The importance of carrying a backpack in the rehabilitation of osteoporotic patients (biomechanical analysis).

Based on a simple biomechanical analysis available to physicians, the article recommends carrying a backpack regularly as a part of the complex rehabilitation of osteoporotic patients. Carrying a backpack in front or on the back is recommended to patients with uncomplicated osteoporosis, while carrying a backpack on the back only is recommended to patients with osteporotic vertebral fractures. The importance of carrying a backpack is based upon removing the muscular dysbalance of the trunk muscles and upon increasing the bone strength by compressive force acting upon the vertebrae and proximal femur and activating osteoblasts to enhance the process of osteoformation. The backpack load is differentiated--patients with vertebral fractures put a weight up to 1 kg into their backpacks, patients without vertebral fractures increase the load up to 2 kg (Fig. 2, Ref. 12).

Biofeedback load technique in the rehabilitation of osteoporotic patients (biomechanical analysis).

Based on a simple biomechanical analysis, available to physicians, the article recommends carrying a backpack regularly as a part of the complex rehabilitation of osteoporotic patients. Carrying a backpack in front or on the back is recommended for patients with uncomplicated osteoporosis, carrying a backpack only on the back is recommended for patients with osteporotic vertebrae fractures. The importance of carrying a backpack is based upon remove the muscular dysbalance of the trunk muscles and upon increasing the bone strength by compressive force acting upon the vertebrae and proximal femur and activating osteoblasts to osteoformation. The backpack load magnitude is differentiated--patients with vertebrae fractures put a weight up to 1 kg into the backpack, patients without vertebrae fractures up to 2 kg.

Femur strength index versus bone mineral density: new findings (slovak epidemiological etudy).

PATIENTS AND METHODS: We analysed the data in the sample (n = 3,215) of East Slovak women with a primary or secondary osteopenia, osteoporosis and with risk factors for osteoporosis, aged 20-89 years, median 59 years, 95% C. I. (59.31; 60.07) obtained from dual energy X-ray absorptiometry device (Prodigy-Primo, GE, USA). Measured variables: 1. left proximal femur: T-score total hip, FSI (femur strength index), 2. lumbarvertebrae L1-L4: BMD (bone mineral density). OBJECTIVES: 1. To estimate and to compare an expected frequency of pathological FSI < 1 and T-score total hip < or = -2.5 SD values in the East Slovak female population. 2. To estimate expected frequency of women with: FSI < 1 and T-score total hip < -2.5 SD (Group A), FSI < 1 and T-score total hip from interval from -1,0 till -2.5 SD (Group B), FSI < 1 and T-score total hip > -1.0 SD (Group C) in the East Slovak female population. 3. To determine, if FSI variable value is a significant predictor of BMD variable values in lumbar vertebrae. RESULTS: 1. In the East Slovak female population we can expect 14.54% ofwomen with FSI values < 1 and 6.25% ofwomen with osteoporosis in the total hip area according to T-score. 2. For the group A we can expect the mean value (mu) from interval (1.41; 2.36)%, for the group B from interval (4.50; 6.03)% and for the group C from interval (6.76; 8.55)%. 3. Between FSI and BMD L1-L4 variable values there is not a statistically significant dependence, because FSI variable is quantitative and qualitative different variable from BMD variable. CONCLUSION: The measurement of FSI variable values may discover a higher percentage of women with a probability of femoral neck fracture by fall than the measurement of BMD variable value in the total hip area. Patient with osteopenia or normal BMD measured in the total hip area may sustain a femoral neck fracture by fall, when she has pathological value of FSI, i.e. she has adverse values of geometric variables of proximal femur(biomechanically unfavourable proximal femur configuration). FSI variable value is not a significant predictor of BMD variable values in lumbar vertebrae L1-L4.

New approach to probability estimate of femoral neck fracture by fall (Slovak regression model).

PATIENTS AND METHODS: 3,216 Slovak women with primary or secondary osteoporosis or osteopenia, aged 20-89 years, were examined with the bone densitometer DXA (dual energy X-ray absorptiometry, GE, Prodigy - Primo), x = 58.9, 95% C.I. (58.42; 59.38). The values of the following variables for each patient were measured: FSI (femur strength index), T-score total hip left, alpha angle - left, theta angle - left, HAL (hip axis length) left, BMI (body mass index) was calculated from the height and weight of the patients. RESULTS: Regression model determined the following order of independent variables according to the intensity of their influence upon the occurrence of values of dependent FSI variable: 1. BMI, 2. theta angle, 3. T-score total hip, 4. alpha angle, 5. HAL. The regression model equation, calculated from the variables monitored in the study, enables a doctor in praxis to determine the probability magnitude (absolute risk) for the occurrence of pathological value of FSI (FSI < 1) in the femoral neck area, i. e., allows for probability estimate of a femoral neck fracture by fall for Slovak women. CONCLUSION: 1. The Slovak regression model differs from regression models, published until now, in chosen independent variables and a dependent variable, belonging to biomechanical variables, characterising the bone quality. 2. The Slovak regression model excludes the inaccuracies of other models, which are not able to define precisely the current and past clinical condition of tested patients (e.g., to define the length and dose of exposure to risk factors). 3. The Slovak regression model opens the way to a new method of estimating the probability (absolute risk) or the odds for a femoral neck fracture by fall, based upon the bone quality determination. 4. It is assumed that the development will proceed by improving the methods enabling to measure the bone quality, determining the probability of fracture by fall (Tab. 6, Fig. 3, Ref. 22). Full Text (Free, PDF) www.bmj.sk.

Bone quality. Elasticity and strength.

The aim of the article is to explain in more detail the biomechanical methods used in determining bone quality as well as to describe basic characteristic bone qualities resulting from the application of these methods. Mechanical properties of biomaterials are characterised by stress-strain curves, produced on the basis of testing the biomaterials by progressive tensile and compressive load. According to these curves, the bone counts among brittle materials. Stress-strain curves under tensile and compressive load for brittle materials comprise proportional limit, elastic limit, and breaking strength. Recognition of biomechanical characteristics of bone quality (proportional limit, elastic limit, breaking strength) helps physicians to understand the importance of measuring the new parameters in bone densitometry by DXA (dual energy X-ray absorptiometry) such as femoral strength index (FSI), and safety factor (SF) (Fig. 2, Ref. 10). Full text (Free, PDF) www.bmj.sk.

Nordic walking--is it suitable for patients with fractured vertebra?

This article brings the biomechanical analysis of sport--Nordic walking--for patients with osteoporotic fractured vertebrae and shows that it is suitable for them. Based on the biomechanical model of skeletal load we have developed a method of walking movement for patients, different from the method of walking movement for healthy people. And so came into being the "first sport" for patients with osteoporotic fractures. They can go for regular walks in easy terrains outdoors with friends and family, and so be liberated from social isolation. It requires only one-off financial costs of buying the poles and special footwear (Tab. 7, Fig. 3, Ref. 14). Full Text (Free, PDF) www.bmj.sk.

Determination of the centre of gravity in the methodology of kinesiotherapy for osteoporotic patients.

The article brings a biomechanical analysis of the determination of the position of gravity centre of trainee in plane, both graphically and by calculation. The importance of determining the position of the gravity centre in different postures of a trainee should not be underestimated, as it belongs to the basic principles in the development of methodology of kinesitherapy for both healthy and ill people. An erudite methodology of kinesitherapy for osteoporotic patients can be developed only on the basis of biomechanical analysis of each exercise element, i.e., it is necessary to have the knowledge of the position of gravity centre, support area and the distance of the gravity centre projection from the stability limit, magnitude of the stability angle, and regularity of mechanical stress acting upon weakened osteoporotic vertebrae. A correctly chosen methodology of kinesitherapy for osteoporotic patients prevents the development of vertebral microfractures, prevents the patient from falling during the exercise, and stimulates the bone neoformation with increasing the bone mineral density and periosteal apposition of bone, followed by the enlargement of the bone cross sectional area as well as that of the cross sectional moment of inertia. The resulting effect is an improvement in bone quality and its mechanical resistance (Tab. 2, Fig. 7, Ref. 11). Full Text (Free, PDF) www.bmj.sk.

Why is it so important to balance the muscular dysbalance in mm. coxae area in osteoporotic patients?

The article presents a biomechanical model of articulatio and mm. coxae with the characteristics of the vectors of reaction forces generated in flexors and extensors (1) in muscular balance; (2) in muscular dysbalance; (2a) with permanent load of the model of a hip by the body weight; (2b) with simulated live load during a fall or an impact. In case of muscular dysbalance the application of action force on a hip during a fall results in a sharp increase of the reaction compressive force in flexors and the tensile force in extensors. Muscular dysbalance of external (extensors) and internal (flexors) muscles of mm. coxae facilitates in this way complicated splintered fractures in the collum femoris area, and in the pertrochanteric and subtrochanteric areas. Muscular balance achieved by balancing exercises and mechanical protection of the joint reduce the risk of splintered and complicated fractures in the described area (Tab. 1, Fig. 5, Photo 9, Ref. 9).

Biomechanical conditions for maintaining body balance in kinesitherapy of osteoporotic patients.

Regularities of mechanical conditions of body's static and dynamic balance are applied not only in movement techniques of sports events, but also in setting up exercises for osteoporotic patients. It is important to set up exercises in which the patient takes such a position where the forces acting upon him (action forces) are in balance with the forces generated in the patient's musculoskeletal system (reaction forces). On the basis of biomechanical analysis of conditions for maintaining a trainee's body balance in training position, we point out the importance of individual exercise in sitting and prone positions led by a rehabilitation instructor, aiming at the removal of muscular dysbalance, before including the patient in group exercise. Following the preparatory exercise, the patient gains greater muscular strength and is able to keep balanced positions easier while standing. The patient's performance in exercise increases and the risk of falling during group exercise diminishes. The aim of the article is to motivate rehabilitation instructors to set up an erudite methodology of kinesitherapy while meeting the conditions of proportional load of musculoskeletal system of osteoporotic patients, based on the principles of biomechanics (Tab. 2, Fig. 1, Ref. 10).

Serum levels of receptor activator of nuclear factor kappaB ligand (RANKL) in healthy women and men.

BACKGROUND: Osteoporosis is one of the most common conditions associated with aging. It is based on an excess of bone resorption over bone formation, leading to an imbalance of bone turnover. The receptor activator of nuclear factor kappaB ligand (RANKL) is an important regulator of bone metabolism. OBJECTIVE: The aim of this investigation was to evaluate potential age- and gender-related changes in free RANKL and total RANKL (free RANKL+RANKL/osteoprotegerin complexes). METHODS: Two hundred and forty volunteers with a median age of 48 years were included in the study. Serum levels of free RANKL and total RANKL were evaluated. RESULTS: On average, men have a 1.77-fold higher free RANKL level and a 2.12-fold higher free/total RANKL ratio than women of the same age. On average, the RANKL levels decrease by approximately 13% every five years. CONCLUSION: This study showed that serum levels of free RANKL and total RANKL decrease with age, and also revealed some gender-related differences.

Why does depression develop in complicated osteoporosis?

PATIENTS AND METHODS: In a prospective study we observed which female patients developed depression following an acute and painful vertebral fracture. For the statistical evaluation of questionnaires we chose randomly 32 patients with depression (out of 33 patients) aged 51-73, and 32 patients without depression (out of 44 patients) aged 52-70. THE AIM OF THE STUDY: To verify the hypothesis that the patients with more traumatic experience in the anamnesis (Questionnaire No. 1) are more depression prone following the osteoporotic vertebrae fractures and their character features are typical for subjects with higher emotional vulnerability (Questionnaire No. 2). STATISTICAL ANALYSIS: 1. Questionnaires 1 and 2 were evaluated by two statistical methods: a) automatization of mathematical and statistical estimates and tests based on binomial distribution; b) ADALINE Programme. 2. Assessment of relative risk for developing depression. RESULTS AND CONCLUSION: We recommend to use questionnaires No. 1 and 2 in female patients with acute painful vertebrae fractures to select patients with the risk of depression development. These patients should be followed more frequently as outpatients and in case of first clinical symptoms of depression should be recommended for special psychiatric care. Early therapy of depression enables to accelerate the mobilisation, rehabilitation and resocialisation of patients, to improve the quality of their lives and to reduce the costs of analgetic treatment of pain, sedatives and rehabilitation (Tab. 10, Fig. 2, Ref. 17).

Which statistical tests for estimating osteoporotic fracture risk?

The article presents an analysis of statistical methods used for estimating fracture risk in patients with osteoporosis. Mathematical relations of different methods are explained (risk--R, risk ratio--RR, RD--risk difference, odds--O, odds ratio--OR, Yule's Q, Yule's Y, logistic model). What is important to keep in mind is that: 1) relative risk and odds ratio are statistics that only describe an association, not causation; 2) relative risk and odds ratio refer to a population, not to an individual patient; 3) the studies of small groups are more likely to find an association that might actually just be due to chance, the larger the groups, the less likely the association between a risk factor and an outcome (fracture); 4) when the incidence of an outcome of interest in the study population is low (<10 %), the OR is close to the RR, the more frequent the outcome becomes, the more the OR will overestimate the RR when it is more than 1 or underestimate the RR when it is less than 1. Sophisticated statistical packages are available which can calculate many of the tests of association but the problem is that the investigator must know which the desirable is. The incorrect option of statistical analysis, the incorrect interpretation of risk ratio or odds ratio and overestimation of the importance of a risk factor may lead to unintentional errors in the economic analysis of potential programs or treatments in osteoporosis. This article could be a contribution for investigators, who are concerned with assessment of fracture risk.

Draft design of a rehabilitation aid for patients with acute painful fractures of vertebrae.

AIM OF THE STUDY: To model the influence of abduction and adduction of the upper limb on the spinal load with the help of the laws of theoretical mechanics and the application of its results in clinical medicine. BIOMECHANICAL SOLUTION: Biomechanical model of an upper limb is demonstrated as a construction consisting of a lever arm and a joint connection in articulation of the shoulder joint. CONCLUSION: Our application of results of the spine load modelling in relation to excess upper limbs load: A) designing a methodology of active therapy aimed at exercising upper limbs for osteoporotic patients, B) the application of basic principles of motoric activity in daily life, C) the draft design of a rehabilitation aid for patients with acute painful fractures of vertebrae in the thoracic area (Fig. 5, Ref. 17).

[Suggestions for standardized collection of morning urine for assessment of NTx levels in patients with osteoporosis]. / Návrh standardizácie ranného odberu mocu pre stanovenie hladín NTx u pacientov s osteoporózou.

UNLABELLED: The authors examined 79 patients (n = 79) with primary and secondary osteoporosis, incl.31 men (nM = 31) aged 31-61 years and 48 women (nF = 48, aged 33 to 65 years. In these patients they assessed NTx (amino-terminal telopeptide of type I collagen of the Ist organic bone matrix) in 24 (NTx24) and 2-hour morning (NTx2) diuresis (from 6 to 8 a.m.). OBJECTIVE: 1. To assess the relationship between values of NTx in th suggested 2-hour diuresis and NTx values in the standard 24- hour diuresis differentiated by sex. 2. To compare the ratio (index) of widths of 95% confidence intervals (CI) for NTx2 and NTx24 with the ratio (index) of reference widths (manual OSTEX, USA) for NTx in the first morning urine (NTx1) and for NTX24 differentiated by sex. 3. Evaluate the suggested 2-hour diuresis for assessment of NTx. STATISTICAL ANALYSIS: Stochastic-determinist linear regression analysis. RESULTS: 1. Between values NTx24 and NTx2 a statistically significant regression correlation was found (p < 0.001) (men: r = 0.352, women r2 = 0.781). The indices of widths of reference limits (IR) of OSTEX Co. USA reach values 2.1 times higher (0.7 times) than indices of widths of CI for osteoporosis (IO) in men as well as women. CONCLUSION: 1. Between values of NTx24 and NTx2 is a significant regression relation. Both urine samples can be used for assessment of the NTx level. 2. Higher values of IR and IO indices for women as well as men confirm a greater dispersal of NTx1 values as compared with NTx2 values. 3. Introduction of two-hour morning diuresis will reduce the extent of variation of NTx values during repeated examinations and provide more accurate information as compared with assessment of NTx in any of the first morning samples of urine according to instructions of the manufacturers of the kits.

Determination of NTx in second-morning urine: a proposal for the standardization of morning urine collection.

UNLABELLED: According to the instruction manual from the producer of kits for determining the levels of aminoterminal telopeptide of type I collagen of organic bone matrix (NTx), the time of the collection of second-morning urine is arbitrary, i.e., a patient can urinate anytime within the period from about 6 to 8:30 a.m. This time interval is within the period of change in the circadian rhythm of the NTx excretion (maximum excretion with transition into fast decrease of excretion). Therefore, we considered it appropriate to standardize the conditions for the collection of second-morning urine and proposed applying the so-called 2-hour morning urine NTx2 (from 6 to 8.00 a.m. after an overnight fast). We examined 48 female patients aged 33-65 years with primary or secondary osteopenia or osteoporosis (all patients had normal renal functions). In these patients we determined NTx (Osteomark, OSTEX, USA) in standardly used 24-hour urine (NTx24) and in the proposed 2-hour morning urine (NTx2). AIM OF THE STUDY: 1) To find a mathematical character for the dependence of values of dependent variable NTx2 on independent variable NTx24 and to evaluate the statistical significance of this dependence; 2) to compare the ratio of the widths of 95% confidence intervals (C. I.) for NTx2 and NTx24 in patients (index: IO) with the ratio of the widths of reference limits for NTx in arbitrary second-morning urine (NTx2ostex) and in 24-hour urine (NTx24ostex) in healthy women (index: IR); 3) to evaluate the proposed 2-hour urine for the determination of NTx. STATISTICAL ANALYSIS: Stochastic and deterministic linear regressive analysis. Index of 95% C. I., index of reference limits. RESULTS: A statistically significant (P < 0.01) regressive dependence (r2 = 0.781) was found between the values of NTx24 and NTx2. The index for the widths of reference limits (IR) was 1.5 times greater than the index for osteopenic and osteoporotic patients (IO), meaning that the scatter of the NTx2ostex values was greater than NTx2 in the proposed 2-hour urine. CONCLUSION: Based on the statistically significant linear regressive dependence between NTx24 and NTx2 values, it is possible to use the proposed 2-hour morning urine to determine NTx levels in women. The introduction of 2-hour morning urine NTx2 could decrease the fluctuation range of NTx values in repeated examinations and in comparison with the determination of NTx2ostex in a random second-morning urine sample could make its values more accurate.

[Changes in bone mineral density in Th12 to L5 vertebrae in female patients with osteoporosis]. / Zmeny v denzite kostného minerálu v stavcoch Th12 az L5 pacientok s osteoporózou.

UNLABELLED: The authors examined 47 female patients, age 50-60 years, with primary and secondary osteopenia and osteoporosis. In each patients they assessed the bone mineral density (BMD) of the cortical and trabecular bone of vertebrae Th12 to L5 by quantitative computer tonmography (QTC). They did not include in the group patients with deformities of the vertebrae grade one, two and three. These deformities were assessed from a lateral X-ray of the thoracic and lumbar spine. OBJECTIVE: To evaluate the importance of assessed BMD values of vertebrae from the biomechanical aspect. STATISTICAL ANALYSIS: Individual groups of assessment of BMD in cortical and trabecular bone for each vertebra were characterized by means of 95% confidence intervals and their means or median values. RESULTS: The BMD of cortical bone increases from Th12 to L5 almost in a linear fashion. BMD of the trabecular bone declines from Th12 to L3, in L4 abd L5 it rises again. The lowest values were recorded in L3. The greatest decline of BMD of the trabecular bone by 24.05% in L3 as compared with reference values of the given age groups were not conditioned by deformities of the vertebrae. The BMD of cortical bone in osteopenic and osteoporotic patients practically did not differ from reference values for the given age group. CONCLUSION: From the presented work ensues that deformities of the vertebrae do not occur as long as the BMD of cortical bone is within the range of reference values despite a decline of BMD in trabecular bone. It is thus more important to investigate the material qualities of cortical bone because the risk of fractures of the vertebrae depends on the elasticity and firmness. Critical BMD values of cortical bone assessed by QCT for the development of fractures are not known so far. QTC of vertebrae due to its higher radiation load and financial costs is not a routine densitometric method. It will be necessary to develop new densitometric methods which will make it possible to assess BMD or another property of cortical bone and assess critical values for the development of vertebral fractures.

[Bone density and its quality]. / Kostná hmota a jej kvalita.

The paper presents the newest knowledge on bones quality, which becomes the main criterion for evaluation of fracture risks and osteoporosis treatment effects. It is necessary to develop new methods of measurement and quantification of bones quality, with regard to the properties of all bone structures, not solely the bone mineral density (BMD) as it was until now. From the most recent studies follows: 1. bone stiffness depends not only on BMD but also on the bone quality, 2. antiosteoporotic treatment can reduce the fracture incidence without significant rise of BMD, 3. BMD is not always an reliant marker of all treatment procedures efficiency in osteoporosis, 4. it is necessary to develop new diagnostic methods for bone quality quantification with the possibility of exact fracture risk determination, 5. in future the influence of antiosteoporotic drugs on bone quality, i.e. on all structures, not only BMD, will be studied. (Ref. 8.)

[Paget's disease of bone--treatment with alendronate, calcium and calcitriol]. / Pagetova kostná choroba--liecba alendronátom, kalciom a calcitriolom.

In the submitted case-history the authors describe the clinical picture, diagnosis and treatment of the non-complicated form of Paget's disease in a 68-year-old patient with typical X-ray findings on the vertebrae, pelvis and left tibia. The laboratory findings revealed liminal alkaline phosphatase (ALP) values, 2.5 times raised values of the aminoterminal telopeptide of collagen I in the organic bone matrix (NTx) in the 24-hour diuresis and slightly elevated osteocalcin (OSCA) levels. The finding of whole-body skeletal scintigraphy was atypical and thus was no diagnostic asset. Aimed transiliacal bone biopsy according to Bordier taken from the pathological focus confirmed the diagnosis of morbus Paget. The patient was treated for six months with the following preparations: Fosamax (monosodium alendronate tablets a 10 mg, Merck Sharp and Dohme, USA) 1 tablet per day, Vitacalcin (calcium carbonate, tablets a 250 mg elemental calcium, Slovakofarma, Slovak Republic) 2 x 1 tablet per day, Rocaltrol (calcitriol tablets a 0.25 ug, Hoffman La Roche, Switzerland) 1 tablet on alternate days). Because of gastrointestinal complaints the authors did not administer 40 mg alendronate per day, as recommended in the American literature. Based on the laboratory finding of normalization of the bone turnover, reduction of the number of osteoplastic foci on the X-ray image of vertebrae and pelvis, regression of the vertebrogenic algic syndrome and improved mobility of the patient, the authors consider the 6-month administration of alendronate, 10 mg per day, calcium carbonate and calcitriol therapeutically effective and successful.

[Linear regression analysis of values of the calciuria index, N-telopetide and bone mineral density in patients with osteoporosis]. / Lineárna regresná analýza hodnôt indexu kalciúrie, N-telopetidu a denzity kostného minerálu u pacientov s osteoporózou.

UNLABELLED: The authors examined 49 patients (n=49) with primary and secndary osteoporosis incl. 37 women aged 41-58 years and 12 men aged 38-56 years. In all they assessed the 24-hour calciuria index (Ca/creatinine), the aminoterminal N-telopetide of collagen I of the organic matrix (NTx24) and the bone mineral density (BMD) in the first three lumbar vertebrae using quantitative computed tomography (QC). OBJECTIVE: To find an answer to the questions:1. Is the calciuria index in the 24-hour diuresis a parameter which provides information on osteresorption? 2. Is there a significant negative correlation between values NTx24 and BMD? 3. Is NTx a sensitive parameter of osteoresorption in men and women with primary or secondary osteoporosis? STATISTICAL ANALYSIS: Linear regression analysis. RESULTS: Correlation coefficients for the correlated groups NTx24 - Ca/creatinine (r = 0.023, p>0.05) and NTx24 - BMD (r = -0.238, p>0.05) were not statistically significant. Statistical significance was recorded in the correlation coefficient for pathologically elevated values of NTx24(zNTx24), correlated with BMD (r = -0.3115, p<0.048). CONCLUSION: 1. The calciuria index in the 24-hour diuresis does not provide information on osteoresorption. 2. Between pathologically elevated values of NTx24 and BMD in L1-L3 is a statistically significant negative correlation. 3. NTx is a sensitive parameter of osteresorptioon in men and women with primary and secondary osteoporosis, it reflects the influence of the bone turnover on the density of the bone mineral.

[NTx--a sensitive laboratory parameter of bone resorption]. / NTx--senzitívny laboratórny parameter osteoresorpcie.

A review of biochemical characteristics, the laboratory principle, as well as the clinical significance and indications of the assessment of the new laboratory parameter of osteoresorption--amino-terminal N-telopeptide of type I collagen of organic bone matrix. NTx is so far the most sensitive biochemical marker of the pathologic bone turn-over. Its assessment is successfully used in: 1. detection of the character of the bone turn-over (osteoresorption) during peri and post-menopause, 2. identification of patients at risk of osteoporosis, 3. monitoring of the effectivity of osteoporosis therapy (biphosphonates, hormonal substitution therapy, calcitonin), 4. diagnosis and control of therapeutic effectivity in M. Paget, 5. early detection of bone metastases in malign diseases. NTx is beneficial in the treatment of out-patients and in clinical practice in the assessment of diagnosis and the therapy of bone metabolic diseases. The advantage of examination resides in easy sample withdrawal and the fast technique of laboratory processing. NTx should become a parameter of routine examination within clinical laboratories.