Milk, rather than other foods, is associated with vertebral bone mass and circulating IGF-1 in female adolescents.

SUMMARY: Low calcium intake hampers bone mineral acquisition in adolescent girls. This study explores dietary calcium sources and nutrients possibly associated with vertebral mass. Milk intake is not influenced by genetic variants of the lactase gene and is positively associated with serum IGF-1 and with lumbar vertebrae mineral content and density. INTRODUCTION: Low calcium intake hampers bone mineral acquisition during adolescence. We identified calcium sources and nutrients possibly associated with lumbar bone mineralization and calcium metabolism in adolescent girls and evaluated the possible influence of a genetic polymorphic trait associated with adult-type hypolactasia. METHODS: Lumbar bone mineral content (BMC), bone mineral density (BMD), and area, circulating IGF-1, markers of bone metabolism, and -13910 LCT (lactase gene) polymorphism; and intakes of milk, dairy products, calcium, phosphorus, magnesium, proteins, and energy were evaluated in 192 healthy adolescent girls. RESULTS: After menarche, BMC, BMD, serum IGF-1, and serum PTH were tightly associated with milk consumption, but not with other calcium sources. All four parameters were also associated with phosphorus, magnesium, protein, and energy from milk, but not from other sources. Girls with milk intakes below 55 mL/day have significantly lower BMD, BMC, and IGF-1 and higher PTH compared to girls consuming over 260 mL/day. Neither BMC, BMD, calcium intakes, nor milk consumption were associated with -13910 LCT polymorphism. CONCLUSIONS: Milk consumption, preferably to other calcium sources, is associated with lumbar BMC and BMD in postmenarcheal girls. Aside from being a major source of calcium, milk provides phosphates, magnesium, proteins, and as yet unidentified nutrients likely to favor bone health.

Sympathetic B antagonist prevents bone mineral density decrease induced by labyrinthectomy.

We previously showed that bilateral vestibular lesion in rats induces a bone loss in weight bearing bones. To determine whether this effect is mediated by the sympathetic nervous system (SNS), bone mineral density (BMD) was measured in 4 groups of 10 female Wistar rats: bilateral labyrinthectomy (Bilab), Bilab with propranolol treatment, sham operated with or withoutpropranolol. In untreated rats, 30 days after lesion Bilab animals showed a reduced BMD in distal femoral metaphysis comparatively to intact rats (p < 0.001). In treated rats, there was no difference in BMD 30 days after lesion. This protective effect of propranolol against bone loss suggests that the vestibular system influence on bone remodeling is mediated by SNS. If this hypothesis is correct, this could have important consequences in devising countermeasures to spaceflight induced bone loss.

[Treatment of pediatric obesity: effects on body composition and physical fitness]. / Prise en charge ambulatoire de l'obésité: effets sur la composition corporelle et la capacité aérobie.

AIMS: To assess the efficiency of an ambulatory weight management programme of pediatric obesity, including 1 gymnastic session per week, on body composition and physical fitness (max). SUBJECTS: Fifteen adolescents participated in the 9-month intervention. BMI and fitness and physical activity assessed by a questionnaire were evaluated at baseline, and after intervention. RESULTS: Prepubescent subjects (N=6): no significant change of BMI, body composition, nor max. Pubescent subjects: significant decrease of BMI, and z score BMI, and % fat mass, increase of fat free mass. Activity questionnaire: non-significant trend to decreased TV watching, significant increase in practice of physical activity during weekend. CONCLUSION: A modest increase in physical practice, included in the dietary-behavioural management of adolescent obesity, is able to improve overweight and physical fitness.

The evolution of weight and body composition in renal transplant recipients: Two-year longitudinal study.

UNLABELLED: Previous series have reported weight gain after kidney transplantation. However few studies have investigated the body composition after kidney transplantation, particularly during longitudinal follow-up. In this prospective study, we assessed the changes in body composition after kidney transplantation. We also analyzed the effect of steroid withdrawal from the immunosuppressive regimen on weight gain and body composition. METHODS: Thirty-eight cadaveric kidney transplant recipients were followed for 2 years posttransplant. Total and segmental body composition were measured by dual energy X-ray absorptiometry (DEXA) at the time of transplantation as well as 3, 6, 12, and 24 months later. RESULTS: In 28 patients (group A), prednisone was stopped by month 6, whereas, in 10 patients (group B), it was continued throughout the study. In the overall patient group, there were no significant changes in body weight. However, a trend to increased weight was observed in group B. In this group, patients showed an early increase in total body fat with a central accumulation of fat mass that was maintained during the follow-up period. On the other hand, total lean mass increased significantly in group A but did not change significantly in group B. CONCLUSION: In summary, overall the group showed no major changes in body weight during the 2 years after transplantation. Steroid withdrawal in kidney transplant recipients may have a significant positive effect on body composition.

Relationship between bone mineralization and aluminium in the healthy infant.

OBJECTIVE: This prospective study was designed to assess the relationship between variations of serum Aluminium levels and bone mineralization, which is one of its target tissues, in healthy premature (PT) and fullterm (FT) infants. STUDY DESIGN: Lumbar spine bone mineral density (BMD) and content (BMC) studied by dual energy X-ray absorptiometry were compared to serum aluminium (S-Al), Ca (S-Ca), P (S-P), osteocalcin, alkaline phosphatase activity (S-AP), and 25 OH Vitamin D (25 OH D) by simple and multiple regressions in healthy PT (n = 44) following their hospital discharge and FT (n = 82). PT (gestational age at birth (mean +/- 1 s.d.) 32 +/- 2 weeks) and FT were 43 +/- 39 and 36 +/- 32 weeks old respectively. RESULTS: In PT multiple stepwise regression analysis including gestational age at birth, postconceptional age and postnatal age displayed only a significant correlation between BMD or BMC and postnatal age and a negative one with S-Al. In FT correlations were found between BMD or BMC and age and S-Ca. CONCLUSIONS: In PT, variations in blood Al are associated with developmental delays. Care should be taken to lessen Al levels, even in healthy PT babies.

Noninvasive methods of bone-mass measurement.

The most widely used noninvasive methods of bone mass measurement include: single photon absorptiometry (SPA), quantitative computed tomography (QCT), dual photon absorptiometry (DPA and DEXA). SPA is used to measure bone mineral content (BMC) of the distal radius. Its advantages are low cost and high precision in vivo (less than 2%), however, correlation between axial and appendicular bone values is poor. Since vertebral fracture is the first complication of osteoporosis, spinal values are the most useful. QCT measurements are performed using available CT scanners and either single or dual energy scanning techniques, computed radiographs for localizing regions-of-interest (ROI) and mineral reference standards for calibration. The advantage of QCT is that it can evaluate pure trabecular bone at the midplane of two to four lumbar vertebral bodies. Single energy in vivo reproducibility is 2-5% in osteoporotics. Radiation exposure with most systems is 100-500 mRem. With DPA scanners, the commonest radiation source used is Gadolinium-153 (44-100keV). The areas of measurement are lumbar vertebrae L2, L3 and L4 and the femoral neck. In vivo lumbar measurement precision is at least 1-2% and radiation exposure is low (less than 10 mRem). DEXA scanners use an X-ray rather than gamma ray source to emit dual energy photons. The advantages of the technique are shorter scan time, lower radiation exposure (less than 3 mRem) and higher precision (less than 1%). In conclusion, measurement of vertebral bone, particularly using DPA and DEXA, is of value in assessing the risk of osteoporosis and in monitoring changes in bone mineral content.

[Bone mineral density and biological markers of bone repair in patients with adrenal incidentaloma: effect of subclinical hypercortisolism]. / Densité minérale osseuse et marqueurs biologiques de remaniement osseux chez des patients porteurs d'incidentalome surrénalien: effet d'un hypercortisolisme infraclinique.

PURPOSE: Some adrenal incidentalomas produce cortisol in mild excess ('subclinical' Cushing's adenomas) and can potentially induce osteopenia. Their diagnosis is usually based on exclusive tumour uptake on adrenal scintigraphy using 131I-6 beta-methyl-iodo-19-norcholesterol and on inadequate cortisol response to dexamethasone (DXM) suppression tests. The aims of the present study were to evaluate bone mineral density (BMD) and metabolic markers of bone turnover in patients with incidentalomas and to test the effect of mild hypercortisolism on bone parameters. METHODS: Thirty-five patients (13 men, 22 postmenopausal women, 49-76 years) with unilateral incidentaloma were studied. BMD was measured by dual X-ray absorptiometry. Two biochemical markers of bone formation, serum osteocalcin (BGP) and bone alkaline phosphatase (bALP), and two markers of bone resorption, urinary free deoxypyridinoline (D-Pyr) and urinary carboxy-telopeptide of bone type 1 collagen (CTX), were measured by radioimmunoassay. D-Pyr and CTX were corrected for creatinine excretion. RESULTS: Median values of lumbar and femoral T-score were -1.125 and -0.920, respectively, whereas corresponding Z-score values where normal (0.105 and 0.120, respectively). Thirty-nine percent of patients had low serum BGP values and 3% had low bALP values; 16% showed elevated D-Pyr/creatinine values and 23% increased CTX/creatinine values. Patients both with suppression of the contralateral adrenal on scintigraphy and with an inadequate cortisol response to 1 mg DXM (> 50 nmol/L) (n = 14) presented a lower femoral T-score (P < 0.02) and, to a lesser extent, a lower femoral Z-score (P = 0.11) than other patients (n = 21). The proportion of increased values of CTX/creatinine (42% versus 11%, P = 0.08) also tended to be higher in the first than in the second group of patients. These two groups of patients were similar in terms of age, but tumour size was larger (P < 0.04) and plasma ACTH value was lower (P < 0.02) in patients with scintigraphic and endocrine abnormalities. CONCLUSION: Subclinical hypercortisolism defined on the basis of scintigraphic and hormonal criteria seems to contribute to bone loss in patients with adrenal incidentaloma. As other possible side effects of mild hypercortisolism, these findings have to be taken into account in the therapeutic management of these patients.

[Gonadal function in primary apparent male osteoporosis. 12 cases]. / Etude de la fonction gonadique au cours de l'ostéoporose masculine en apparence primitive. Douze cas.

The testicular endocrine function was studied in 12 patients aged from 33 to 76 years (mean: 56.3 +/- 11.5 years) presenting with an apparently primary vertebral osteoporosis and in 14 age-matched controls (mean: 52.6 +/- 12.8 years). The mean bone mineral content, measured in the vertebral column by biphoton absorptiometry, was lower in patients than in control (P +/- 0.01). Plasma levels of testosterone, oestradiol, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were the same in both groups. In two patients of each group, a rise of LH with normal testosteronaemia was suggestive of compensated Leydig's cell deficiency. There was no correlation between bone mineral content, plasma testosterone, LH, FSH level and the subjects' weight and height. However, a positive correlation was found between plasma oestradiol level and bone mineral contents in patients with osteoporosis (P +/- 0.01) ans in all subjects under study (P +/- 0.05). This study shows that primary osteoporosis is not due to testicular deficiency and suggests a possible action of oestradiol on male bone.

[Dual x-ray absorptiometry assessment of bone density of the proximal tibia in advanced-stage degenerative disease of the knee]. / Evaluation de la densité osseuse mesurée par absorbtiométrie biphotonique à rayons X DXA (dual x-ray absorbtiometry) de l'extrémité supérieure du tibia dans la gonarthose évoluée.

PURPOSE OF THE STUDY: Axial deformity secondary to degenerative joint disease of the knee can modify stress forces. Certain studies have reported an inversely proportional relationship between degenerative disease and osteoporosis. The aim of this prospective study was to quantify the horizontal linear distribution of bone density using dual x-ray absorptiometry (DXA) of the proximal tibia as a function of the femoral neck bone density in patients with knee osteoarthritis. MATERIAL AND METHODS: Between September 1996 and March 1998, 90 cases of primary degenerative joint disease of the knee were programmed for total knee arthroplasty. Prior to the procedure, the patients were assessed clinically and radiologically according to the International Knee Society (IKS) criteria. The mechanical femorotibial angle was measured in all patients and the varus angles were recorded. Most of the patients were women (65 p. 100) with a mean age of 70 +/- 5 years. Valgus knees were excluded from this series. The mean mechanical femorotibial angle was 172 +/- 5 degrees. Fifteen patients had a normal axis (16 p. 100), 32 had a varus measuring 4 degrees to 10 degrees (35 p. 100) and 43 had a varus measuring 10 degrees or more (48 p. 100). The overall varus distance was 6.4 +/- 2 cm. All patients had two DXA explorations: femoral neck to determine the bone status according to the WHO criteria (normal, osteopenia, osteoporosis), knee to determine the linear distribution of bone density of the proximal tibia. A 7 mm high band including 7 regions of interest covering the width of the tibia were explored in the area where the tibial cut was to be made. These 7 regions of interest were: R1, R2 under the lateral compartment, R6, R7 under the medial compartment, and R3, R4, R5 on either side of the tibial spines. The level of significance was set at 5 p. 100. RESULTS: The mean Z score (0.54 +/- 1) in the 90 patients showed a symmetrical distribution. These patients were representative of their age range. Their T score was - 1.40 +/- 1 (m +/- SD) and most had osteopenia (54 p. 100) according to the WHO criteria, although 16 p. 100 had osteoporosis. Mean bone density of the knee was 0.898 +/- 0.163 g/cm(3) and was correlated with that of the femoral neck (r=0.61, p=0.001). There were significant correlations between the differences in the bone densities of the knee compartments (R6-R2, R7-R1) and the mechanical femorotibial angle [(r=0.39, p=0.0001); (r=0.52, p=0.001)]. Irrespective of the overall bone density, there was a strong medial compartment overloading, which correlated with the degree of varus deformation. CONCLUSION: DXA assessment of bone mineral density of the proximal tibia is a simple, reliable, precise and reproducible method. The distribution of bone density in the degenerative knee depends on the degree of deformation. The average level depends on the subject's general state of mineralization. Osteoporosis does not protect against degeneration of the knee joint since 16 p. 100 of our patients had osteoporosis according to the WHO criteria.

Comparison and cross-calibration of DXA systems: ODX-240 and Sophos L-XRA versus Hologic QDR-4500, for spinal bone mineral measurement. Translation of a reference database.

Replacement of dual-energy X-ray densitometry equipment may be necessary in time as a result of upgrading systems or new equipment. The lack of standardization in bone mineral density (BMD) measurements is known. Standardization efforts have been made for several years by the European Union under its organization COMAC-BME (Comité d'Actions Concertés-BioMedical Engineering) and by the International Committee for Standards in Bone Measurement. Cross-calibration is generally considered to be the result of linear regression between the measurements obtained with two densitometers. A major disadvantage of the regression method is the noncompatibility of the two formulae of calibration (Y versus X and X versus Y). In this study we considered cross-calibration in terms of a structural model that produced circular equations when, for example, three systems were cross-calibrated. Cross-calibration in this study was calculated from the measurement of the lumbar BMD of a population of 204 patients, with Hologic QDR-4500, ODX-240 and Sophos L-XRA systems. In vitro accuracy and short-term reproducibility of the three systems were studied. Using the structural calibration equation we transformed a reference database for L2-4 BMD obtained from a population of 983 French females, aged 11-47 years, on an ODX-240 to a reference database for a Hologic QDR-4500. A new young adult reference was obtained and consequently a new evaluation of the T-score for the Hologic QDR-4500.

[Postmenopausal osteoporosis: early detection of subjects at risk using spinal dual photon absorptiometry]. / Ostéoporose post-ménopausique: dépistage précoce des sujets à risque par absorptiométrie biphotonique rachidienne.

With quantification techniques of the spinal bone condition, especially with spinal biphotonic absorptiometry, early screening of patients risking subsequent development of osteoporosis complicated with vertebral compression is possible. An investigation was conducted in Lower Normandy, in 386 women who had undergone menopause or an ovariectomy, with ages ranging between 40 and 56 years; 274 were in a peri-menopausal state. We had previously established a curve of the bone mineral content according to age. From this curve, in semilogarhythmic representation, we assessed each patient's risk. This risk is considered as high in 30 p. cent of the patients, non existent in 52 p. cent and 18 p. cent are borderline. The percentage of high risk patients increases with the number of years since menopause. It is hoped that the incidence of osteoporosis will decrease with early screening and preventive therapeutic measures.

[Arthroscopy of the knee. Diagnostic value. 1005 cases]. / Arthroscopie du genou. Intérêt diagnostique. 1 005 cas.

The authors have performed 1 005 arthroscopies of the knee for diagnostic purposes. The exploratory method has made it possible to correct the initial diagnosis in 50% of the cases, to avoid arthrotomy in 10% and to suggest surgery in 9%. The most common cause of error was the radioclinical confusion between patellar and medial meniscus symptoms. The most frequent associated lesions were patellar chondropathy (73%), condylar chondropathy (33%) and middle patellar folds (34%).

Heritability of bone mineral density.

OBJECTIVE: To evaluate the influence of genetic background as a determinant of peak bone mass. PATIENTS AND METHODS: We compared lumbar spine bone mineral density in 175 girls with a bone age of 16 years or older and in their premenopausal mothers. We also investigated the influence of a family history of osteoporosis on lumbar spine bone mineral density in 275 women and their 559 daughters. RESULTS: In the 175 mother-daughter pairs, heritability (h2) was significantly different from 0 (P < 0.0001) for lumbar spine bone mineral density (h2 = 53%; 95% confidence interval [95% CI] = 28.5-77.6%), bone mineral content (h2 = 62.3%; 95% CI = 37.7-86.8%), bone mineral density adjusted for body mass index (h2 = 56%; CI = 31.5-80.5%), and bone mineral content adjusted for body mass index (h2 = 68.2%; CI = 43.6-92.7%). However, the heritability estimations lacked accuracy, as shown by the wide 95% CIs. Osteopenia and osteoporosis were found in 16.4% and 1% of the mothers, respectively. In the subgroup defined by osteopenia or osteoporosis in the mother, lumbar spine bone mineral density was significantly higher in the daughters than in the mothers (0.994 +/- 0.095 g/cm2 versus 0.895 +/- 0.098 g/cm2; P < 0.0001), whereas the opposite was true in the subgroup defined by normal bone mass in the mothers (1.068 +/- 0.110 g/cm2 versus 1.109 +/- 0.098 g/cm2; P = 0.0003). Nevertheless, lumbar spine bone mineral density was significantly lower in the daughters of low-bone-mass women than in those of normal-bone-mass women (0.994 +/- 0.009 g/cm2 versus 1.069 +/- 0.012 g/cm2; P = 0.0006). These findings suggest a role of genetic factors inherited from the father and also indicate that bone mass gains during adulthood contribute to achievement of the optimal peak bone mass. In the family history study, bone mass was lower in the subjects with a family history of osteoporosis (123 of the 559 daughters, Z-scores normalized for height, weight, and pubertal status: bone mineral density Z-score, -0.054 +/- 1.104; bone mineral content Z-score, -0.014 +/- 1.079; 58 of the 275 mothers: bone mineral density, 1.048 +/- 0.107 g/cm2; bone mineral content, 43.3 +/- 6.8 g) than in those without a family history of osteoporosis (436 daughters, bone mineral density Z-score, 0.006 +/- 0.981; bone mineral content Z-score, -0.007 +/- 0.985; 217 mothers: bone mineral density, 1.070 +/- 0.127 g/cm2; bone mineral content, 43.8 +/- 6.7 g); however, none of these differences were statistically significant. CONCLUSION: Our findings challenge the currently popular concept of marked bone mass heritability but are consistent with early genetic influences on lumbar spine bone mass. Thus, optimization of the peak bone mass acquired during growth may help to prevent osteoporosis.

Clinical usefulness of a bone mineral measurement method on the femoral shaft.

An improved version of a previously described photon absorptiometry method for measuring the bone mineral content of the femoral shaft is presented. The study included 267 healthy persons, who served as control subjects, and 31 osteoporotic and 3 osteomalacic female patients. A monoenergetic source of 241Am was used and a fully automatic apparatus designed. The examinations were recorded with an independent microcomputer and secondarily processed by the nuclear unit central computer. The guidelines of Cameron and West were used to perform various calculations from the initial absorption curve, and the clinical usefulness of these was tested. On the one hand, cortical bone density (CBD) and bone linear attenuation coefficient (BLAC) were found adequately to differentiate between osteoporotics and controls, but we defined a discriminative function (F) which allowed even better separation between the two groups. On the other hand, bone index (BI) was found to be the best parameter to follow an individual patient during therapy. These results underline the usefulness of these calculations for detecting and monitoring the progress of pathological states.

In corticosteroid-treated respiratory diseases, monofluorophosphate increases lumbar bone density: a double-masked randomized study.

The efficacy of a monofluorophosphate-calcium combination (MFP-Ca) in increasing lumbar bone mineral density (BMD) was assessed in a prospective double-masked study. Patients (n = 35), who had been treated for 1 year or more with prednisone-equivalent doses > or = 7 mg/day for asthma or other respiratory diseases, were randomly assigned to receive twice a day, for 2 years, either one MFP-Ca tablet [100 mg sodium monofluorophosphate (13.2 mg F-) + 500.5 mg Ca2+] or one Ca tablet (500.5 mg Ca2+). BMD was measured from L2 to L4 using a dual photon absorptiometer. The eligible patients (7 premenopausal women, 21 men), who had no previous vertebral fractures and were aged 46.5 (21-65) years, had received 18 (7.5-60) mg prednisone-equivalent/day and had a mean lumbar BMD of 0.917 +/- 0.141 g/cm2 at baseline (MO); in these 28 patients, the mean increase in lumbar BMD at final assessment was significantly greater in the MFP-Ca group (p = 0.05; Mann-Whitney). There was also a significant difference after 2 years between the two groups (p = 0.05, ANOVA) in favour of MFP-Ca, with an increase in lumbar BMD of 11% (MFP-Ca) compared with 1% (Ca); thus, with MFP-Ca, lumbar BMD increased by an average of approximately 5.5%/year. There was no statistically significant difference between the two groups in doses of corticosteroids used during the 2 study years, rate of vertebral fractures, or frequency of side-effects (which were all minor). No bone fissure was observed. Thus, the daily dose of 200 mg monofluorophosphate (26.4 mg F-) combined with 1 g Ca2+ in patients with long-term corticosteroid-treated respiratory diseases appears to be a safe and efficient way of increasing lumbar BMD, suggesting that its use should be further studied in corticosteroid-induced osteoporosis.

Evolution of lumbar bone mineral content during adolescence and adulthood: a longitudinal study in 395 healthy females 10-24 years of age and 206 premenopausal women.

In a longitudinal study of 395 normal 10- to 24-year-old female volunteers, 105 of whom were initially premenarcheal, lumbar bone mineral density (BMD) and content (BMC) were measured by dual-energy X-ray absorptiometry (DXA) at inclusion and after a 2-year interval. The mean age of menarche was 13.1 +/- 1.1 years (n = 395). In a multiple regression analysis the BMD and BMC relative gains were highly correlated with the height and weight relative gains and with the time since menarche (r = 0.91 and r = 0.93, respectively). The mean relative annual increments in body height, in L2-4 vertebral height, in BMD and in BMC peaked respectively at 1.5, 1.0, 0.6 and 0.7 years before menarche. The four perimenarcheal years, beginning with the first pubertal clinical signs, are essential for bone acquisition, since 46.7% of adult BMC is acquired during this period. Two years after menarche, BMC is 85% of the adult value. Seven years after menarche no further significant variation in BMC is observed. In 206 menstruating women 27-47 years old, a DXA lumbar measurement was also performed after a 4-year interval. There was a small but significant increase of 0.3%/year in BMD and 0.7%/year in BMC, contrasting with the results in the young population. This could be explained by a volumetric expansion with aging, which is supported by a small increase in L2-4 area (0.4%/year). In conclusion, this longitudinal study on the lumbar site emphasizes the importance of the pre- and perimenarcheal period, when half of lumbar adult BMC is acquired. This suggests that greater attention must be paid to this period regarding nutrition and physical activity.

Distribution of bone mineral density at the proximal tibia in knee osteoarthritis.

One hundred and thirteen knees with osteoarthritis (OA) were studied to assess the distribution of bone mineral density (BMD) in the proximal tibia and the potential relation between osteoarthritis and osteoporosis in evaluating hip BMD. All patients had severe knee pain and were diagnosed with Kellgren and Lawrence grade IV osteoarthritis. According to the magnitude of the axial deformity, four categories were created: varus>10 degrees ( 28.3%), varus 4-10 degrees (38.9%), aligned 180 +/- 3 degrees (13.3%), and valgus>4 degrees (19.5%). For each category, the medial and lateral proximal tibial density were assessed. BMD was measured at the femoral neck and at 14 regions of interest (ROI) in the proximal part of the tibia using dual X-ray absorptiometry. Based on the femoral neck BMD, patients were classified according to the World Health Organization (WHO) definition of osteoporosis. The mean knee BMD was positively correlated with the hip BMD value (knee BMD m = 0.38 + 0.73 x hip BMD, r = 0.60, P<0.001). The knee BMD distribution of the 113 patients was negatively correlated with the axial deformity (BMD MT-LT = 5.15 - 0.027 x HKA, r = 0.77, P<0.0001). In the varus deformity, BMD of the medial side was higher than that of the lateral side with an important asymmetry (0.587 g/cm2). This asymmetry was also found in the valgus deformity for the lateral side but was less important (-0.112 g/cm2). With equal deformity, the asymmetry of BMD was higher in varus deformity (0.587 g/cm2) than in valgus deformity (-0.112 g/cm2). Asymmetry of the knee BMD distribution revealed that progression of the deformity (either varus or valgus) with joint space narrowing led to an increase in the medio-lateral difference of the proximal tibia density. Lesser severity of Kellgren and Lawrence grades may reveal different results. Twenty patients with osteoporosis developed knee osteoarthritis (OA) and the relation between osteoporosis and knee OA remains unclear.

[Spinal biphotonic absorptiometry]. / L'absorptiométrie biphotonique rachidienne.

Spinal biphotonic absorptiometry allows a quantitative investigation of bone mineralisation. The study of a control and an osteoporotic population allowed the definition of the fracture threshold independent of age and the curve of the variation in the mineral content with aging. A good correlation was observed with computed tomography. The criteria of definition of a population at risk for the purposes of a longitudinal study are proposed. Biphotonic absorptiometry is an excellent examination for the detection of demineralisation and for the monitoring of treated subjects.