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PubMed1995

Changes in bone mineral density of the proximal tibia after uncemented total knee arthroplasty. A 3-year follow-up of 25 knees.

We measured bone remodeling of the proximal tibia prospectively for 3 years after uncemented total knee arthroplasty (TKA) in 25 knees with primary arthrosis. In the trabecular bone below the tibial component, bone mineral density (BMD) was measured in 6 different regions of interest (ROI), using dual photon absorptiometry (DPA). In the tibial condyles, where the change in knee alignment indicated that the load was reduced postoperatively, a fast bone loss of 7-20% was seen during the first 6 months after surgery. A small, but significant increase in BMD of 2-7% was seen in the tibial condyles, where the load was increased. On average, the density for all ROI below the tibial component showed a significant and progressive decrease in BMD, reaching 22% at 3 years follow-up.

Absorptiometry, Photon↗

PubMed1996

Decreased bone density of the distal femur after uncemented knee arthroplasty. A 1-year follow-up of 29 knees.

We measured the early adaptive bone remodeling of the distal femur prospectively for 1 year after uncemented total knee arthroplasty (TKA) in 29 knees with primary arthrosis. 18 patients were randomized to receive a PCA Modular femoral component (n 9) or a modified version of the same prosthesis (n 9) with an altered location of the porous coating. The other 11 patients (n 11) formed a consecutive series with the Duracon femoral component. In the trabecular bone above the femoral component, bone mineral density (BMD) was measured in 2 regions of interest (ROI) anteriorly to the fixation pegs (ROI 1) and above the pegs (ROI 2), using dual photon absorptiometry (DPA). There were no differences between the Modular component and the modified version regarding the postoperative decrease in BMD. There was a decrease in BMD in both ROI 1 and ROI 2 with all 3 different femoral components, and in both ROIs the highest bone loss rate was observed during the first 3 months after surgery. On average (n 29), a significant bone loss of 44% and 19% in ROI 1 and ROI 2, respectively, was reached at the 1-year follow-up, compared to the initial values. A decrease of this magnitude in BMD in the anterior distal femur 1 year after TKA may be an important determinant of periprosthetic fracture and later failure of the femoral component. In this experimental set-up, a modified femoral component with an altered location of the porous coating did not influence the development of bone loss.

Absorptiometry, Photon↗

PubMed1998

Effect of nasal salmon calcitonin on post-traumatic osteopenia following ankle fracture. A randomized double-blind placebo-controlled study in 24 patients.

With the aim of preventing postfracture osteopenia, we randomized 24 patients with internally fixed ankle fractures to 3 months of treatment with placebo or 200 IU nasal salmon calcitonin (sCT) in a prospective, double-blind design. 3 patients were excluded, leaving 11 patients in the placebo group and 10 in the sCT group for study. Bilateral measurements of bone mineral content (BMC) in the coronal plane of the proximal tibia were performed by dual photon absorptiometry (DPA) postoperatively within 7 days of the fracture and after 1.5, 3 and 6 months. 3 months after the fracture, BMC in the injured legs had decreased by 14% in the placebo group and 2.1% in the sCT group. This difference was not statistically significant. In the healthy legs, a statistically significant intergroup difference was seen 6 weeks after the fracture, caused by a tendency towards a decrease in BMC of 4.6% in the placebo group, while BMC in the sCT group had increased by 7.4%. Nasal sCT may to some extent, but in this study not significantly, reduce postfracture osteopenia, and cause a significant effect on BMC in the healthy leg.

Absorptiometry, Photon↗

PubMed1995

[A study of osteopenia in elderly diabetic patients].

It is well known that IDDM cases can be complicated with osteopenia, but most of these results were reported using single photon absorptiometry. There have been few reports of diabetic osteopenia using dual energy X-ray absorptiometry (DXA), a method that is excellent for precise bone mineral measurement. Osteoarthritis and osteophytes of unknown origin in the lumbar vertebrae are often observed in elderly NIDDM patients. In this study, we examined the clinical characteristics of decreased bone mineral density (BMD) and whether anteroposterior (AP) scanning of the lumbar vertebrae (L2-L4) provides sufficient informations concerning osteopenia in elderly diabetic patients. The study was performed using DXA, which can quantify regional BMD throughout the body. The BMD in the total body and that in the lumbar vertebrae were measured by DXA (Lunar Co.) in 68 diabetics over age 60, 33 males and 35 females, mean age 68 +/- 8 yr, (mean +/- SD) and in 94 middle-aged diabetics (40 to 59), 56 males and 38 females, mean age 51 +/- 4 yr. The percentage of decrease in regional BMD in diabetic patients differed significantly by age and gender. The BMD in the head and spine especially decreased after menopause in women. However, the BMD of the leg and spine did not decrease with age in men. When the BMD of the lumbar vertebrae was plotted against the Y axis and the BMD in the total body against the X axis, the slope of the curve showed a greater increase in elderly diabetics than that in middle aged diabetics (1.8 vs 1.5) suggesting the BMD in the lumbar vertebrae has been overestimated.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1994

Bone mineral content of the spine and proximal femur in female patients with hip fracture.

Measurement of bone density in the spine and hip by quantitative computed tomography (QCT) and dual photon absorptiometry (DPA) was performed in 36 women with hip fracture. Hip density by DPA was determined at three anatomic subregions of the hip. Comparison to normals revealed an average decrease in hip bone density by 15% below controls. Spine density measurements were not significantly different from that of controls. Correlations of hip and spine densities varied by hip subregion. This study demonstrated that bone density measurement methods and measurement at one axial site may not accurately reflect bone density at appendicular subregions.

Absorptiometry, Photon↗

PubMed1990

Bone density of élite female athletes with stress fractures.

To investigate whether stress fractures occurring in élite female athletes are related to reductions in bone mineral density (BMD), we measured BMD in nine athletes with such fractures and nine athletes without fractures who were matched for age, weight, height and sport. BMD was measured in three regions: upper limbs (distal radius), axial skeleton (lumbar spine) and lower limbs (femoral neck) by photon absorptiometry. The number of menses per year was significantly less (P less than 0.04) and the age of menarche was significantly delayed (mean +/- SD; 16.1 +/- 0.4 v. 14.4 +/- 1.5 years, P less than 0.02) in the fracture group compared with the non-fracture group. There was no significant difference in BMD between the two groups at any of the measurement sites. Moreover although the fractures occurred mainly in lower limb bones, at sites characterised by predominantly cortical bone, all athletes had femoral neck BMD values within the 95% confidence limits for normal non-athletic women. We conclude that stress fractures in élite female athletes are largely independent of BMD.

Absorptiometry, Photon↗

PubMed1990

[Bone mineral content after successful renal transplantation].

In the present investigation, serial measurements of bone mineral content before and after successful renal transplantation were evaluated by single photon absorptiometry, using a Bone Mineral Analyser (Norland Corp., USA). Twenty-four renal transplant recipients, whose grafts were well functioning for more than 6 months, were the subjects of this study; they were divided into two groups: one was AZP group which includes 12 patients receiving azathioprine and high dose of steroid and another was CYA group which includes 12 patients receiving cyclosporin A and low dose steroid as immunosuppressants. In both groups patients were similar in regard to age, source of donor, duration on dialysis prior to transplant. Variation rate of bone mineral content was calculated as follows: b-a/a x 100 (a; value before transplantation, b; value after transplantation). Nonpaired t-test was used when comparing the values of both groups. The results were as follows: 1) AZP group showed no improvement of BMC after 24 months, but only one patient showed improvement of BMC after 36 months. 2) In CYA group, improvement of BMC was found in 5 out of 11 patients after 12 months, in 7 out of 10 patients after 24 months and in 4 out of 4 patients after 36 months. 3) The cumulative dose of methyl-prednisolone was significantly lower in CYA group than in AZP group both one and three months after transplantation (p less than 0.001). It is concluded that the cumulative dose of methyl-prednisolone may have an important factor in the recovery of bone.

Absorptiometry, Photon↗

PubMed2000

Bone mineral density and risk of incident and progressive radiographic knee osteoarthritis in women: the Framingham Study.

OBJECTIVE: To examine the relations of bone mineral density (BMD) and change in BMD to risk of incident and progressive radiographic knee osteoarthritis (OA) in a longitudinal cohort study. METHODS: Female participants aged 63 to 91 years (mean age 71) in the Framingham Study received anteroposterior weight bearing knee radiographs at biennial examinations 18 (1983-85) and 22 (1992-93). Knee radiographs were given scores for global severity of OA (Kellgren-Lawrence scale: range 0 to 4) and for the presence of osteophytes and joint space narrowing (range 0 to 3). Femoral neck BMD was assessed using dual photon absorptiometry at examination 20 and dual x-ray absorptiometry at examination 22. We examined the relations of BMD at examination 20 and its change between examination 20 and examination 22 to incident and progressive knee OA, as well as to worsening of individual radiographic features adjusting for age, body mass index, and other potential confounding factors. RESULTS: In total, 473 women (ages 63 to 91 yrs) had complete assessments. Over 8 years of followup, risk of incident radiographic knee OA increased from 5.6% among women in the lowest age-specific quartile of BMD to 14.2, 10.3, and 11.8% among women in the 2nd, 3rd, and highest quartiles, respectively. Multivariate adjusted OR of incident OA for each increase quartile of BMD were 1.0, 2.5, 2.0, and 2.3, respectively (p for trend = 0.222). This was mainly reflected in an increased risk of osteophyte development. However, risk of progressive OA decreased from 34.4 to 22.0, 20.3, and 18.9% as BMD increased. Compared to those in the lowest quartile of BMD, adjusted OR for progressive disease were 0.3, 0.2, and 0.1 among women in the 2nd, 3rd, and highest quartiles (p for trend <0.001), respectively, mainly due to its effect on lowering the risk of joint space loss. Compared to those who lost BMD >0.04 g/cm2 over the followup period, women who gained BMD were at increased risk of incident but at a significantly decreased risk of progressive knee OA. BMD change was not associated with osteophyte development, but gain in BMD lowered the risk of joint space loss. CONCLUSION: High BMD and BMD gain decreased the risk of progression of radiographic knee OA, but may be associated with an increased risk of incident knee OA. The protective effect was mainly through its influence on reducing the risk of joint space loss. Our results offer insights into how bone may affect the course of the most common joint disease, and thus may have potential therapeutic implications.

Absorptiometry, Photon↗

PubMed1995

Current methods and advances in bone densitometry.

Bone mass is the primary, although not the only, determinant of fracture. Over the past few years a number of noninvasive techniques have been developed to more sensitively quantitate bone mass. These include single and dual photon absorptiometry (SPA and DPA), single and dual X-ray absorptiometry (SXA and DXA) and quantitative computed tomography (QCT). While differing in anatomic sites measured and in their estimates of precision, accuracy, and fracture discrimination, all of these methods provide clinically useful measurements of skeletal status. It is the intent of this review to discuss the pros and cons of these techniques and to present the new applications of ultrasound (US) and magnetic resonance (MRI) in the detection and management of osteoporosis.

Absorptiometry, Photon↗

PubMed2001

Prediction of bone fracture by bone mineral density in Taiwanese.

BACKGROUND AND PURPOSE: This study evaluated whether lumbar spine bone mineral density (BMDL) and the rate of change of BMDL could predict the risk of bone fracture in Taiwanese. METHODS: In 1989, a baseline survey was carried out in Lin-Kou Township. BMDL was measured using dual photon absorptiometry in 404 healthy volunteers. In 1994/95, a second survey was conducted to reexamine the BMDL and fracture history as well as the risk factors associated with fracture in these subjects. Fractures were classified according to the causes of the injury as severe or mild trauma. RESULTS: Of the 404 original examinees, 381 (79%) participated in the second survey. Twenty-six subjects had experienced a total of 32 fracture incidents during their lifetime and 10 subjects had experienced fracture during the observation period. After adjusting for the effect of body mass index, gender, and age, each standard deviation of decrease in BMDL was found to be associated with a significant 2.38-fold increase in the risk of mild trauma fracture, and a BMDL below the fracture threshold was associated with a 3.93-fold increase of fracture risk. Higher BMDL change rates were found in subjects with a history of fracture. CONCLUSION: This study indicates the importance of maintaining the BMDL above the fracture threshold (1 g/cm2). The strategy for fracture prevention should be directed at prevention of age-related bone loss.

Absorptiometry, Photon↗

PubMed1999

[Relationship between bone mineral density and blood and urine biochemical indices in women].

OBJECTIVE: To study the relationship between bone mineral density (BMD) and some biochemical indices in their blood and urine of women. METHODS: Fasting urinary calcium (Ca) and creatinine (Cr), ratio of Ca to Cr, urinary hydroxyproline (Hyp), ratio of Hypr to Cr were determined in 163 healthy women, and activity of serum alkaline phosphatase (AKP) were determined in 182 healthy women. BMD at the 1/10 lower end and 1/3 middle-lower site of the radius were measured with single photon absorptiometry for all of them. RESULTS: Serum AKP and ratio of urinary Hyp/Cr increased with age, especially postmenopause, and correlated negatively with BMD. Fasting urinary Ca/Cr ratio also increased with age, especially postmanopause, but not correlated with BMD. CONCLUSION: Serum AKP and fasting urine Hyp/Cr ratio could be used as indicators to reflect bone remodeling and absorption, respectively.

Absorptiometry, Photon↗

PubMed2000

[Bone mineral density and exercises: a cross-sectional study on Chinese athletes].

OBJECTIVES: To evaluate the effect of exercise to osteoporosis by bone mineral density (BMD) measurement of athelets comparing normal individuals in general population. METHODS: BMD of radium, lumber spine, and femoral neck were measured by single photon absorptiometry (SPA), quantitative CT (QCT), and dual X-ray absorptiometry (DXA) respectively in athletes (n = 162, male 79, female 83) and age matched non-athletes normal population (n = 204, male 91, female 113) in Beijing. RESULTS: BMD of all sites in all age groups of both male and female athletes are significantly higher comparing with that in non-athletic population. This predominance in athletes is even more distinctive in peak bone mass. Peak bone mass of male athletes is significantly higher than that of female athletes. Bone loss with age is less apparent in athletes than in control. However, there is an accelerated decline of BMD in lumber spine and femoral neck in 30-39 year age group in both male and female athletes, which may be due to the wanting of physical exercise. CONCLUSIONS: Long term regular proper exercise started in adolescence may play a very important role in the prevention of osteoporosis by improving peak bone mass and decreasing bone loss.

Absorptiometry, Photon↗

PubMedDate not supplied

[Bone mineral density in cosmonauts after flights lasting 4.5-6 months on the Mir orbital station].

A technique of quantitative digital roentgenography (QDR) being a current modification of dual photon absorptiometry (DPA) was used to measure bone mineral density (BMD) in the crewmembers of the 6-9th expeditions onboard Mir orbital station after space missions of 132 to 176 days in duration. Total mineral losses were, on average, 0.4% of a preflight level, and in the most test subjects the postflight BMD of the skull, ribs and arms increased and that of lumbar vertebrae, pelvis and legs decreased. The most marked local postflight mineral losses occurred in the proximal femur bone (the femoral neck and the greater trochanter--up to 14%). The observed changes did not depend on flight duration. These findings are being compared to the results of similar studies conducted during the 120-day (NASA) and 370-day (IBMP) hypokinesia experiments. The possibility of existing the general mechanism of modifying mineral status of the skeleton due to different situation related deficiency of musculoskeletal load.

Absorptiometry, Photon↗

PubMedDate not supplied

Computed tomography with monochromatic x rays.

Recent advances in the development of synchrotron facilities that provide high-energy and high-flux x-ray beams allow the use of monochromatic x rays at a < 0.5% energy bandwidth (i.e. energy width of < 500 eV at 100 keV) for computed tomography (CT) of humans. Such CT systems will consist of a fixed, horizontal, low-divergence fan beam and a seated subject rotating about a vertical axis. Compared to conventional CT, the new system should significantly improve contrast resolution of the image and provide better image quantification because of its lack of beam-hardening effects and its efficient implementation of energy-selective imaging methods such as dual-photon absorptiometry and K-edge subtraction with high-atomic-number (high-Z) contrast-enhancement elements. Further, the nearly parallel synchrotron x-ray beam geometry minimizes patient-to-detector scattering when the detector is positioned far from the patient. The design considerations and the expected performance of monochromatic CT are described, in particular those of the CT being developed at the National Synchrotron Light Source. The potential applications of the method in neuroradiology, cardiac and vascular imaging, bone densitometry, lung imaging, and radiotherapy are discussed. The future of monochromatic CT in research and in clinical diagnostics is also reviewed, as are the prospects for development of compact sources of x rays with narrow-energy bandwidths.

Absorptiometry, Photon↗

PubMed1992

Bone gain in young adult women.

OBJECTIVE: To test whether bone mass increases in healthy nonpregnant white women during early adult life after cessation of linear growth; and to test whether various self-chosen levels of physical activity and nutrient intake or use of oral contraceptives influences this increase in bone mass. DESIGN: Longitudinal prospective study of up to 5 years of 156 healthy college-aged women full-time students attending professional schools in universities in the Omaha, Neb, area. SETTING: University medical center. PARTICIPANTS: A convenience sample of healthy women students from Omaha-area professional schools. Any candidate with an illness, condition, or medication (except oral contraceptives) thought to affect general health or bone mass was excluded. INTERVENTIONS: None. OUTCOME MEASURES: Clinical and family histories of disease, particularly osteoporosis; oral contraceptive use; bone mineral densities of the spine, forearm, and total body by dual- and single-photon absorptiometry; estimates of nutrient intake by repeated 7-day diet diaries; and measures of physical activity using a physical activity monitor. RESULTS: The median gain in bone mass for the third decade of life, expressed as a percentage per decade, was 4.8% for the forearm, 5.9% for lumbar bone mineral content, 6.8% for lumbar bone mineral density, and 12.5% for total body bone mass (P < .0001 in all cases). By both bivariate and multiple regression analysis the rate of gain in bone density of the spine was negatively correlated with age and positively correlated with calcium/protein intake ratio and physical activity (multiple r = .31; P = .004). Bivariate analysis showed that use of oral contraceptives was associated with greater gain in total body bone mass (r = .31, P = .01). The estimated age when mineral acquisition ceased ranged from 28.3 years to 29.5 years at the several study sites. CONCLUSIONS: Gain in bone mass occurs in healthy young women during the third decade of life. Physical activity and dietary calcium intake both exert a positive effect on this bone gain. Use of oral contraceptives exerts a further independent positive effect. Changes in life-style among college-aged women, involving relatively modest increases in physical activity and calcium intake, may significantly reduce the risk of osteoporosis late in life.

Absorptiometry, Photon↗

PubMed1992

Bone density in postmenopausal women: high impact vs low impact exercise.

This 1 year study examined the effect of high impact and low impact activities on bone mineral density (BMD) at the lumbar vertebrae (L2-L4) in healthy, sedentary, early postmenopausal women. Fifteen subjects whose postmenopausal status was verified by the blood levels of follicle stimulating hormone (FSH) and estradiol were chosen. These subjects were tested on the following variables: BMD via dual photon absorptiometry, heart rate response to the Balke treadmill test, percent fat via skinfolds, and a 3-d dietary analysis. Subjects were matched and then assigned randomly to one of three groups: (a) a control nonexercising group, (b) a low impact exercise group, and (c) a high impact exercise group. The control nonexercising group experienced a significant linear decrease in BMD during the study (F = 12.63, P = 0.002). Both the low and high impact exercise groups maintained BMD during the study (F = 0.04, P = 0.85; F = 1.08, P = 0.31, respectively). The difference in BMD between the low impact and the high impact exercise groups was not significant (F = 0.36, P = 0.55). In conclusion, 20 min of moderate intensity low impact or high impact exercise 3 d.wk-1 for 1 yr is effective in maintaining BMD in early postmenopausal women.

Absorptiometry, Photon↗

PubMedDate not supplied

[Bone density in swimmers].

Bone mineral density of the non-dominant forearm was measured by single-photon absorptiometry at a proximal site (PBMD) and at a more distal site (DBMC) in 9 competitive male swimmers, aged 18 to 23 years, who had been training for 12 +/- 2 years, 10.3 +/- 5.6 hours a week. The results were compared with 25 age-matched controls. PBMD was m +/- SD 0.57 +/- 0.02 g/cm2 in the swimmers and 0.57 +/- 0.05 g/cm2 in the controls. DBMD was 0.45 +/- 0.02 g/cm2 in the swimmers and 0.45 +/- 0.03 g/cm2 in the controls. No difference was found between the two groups. We can therefore conclude that swimming, in absence of gravity, didn't provide our athletes with an effective mechanical load capable to increase bone density of the forearm.

Absorptiometry, Photon↗

PubMed1992

[Radiologic diagnosis of osteoporosis. Current methods and outlook].

Osteoporosis is defined as a decrease in bone mass and structural changes in bone leading to an increase in fractures. Early diagnosis as quantification of prophylaxis and treatment are of great interest. A number of non-invasive techniques are available for measuring bone mass at multiple sites of the skeleton. This article reviews basic methodology and developments in radiography as in x-ray or gamma photon absorptiometry, quantitative computed tomography, ultrasound velocity and attenuation and magnetic resonance imaging. Clinical applications of these methods are discussed. The still experimental use of ultrasound and MRI in assessment of bone-mineral content may also give information on bone quality.

Absorptiometry, Photon↗