Different Types Of Bone Research Articles

Allogenic Bone and Bone Healing

Within the scope of the specialty, the use of exogenous materials capable of promoting bone regeneration or bone healing constitutes an extremely valuable adjunct to current reconstructive modalities. Areas where these technologies may be applied include the reconstruction of skeletal defects, correction of developmental clefts, augmentation of alveolar ridges for dental implants, accelerated repair of fracture and osteotomy sites and the treatment of non-unions. Where defects or non-unions exist, the principal advantage of utilizing bone substitutes is the avoidance or minimization of autogenous bone harvesting. Appropriate selection of existing materials or the development of new substitutes relies upon a comprehensive understanding of the physiological mechanisms involved in bone formation. These processes, osteogenesis, osteoinduction and osteoconduction, will be summarized and the abilities of several commercially available products to promote these biological mechanisms reviewed. Proper material selection must also take into account the various functional requirements posed by a specific skeletal defect. Included in these considerations are loading patterns, physical characteristics of the defect, and potential for exposure to an external environment. The physical properties of different types of bone substitutes will be discussed in relation to these demands.

An overview of bone sonometry

Measurement of the linear acoustic parameters of bone (speed of sound, SOS, and broadband attenuation, BUA) is the foundation of current bone ultrasonometry, which has become a well-established technique in osteoporosis diagnostics. Like X-ray densitometry techniques, QUS has been adapted to assess different skeletal sites consisting of different types of bone. Devices are currently available to measure easily accessible peripheral sites such as the heel, fingers, wrist or tibia. In this contribution, we will review the current state of development and we will outline a few promising developments.

Comparing Levels of Subsistence Stress amongst Norse Settlers in Iceland and Greenland using Levels of Bone Fat Exploitation as an Indicator

The background to the Icelandic and Greenlandic sites under investigation is outlined and prior work on the Norse economies of the two islands is discussed. The importance of fat in the diet and the use of levels of bone marrow and grease exploitation as an indicator of subsistence stress are explained. The methodology for establishing levels of bone fat exploitation is outlined. This methodology involves the detailed study of fragmentation levels of different types of bone, study of bone fracture types and many other taphonomic indicators. The results of the study are described and discussed. On Greenland, the Norse inhabitants exploited almost all available fat from land mammal bones, leaving only the ribs. It is argued that this indicates a severe level of subsistence stress amongst the Greenlanders that is most likely related to a seasonal dearth in resources. On Iceland, whilst a certain amount of bone marrow is almost certainly exploited, the settlers appear to almost totally ignore the potential to exploit bone grease. This is likely to be indicative of a much more healthy subsistence economy than on Greenland. These results are discussed in relation to differing climate, availability of good soil, fishing practices and seasonal rounds.

NK1, NK2, NK3 and CGRP1 receptors identified in rat oral soft tissues, and in bone and dental hard tissue cells.

The distribution of the tachykinin receptors neurokinin-1 (NK1), neurokinin-2 (NK2) and neurokinin-3 (NK3), and the calcitonin gene-related peptide-1 (CGRP1) receptor were examined in rat teeth and tooth-supporting tissues by immunohistochemical methods and light and confocal microscopy. Western blot analysis was performed to identify the NK1- and the CGRP1-receptor proteins in the dental pulp. The results showed that odontoblasts and ameloblasts, cementoblasts and cementocytes, osteoblasts and osteocytes are all supported with the tachykinin receptors NK1 and NK2, but a distinct, graded cellular labeling pattern was demonstrated. The ameloblasts were also positive for CGRP1 receptor. Blood vessels in oral tissues expressed the tachykinin receptors NK1, NK2 and NK3, and the CGRP1 receptor. Both gingival and Malassez epithelium were abundantly supplied by NK2 receptor. Pulpal and periodontal fibroblasts demonstrated NK1 and NK2 receptors. Western blot analysis identified both the NK1- and the CGRP1-receptor proteins in the dental pulp. These results clearly indicate that the neuropeptides substance P, neurokinin A, neurokinin B and CGRP, released from sensory axons upon stimulation, directly modulate the function of the different types of bone and dental hard tissue cells, and regulate functions of blood vessels, fibroblasts and epithelial cells in oral tissues.

Purification of matrix Gla protein from a marine teleost fish, Argyrosomus regius: calcified cartilage and not bone as the primary site of MGP accumulation in fish.

Matrix Gla protein (MGP) belongs to the family of vitamin K-dependent, Gla-containing proteins, and in mammals, birds, and Xenopus, its mRNA was previously detected in extracts of bone, cartilage, and soft tissues (mainly heart and kidney), whereas the protein was found to accumulate mainly in bone. However, at that time, it was not evaluated if this accumulation originated from protein synthesized in cartilage or in bone cells because both coexist in skeletal structures of higher vertebrates and Xenopus. Later reports showed that MGP also accumulated in costal calcified cartilage as well as at sites of heart valves and arterial calcification. Interestingly, MGP was also found to accumulate in vertebra of shark, a cartilaginous fish. However, to date, no information is available on sites of MGP expression or accumulation in teleost fishes, the ancestors of terrestrial vertebrates, who have in their skeleton mineralized structures with both bone and calcified cartilage. To analyze MGP structure and function in bony fish, MGP was acid-extracted from the mineralized matrix of either bone tissue (vertebra) or calcified cartilage (branchial arches) from the bony fish, Argyrosomus regius, separated from the mineral phase by dialysis, and purified by Sephacryl S-100 chromatography. No MGP was recovered from bone tissue, whereas a protein peak corresponding to the MGP position in this type of gel filtration was obtained from an extract of branchial arches, rich in calcified cartilage. MGP was identified by N-terminal amino acid sequence analysis, and the resulting protein sequence was used to design specific oligonucleotides suitable to amplify the corresponding DNA by a mixture of reverse transcription-polymerase chain reaction (RT-PCR) and 5'rapid amplification of cDNA (RACE)-PCR. In parallel, ArBGP (bone Gla protein, osteocalcin) was also identified in the same fish, and its complementary DNA cloned by an identical procedure. Tissue distribution/accumulation was analyzed by Northern blot, in situ hybridization, and immunohistochemistry. In mineralized tissues, the MGP gene was predominantly expressed in cartilage from branchial arches, with no expression detected in the different types of bone analyzed, whereas BGP mRNA was located in bone tissue as expected. Accordingly, the MGP protein was found to accumulate, by immunohistochemical analysis, mainly in the extracellular matrix of calcified cartilage. In soft tissues, MGP mRNA was mainly expressed in heart but in situ hybridization, indicated that cells expressing the MGP gene were located in the bulbus arteriosus and aortic wall, rich in smooth muscle and endothelial cells, whereas no expression was detected in the striated muscle myocardial fibers of the ventricle. These results show that in marine teleost fish, as in mammals, the MGP gene is expressed in cartilage, heart, and kidney tissues, but in contrast with results obtained in Xenopus and higher vertebrates, the protein does not accumulate in vertebra of non-osteocytic teleost fish, but only in calcified cartilage. In addition, our results also indicate that the presence of MGP mRNA in heart tissue is due, at least in fish, to the expression of the MGP gene in only two specific cell types, smooth muscle and endothelial cells, whereas no expression was found in the striated muscle fibers of the ventricle. In light of these results and recent information on expression of MGP gene in these same cell types in mammalian aorta, it is likely that the levels of MGP mRNA previously detected in Xenopus, birds, and mammalian heart tissue may be restricted to regions rich in smooth muscle and endothelial cells. Our results also emphasize the need to re-evaluate which cell types are involved in MGP gene expression in other soft tissues and bring further evidence that fish are a valuable model system to study MGP gene expression and regulation.

In vivo behaviour of hydroxyapatite coatings on titanium implants: a quantitative study in the rabbit

The aim of this study was to evaluate quantitatively the behaviour of in vivo hydroxyapatite coated implants (HA) in the rabbit over time, and to compare the results with observations made on titanium plasma spray implants (TPS). Results were analysed according to the percentage of bone contact. Eighteen HA cylindrical implants (3.25×8 mm) and 6 TPS cylindrical implants from Steri-Oss were placed in the epiphysis of the femur in 24 white rabbits. Each rabbit received one implant. Three rabbits with one HA implant ( n=3) and 1 rabbit with one TPS implant ( n=1) were sacrificed after implantation periods of 2, 4, 6, 8, 10 and 12 months. Implants were cut along the long axis and prepared for histological and histomorphometrical evaluations. Measurements of coating thickness and percentage of bone contact were performed with scanning electron microscopy analysis on the sides of the implant, in 3 different types of bone, namely cortical, trabecular and marrow. In cortical bone, dense bone was apposed to the HA implants: from 92.3±5.5% at 2 months to 89.6±6.5% at 1 year, with no significant regression of HA thickness ( P=0.37). TPS coating showed less bone contact, but thickness was stable ( P=0.46). In trabecular zone, where bone contact was less pronounced, a significant regression of HA coatings thickness ( P<0.05) was observed. Nevertheless TPS coatings were stable ( P=0.81). Histomorphometrical results demonstrated that a highly significant regression ( P<0.0001) of HA thickness was observed in the marrow area, where the bone-to-implant contact never exceeded 7.6% from 2 to 12 months. TPS coating did not reveal any sign of resorption ( P=0.88), despite a rare bone contact. Histological analysis revealed inflammatory and giant cells, principally in the marrow area in contact with HA coating, but always in restrictive numbers. We conclude that bone contact protected the HA coating from resorption.

The significance of high bone density in children

The significance of high bone density in children

The role of an effective isotropic tissue modulus in the elastic properties of cancellous bone

Conceptually, the elastic characteristics of cancellous bone could be predicted directly from the trabecular morphology — or architecture — and by the elastic properties of the tissue itself. Although hardly any experimental evidence exists, it is often implicitly assumed that tissue anisotropy has a negligible effect on the apparent elastic properties of cancellous bone. The question addressed in this paper is whether this is actually true. If it is, then micromechanical finite element analysis (μ-FEA) models, representing trabecular architecture, using an `effective isotropic tissue modulus’ should be able to predict apparent elastic properties of cancellous bone. To test this, accurate multi-axial compressive mechanical tests of 29 whale bone specimens were simulated with specimen-specific μ-FEA computer models built from true three-dimensional reconstructions. By scaling the μ-FEA predictions by a constant tissue modulus, 92% of the variation of Young's moduli determined experimentally could be explained. The correlation even increased to 95% when the μ-FEA moduli were scaled to the isotropic tissue moduli of individual specimens. Excellent agreement was also found in the elastic symmetry axes and anisotropy ratios. The prediction of Poisson's ratios was somewhat less precise at 85% correlation. The results support the hypothesis; for practical purposes, the concept of an `effective isotropic tissue modulus’ concept is a viable one. They also suggest that the value of such a modulus for individual cases might be inferred from the average tissue density, hence the degree of mineralization. Future studies must clarify how specific the tissue modulus should be for different types of bone if adequate predictions of elastic behavior are to be made in this way.

In Vivo Bone Response to Biomechanical Loading at the Bone/Dental-Implant Interface

Since dental implants must withstand relatively large forces and moments in function, a better understanding of in vivo bone response to loading would aid implant design. The following topics are essential in this problem. (1) Theoretical models and experimental data are available for understanding implant loading as an aid to case planning. (2) At least for several months after surgery, bone healing in gaps between implant and bone as well as in pre-existing damaged bone will determine interface structure and properties. The ongoing healing creates a complicated environment. (3) Recent studies reveal that an interfacial cement line exists between the implant surface and bone for titanium and hydroxyapatite (HA). Since cement lines in normal bone have been identified as weak interfaces, a cement line at a bone-biomaterial interface may also be a weak point. Indeed, data on interfacial shear and tensile "bond" strengths are consistent with this idea. (4) Excessive interfacial micromotion early after implantation interferes with local bone healing and predisposes to a fibrous tissue interface instead of osseointegration. (5) Large strains can damage bone. For implants that have healed in situ for several months before being loaded, data support the hypothesis that interfacial overload occurs if the strains are excessive in interfacial bone. While bone "adaptation" to loading is a long-standing concept in bone physiology, researchers may sometimes be too willing to accept this paradigm as an exclusive explanation of in vivo tissue responses during experiments, while overlooking confounding variables, alternative (non-mechanical) explanations, and the possibility that different types of bone (e.g., woven bone, Haversian bone, plexiform bone) may have different sensitivities to loading under healing vs. quiescent conditions.

Bone structure, metabolism, and physiology: its impact on dental implantology.

When placing implants in the mandible or maxilla, it is important for clinicians to understand the process of bone remodeling, the different types of bone, and how these factors can affect the integration of osseous dental implants. Approximately 0.7% of a human skeleton is resorbed daily and replaced by new healthy bone. With aging and metabolic disease states, the normal turnover process may be reduced, resulting in an increase in the mean age of the present bone. This increase can affect the placement and integration of implants. Herein follows a discussion of different types of bone cells, the metabolism of bone, the microscopic, macroscopic, and molecular structure of bone, and the process of bone modeling and remodeling.

Sex differences in absolute rates of bone resorption in young rats: Appendicular versus axial bones

This study compares absolute rates of bone resorption and formation at the organ level in adolescent Sprague-Dawley rats as a function of sex and type of bone. Bone resorption and formation were quantified in rapidly growing male and female rats (4-7 weeks of age) who were multiply prelabeled with [3H]tetracycline. Ten different whole bones were compared: four cranial or appendicular bones and six axial bones. Absolure rate of bone resorption was measured isotopically by the loss of 3H-tetracycline from each whole bone. Bone growth was quantified in terms of relative and absolute increase in bone calcium mass. When the rates of bone resorption (loss of [3H]-tetracycline as percent of whole bone per 3 weeks) were compared between sexes, the six axial bones showed significantly higher rates (P < 0.05-0.001) in males (64-73) than in females (37-66). No significant sex differences were observed in rate for the two cranial and two appendicular bones. During 4-7 weeks of age, a comparison of bone masses showed that only one bone (calvaria) gained more mass in the male and two bones (mandible and humerus) gained more mass in the female. In contrast, five of six axial bones gained more mass in the female. Thus, 7 out of 10 bones were larger in the female. In growing male and female rats, an inverse relationship appears between rate of bone resorption and mass for most of the axial bones; this relationship was not apparent for cranial or appendicular bones. Sexual dimorphism was consistently seen by greater axial bone mass in females. However, greater rates of bone resorption were seen in male axial bones but not in cranial or appendicular bones. It is apparent that the different types of bones are heterogeneous in their rates of resorption and formation during this period of growth.

Two compartments of slowly exchangeable sodium in bone

The commonly accepted concept of sodium kinetics is a two-compartment system where total sodium (NaT) is the sum of bone sodium (NaB) and soft tissue sodium (NaST). On the basis of the experiments described, the authors propose that the slowly exchangeable sodium (NaSE) is equated with NaB and the quickly exchangeable sodium (NaQE) with NaST. They propose that NaB be subdivided into two compartments, NaB=NaSEI+NSEII, where I refers to sodium on the bone mineral crystal surface (NaBI=NaBMCS) and II refers to sodium in the bone mineral crystal interior (NaSEII=NaBMCI). The above experiment was repeated with ashed samples of the rabbit femur (Pilecka and Rakovic, 1991). In this case, the release of the radiotracer on stirring was nearly abolished, which is in perfect agreement with a known concept of the thermal recrystallization of the bone mineral (Neuman and Neuman, 1958). Further evidence about the heteroionic exchange can be acquired by in vitro experiments performed under different conditions, with different types of bones and with different ions.

A probabilistic approach to bone fracture analysis

Bones are biological structural materials made of dynamically adaptable tissues. They can be considered as complex natural composite materials with load bearing constituents such as osteons and interstitial lamellae cemented with weak bonding materials. In addition, they contain Haversian and Volkmann canals that are functionally needed but are structurally weak. Because of large variation in microstructure, the strength of a bone varies from bone to bone and animal to animal. In this study the applicability of Weibull statistics to fracture strength of bones has been evaluated. The statistics is based on the weakest link theory and has been used successfully for probabilistic design of critical engineering structural components. The analysis shows that the statistics is valid when applied to each type of bone and it differentiates data from different types of bones. The analysis provides an insight in terms of how nature designs its load bearing structures by the process of natural selection.

The Influence of Bone and Bone Cement Debris on Counterface Roughness in Sliding Wear Tests of Ultra-High Molecular Weight Polyethylene on Stainless Steel

Studies of explanted hip prostheses have shown high wear rates of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups and roughening of the surface of the metallic femoral head. Bone and bone cement particles have also been found in the articulating surfaces of some joints. It has been proposed that bone or bone cement particles may cause scratching and deterioration in the surface finish of metallic femoral heads, thus producing increased wear rates and excessive amounts of wear debris. Sliding wear tests of UHMWPE pins on stainless steel have been performed with particles of different types of bone and bone cement added. Damage to the stainless steel counterface and the motion of particles through the interface have been studied. Particles of bone cement with zirconium and barium sulphate additives and particles of cortical bone scratched the stainless steel counterface. The cement particles with zirconium additive produced significantly greater surface damage. The number of particles entering the contact and embedding in the UHMWPE pin was dependent on particle size and geometry, surface roughness and contact stress. Particles are likely to cause surface roughening and increased wear rates in artificial joints.

Decreasing rates of bone resorption in growing rats in vivo: Comparison of different types of bones

This study quantifies rates of bone resorption by measuring the kinetic loss of 3H-tetracycline in vivo from the five different types of whole bones in four ages of normal male rats: appendicular bone (femur), cephalic bone (calvarium), axial bones (sixth lumbar vertebrae and sternum), and pelvis. The skeletons of newborn (0–2 weeks), weanling (4–7 weeks), adolescence (10–14 weeks), and mature (15–23 weeks) of Sprague Dawley rats were multiply labeled with 3H-tetracycline. The radioactivity in whole calvaria, the 6th lumbar vertebra, sternum, pelvis and femur was quantified to calculate the time course of tetracycline loss. The isotopic half lives ( t 1 2 ) were different for each age group and each bone, but the rates of resorption were usually the highest in the newborn rats. In the youngest animals, the t 1 2 for the femur, vertebrae, and sternum was 1.5 week, for the pelvis it was 2.0 week, and for the calvarium it was 2.5 week. In the oldest age group, t 1 2 for the femur was 28 week, for the calvarium was 19 week, for the sternum and pelvis was 16.5 week, and for the vertebrae was 13 week. For cephalic bones and femur, the greatest decrement in the rate of resorption occurred in the first 7 weeks of life (−52% and −72%, respectively). The axial bones and pelvis maintained a uniformly high resorptive rate until 7 weeks of age, which waned sharply at adolescence (−70% to −78%). At maturity the resorptive rate of these bones was less than 16% of the rate in the newborn. In general, there appears to be an increase in the metabolic heterogeneity of the skeleton in terms of bone resorption after the neonatal period.

Quantitative computed tomography in measurement of vertebral trabecular bone mass

Measurement of bone mineral concentration (BMC) can be done by several modalities. Quantitative computed tomography (QCT) can be used for measurements at different sites and with different types of bone (trabecular-cortical). This study presents a modified method reducing the influence of fat. Determination of BMC was made from measurements with single-energy computed tomography (CT) of the mean Hounsfield number in the trabecular part of the L1 vertebra. the method takes into account the age-dependent composition of the trabecular part of the vertebra. as the amount of intravertebral fat increases with age, the effective atomic number for these parts decreases. This results in a non-linear calibration curve for single-energy CT. Comparison of BMC values using the non-linear calibration curve or the traditional linear calibration with those obtained with a pixel-by-pixel based electron density calculation method (theoretically better) showed results clearly in favor of the non-linear method. the material ...

Quantitative Computed Tomography in Measurement of Vertebral Trabecular Bone Mass

Measurement of bone mineral concentration (BMC) can be done by several modalities. Quantitative computed tomography (QCT) can be used for measurements at different sites and with different types of bone (trabecular-cortical). This study presents a modified method reducing the influence of fat. Determination of BMC was made from measurements with single-energy computed tomography (CT) of the mean Hounsfield number in the trabecular part of the L1 vertebra. The method takes into account the age-dependent composition of the trabecular part of the vertebra. As the amount of intravertebral fat increases with age, the effective atomic number for these parts decreases. This results in a non-linear calibration curve for single-energy CT. Comparison of BMC values using the non-linear calibration curve or the traditional linear calibration with those obtained with a pixel-by-pixel based electron density calculation method (theoretically better) showed results clearly in favor of the non-linear method. The material consisted of 327 patients aged 6 to 91 years, of whom 197 were considered normal. The normal data show a sharp decrease in trabecular bone after the age of 50 in women. In men a slower decrease was found. The vertebrae were larger in men than in women.

Nonhomogeneous Distribution of Leukemia in the Bone Marrow During Minimal Residual Disease

AbstractIn a rat model (BNML) for human acute myelocytic leukemia the distribution of leukemic cells in bone marrow samples from various sites was investigated, using monoclonal antibodies (MoAbs) and flow cytometry. Rats were studied before chemotherapy as well as thereafter, ie, in the “minimal residual disease” (MRD) phase. Bone marrow from different types of bones was analyzed from each animal. Before treatment, the ratio of the measured extreme values (ie, highest/lowest value) for leukemic cell frequencies in bones from individual rats ranged from 3.7 to 11.7. During the MRD phase the ratios of the extremes ranged from a factor of 36 to more than 13,000 from one rat to another. The variability between bones of comparable size was estimated by studying the ribs from each individual animal. Within individuals the extremes differed by a factor of 1.2 to 4.0 before chemotherapy and from 2.4 to >320 after chemotherapy. The variability within the marrow cavity of a single bone was determined by analyzing multiple samples from femoral bones cut into slices. The leukemic cell frequency appeared to vary considerably, ie, before treatment from 1.7 to 7.3 and during MRD from 4 to 28,000. The presented data may contribute to understanding the sometimes conflicting observations in leukemic patients. Improvement of methods for detecting MRD will not automatically lead to a more accurate estimation of the total tumor burden. The reliability of diagnoses based on the analysis of single bone marrow aspirates appears to be highly questionable.

Nonhomogeneous distribution of leukemia in the bone marrow during minimal residual disease

In a rat model (BNML) for human acute myelocytic leukemia the distribution of leukemic cells in bone marrow samples from various sites was investigated, using monoclonal antibodies (MoAbs) and flow cytometry. Rats were studied before chemotherapy as well as thereafter, ie, in the “minimal residual disease” (MRD) phase. Bone marrow from different types of bones was analyzed from each animal. Before treatment, the ratio of the measured extreme values (ie, highest/lowest value) for leukemic cell frequencies in bones from individual rats ranged from 3.7 to 11.7. During the MRD phase the ratios of the extremes ranged from a factor of 36 to more than 13,000 from one rat to another. The variability between bones of comparable size was estimated by studying the ribs from each individual animal. Within individuals the extremes differed by a factor of 1.2 to 4.0 before chemotherapy and from 2.4 to greater than 320 after chemotherapy. The variability within the marrow cavity of a single bone was determined by analyzing multiple samples from femoral bones cut into slices. The leukemic cell frequency appeared to vary considerably, ie, before treatment from 1.7 to 7.3 and during MRD from 4 to 28,000. The presented data may contribute to understanding the sometimes conflicting observations in leukemic patients. Improvement of methods for detecting MRD will not automatically lead to a more accurate estimation of the total tumor burden. The reliability of diagnoses based on the analysis of single bone marrow aspirates appears to be highly questionable.

A practice‐orientated study of the complex „processing and handling–application–resultant properties”︁ of autopolymerizing PMMA bone cements

AbstractBone cements which are used for the fixation of alloplasties as well as for filling and/or bridging of bone defects had been intensively investigated during the past 15 years. Scientists payed close attention to the subjects of “biocompatibility in view of chemical and thermal effects; polymerization process; structure and properties of bone cements”. As a rule, especially tests for the evaluation of strength properties were carried out with more or less standardized and relatively small specimen. The fund of experience, obtained by the methods mentioned above, don't let us hope to have any further significant progress concerning the transferability of these results to practise. A possible step further in the approximation of model experiments with respect to practical problems in the author's opinion should be the methodically combination of the known single aspects to a larger total complex. As a start in this direction a testing method was developed which enables processing and insertion of bone cements as well as the implantation of endoprostheses‐shafts into tubular spaces under similar geometrical and thermal conditions as they are present in big tubular bones.Shape and dimensions of the originated bone cement‐ “quivers” or “jackets” are chosen in a way that experiments are practicable for the comparison of different types of bone cements and implantating methods as well as the testing of intended or unintended admixtures (for example X‐ray contrast agent, antibiotics, blood) with respect to the mechanical loading capacity.Furthermore comparisons with the results of conventional mechanical material testings are possible.The contruction of the testing apparatus and the testing procedure will be presented. Its applicability for tests to compare different types of bone cements with respect to the parameters “processing and insertion method”, “implantating endoprostheses‐shafts” and “admixtures” will be discussed by means of obtained results. Finally the question is asced wether a method like this can be an aid for training and objectively valuation of the methodical abilities of budding operating surgeons in this field.