less, P<0.05). No changes in BMD of trabecular or cortical bone of radius and ulna were detected in subjects with paraplegia. The trabecular BMD of tibia was significantly reduced 6 months (5% less, P<0.05) and 12 months after SCI (15% less, P<0.05) in all subjects with SCI. The cortical bone density of the tibia only was decreased after a year following SCI (7% less, P<0.05). No significant difference between both groups, subjects with paraplegia and subjects with tetraplegia was found for tibia cortical or trabecular BMD. There was no significant influence for the physical activity level or the degree of spasticity on bone mineral density in all subjects with SCI. CONCLUSIONS: Twelve months after SCI a significant decrease of BMD was found in trabecular bone in radius and in tibia of subjects with tetraplegia. In subjects paraplegia, a decrease only in tibia BMD occurred. Intensity of physical activity did not significantly influence the loss of BMD in all subjects with para- and tetraplegia. However, in some subjects regular intensive loading exercise activity in early rehabilitation (tilt table, standing) can possibly attenuate the decrease of BMD of tibia. No influence was found for the degree of spasticity on the bone loss in all subjects with SCI.

Adult↗
PubMed1998

Comparison of three-point bending test and peripheral quantitative computed tomography analysis in the evaluation of the strength of mouse femur and tibia.

We compared the mechanical and densitometric testing methods in evaluating the mechanical strength of mouse cortical bones. The femora and tibiae of 10 male mice (weight 32.8 +/- 4.0 g) were utilized. Volumetric cortical bone mineral density (vCtBMD), cross-sectional cortical area at midshaft (CSA), cross-sectional moment of inertia (CSMI), and strength strain index (SSI) were measured by peripheral quantitative computed tomography (pQCT). The precision of pQCT expressed as a coefficient of variation (CV) was 1.1%, 2.7%, and 6.4% for vCtBMD, CSA, and CSMI, respectively. The mechanical properties were measured by a three-point bending test. The method error measured from paired bones was 7.3%-10.1% for breaking bending force, 15.0%-15.2% for stiffness, 2.0%-2.4% for vCtBMD, 5.2%-6.4% for CSA, 13.5%-17.6% for CSMI, and 8.9%-18.1% for SSI. CSMI and CSA were found to be the best explanatory variables for the breaking force of femur and tibia, respectively, while CSA and CSMI were the best predictors for the elastic modulus of femur and tibia, respectively. CSA had a higher correlation with mechanical parameters than vCtBMD. On the basis of this study, the mechanical tests and the pQCT measurements are relevant in biomechanical studies on mouse bones and justify the use of the murine model. High-resolution pQCT gives better precision than the three-point bending test in studies of mouse bones.

Animals↗
PubMed2001

Modeling of cross-sectional bone size, mass and geometry at the proximal radius: a study of normal bone development using peripheral quantitative computed tomography.

It is becoming increasingly accepted that bone size is an important determinant of bone mass. Studies on the development of bone size may therefore promote a better understanding of the basis of diseases which are due to low bone mass. Here, we characterize the temporal changes in cross-sectional bone size, geometry and mass at the radial diaphysis in healthy subjects from 6 to 40 years of age (n = 469; 273 females). Peripheral quantitative computed tomography was used to measure total and cortical cross-sectional area, bone mineral content (BMC) and volumetric bone mineral density (BMD) at the site of the forearm whose distance from the ulnar styloid process corresponded to 65% of forearm length. Over the age range of the study, total cross-sectional area increased by 39 mm2 (50%) in females and by 85 mm2 (116%) in males. Cortical area increased to a similar extent in both sexes. Between 6-7 years and adulthood, BMC increased by 52 mg/mm (111%) in females and by 73 mg/mm (140%) in males and was significantly higher in males after the age of 15 years. Volumetric BMD increased by 246 mg/cm3 (48%) in females but by only 132 mg/cm3 (23%) in males and was significantly higher in women than in men. In summary, these data show that BMC in men is higher than in women, because periosteal modeling continues longer in boys than in girls. Volumetric BMD is higher in women, partly because the size of the marrow cavity does not increase in girls as it does in boys.

Adolescent↗
PubMed2004

Interpretation of whole body dual energy X-ray absorptiometry measures in children: comparison with peripheral quantitative computed tomography.

The assessment of bone health in children requires strategies to minimize the confounding effects of bone size on dual energy X-ray absorptiometry (DXA) areal bone mineral density (BMD) results. Cortical bone composes 80% of the total skeletal bone mass. The objective of this study was to develop analytic strategies for the assessment of whole body DXA that describe the biomechanical characteristics of cortical bone across a wide range of body sizes using peripheral quantitative computed tomography (pQCT) measures of cortical geometry, density (mg/mm(3)), and strength as the gold standard. Whole body DXA (Hologic QDR 4500) and pQCT (Stratec XCT-2000) of the tibia diaphysis were completed in 150 healthy children 6-21 years of age. To assess DXA and pQCT measures relative to age, body size, and bone size, gender-specific regression models were used to establish z scores for DXA bone mineral content (BMC) for age, areal BMD for age, bone area for height, bone area for lean mass, BMC for height, BMC for lean mass, and BMC for bone area; and for pQCT, bone cross-sectional area (CSA) for tibia length and bone strength (stress-strain index, SSI) for tibia length. DXA bone area for height and BMC for height were both strongly and positively associated with pQCT CSA for length and with SSI for length (all P < 0.0001), suggesting that decreases in DXA bone area for height or DXA BMC for height represent narrower bones with less resistance to bending. DXA BMC for age (P < 0.01) and areal BMD (P < 0.05) for age were moderately correlated with strength. Neither DXA bone area for lean mass nor BMC for lean mass correlated with pQCT CSA for length or SSI for length. DXA BMC for bone area was weakly associated with pQCT SSI for length, in females only. Therefore, normalizing whole body DXA bone area for height and BMC for height provided the best measures of bone dimensions and strength. DXA BMC normalized for bone area and lean mass were poor indicators of bone strength.

Absorptiometry, Photon↗
PubMed1998

Accuracy of cortical and trabecular bone measurements with peripheral quantitative computed tomography (pQCT).

In order to assess the accuracy of peripheral QCT (Stratec XCT 960) we analysed scans of the European Forearm Phantom and another phantom consisting of K2HPO4 encased in aluminium tubes to simulate cortical walls. Additionally 14 cadaveric forearm specimen scans were compared to CT scans acquired on a GE9800Q. The accuracy for density assessment of the European Forearm Phantom was better than 3%. A small increase in density was observed with increasing thickness of the aluminium wall (10% for each mm). Density measurements within the wall were confounded by limited spatial resolution. For a thickness of less than 4 mm, the density within the wall was underestimated by up to 40%. The measurement of mineral content was not influenced by this effect and showed an accuracy error of less than 6%. The agreement of density measurements on the different CT systems was very strong (R2 > 0.96; RMSE < 6.2%). Our findings suggest that the Stratec pQCT scanner very accurately measures volumetric trabecular and total bone mineral densities at the distal radius while the assessment of cortical density is associated with considerable inaccuracies due to limited spatial resolution.

Aluminum↗
PubMed1999

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.

Animals↗
PubMed2003

Bone mineral density of the mandible in ovariectomized rats: analyses using dual energy X-ray absorptiometry and peripheral quantitative computed tomography.

INTRODUCTION: Although previous studies have shown that maxillary molar extraction in ovariectomized (OVX) animals causes mandibular loss of bone, it is still questionable as to whether estrogen deficiency affects mandibles with functional occlusion. MATERIALS AND METHODS: To answer this question, 13-week-old female Sprague-Dawley rats were bilaterally OVX or sham-operated. After 109 days, the bone mineral density (BMD) of the femurs and mandibles was measured using dual-energy X-ray absorptiometry (DEXA) and peripheral quantitative computed tomography (pQCT). RESULTS: In DEXA analysis, although the BMD of the total mandible of the OVX rats was similar to that of the sham-operated rats, the BMD of the condylar region in the OVX rats had decreased by 12.5%. In pQCT analysis, decrease in trabecular BMD of the mandibular bone was detectable but low in the molar region (maximal 13%), whereas no difference was seen in cortical BMD. In the femurs, the trabecular bone prominently decreased in OVX rats (30% decrease in pQCT analysis) as previously reported. CONCLUSION: This study revealed regional differences in the mandibular bone decrease in OVX rats. Although the mechanism of low susceptibility of the mandible to estrogen-deficient conditions remains unknown, it is likely that mechanical stress derived from functional occlusion is preventing bone loss in this pathological condition. Furthermore, this study demonstrated the advantage of pQCT in analyzing rat mandibular bone.

Absorptiometry, Photon↗
PubMed2003

Precision and accuracy of peripheral quantitative computed tomography (pQCT) in the mouse skeleton compared with histology and microcomputed tomography (microCT).

UNLABELLED: pQCT was evaluated for accuracy of phenotypic characterization of mouse bone in vivo. Bones (tibia, femur, spine) of 27 animals were measured ex vivo with pQCT, microCT, and histomorphometry and of 23 mice in vivo (pQCT). pQCT yielded satisfactory in vivo precision and accuracy in skeletal characterization. INTRODUCTION: Important aspects of modern skeletal research depend on the phenotypic characterization of genetically manipulated mice, with some approaches requiring in vivo measurement. Peripheral quantitative computed tomography (pQCT) is applicable in vivo and provides opportunities to determine a large variety of bone parameters. Here we test the ex vivo and in vivo reproducibility of pQCT, and its accuracy in comparison with histomorphometry and microcomputed tomography (microCT). MATERIALS AND METHODS: We examined the tibia, femur, and lumbar spine of 27 mice ex vivo with high-resolution pQCT, using two mouse models (wild-type and ob/ob) with known differences in bone density. Measurements were repeated three times at different days in nine animals. In a second experiment, 23 animals (10 wild-type and 13 bGH transgenic mice) were repeatedly measured in vivo at 12 and 13 weeks of age, respectively. RESULTS: Among metaphyseal sites, the ex vivo precision was highest at the distal femur (RMS CV < 1% for density and < 2% for area). The correlation between density (pQCT) and bone volume fraction (histomorphometry) was r2 = 0.79 (tibia, femur, and spine), and that with microCT was r2 = 0.94 (femur). At the diaphysis, the precision was highest at the femur (< 2% for total and cortical area), and the correlation with microCT was r2 > 0.77. The in vivo precision for bone density (distal femur) was 2.3-5.1%, and that for absolute and relative cortical area (tibia) was 3.1% and 2.2%. CONCLUSIONS: The results show that pQCT can yield satisfactory precision and accuracy in skeletal characterization of mouse bones, if properly applied. The potential advantage of pQCT is that it provides a large set of parameters on bone properties and that it can be used in vivo, extending the available methodological repertoire for genetic studies.

Animals↗
PubMed2006

Peripheral quantitative computed tomography (pQCT) is useful for monitoring bone mineral density of the patients who receive hormone replacement therapy.

OBJECTIVE: A forearm fracture (Colles' fracture) is often the first sign of osteoporosis and should alert the patient and physician to the possibility of underlying skeletal fragility. Therefore, the establishment of a more accurate and reliable method for the measurement of bone mineral density (BMD) at the distal radius would be beneficial for the patients who suffer from osteoporosis. The objective of the present study was to evaluate the usefulness of peripheral quantitative computed tomography (pQCT) to assess the change of BMD at the distal radius in early postmenopausal women who receive hormone replacement therapy (HRT). METHODS: Twenty healthy early postmenopausal women who were diagnosed as osteoporosis or osteopenia were randomized to either HRT or placebo treatment. We analyzed BMD of the distal radius by pQCT, lumbar spine by dual-energy X-ray absorptiometry (DXA) and the biochemical markers of bone turn over (osteocalcin, deoxypyridinoline) every 6 months. RESULTS: The placebo group showed a significant decrease from the baseline in the trabecular BMD of the radius at 12 months (7.4+/-2.5%) (p<0.05), whereas the HRT group showed a slight increase (0.7+/-2.2%). The changes in the trabecular BMD of the radius between the HRT and placebo groups were statistically different at 12 months (p<0.05). On the other hand, in the cortical BMD of the radius, no significant differences were seen between the changes of bone densities in the HRT and control groups after 1 year of treatment. pQCT could detect a significant loss of BMD of the radius in early postmenopausal women after 1 year and HRT prevented its loss. CONCLUSION: Our preliminary clinical trial showed that pQCT might be useful for the early detection of bone loss in early postmenopausal women and for the monitoring BMD of the patients who receive HRT.

Absorptiometry, Photon↗
PubMed2001

Intracapsular hip fracture and the region-specific loss of cortical bone: analysis by peripheral quantitative computed tomography.

Generalized bone loss within the femoral neck accounts for only 15% of the increase in intracapsular hip fracture risk between the ages of 60 and 80 years. Conventional histology has shown that there is no difference in cancellous bone area between cases of intracapsular fracture and age and sex-matched controls. Rather, a loss of cortical bone thickness and increased porosity is the key feature with the greatest change occurring in those regions maximally loaded during a fall (the inferoanterior [IA] to superoposterior [SP] axis). We have now reexamined this finding using peripheral quantitative computed tomography (pQCT) to analyze cortical and cancellous bone areas, density, and mass in a different set of ex vivo biopsy specimens from cases of intracapsular hip fracture (female, n = 16, aged 69-92 years) and postmortem specimens (female, n = 15, aged 58-95 years; male, n = 11, aged 56-86 years). Within-neck location was standardized by using locations at which the ratio of maximum to minimum external diameters was 1.4 and at more proximal locations. Cortical widths were analyzed using 72 radial profiles from the center of area of each of the gray level images using a full-width/half-maximum algorithm. In both male and female controls, cancellous bone mass increased toward the femoral head and the rate of change was gender independent. Cancellous bone mass was similar in cases and controls at all locations. Overall, cortical bone mass was significantly lower in the fracture cases (by 25%; p < 0.001) because of significant reductions in both estimated cortical area and density. These differences persisted at locations that are more proximal. The mean cortical width in the cases was significantly lower in the IA (22.2%;p = 0.002) and inferior regions (19%;p < 0.001). The SP region was the thinnest in both cases and controls. These data confirm that a key feature in the etiology of intracapsular hip fracture is the site-specific loss of cortical bone, which is concentrated in those regions maximally loaded during a fall on the greater trochanter. An important implication of this work is that the pathogenesis of bone loss leading to hip fracture must be by a mechanism that varies in its effect according to location within the femoral neck Key candidate mechanisms would include those involving locally reduced mechanical loading. This study also suggests that the development of noninvasive methodologies for analyzing the thickness and estimated densities of critical cortical regions of the femoral neck could improve detection of those at risk of hip fracture.

Aged↗
PubMed1996

Changes in the cortical and trabecular bone compartments with different types of menopause measured by peripheral quantitative computed tomography.

Our objective was to study the changes in the bone mineral density of the cortical and trabecular compartments with different types of menopause. A total of 153 normal postmenopausal women (mean age 48 +/- 5 years) were studied. The women were divided into three groups based on mean age at menopause: early menopause (menopause before 43 years), normal menopause (menopause at 44-52 years), and late menopause (menopause after 52 years). The number of years since menopause was similar in all three groups (+/- 5 years). Cortical and trabecular bone mineral density was determined in all the women using peripheral quantitative computed tomography. Our results show that only the trabecular bone mineral density differed significantly among the groups (Kruskal-Wallis: P = 0.0029). The women with early menopause had a lower trabecular bone density than the women with normal and late menopause (P = 0.0019 and P < 0.0001, respectively). Among the women with early menopause, 22 had experienced menopause before the age of 40 and 25 after the age of 40; there were significant differences in trabecular bone mineral density between these two subgroups (P < 0.05). Trabecular bone mineral density, the only variable studied that varied among the groups, correlated significantly with the duration of reproductive life (simple linear regression: r = 0.340, P < 0.0001). In conclusion, these findings emphasize the importance of the duration of reproductive life as a determinant of bone mass in women.

Adult↗
PubMed2002

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 (microFE) analyses with models based on three-dimensional peripheral quantitative computer tomography (3D-pQCT) images (isotropic voxel resolution of 165 microm) 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, microFE 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 (R(2) = 0.75 p < 0.001). Lower correlations were found with bone mass (R(2) = 0.48, p < 0.001) and bone structural parameters (R(2) = 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.

Aged↗
PubMed2001

Geometric properties of distal radius and pathogenesis of Colles fracture: a peripheral quantitative computed tomography study.

It is well known among clinicians that Colles fracture patients may have normal projected axial bone mineral density and that bone mass is not synonymous with bone strength. The aim of this work was to investigate whether cross-sectional properties of the distal radius in female patients with recent Colles fracture differ from those of a younger group of normal women without fracture. It was hypothesized that patients with Colles fracture had petite distal radii and that cortical thinning and reduced cortical and trabecular volumetric density are dominant features of this fracture type. We used a multilayer high-precision peripheral quantitative computed tomography (pQCT) device with a long-term precision error of 0.1% for a dedicated phantom during the measurement period (152 d). Clinical measurements were made at an ultradistal site rich in trabecular bone and a less ultradistal site rich in cortical bone. The results show that the following pQCT variables were significantly reduced in the nonfractured radius of the Colles fracture cases: mean ultradistal trabecular volumetric density, mean ultradistal and distal cortical volumetric density, mean ultradistal and distal cortical thickness (p < 0.001 for all differences). The outer cortical diameter, cross-sectional bone area, and cortical bending moment of inertia were not statistically different in the two groups. Thus, it would appear that Colles fracture cases did not have petite distal radii. The results suggest that the deforming force of Colles fracture has a transaxial direction (fall on outstretched arm), resulting in a crush fracture, and that it is not a bending force. We suggest that Colles fracture occurs as a result of the combined effect of a fall on the out-stretched arm, low trabecular and cortical volumetric bone density, and reduced cortical thickness.

Adult↗
PubMed2004

Musculoskeletal and functional muscle-bone analysis in children with rheumatic disease using peripheral quantitative computed tomography.

Bone demineralization is a severe complication of juvenile idiopathic arthritis (JIA) and other rheumatic diseases. To identify patients, who are at risk of bone disease, musculoskeletal analysis is performed. Furthermore, a more functional approach is needed to assess, whether bone strength is adequate for muscle force and whether muscle force is adequate for body size. In patients with a chronic disease it is most important to differentiate between primary bone problems and those that are secondary to low muscle force. To implement this approach, we measured musculoskeletal parameters of the radius in 94 patients with juvenile idiopathic arthritis of different subtypes and connective tissue disease using peripheral quantitative computed tomography. The four groups consisted of patients with oligoarticular (n = 31), polyarticular (n = 27), systemic JIA (n = 20) and connective tissue disease (CTD) (n = 16). All patients with systemic JIA and CTD and 56% of the patients with polyarticular JIA were under treatment with glucocorticoids. In general, the longer the duration of the disease and the more severe the subtype of the rheumatic disease, the shorter the height and the lower the bone density and bone strength parameters. Mean height, bone mineral content (BMC) and muscle cross-sectional area (CSA) were low for age, but muscle CSA was normal for height with the exception of patients with polyarticular disease. In the systemic JIA group the ratio of BMC per muscle CSA was decreased by -1.7+/-2.7 SD (P < 0.05), suggesting that bone strength was not adequately adapted to muscle force. This was even more expressed in females than in males (14 versus 3). These patients need closer follow up and potential specific therapeutic intervention.

Adolescent↗
PubMed2001

Comparison of bone parameters by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography in Hutterite vs. non-Hutterite women aged 35-60 years.

A previous report of elevated dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) Z scores suggests that Hutterite females might be significantly less likely to develop osteoporosis compared with other U.S. females. In the present study, we sought to determine if high Hutterite DXA BMD Z scores were elevated because of larger bone size. Hutterites reside in isolated, self-sufficient colonies with an emphasis on agricultural production, and girls enter a strenuous task rotation at age 15 years. We obtained cross-sectional bone measurements of the 66% distal tibia using peripheral quantitative computed tomography (pQCT) to compare bone size and geometry on 97 Hutterite and 30 non-Hutterite women, aged 35-60 years. Total body (TB) and lumbar bone mineral content (BMC), BMD, and bone area measurements by DXA were available on a subset of the study population. We identified no differences between groups in pQCT total bone area, cortical bone area, or cortical bone density. Larger bone area by DXA was apparent in Hutterites compared with non-Hutterites at the TB (least square means: 2038 +/- 8 cm2 vs. 1953 +/- 19 cm2, p < 0.05) and lumbar (least square means: 58 +/- 0.5 cm2 vs. 57 +/- 2 cm2, p < 0.01) sites. TB BMC adjusted for TB bone area was marginally higher in Hutterites compared with non-Hutterites (least square means: 2341 +/- 15 g vs. 2281 +/- 30 g, p = 0.08). Hutterites had marginally higher TB BMD Z scores when controlling for weight and age (least square means: 1.3 +/- 0.1 vs. 0.8 +/- 0.2, p = 0.07). Hutterites had higher lumbar BMC adjusted for lumbar bone area and weight (least square means: 65 +/- 1 g vs. 58 +/- 2 g, p < 0.01) and higher weight-and age-adjusted lumbar BMD Z scores (least square means: 1.1 +/- 0.1 vs. 0.1 +/- 0.4, p = 0.01). Our data indicate that a true advantage in trabecular bone density probably exists among Hutterite women aged 35-60 years. Hutterite women might be protected against age-related fractures because of their larger bone size and higher bone density at normally susceptible trabecular sites.

Absorptiometry, Photon↗
PubMed2004

Effects of unilateral sciatic neurectomy on growing rat femur as assessed by peripheral quantitative computed tomography, Fourier transform infrared spectroscopy and bending test.

We studied the effects of unilateral sciatic neurectomy (USN) on the development of the femoral shaft in the 30 growing Wistar-derived rats aged 5 weeks. Rats were allocated to three groups. One of these was immediately used for measurements, and the remaining 2 groups underwent USN of internal control. Specimens obtained from each group were divided into 2 subgroups: left femurs of each group served as the control subgroup (CONT) and right femurs from each group as the USN-operated subgroup (USN-OP). The 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). A three-point bending test was performed to analyze the biomechanical effects of sciatic neurectomy. USN-OP showed a significant decrease in cortical BMC, bone area, and periosteal circumference compared with CONT. The mineral/matrix ratio of cortical bone did not differ significantly between USN-OP and CONT. Strength and stiffness were significantly decreased in USN-OP compared with CONT. The results showed that USN inhibited periosteal bone formation, but has no significant effects on the mineral/matrix ratio of cortical bone in femurs.

Animals↗