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PubMed1996

[Densitometric studies of the tensile strength of the proximal femur].

The prognostic assessment of the fracture resistance of the proximal femur is of great importance to the age related increasing incidence of femur neck fractures. This is particularly important in sport for the elderly. The statistical relationship between the osteodensitometrically determined bone density and the risk of a femur neck fracture has been shown in epidemiological studies, whereby the determination of bone density at the proximal femur has provided the most precise predictive results. The present investigation determines the direct relationship between bone density and fracture resistance. Twenty isolated femurs were investigated with the DPX-L-system (Lunar) to measure the bone density in three different areas of the metaphysia as well as important morphometric parameters. Subsequently the femora were fractured in a special device which also recorded the forces required for fracture. The statistical analysis showed a high correlation between the fracture forces and the bone density of the femur neck and trochanter regions. This was true to a lesser extent in the Ward triangle. No significant correlation was found to the morphometric parameters. Quite different forces with considerably greater amplitudes can occur in falls. These may also be absorbed by different structures such as muscle tissue, and, therefore not act directly upon the femur neck. Despite these limitations the determination of bone density appears to permit the individual estimation of fracture risk of the femur neck.

Absorptiometry, Photon↗
PubMed2003

Trabecular bone tissue strains in the healthy and osteoporotic human femur.

UNLABELLED: Quantitative information about bone tissue-level loading is essential for understanding bone mechanical behavior. We made microfinite element models of a healthy and osteoporotic human femur and found that tissue-level strains in the osteoporotic femoral head were 70% higher on average and less uniformly distributed than those in the healthy one. INTRODUCTION: Bone tissue stresses and strains in healthy load-adapted trabecular architectures should be distributed rather evenly, because no bone tissue is expected to be overloaded or unused. In this study, we evaluate this paradigm with the use of microfinite element (microFE) analyses to calculate tissue-level stresses and strains for the human femur. Our objectives were to quantify the strain distribution in the healthy femur, to investigate to what extent this distribution is affected by osteoporosis, to determine if osteoporotic bone is simply bone adapted to lower load levels, and to determine the "safety factor" for trabecular bone. MATERIALS AND METHODS: microFE models of a healthy and osteoporotic proximal femur were made from microcomputed tomography images. The models consisted of over 96 and 71 million elements for the healthy and osteoporotic femur, respectively, and represented their internal and external morphology in detail. Stresses and strains were calculated for each element and their distributions were calculated for a volume of interest (VOI) of trabecular bone in the femoral head. RESULTS: The average tissue-level principal strain magnitude in the healthy VOI was 304 +/- 185 microstrains and that in the osteoporotic VOI was 520 +/- 355 microstrains. Calculated safety factors were 8.6 for the healthy and 4.9 for the osteoporotic femurs. After reducing the force applied to the osteoporotic model to 59%, the average strain compared with that of the healthy femur, but the SD was larger (208 microstrains). CONCLUSIONS: Strain magnitudes in the osteoporotic bone were much higher and less uniformly distributed than those in the healthy one. After simulated joint-load reduction, strain magnitudes in the osteoporotic femur were very similar to those in the healthy one, but their distribution is still wider and thus less favorable.

Aged↗
PubMed2000

Deferoxamine-induced bone dysplasia in the distal femur and patella of pediatric patients and young adults: MR imaging appearance.

OBJECTIVE: We investigated the MR imaging appearance of deferoxamine-induced bone dysplasia in the distal femur and patella in patients with thalassemia major. MATERIALS AND METHODS: Thirty-five patients with homozygous ss-thalassemia major who were undergoing regular transfusions and chelation therapy underwent coronal T1-weighted MR imaging of the femur, including the femoral head and the distal femoral epiphysis. Additional coronal fat-saturated dual-echo and sagittal T1-weighted images of the distal femur and patella were obtained in 11 patients who were suspected of having distal femoral lesions on the basis of the coronal T1-weighted images of the entire femur. RESULTS: No dysplastic change was detected in the proximal femur on coronal T1-weighted images. In 22 distal femurs of 11 patients, the following abnormalities were detected on MR imaging: blurred physeal-metaphyseal junction (n = 22), distal metaphyseal areas of hyperintensity (n = 21), physeal widening (n = 18), metadiaphyseal lesions (n = 11), epiphyseal lesions (n = 10), and patellar lesions (n = 2). Physeal widening and distal metaphyseal hyperintense areas were all more pronounced peripherally. Of the 21 distal metaphyseal hyperintensities, lateral abnormalities were larger than medial abnormalities in 16. Of the 18 distal femurs in which physeal widening was detected, the lateral widening was more marked than the medial widening in 12. Patients with MR imaging evidence of bone dysplasia have a significantly (p = 0.003) greater height reduction than patients without such evidence of bone dysplasia. CONCLUSION: Deferoxamine-induced bone dysplasia in the distal femur and patella is represented by a spectrum of morphologic changes in the epiphysis, physis, metaphysis, and metadiaphysis on MR imaging.

Adolescent↗
PubMed2004

Comparative assessment of bone mineral measurements obtained by use of dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and chemical-physical analyses in femurs of juvenile and adult dogs.

OBJECTIVE: To compare bone mineral measurements obtained by use of dual-energy x-ray absorptiometry (DEXA), peripheral quantitative computed tomography (pQCT), and chemical-physical analyses and determine effects of age and femur size on values obtained for the various techniques. SAMPLE POPULATION: Femurs obtained from 15 juvenile and 15 adult large-breed dogs. PROCEDURE: n each femur, 7 regions of interest were examined by use of DEXA to measure the bone mineral content (BMC) and bone mineral density (BMD), and 5 were examined by use of pQCT to measure BMD. Among these, 1 region was examined by both noninvasive methods and an invasive method. Volume of the femur was determined by water displacement. Volumetric bone density (VBD) was calculated. Calcium (Ca), phosphorus (P), total Ca, and total P contents were determined. RESULTS: DEXA- and pQCT-derived results revealed that all values increased with age in juvenile dogs. In adults, VBD and pQCT-derived BMD decreased significantly and DEXA-derived BMD increased with increasing femur length. The pQCT-derived BMD correlated well with VBD and Ca content, whereas DEXA-derived BMC was strongly correlated with Ca content. In juveniles, values correlated regardless of the technique used, whereas in adult dogs, DEXA-derived BMD did not correlate with pQCT-derived BMD, Ca concentration, or VBD unless data were adjusted on the basis of femur length. CONCLUSIONS AND CLINICAL RELEVANCE: DEXA-derived BMD adjusted for femur length yields approximately the same percentage variability in VBD as for pQCT-derived BMD. However, pQCT-derived BMD is still more sensitive for determining variability BMD in Ca concentration, compared with DEXA-derived BMD adjusted for femur length.

Absorptiometry, Photon↗
PubMed1987

Pitfalls in femur length measurements.

The following study was performed to determine the precise anatomic correlate for the end points of sonographic measurement of the fetal femur. A cadaveric fetal thigh was dissected in layers and correlated with sonographic images. The margins of the osseous portion of the femur were determined on sonograms. Potential for underestimating femur length (oblique images) and overestimating femur length (including nonosseous portions of the femur in measurement) can be eliminated by requiring a view of the femur which includes the epiphyseal cartilages. In this way, the margins of the osseous portion may be accurately estimated, and there is assurance that the entire shaft has been visualized. Images of the dissected specimen indicate that the "distal femur point," which may cause confusion in measurement, is not a part of the osseous femur, but probably represents a specular reflection from the lateral surface of the distal epiphysis.

Age Determination by Skeleton↗
PubMed2003

[The reconstruction of three-dimension morphology of proximal femur].

OBJECTIVES: To reconstruct the morphology of the proximal femur and measure the parameters of them by means of the computer-aided design (CAD) in order to provide help to the design and research of the domestic prosthesis, event for the selection of the adapted implant for the doctors before operation. METHODS: The data of 160 healthy Chinese proximal femur images were obtained by the PHLLIP SR7000 computer tomography. The correlative parameters were measured exactly by medical imaging software. Then the imaging data were input into an computerized contouring program which generates the three dimensional coordinates representing periosteal and endosteal contours of the femur for each CT slice. Though the computer-aided design (CAD) software, the three-dimensional solid model was reconstructed by the vectorisation of image contours. In the circumstance of CAD system, the bone axis is defined as the line across the geometric center of the cross-section of the isthmus and 20 mm above the lesser trochanter mid-point. We measured the parameters of the endosteal and periosteal dimensions of the medullary canal. RESULTS: The parameters of the medullary canal measured with the reconstructed normal Chinese femur have significant difference from that measured with the Caucasian's. The extracortical and endosteal parameters of male have significant differences from most of female's. However, there were no significant differences in endosteal width between different age groups in two gender groups. From the proximal to the distal femur, the intersection angles between the longest mediolateral endosteal diameters of the slices and the plane of the femoral neck were increased. CONCLUSIONS: The reconstructive femur contains more information and can be cut at arbitrary levels which means it is facility to the research of the Morphology of the Proximal femur and the measurement of relative parameters. It is necessary to design the prosthesis which fit anatomic parameters of the Chinese femur. It needs to further study whether the gender factor will be considered in the prosthesis design. The angle between the anteversion and the helitorsion at the level 20 mm above the lesser trochanter midpoint should be noticed by the implant designers and doctors.

Aged↗
PubMed2005

Evaluation of femur angle abduction/adduction and bone mineral density values.

Bone densitometry using fan-beam technology allows both femurs to be rapidly measured with the aid of a bilateral foot-positioning tool to keep both legs in internal rotation. The Lunar Prodigy system uses a bilateral foot-positioning tool with a fixed interpedal width. The aim of this study was to determine whether the small degrees of femur abduction and adduction introduced by a fixed interpedal width-positioning tool influences the femur bone mineral density (BMD) measurements. Two-hundred patients had the total femur (FTot), femoral neck (FN), femoral shaft (FS), and femoral trochanter (FT) BMD, and angles of femoral abduction and adduction measured. Of all subjects, 26.5% had an absolute difference in femur angulation of 1 degrees , 77.5% had 5 degrees and 97% had 10 degrees. There was no significant correlation between the right-to-left differences in femur angles and the absolute right-to-left differences in FTot, FN, FS, and FT BMD. The introduction of small degrees of femur angulation with the fixed interpedal width bilateral foot positioner does not significantly affect the measured BMD at the various femur regions.

Absorptiometry, Photon↗
PubMed2007

Finite element analysis of impact loads on the femur.

OBJECTIVE: To investigate the stress distribution and fracture mechanism of proximal femur under impact loads. METHODS: The image data of one male's femur were collected by the Lightspeed multi-lay spiral computed tomography. A 3D finite element model of the femur was established by employing the finite element software ANSYS, which mainly concentrated on the effects of the directions of the impact loads arising from intense movements and the parenchyma on the hip joint as well as those of the femur material properties on the distribution of the Mises equivalent stress in the femur after impact. RESULTS: The numerical results about the effects of the angle sigma of the impact loads to the anterior direction and the angle gamma of the impact loads to the femur shaft on the bone fracture were given. The angle sigma had larger effect on the stress distribution than the angle gamma, which mainly represented the fracture of the upper femur including the femoral neck fracture when the posterolateral femur was impacted. This result was consistent with the clinical one. The parenchyma on the hip joint has relatively large relaxation effect on the impact loads. CONCLUSIONS: A 3D finite element analysis model of the femoral hip joint under dynamic loads is successfully established by using the impact dynamic theory.

Femur↗
PubMedDate not supplied

Migration of the femur head in rheumatoid coxitis.

The direction of penetration of the destroyed femoral head into the acetabulum in rheumatoid coxitis has been determined by means of the method of geometrical analysis in 81 affected hip joints. Of 48 patients, the duration of coxitis was 1-17 years (mean 4 years). Displacement of the femur head, destroyed by rheumatoid inflammation, was expressed in millimeters by means of a geometrical parameter called "transposition of the center of the femur head". The direction of transposition of the femur head into the deepened acetabulum has been expressed quantitatively by authors making use of the new geometrical parameter "the angle of transposition of the center of the femur head" which is referred to as angle delta. The angle delta is an angle between the line of transposition of the femur head center (tC) and its vertical component. The mean value of the delta angle for the entire group investigated measured 27.6 degrees and ranged from -5 degrees to +54 degrees, whereby an angle of 0 degrees marked the cranial direction of transposition, positive values marked the craniomedial transposition direction of the femur head. The angle delta varied from 21 degrees to 40 degrees in the majority of affected hip joints. The values of the delta angle were constant in every hip joint, thus indicating that the direction of transposition of the femur head did not change in the course of the progression of rheumatoid coxitis. It was found and statistically confirmed that no reciprocal dependence existed between the rate of progression of coxitis and the direction of displacement of the femur head into the acetabulum.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1989

Altering local soft-tissue circulation fails to halt venous drainage from the femur.

It has been suggested that tourniquet application proximal to bone biopsy in an extremity can reduce the number of tumor cells spread through circulation. This study investigates the anatomical pathway through which rapid cell spread could occur. Radioactively labeled 15-mu microspheres were injected into the medullary canal of rat femurs. The ratio of injected particles found in the femur was compared among groups that received application of a tourniquet prior to injection, no tourniquet, or transection of all soft tissue proximal to the injection site. Obliteration of circulation in the soft tissue surrounding the femur with a tourniquet or tissue transection did not alter the spread of particles from the femur. The pulmonary circulation trapped approximately 95% of particles reaching the lungs, limiting their access to peripheral arterial circulation. If the number of particles injected into the femur was increased, the number of particles leaving the femur increased at an even greater rate. These data suggest that (1) a particle can exit the femur without traveling through the soft tissue surrounding the femur; (2) most particles that reach the lung are retained; and (3) the injected bone acts as a sponge, retaining some particles and permitting the rest to enter the venous drainage.

Animals↗
PubMed1980

Hemopoietic support capacity of W/WV femurs and tibias.

We evaluated the capacity of "stromal stem cells" of the bones of W/WV mice to effect regeneration of functional "stromal" tissue by implanting femurs and tibias from congenic W/WV and +/+ mice subcutaneously into congenic mice of normal hematologic phenotypes. Eight weeks after implantation, we assayed the hemopoietic progenitor cell contents of the bones. Pluriopotent hemopoietic stem cells (CFUs) were assayed by the spleen colony forming assay in lethally irradiated CAF1 mice. Granulocyte/macrophage progenitor cells (CFUGM) and early erythroid (BFUe) and late erythroid (CFUE) progenitor cells were assayed in agar and methylcellulose semi-solid culture systems, respectively. total cellularity was greater in implanted W/WV femurs and tibias than in +/+ femurs. Although there was substantial variation in the repopulation of W/WV femurs compared to that of +/+ femurs, on the whole, in the W/WV implanted femurs, the numbers of CFUs may have been slightly less and the numbers of maturer progenitor cells slightly greater than they were in the +/+ femurs. All of the progenitor cells assayed were more numerous in the implanted W/WV tibias than in the +/+ tibias. These findings suggest that "stromal stem cells" of W/WV marrow are not defective. In addition, the fact that there were more CFUs in th W/WV that in the +/+ tibias suggests that the CFUs which are native to the implanted bones are not needed to effect reconstitution of normal numbers of CFUs in the implants as all of the CFUs detected in W/WV femurs must have come from the host, for W/WV CFUs do not form surface spleen colonies and, therefore, would not have been counted.

Anemia, Hemolytic, Congenital↗
PubMed1994

The influence of fixed rotational deformities of the femur on the patellofemoral contact pressures in human cadaver knees.

Patellofemoral contact pressures resulting from fixed rotational deformities of the femur were studied in human cadaver knees. The increase in the degree of fixed rotational deformities of the femur results in a nonlinear increase in patellofemoral contact pressures on the contralateral facets of the patella (i.e., external rotational deformity resulted in a contact pressure increase on the medial facet, and internal rotational deformity resulted in a contact pressure increase on the lateral facet of the patella). With the initial isometric tension of 200 N in the quadriceps tendon for 30 degrees, 60 degrees, 90 degrees, and 120 degrees knee flexion, the peak contact pressure showed no significant differences between the medial and lateral facets of the patella in its anatomic position. At 20 degrees of rotational deformity of the femur, only a slight increase was noted for the tension in the quadriceps tendon and the patellofemoral contact pressures on the contralateral facets of the patella. However, at 30 degrees rotational deformity of the femur, both the external and internal rotational deformity of the femur showed a significant increase in the tension of the quadriceps tendon and the patellofemoral contact pressures on contralateral facets of the patella. The greatest increase in patellofemoral contact pressures was observed at 30 degrees and 60 degrees knee flexion for both the external and internal rotational deformity of the femur. The external rotational deformity of the femur for all knee flexion angles showed significantly higher peak patellofemoral contact pressure increases on the medial facet of the patella as compared with the lateral patellofemoral contact pressure increase resulting from internal rotational deformity of the femur.

Aged↗
PubMed1998

A new technique for morphologic measurement of the femur. Its application for Japanese patients with osteoarthrosis of the hip.

The cementless femoral prostheses developed in Western countries have commonly been used for Japanese patients, but it has been noted that it is difficult to achieve a good fit between the cementless femoral prostheses and some femora. In Japan, there are many patients with secondary osteoarthrosis (OA) of the hip, but Western designed femoral prostheses seem to be mainly for use with primary OA of the hip. To design femoral prostheses better suited to Japanese patients, a new method to study the morphometry of the femur is required--one which can determine the particular features of the femur in Japanese patients. In this study, a new morphologic measurement technique of the femur is proposed and applied to a number of Japanese OA patients in order to demonstrate its efficacy. In this technique, a three-dimensional solid model based on the outer and inner borders of the femoral cortex is constructed from 3-D CT images and computer-aided design (CAD) software. The bone axis is defined as the line of best fit to the centers of gravity of the femur cross sections in each CT plane by using the least square method. A new femur coordinate system is considered based on this bone axis. The corrected outer borders of the cortex are reconstructed in sections perpendicular to the bone axis. The angle between the principal axis of inertia of the sections and a plane defined by the femur coordinate system is selected as providing a good measurement of the torsion value to characterize the femur morphology. The angles of principal axis were measured in 110 OA and 36 normal hips, and then compared with each other. A significant difference between the OA and normal group was observed especially in the proximal region above the section 6 mm below the level of the lesser trochanter. It is suggested that the anteversion of the femoral neck influences the torsion of the parts below the lesser trochanter. From the results, it is demonstrated that the proposed measurement technique is a reliable and efficient means of determining femur morphology.

Adult↗
PubMed1996

Reconstruction of femur length from markers of its proximal end.

Length of femur and stature are of forensic and anthropological significance. Bony markers such as the head and neck of the femur can be of use in determining the femoral length when only a fragment of the proximal femur is available. A total of 171 South Indian unpaired femora, devoid of gross pathology and grouped by genders and sides, were used to measure the neck-shaft angle, neck length, intertrochanteric apical axis length, maximum vertical diameter of the femur head, and maximum femur length. The data were statistically analyzed for regression. Length of femur significantly correlated with the other dimensions. Simple (linear) regression equations of the length of femur against the neck-shaft angle, neck length, intertrochanteric apical axis length, and maximum vertical diameter of the head have been derived. The equations seem to be robust and can be used for different populations.

Adult↗
PubMed2003

Mortality after reamed intramedullary nailing of bilateral femur fractures.

We performed retrospective review of 743 patients treated with reamed intramedullary nailing of a femoral shaft fracture was done to assess the clinical impact of bilateral femur fractures on the mortality, hospital stay, and length of intensive care treatment in patients with blunt trauma. Unilateral injuries occurred in 689 patients and bilateral injuries occurred in 54 patients. Mortality in patients with bilateral femur fractures was 5.6% compared with 1.5% in patients with unilateral femur fractures. The two groups were analyzed using multiple linear regression and logistic regression with age and Injury Severity Scores as covariants to allow for comparison of similarly injured groups as predicted by the Injury Severity Scores. Bilateral femur fractures still were associated with a significantly higher mortality, longer length of stay in the hospital, and longer length of stay in the intensive care unit. As expected, when analyzed separately, patients with bilateral femur fractures had significantly higher Injury Severity Scores, longer lengths of stay in the intensive care unit, and longer lengths of stay in the hospital. Patients with bilateral femur fractures have an increased mortality when compared with patients with unilateral femur fractures after controlling for Injury Severity Score and age. When used alone, the Injury Severity Score underestimates the contribution of a second femur fracture.

Adolescent↗
PubMedDate not supplied

The definition and treatment of pediatric subtrochanteric femur fractures with titanium elastic nails.

PURPOSE: Titanium elastic nailing (TEN) has become more common in the treatment of pediatric femur fractures in many European centers and in North America over the past several years. Prior studies have shown that the use of TEN for midshaft femur fractures results in excellent outcomes with an earlier return to activity, earlier mobilization, and a shortened hospital stay. However, subtrochanteric femur fractures continue to remain a difficult subset of fractures to care for, with loss of reduction and nonunion being significant complications. Studies have differed regarding the definition of pediatric subtrochanteric femur fractures. The purpose of this study is to establish a reproducible method of defining pediatric subtrochanteric fractures and then apply that definition in a retrospective review of 13 patients who sustained subtrochanteric femur fractures treated with TEN at North Carolina Baptist Hospital using a modified technique that allows for improved fracture stability. METHODS: Charts and radiographs were retrospectively reviewed for all pediatric patients sustaining subtrochanteric femur fractures treated with TEN from the period of 2000 to 2004 at Wake Forest University. The TEN outcome measures scale was applied to determine their results. RESULTS: TEN allowed rapid mobilization with excellent or satisfactory clinical and radiographic results in all patients. CONCLUSIONS: Results suggest that the use of TEN for subtrochanteric femur fractures is a safe and effective method of fixation that benefits patients through early mobilization, shorter hospital stays, and fewer complications. SIGNIFICANCE: By applying the definition of subtrochanteric femur fractures described by the authors, results of future studies can be objectively compared and classified. TEN is a safe and effective alternative for treating most pediatric subtrochanteric fractures by decreasing the morbidity that occurs with other treatment modalities.

Adolescent↗
PubMed1996

Stress and strain distribution within the intact femur: compression or bending?

The aim of this research was to test the hypothesis that the intact femur is loaded predominately in compression. The study was composed of two parts: a finite element analysis of the intact femur to assess if a compressive stress distribution could be achieved in the diaphyseal region of the femur using physiological muscle and joint contact forces; a simple radiological study to assess the in vivo deflections of the femur during one legged stance. The results of this investigation strongly support the hypothesis that the femur is loaded primarily in compression, and not bending as previously thought. The finite element analysis demonstrated that a compressive stress distribution in the diaphyseal femur can be achieved, producing a stress distribution which appears to be consistent with the femoral cross-sectional geometry. The finite element analysis also predicted that for a compressive load case there would be negligible deflections of the femoral head. The radiological study confirmed this, with no measurable in vivo deflection of the femur occurring during one legged stance.

Adult↗
PubMed1975

Effects of long-term rotation and hypergravity on developing rat femurs.

Male and female Sprague-Dawley rats derived from a single mating were raised for three generations under constant centrifugation at 1.03 G (Rotation Controls) and at 2 G. When the third generation rats were 3 months old, they were sacrificed, and their femurs removed. After fixation and cleaning, the femurs were then measured for length and diameter. Then right femurs were sectioned longitudinally, left femurs transversely. After staining with Hematoxylin and Eosin, right femurs were examined for ossification patterns and left femurs were measured for cortical thickness. All rotation control rats showed marked stimulation of ossification in the femoral head, and males showed significant cortical thinning when compared to non-rotated earth gravity controls. All 2 G femurs showed decreased length and aspect (L/D) ratios, and increased cortical thickness/diameter ratios when compared to earth controls or rotation controls. Ossification of the femoral head was slightly advanced, while the distal epiphyseal plate was thinned.

Animals↗