Epiphyseal Region Research Articles

Thermal Conductivity of Human Bone in Cryoprobe Freezing as Related to Density.

Cryoprobes create localized cell destruction through freezing. Bone is resistant to temperature flow but is susceptible to freezing necrosis at warmer temperatures than tumor cells. Few studies have determined the thermal conductivity of human bone. No studies have examined conductivity as related to density. The study goal was to examine thermal conductivity in human bone while comparing differences between cancellous and cortical bone. An additional goal was to establish a relationship between bone density and thermal conductivity. Six knee joints from 5 cadavers were obtained. The epiphyseal region was sliced in half coronally prior to inserting an argon-circulating cryoprobe directed away from the joint line. Thermistor thermometers were placed perpendicularly at measured increments, and the freezing cycle was recorded until steady-state conditions were achieved. For 2 cortical samples, the probe was placed intramedullary in metaphyseal samples and measurements were performed radially from the central axis of each sample. Conductivity was calculated using Fournier's Law and then plotted against measured density of each sample. Across samples, density of cancellous bone ranged from 0.86 to 1.38 g/mL and average thermal conductivity ranged between 0.404 and 0.55 W/mK. Comparatively, cortical bone had a density of 1.70 to 1.86 g/mL and thermal conductivity of 0.0742 to 0.109 W/mK. A strong 2-degree polynomial correlation was seen (R2=0.8226, P<.001). Bone is highly resistant to temperature flow. This resistance varies and inversely correlates strongly with density. This information is clinically relevant to maximize tumor ablation while minimizing morbidity through unnecessary bone loss and damage to surrounding structures. [Orthopedics. 2017; 40(2):90-94.].

Coordinate and synergistic effects of extensive treadmill exercise and ovariectomy on articular cartilage degeneration.

BackgroundAlthough osteoarthritis (OA) is a multifactorial disease, little has been reported regarding the cooperative interaction among these factors on cartilage metabolism. Here we examined the synergistic effect of ovariectomy (OVX) and excessive mechanical stress (forced running) on articular cartilage homeostasis in a mouse model resembling a human postmenopausal condition.MethodsMice were randomly divided into four groups, I: Sham, II: OVX, III: Sham and forced running (60 km in 6 weeks), and IV: OVX and forced running. Histological and immunohistochemical analyses were performed to evaluate the degeneration of articular cartilage and synovitis in the knee joint. Morphological changes of subchondral bone were analyzed by micro-CT.ResultsMicro-CT analyses showed significant loss of metaphyseal trabecular bone volume/tissue volume (BV/TV) after OVX as described previously. Forced running increased the trabecular BV/TV in all mice. In the epiphyseal region, no visible alteration in bone morphology or osteophyte formation was observed in any of the four groups. Histological analysis revealed that OVX or forced running respectively had subtle effects on cartilage degeneration. However, the combination of OVX and forced running synergistically enhanced synovitis and articular cartilage degeneration. Although morphological changes in chondrocytes were observed during OA initiation, no signs of bone marrow edema were observed in any of the four experimental groups.ConclusionWe report the coordinate and synergistic effects of extensive treadmill exercise and ovariectomy on articular cartilage degeneration. Since no surgical procedure was performed on the knee joint directly in this model, this model is useful in addressing the molecular pathogenesis of naturally occurring OA.

Transplantation of human neonatal foreskin stromal cells in ex vivo organotypic cultures of embryonic chick femurs.

We have previously reported that human neonatal foreskin stromal cells (hNSSCs) promote angiogenesis in vitro and in chick embryo chorioallantoic membrane (CAM) assay in vivo. To examine the in vivo relevance of this observation, we examined in the present study the differentiation potential of hNSSCs in ex vivo organotypic cultures of embryonic chick femurs. Isolated embryonic chick femurs (E10 and E11) were cultured for 10 days together with micro-mass cell pellets of hNSSCs, human umbilical vein endothelial cells (HUVEC) or a combination of the two cell types. Changes in femurs gross morphology and integration of the cells within the femurs were investigated using standard histology and immunohistochemistry. After 10 days, the femurs that were cultured in the presence of hNSSCs alone or hNSSC + HUVEC cells grew longer, exhibited thicker diaphysis and an enlarged epiphyseal region compared to control femurs cultured in the absence of cells. Analysis of cell–femur interactions, revealed intense staining for CD31 and enhanced deposition of collagen rich matrix along the periosteum in femurs cultured with hNSSCs alone or hNSSCs + HUVEC and the most pronounced effects were observed in hNSSC + HUVEC cultures. Our data suggest that organotypic cultures can be employed to test the differentiation potential of stem cells and demonstrate the importance of stem cell interaction with 3D-intact tissue microenvironment for their differentiation.

Histologic Examination of an Assemblage of Psittacosaurus (Dinosauria: Ceratopsia) Juveniles From the Yixian Formation (Liaoning, China)

Psittacosaurus is one of the most abundant dinosaurs known, which allows for extensive study of its growth and form. Previous studies have evaluated growth trajectories of Psittacosaurus using bone histology. However, we present the first study of Psittacosaurus comparative juvenile histology and describe the histology of Psittacosaurus within its first year of life based on multiple sections taken from an exquisite monospecific assemblage of juveniles from the Yixian Formation in Liaoning, China. Specimens studied had femur lengths ranging from 30 to 36 mm. The five juveniles examined all have similar histologic patterns in the midshaft and epiphyseal regions showing that there is limited plasticity in bone development in juvenile Psittacosaurus and that all of the specimens in the assemblage were likely the same age. The microstructure patterns are compatible with the hypothesis that Psittacosaurus was precocial and that these juveniles were neonates. Based on comparisons with other juvenile ornithischians, juvenile Psittacosaurus had a growth rate similar to Orodromeus, slower than that of Maiasaura, Dysalotosaurus, or hadrosaurs consistent with small body size. Our results support previous studies that demonstrated that the orientation of vascular canals is likely not solely reflective of growth rate, but is also affected by underlying biomechanical, structural processes. The number of studies done on theropod and sauropodomorph histology dwarfs those of ornithischians. More studies of ornithischian histology are necessary in order to better establish phylogenetic trends in microstructure and to learn more about growth in this important clade.

Giant cell tumor of bone arising in long bones possibly originates from the metaphyseal region.

Giant cell tumor of bone (GCTB) is a primary benign bone tumor with a locally aggressive character. Definitive descriptions of the site of origin for this type of tumor are not available. The aim of the present study was to evaluate the site of origin of GCTB of long bones with regards to epiphyseal lines by means of radiographic examination. For that purpose, plain X-ray scans of 71 GCTBs arising in long bones were retrospectively reviewed. The tumor locations were the distal femur in 31 cases, proximal femur in 11 cases, proximal tibia in 13 cases, distal radius in 6 cases, proximal humerus in 5 cases and proximal fibula in 5 cases. The vertical center (VC) of the tumor was determined with X-ray anteroposterior view, and the correlation between the VC and the epiphyseal line, and between the distance from the epiphyseal line to the VC and tumor area or volume were analyzed using a regression model equation based on scatter plot diagrams. The VC of the tumor was located in the metaphyseal region in 57 cases, in the epiphyseal line in 11 cases and in the epiphyseal region in 3 cases. In cases of GCTB located in the distal femur or proximal tibia, significant correlations between the distance from the VC to the epiphyseal line and tumor area or volume were identified. The site of origin of GCTB was estimated to be located in the metaphyseal region. GCTB often occurs in mature patients, which renders it challenging to estimate the true site of origin of this lesion, since the metaphyseal line has disappeared in mature patients. The results of the present study suggest that GCTB possibly originates in the metaphyseal region.

Feature description with SIFT, SURF, BRIEF, BRISK, or FREAK? A general question answered for bone age assessment

Solving problems in medical image processing is either generic (being applicable to many problems) or specific (optimized for a certain task). For example, bone age assessment (BAA) on hand radiographs is a frequent but cumbersome task for radiologists. For this problem, many specific solutions have been proposed. However, general-purpose feature descriptors are used in many computer vision applications. Hence, the aim of this study is (i) to compare the five leading keypoint descriptors on BAA, and, in doing so, (ii) presenting a generic approach for a specific task. Two methods for keypoint selection were applied: sparse and dense feature points. For each type, SIFT, SURF, BRIEF, BRISK, and FREAK feature descriptors were extracted within the epiphyseal regions of interest (eROI). Classification was performed using a support vector machine. Reference data (1101 radiographs) of the University of Southern California was used for 5-fold cross-validation. The data was grouped into 30 classes representing the bone age range of 0–18 years. With a mean error of 0.605 years, dense SIFT gave best results and outperforms all published methods. The accuracy was 98.36% within the range of 2 years. Dense SIFT represents a generic method for a specific question.

Morphological evaluation of cartilage development in the distal femoral epiphysis of human fetuses

Abstract Introduction: The epiphysis cartilage in the knee joint has been widely studied in recent decades due to the joint complexity and its clinical importance. However, there is little information about morphological and ultrastructural aspects of normal cartilage development of the knee joint, particularly in human fetuses of different age, which could contribute to a better understanding of diseases and malformations during development. Materials and Methods: This research was performed with 20 human fetuses covering the age range 16 to 31 weeks of intrauterine life, which were divided into 4 groups (n = 5). Morphometric analysis of the distal femoral epiphysis cartilage were realized for the parameters: chondrocytes area, percent density of chondrocyte and extracellular matrix (ECM), as well as qualitative analysis of the distribution, organization and characterization of collagen fibers making use of Picrosirius staining under analysis with polarized light. Results: It was verified that the chondrocytes area and density of ECM increased with advancing age, while the density of chondrocytes decreased. Also in the epiphyseal region, immature cartilage of younger fetuses, initially with characteristics of a proliferation zone starts to present, in older age fetuses, characteristics of a maturation zone, with larger chondrocytes and more distant from each other. In the epiphysis surface the organization and orientation of the collagen ibers changed in different groups, from an irregular orientation in the younger fetuses group, to a pantograph organization in the most developed fetuses group. Conclusion: During fetal development, the maturation of cartilage combines increasing ECM percent density and changes in the collagen fibers organization and orientation, contributing to the required cartilage properties for each stage of its development.

The canine epiphyseal-derived mesenchymal stem cells are comparable to bone marrow derived-mesenchymal stem cells.

Mesenchymal stem cells (MSCs) hold great potential in cell therapy and have attracted increasing interests in a wide range of biomedical sciences. However, the scarcity of MSCs and the prolonged isolation procedure limited the clinical application. To address these 2 issues, we developed a method to isolate MSCs from bone biopsy tissues of euthanized canine body donors. Compared to the traditional method to isolate MSCs from aspirated bone marrow (BMSCs), the isolation procedure for MSCs from harvested epiphyseal cancellous bone (EMSCs) was less time-consuming. The isolated EMSCs had similar plastic-adherence, tri-lineage differentiation and consistent surface marker profiles compared to BMSCs. We harvested BMSCs and EMSCs from 24 euthanized cases from clinics and 42 euthanized donors from a local shelter. The successful rate for EMSC isolation is significantly higher compared to BMSC isolation, while the other properties of the isolated MSCs including the clonogenicity, proliferative potentials and molecular phenotypes were not discernibly different between the MSCs established by the two methods. In conclusion, we demonstrated a new procedure to harvest MSCs by bone biopsy at the epiphyseal region. This method is less time consuming and more reliable, and the resulting MSCs are comparable to those harvested by bone marrow aspiration. The combination of the two methods can greatly improve the efficiency to harvest MSCs.

Influence of chronic stroke impairments on bone strength index of the tibial distal epiphysis and diaphysis.

The influence of various stroke impairments on bone health is poorly understood. This study showed that muscle function and small artery compliance were more strongly associated with the bone strength index at the tibial diaphyseal and epiphyseal regions, respectively. These impairments should be targeted in promoting bone health post-stroke. This study examined the bone structural properties of the tibial distal epiphysis and diaphysis after chronic stroke and identified the clinical correlates of the bone strength index measured at these sites. The tibial distal epiphysis (4% site) and diaphysis (66% site) were scanned on both sides in 66 chronic stroke patients and 23 control participants using peripheral quantitative computed tomography. Dynamic knee muscle strength, balance function, spasticity, arterial compliance, and endurance were also measured in the stroke group. At the 4% site, multivariate analysis showed a significant side×group interaction effect (Wilk's lambda=3.977, p<0.001), with significant side-to-side differences in total volumetric bone mineral density (vBMD), trabecular vBMD, and bone strength index in the stroke group, but not in the control group. A significant side×group interaction was also found at the 66% site (Wilk's lambda=4.464, p<0.001), with significant side-to-side differences in cortical vBMD, cortical area, cortical thickness, and bone strength index in the stroke group only. Balance and endurance were independently associated with bone strength index at both tibial sites in the paretic leg (p<0.05) after adjusting for relevant factors in multivariate regression analysis. Small artery compliance and muscle strength were significantly associated with the bone strength index at the 4% site and 66% site, respectively. The influence of various stroke impairments on bone was region-specific. While muscle function was more strongly associated with the bone strength index in the diaphyseal region, the effect of vascular health was more apparent in the tibial epiphysis in the paretic leg.

MicroRNA-146a regulates human foetal femur derived skeletal stem cell differentiation by down-regulating SMAD2 and SMAD3.

MicroRNAs (miRs) play a pivotal role in a variety of biological processes including stem cell differentiation and function. Human foetal femur derived skeletal stem cells (SSCs) display enhanced proliferation and multipotential capacity indicating excellent potential as candidates for tissue engineering applications. This study has examined the expression and role of miRs in human foetal femur derived SSC differentiation along chondrogenic and osteogenic lineages. Cells isolated from the epiphyseal region of the foetal femur expressed higher levels of genes associated with chondrogenesis while cells from the foetal femur diaphyseal region expressed higher levels of genes associated with osteogenic differentiation. In addition to the difference in osteogenic and chondrogenic gene expression, epiphyseal and diaphyseal cells displayed distinct miRs expression profiles. miR-146a was found to be expressed by human foetal femur diaphyseal cells at a significantly enhanced level compared to epiphyseal populations and was predicted to target various components of the TGF-β pathway. Examination of miR-146a function in foetal femur cells confirmed regulation of protein translation of SMAD2 and SMAD3, important TGF-β and activin ligands signal transducers following transient overexpression in epiphyseal cells. The down-regulation of SMAD2 and SMAD3 following overexpression of miR-146a resulted in an up-regulation of the osteogenesis related gene RUNX2 and down-regulation of the chondrogenesis related gene SOX9. The current findings indicate miR-146a plays an important role in skeletogenesis through attenuation of SMAD2 and SMAD3 function and provide further insight into the role of miRs in human skeletal stem cell differentiation modulation with implications therein for bone reparation.

Clinicopathologic differential diagnosis of giant cell-rich osteosarcoma and giant cell tumor of bone

To study the clinicopathologic features and differential diagnosis of giant cell-rich osteosarcoma (GCRO) and giant cell tumor of bone (GCT). The clinical, radiologic, pathologic and immunohistochemical features of 18 cases of GCRO and 118 cases of GCT were evaluated. The mean age of patients with GCRO was 24.6 years. Fifteen of the 18 cases arose in the metaphysis of long bones. GCRO presented as a large poorly-defined mixed lytic and blastic mass, associated with cortical destruction and formation of large soft tissue component. Histologically, GCRO was characterized by a predominance of numerous osteoclast-like giant cells admixed with scanty osteoid which was formed by neoplastic cells in different levels of anaplasia and pleomorphism. In the 118 cases of GCT studied, the mean age of patients was 34.5 years. Most of them (108 cases) arose in the epiphyseal region of long bones. They usually presented as expansile eccentric and osteolytic lesions. Invasive GCT displayed local cortical destruction. Histologic examination of GCT revealed the presence of large number of osteoclast-like giant cells and mononuclear stromal cells. The mononuclear stromal cells possessed poorly defined cytoplasm, showed little cytological atypia and did not carry atypical mitotic figures. They were positive for p63 (83.9%, 99/118). Reactive bone could be observed at the periphery. GCRO represents a special form of osteosarcoma which shows overlapping clinicopathologic features with invasive GCT. The presence of nuclear atypia, atypical mitoses and osteoid matrix produced directly by neoplastic cells are more in favor of GCRO. These features however may not be demonstrated in full in limited small biopsy samples. It is thus important to analyze all clinical, radiologic and pathologic features before a definitive diagnosis is made.

Morphological modifications of knee articular cartilage in bullfrogs (Lithobates catesbeianus) (Anura: Ranidae) during postmetamorphic maturation

The organization of knee articular cartilage of the bullfrog (Lithobates catesbeianus) differs in relation to morphofunctional adaptation in many aspects from similar structures in mammals. Thus, we investigated the structural organization and distribution of the extracellular matrix components in three articular cartilage regions in the distal epiphysis of the femur and proximal epiphysis of the tibia in male bullfrogs at 7, 540 and 1,080 days after metamorphosis. Cartilage thickness and cell density decreased in all regions with age. The basophilia differed among cartilage sites during aging. Calcium deposits were detected in growth cartilage of the femur and tibia in older animals. Immunohistochemical staining for chondroitin-6-sulfate was positive in the pericellular and territorial matrix in all samples. Positive immunostaining for type I collagen was observed in the superficial layer at all ages and in ossification centers of older animals. Reactivity to type II collagen was intense and was found throughout the stroma at all ages. Ultrastructural analysis of the epiphyseal region, in young animals, showed that the cytoplasm of chondrocytes was rich in rough endoplasmic reticulum, Golgi complex and mitochondria. In old animals, were observed a reduction in the size and number of mitochondria, disintegration of rough endoplasmic reticulum, and vacuolization of the Golgi complex. The bullfrog articular cartilage presented structural and organizational changes during aging which may contribute to the functional cartilage deterioration in old animals.

Application of Tendon-Derived Stem Cell Sheet for the Promotion of Graft Healing in Anterior Cruciate Ligament Reconstruction

Background: Both osteointegration and remodeling of graft midsubstance (collectively called graft healing) are slow processes after anterior cruciate ligament (ACL) reconstruction. Tendon-derived stem cells (TDSCs) form a cell sheet after treatment with connective tissue growth factor (CTGF) and ascorbic acid, which exhibits higher tenogenic and maintains high chondro-osteogenic gene expression of TDSCs. No external scaffold is required for cell delivery. Hypothesis: Wrapping the TDSC sheet around the ACL graft would promote early graft healing in a rat model. Study Design: Controlled laboratory study. Methods: Green fluorescent protein (GFP) rat TDSCs were treated with connective tissue growth factor and ascorbic acid to promote cell sheet formation. Rats undergoing unilateral ACL reconstruction were divided into a control group and a TDSC group. The tendon graft was wrapped with the GFP-TDSC sheet before graft insertion in the TDSC group. At weeks 2, 6, and 12 after reconstruction, the samples were harvested for computed tomography imaging and histologic or biomechanical testing. The fate of the transplanted cell sheet was examined by immunohistochemical staining of GFP. Results: There were significantly higher tunnel bone mineral density (BMD) (42.3% increase, P = .047) and bone volume/total volume (BV/TV) (625% increase, P = .009) at the metaphyseal region of the tibial tunnel at week 2 and at the femoral tunnel at week 6 (BMD: 30.8% increase, P = .014; BV/TV: 100% increase, P = .014) in the TDSC group compared with the control group. Only the TDSC group showed a time-dependent increase in tunnel BMD (overall P = .038) and BV/TV (overall P = .015) at the epiphyseal region of the tibial tunnel. Semiquantitative image analysis showed better graft osteointegration and higher intra-articular graft integrity with lower cellularity and vascularity, better cell alignment, and higher collagen birefringence in the TDSC group. The ultimate load at week 2 (52.5% increase, P = .027) and stiffness at week 6 (62% increase, P = .008) were significantly higher in the TDSC group. Cells positive for GFP were observed in all samples in the TDSC group at week 2 but became reduced with time after reconstruction. Conclusion: The TDSC sheet improved early graft healing after ACL reconstruction in the rat model. Clinical Relevance: The TDSC sheet could potentially be used for the promotion of graft healing in ACL reconstruction.

Structure Model Index Changes in the Femoral Epiphyseal Region on Micro-Computed Tomography Caused by a Supplement Diet in Ovariectomized Rats

We have developed a novel supplement diet for osteoporosis prevention that contains fructo- oligosaccharide, isoflavone, and calcium citrate, in addition to calcium phosphate (high mineral diet: HMD). The present study aimed to clarify whether rats with osteoporosis fed an HMD showed an improved structure model index (SMI) in the femoral epiphyseal region compared with rats fed a normal mineral diet (NMD). The experiment used 20-week-old ovariectomized rats divided into an NMD group (n=6) and an HMD group (n=6).� After 24 weeks on the diet, this study examined the changes in SMI and the 3-dimensional pseudocolor map (3D-map) using micro-computed tomography. Compared to the NMD group, the HMD group had significantly greater Trabecular Thickness (Tb. Th) and Trabecular Number, and shorter Trabecular Separation and Trabecular Spacing, indicating highly dense trabeculae. The trabeculae of the NMD group had low Tb. Th and bone volume / tissue volume (BV/TV), indicating a thin, rod-like shape, but the trabeculae of the HMD group had significantly greater Tb. Th and BV/TV, demonstrating a thick, plate-like structure. In the sagittal section image of the 3D-map, the trabecular bone of the NMD group showed low bone mineral density (BMD), represented by light blue and purple colors, on the growth plate side of the inner portion of the cortical bone, indicating near complete resorption of the trabecular bone. The trabecular bone of the HMD group showed moderate to low BMD, represented by light blue and green colors, on the growth plate side, indicating a greater trabecular bone density compared to the NMD group. The present results showed that the intake of HMD, compared to NMD, maintains the trabecular structure by preventing trabecular bone resorption, indicating the usefulness of HMD intake.

Hypoxia-Adapted Myeloma Cells Possess Stem Cell Character

The prognosis of patients with multiple myeloma (MM) has been improved by the emergence of new molecular targeting agents including proteasome inhibitors and immunomodurating agents. Nevertheless, MM remains incurable at present because it is likely that MM stem cells are resistant to these targeting agents. Thus, it is important to further investigate the biology of MM stem cells to cure the MM patients. We have demonstrated that b-catenin is a novel and attractive target against MM (Ashihara et al. Clin Cancer Res, 2009; Yao et al. Blood Cancer J, 2011). We next investigate novel targets focused on the hypoxic bone marrow (BM) environment.BM is known to have low levels of oxygen, particularly at the epiphysis, which is distant form the BM arterial blood supply. Normal hematopoietic stem cells (HSCs) reside in this hypoxic epiphyseal region “niche”, and HSCs are protected from DNA damage induced by reactive oxygen species. We have previously found that chronic myelogenous leukemia (CML) cells engrafted in the BM survived and proliferated in the severely hypoxic environment and that these hypoxia-adapted (HA) leukemic cells acquired stem cell-like characters (Takeuchi et al. Cell Death Differ, 2010). In this study, we investigated the characteristics of hypoxia-adapted MM (HA-MM) cells. We first confirmed oxygen status in the BM of the MM cell-engrafted mice. Irradiated NOD/SCID mice were inoculated with 2 x 106 AMO-1 cells. After 2 or 4 weeks transplantation, we sacrificed mice and confirmed engraftment. The inoculated MM cells engrafted in the epiphysis in recipient mice after 2 weeks transplantation, and populated endosteum of epiphysis after 4 weeks. These MM cells were positive for pimonidazole, which specifically accumulated in hypoxic cells (< 1.3% O2 concentration). These observations suggested that MM cells resided in the BM are hypoxic. We then established AMO-1, OPM-2, and IM-9 HA-MM cells cultured under hypoxic conditions (O2 1%). These HA cells can continue to proliferate in hypoxic conditions for more than six months. In flow cytometric analysis, the G0 fraction cells as well as side population fraction cells significantly increased in HA-MM cells compared with those in the parental MM cells. We next transplanted parental or HA-MM AMO-1 cells with same cell numbers into irradiated NOD/SCID mice. The survival durations of mice transplanted with HA-AMO-1 cells were significantly shorter than that of mice transplanted with parental cells. Moreover, in serial transplantation experiments, all 5 HA-MM cell-transplanted mice died of MM whereas 1 out of 5 parental MM cell-transplanted mice (Figure 1). Quantitative RT-PCR analysis demonstrated that Sox2, Oct3, and Nanog mRNA transcripts increased in the HA-MM AMO-1 cells (Figure 2). We next investigated the signaling pathway activated in HA-MM cells. Interestingly, phosphorylated Smad2 expression was increased in HA-AMO-1 cells. These findings suggest that HA-MM cells possess stem cell-like character, and these cells may provide a useful model to investigate the mechanism of MM stem cells (myeloma-initiating cells) resistant to molecular target agents. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Bone mineral and stiffness loss at the distal femur and proximal tibia in acute spinal cord injury

Computed tomography and finite element modeling were used to assess bone mineral and stiffness loss at the knee following acute spinal cord injury (SCI). Marked bone mineral loss was observed from a combination of trabecular and endocortical resorption. Reductions in stiffness were 2-fold greater than reductions in integral bone mineral. SCI is associated with a rapid loss of bone mineral and an increased rate of fragility fracture. The large majority of these fractures occur around regions of the knee. Our purpose was to quantify changes to bone mineral, geometry, strength indices, and stiffness at the distal femur and proximal tibia in acute SCI. Quantitative computed tomography (QCT) and patient-specific finite element analysis were performed on 13 subjects with acute SCI at serial time points separated by a mean of 3.5 months (range 2.6-4.8 months). Changes in bone mineral content (BMC) and volumetric bone mineral density (vBMD) were quantified for integral, trabecular, and cortical bone at epiphyseal, metaphyseal, and diaphyseal regions of the distal femur and proximal tibia. Changes in bone volumes, cross-sectional areas, strength indices and stiffness were also determined. Bone mineral loss was similar in magnitude at the distal femur and proximal tibia. Reductions were most pronounced at epiphyseal regions, ranging from 3.0 % to 3.6 % per month for integral BMC (p < 0.001) and from 2.8 % to 3.4 % per month (p < 0.001) for integral vBMC. Trabecular BMC decreased by 3.1-4.4 %/month (p < 0.001) and trabecular vBMD by 2.7-4.7 %/month (p < 0.001). A 3.8-5.4 %/month reduction was observed for cortical BMC (p < 0.001); the reduction in cortical vBMD was noticeably lower (0.6-0.8 %/month; p ≤ 0.01). The cortical bone loss occurred primarily through endosteal resorption, and reductions in strength indices and stiffness were some 2-fold greater than reductions in integral bone mineral. These findings highlight the need for therapeutic interventions targeting both trabecular and endocortical bone mineral preservation in acute SCI.

Contemporary Management of Metastatic Bone Disease

Metastatic bone disease has a significant effect on a patient's mortality and health-related quality of life. An aging US population and improved survival rates of patients with cancer have led to an increase in the incidence of symptomatic bony metastatic lesions that may require orthopaedic care. Skeletal-related events in neoplastic disease include pain, pathologic fracture, hypercalcemia, and neural compression, including spinal cord compression. The clinical evaluation and diagnostic study of a patient with a skeletal lesion of unknown etiology should be approached carefully. In patients with widespread metastatic disease, the treatment of a skeletal-related event may be limited to stabilization of the pathologic fracture or local disease control. The treatment of metastatic bone disease is guided by the nature of the skeletal-related event, the responsiveness of the lesion to adjuvant care, and the overall condition and survival expectations of the patient. Impending pathologic fractures are often more easily treated, with less morbidity and easier recovery for patients, than completed fractures. Quality of life is the most important outcome measure in these patients. When surgery is indicated, the approach, choice of fixation, and use of adjuvant should allow for immediate and unrestricted weight bearing. Because metastatic lesions to the skeleton have a limited capacity for spontaneous healing, surgical fixation should be durable for the life expectancy of the patient. In the epiphyseal region of long bones, replacement arthroplasty is generally preferred over internal fixation. Metaphyseal and diaphyseal regions can generally be addressed with intramedullary nailing or plate fixation with adjuvant. The specific treatment of acetabular lesions is dictated by the anatomy and the degree of bone loss. Spinal stability and neural compromise are important considerations in choosing a strategy for managing spine tumors. Effective surgical approaches to metastatic disease of the spine may include vertebral augmentation or open decompression and realignment of the spinal column with internal fixation. Radiation therapy is an important adjunctive modality in the treatment of metastatic bone disease. Medical management consists of symptom control, cytotoxic chemotherapy, and targeted therapy. Emerging technologies, including radiofrequency ablation, cementoplasty, and advances in intraoperative imaging and navigation, show promise in the treatment of metastatic bone disease.

A micro-architectural evaluation of osteoporotic human femoral heads to guide implant placement in proximal femoral fractures

Background and purpose The micro-architecture of bone has been increasingly recognized as an important determinant of bone strength. Successful operative stabilization of fractures depends on bone strength. We evaluated the osseous micro-architecture and strength of the osteoporotic human femoral head.Material and methods 6 femoral heads, obtained during arthroplasty surgery for femoral neck fracture, underwent micro-computed tomography (microCT) scanning at 30 μm, and bone volume ratio (BV/TV), trabecular thickness, structural model index, connection density, and degree of anisotropy for volumes of interest throughout the head were derived. A further 15 femoral heads underwent mechanical testing of compressive failure stress of cubes of trabecular bone from different regions of the head.Results The greatest density and trabecular thickness was found in the central core that extended from the medial calcar to the physeal scar. This region also correlated with the greatest degree of anisotropy and proportion of plate-like trabeculae. In the epiphyseal region, the trabeculae were organized radially from the physeal scar. The weakest area was found at the apex and peripheral areas of the head. The strongest region was at the center of the head.Interpretation The center of the femoral head contained the strongest trabecular bone, with the thickest, most dense trabeculae. The apical region was weaker. From an anatomical and mechanical point of view, implants that achieve fixation in or below this central core may achieve the most stable fixation during fracture healing.

Bone Age Assessment

Bone age assessment defined as the measure of skeletal development is most often used in pediatrics and forensics to estimate the true age of a person. It is usually done by comparing the left hand X-ray of a person with the hand radiographs in the standard atlas or based on local regions of interests (ROI) that include epiphyseal regions of the phalanges (14 ROI’s).Both these assessments were labour intensive, prone to discrepancies and can only be used to estimate the age till 18. Hence there is a need to develop automated method to assess the bone age by exploiting the appropriate features. This paper attempts to identify a procedure in recognizing the respective bone that belongs to male or female with its corresponding age. The automated procedure comprises of segmentation of metacarpals using area based statistics followed by typical feature extraction. Nine features are extracted for the experimental study. A back propagation neural network is then applied to classify whether the given sample refers to male or female bone. It is observed from the simulation results that the proposed procedure is found to be less computation burden and the results are found to be comparable with the existing work reported in the literature.

AB1168 Clinical disease activity scores of knee joints in newly diagnosed JIA predicts reduction in bone pixel value detected by computed radiography

ObjectivesTo evaluate the relationship between Computed Radiography (CR) Pixel values and disease activity scores obtained for the knees of newly diagnosed Juvenile Idiopathic Arthritis (JIA) children.MethodsChildren with newly diagnosed untreated...