Background Body phosphorus metabolism exhibits a circadian rhythm over the 24-h daily cycle.The egg laying behavior makes laying hens a very special model for investigating phosphorus circadian rhythms.There is lack o...Background Body phosphorus metabolism exhibits a circadian rhythm over the 24-h daily cycle.The egg laying behavior makes laying hens a very special model for investigating phosphorus circadian rhythms.There is lack of information about the impact of adjusting phosphate feeding regimen according to daily rhythm on the phosphorus homeostasis and bone remodeling of laying hens.Methods and results Two experiments were conducted.In Exp.1,Hy-Line Brown laying hens(n=45)were sampled according the oviposition cycle(at 0,6,12,and 18 h post-oviposition,and at the next oviposition,respectively;n=9 at each time point).Diurnal rhythms of body calcium/phosphorus ingestions and excretions,serum calcium/phosphorus levels,oviduct uterus calcium transporter expressions,and medullary bone(MB)remodeling were illustrated.In Exp.2,two diets with different phosphorus levels(0.32%and 0.14%non-phytate phosphorus(NPP),respectively)were alternately presented to the laying hens.Briefly,four phosphorus feeding regimens in total(each included 6 replicates of 5 hens):(1)fed 0.32%NPP at both 09:00 and 17:00;(2)fed 0.32%NPP at 09:00 and 0.14%NPP at 17:00;(3)fed 0.14%NPP at 09:00 and 0.32%NPP at 17:00;(4)fed 0.14%NPP at both 09:00 and 17:00.As a result,the regimen fed 0.14%NPP at 09:00 and 0.32%NPP at 17:00,which was designed to strengthen intrinsic phosphate circadian rhythms according to the findings in Exp.1,enhanced(P<0.05)MB remodeling(indicated by histological images,serum markers and bone mineralization gene expressions),elevated(P<0.05)oviduct uterus calcium transportation(indicated by transient receptor potential vanilloid 6 protein expression),and subsequently increased(P<0.05)eggshell thickness,eggshell strength,egg specific gravity and eggshell index in laying hens.Conclusions These results underscore the importance of manipulating the sequence of daily phosphorus ingestion,instead of simply controlling dietary phosphate concentrations,in modifying the bone remodeling process.Body phosphorus rhythms will need to be maintained during the daily eggshell calcification cycle.展开更多
This study aims to solve the nonlinear fractional-order mathematical model(FOMM)by using the normal and dysregulated bone remodeling of themyeloma bone disease(MBD).For themore precise performance of the model,fractio...This study aims to solve the nonlinear fractional-order mathematical model(FOMM)by using the normal and dysregulated bone remodeling of themyeloma bone disease(MBD).For themore precise performance of the model,fractional-order derivatives have been used to solve the disease model numerically.The FOMM is preliminarily designed to focus on the critical interactions between bone resorption or osteoclasts(OC)and bone formation or osteoblasts(OB).The connections of OC and OB are represented by a nonlinear differential system based on the cellular components,which depict stable fluctuation in the usual bone case and unstable fluctuation through the MBD.Untreated myeloma causes by increasing the OC and reducing the osteoblasts,resulting in net bone waste the tumor growth.The solutions of the FOMM will be provided by using the stochastic framework based on the Levenberg-Marquardt backpropagation(LVMBP)neural networks(NN),i.e.,LVMBPNN.The mathematical performances of three variations of the fractional-order derivative based on the nonlinear disease model using the LVMPNN.The static structural performances are 82%for investigation and 9%for both learning and certification.The performances of the LVMBPNN are authenticated by using the results of the Adams-Bashforth-Moulton mechanism.To accomplish the capability,steadiness,accuracy,and ability of the LVMBPNN,the performances of the error histograms(EHs),mean square error(MSE),recurrence,and state transitions(STs)will be provided.展开更多
Dental implant is an effective method in the treatment of missing teeth.The process of osseointegration of implant teeth involves the coordinated operation of immune system and bone system.The interaction between cell...Dental implant is an effective method in the treatment of missing teeth.The process of osseointegration of implant teeth involves the coordinated operation of immune system and bone system.The interaction between cells is closely related to bone formation and repair.Exosomes are important intercellular communication molecules.They were originally found in the supernatant of sheep erythrocytes cultured in vitro.They are micro vesicles with a diameter of 40~150 nm.They exist in a variety of cells and body fluids.They enter the target cells by endocytosis and transport,affecting the expression of cell genes and changing the fate of cells.It has an important regulatory function in the microenvironment of implant bone binding.It plays a role in bone remodeling through small molecular RNA,specific proteins and other growth factors secreted by different cells.This article reviews the role of bone derived cellderived exosomes in bone remodeling and their function in implant osseointegration.展开更多
Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existin...Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that micro RNAs(mi RNAs), known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression,and growing numbers of novel mi RNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis,and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of mi RNAs in regulating bone remodeling as well as novel applications for mi RNAs in biomaterials for therapeutic purposes.展开更多
Lipoprotein receptor-related protein 6 (LRP6) plays a critical role in skeletal development and homeostasis in adults. However, the role of LRP6 in mesenchymal stem cells (MSCs), skeletal stem cells that give rise...Lipoprotein receptor-related protein 6 (LRP6) plays a critical role in skeletal development and homeostasis in adults. However, the role of LRP6 in mesenchymal stem cells (MSCs), skeletal stem cells that give rise to osteoblastic lineage, is unknown. In this study, we generated mice lacking LRP6 expression specifically in nestin+ MSCs by crossing nestin-Cre mice with LRP6 flox mice and investigated the functional changes of bone marrow MSCs and skeletal alterations. Mice with LRP6 deletion in nestin+ cells demonstrated reductions in body weight and body length at I and 3 months of age. Bone architecture measured by microCT (uCT) showed a significant reduction in bone mass in both trabecular and cortical bone of homozygous and heterozygous LRP6 mutant mice. A dramatic reduction in the numbers of osteoblasts but much less significant reduction in the numbers of osteoclasts was observed in the mutant mice. Osterix+ osteoprogenitors and osteocalcin+ osteoblasts significantly reduced at the secondary spongiosa area, but only moderately decreased at the primary spongiosa area in mutant mice. Bone marrow MSCs from the mutant mice showed decreased colony forming, cell viability and cell proliferation. Thus, LRP6 in bone marrow MSCs is essential for their survival and proliferation, and therefore, is a key positive regulator for bone formation during skeletal growth and remodeling.展开更多
A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creat...A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model. Not only can the model compare reasonably well with these ex- perimental results such as the increase percentage of final values of bone mineral content (BMC) and bone fracture en- ergy (BFE) among different loading schemes (which proves the validity of the model), but also predict the realtime devel- opment pattern of BMC and BFE, as well as the dynamics of osteoblasts (OBA), osteoclasts (OCA), nitric oxide (NO) and prostaglandin E2 (PGE2) for each loading scheme, which can hardly be monitored through experiment. In conclusion, the model is the first of its kind that is able to provide an in- sight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechan- ical stimulus in order to start resorption/formation of bone mass. More importantly, this model has laid a solid foun- dation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimu- lus can be investigated. The to-be identified control mecha- nism will help to develop effective drugs and combined non- pharmacological therapies to combat bone loss pathologies. Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.展开更多
Bone loss associated with type 1 diabetes mellitus(T1DM)begins at the onset of the disease,already in childhood,determining a lower bone mass peak and hence a greater risk of osteoporosis and fractures later in life.T...Bone loss associated with type 1 diabetes mellitus(T1DM)begins at the onset of the disease,already in childhood,determining a lower bone mass peak and hence a greater risk of osteoporosis and fractures later in life.The mechanisms underlying diabetic bone fragility are not yet completely understood.Hyperglycemia and insulin deficiency can affect the bone cells functions,as well as the bone marrow fat,thus impairing the bone strength,geometry,and microarchitecture.Several factors,like insulin and growth hormone/insulin-like growth factor 1,can control bone marrow mesenchymal stem cell commitment,and the receptor activator of nuclear factor-κB ligand/osteoprotegerin and Wnt-b catenin pathways can impair bone turnover.Some myokines may have a key role in regulating metabolic control and improving bone mass in T1DM subjects.The aim of this review is to provide an overview of the current knowledge of the mechanisms underlying altered bone remodeling in children affected by T1DM.展开更多
Mesenchymal stem cells(MSCs)have been widely exploited as promising candidates in clinical settings for bone repair and regeneration in view of their self-renewal capacity and multipotentiality.However,little is known...Mesenchymal stem cells(MSCs)have been widely exploited as promising candidates in clinical settings for bone repair and regeneration in view of their self-renewal capacity and multipotentiality.However,little is known about the mechanisms underlying their fate determination,which would illustrate their effectiveness in regenerative medicine.Recent evidence has shed light on a fundamental biological role of autophagy in the maintenance of the regenerative capability of MSCs and bone homeostasis.Autophagy has been implicated in provoking an immediately available cytoprotective mechanism in MSCs against stress,while dysfunction of autophagy impairs the function of MSCs,leading to imbalances of bone remodeling and a wide range of aging and degenerative bone diseases.This review aims to summarize the up-to-date knowledge about the effects of autophagy on MSC fate determination and its role as a stress adaptation response.Meanwhile,we highlight autophagy as a dynamic process and a double-edged sword to account for some discrepancies in the current research.We also discuss the contribution of autophagy to the regulation of bone cells and bone remodeling and emphasize its potential involvement in bone disease.展开更多
Type 2 diabetes (T2D) is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis (OA). Accordingl...Type 2 diabetes (T2D) is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis (OA). Accordingly, we investigated alterations in subchondral bone remodeling, microstructure and strength in knees from T2D patients and their association with cartilage degradation. Tibial plateaus were collected from knee OA patients undergoing total knee arthroplasty and divided into non-diabetic (n---70) and diabetes (n = 51) groups. Tibial plateaus were also collected from cadaver donors (n = 20) and used as controls. Subchondral bone microstructure was assessed using micro-computed tomography. Bone strength was evaluated by micro-finite-element analysis. Cartilage degradation was estimated using histology. The expression of tartrate-resistant acidic phosphatase (TRAP), osterix, and osteocalcin were calculated using immunohistochemistry. Osteoarthritis Research Society International (OARSI) scores of lateral tibial plateau did not differ between non-diabetic and diabetes groups, while higher OARSI scores on medial side were detected in diabetes group. Lower bone volume fraction and trabecular number and higher structure model index were found on both sides in diabetes group. These microstructural alterations translated into lower elastic modulus in diabetes group. Moreover, diabetes group had a larger number of TRAP~ osteoclasts and lower number of Osterix~ osteoprogenitors and Osteocalcin~ osteoblasts. T2D knees are characterized by abnormal subchondral bone remodeling and microstructural and mechanical impairments, which were associated with exacerbated cartilage degradation. In regions with intact cartilage the underlying bone still had abnormal remodeling in diabetes group, suggesting that abnormal bone remodeling may contribute to the early pathogenesis of T2D-associated knee OA.展开更多
The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism,...The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.展开更多
BACKGROUND Pulsatile tinnitus(PT)is a potentially disabling symptom that has received increasing attention.Multiple causes of PT have been confirmed by targeted treatment.However,dynamic changes of related structures ...BACKGROUND Pulsatile tinnitus(PT)is a potentially disabling symptom that has received increasing attention.Multiple causes of PT have been confirmed by targeted treatment.However,dynamic changes of related structures in PT patients with multiple causes after stenting for ipsilateral transverse sinus stenosis(TSS)have not been previously reported.We report such a case and present postoperative computed tomography venography(CTV)follow-up findings to demonstrate the decreased sigmoid sinus diverticulum and bone remodeling.CASE SUMMARY A 45-year-old man suffered from left-sided PT for 15 years that was occasionally accompanied by headache and dizziness.Pre-operative CTV revealed left-sided sigmoid sinus wall anomalies(SSWAs),TSS,outflow dominance,large posterior condylar emissary vein,and an empty sella turcica.A cerebrospinal fluid pressure of 270 mmH2O was further detected.The sound disappeared immediately after stenting for ipsilateral TSS,with no recurrence during 2 years of follow-up.After the procedure,the patient underwent four consecutive CTV examinations.The diverticulum decreased 6 mo after the procedure with new bone remodeling.The density of the remodeled bone was further increased 1 year later,and a hardened edge was formed 2 years later.CONCLUSION PT associated with SSWAs,TSS,and idiopathic intracranial hypertension can be cured by stenting for TSS alone.And bone remodeling around SSWAs is a more significant finding.展开更多
Presently, several different graft materials are employed in regenerative or corrective bone surgery. However current misconceptions about these biomaterials, their use and risks may compromise their correct applicati...Presently, several different graft materials are employed in regenerative or corrective bone surgery. However current misconceptions about these biomaterials, their use and risks may compromise their correct application and development. To unveil these misconceptions, this work briefly reviewed concepts about bone remodeling, grafts classification and manufacturing processes, with a special focus on calcium phosphate materials as an example of a current employed biomaterial. Thus a search on the last decade was performed in Medline, LILACS, Scielo and other scientific electronic libraries using as keywords biomaterials, bone remodeling, regeneration, biocompatible materials, hydroxyapatite and therapeutic risks. Our search showed not only an accelerated biotechnological development that brought significant advances to biomaterials use on bone remodeling treatments but also several therapeutic risks that should not be ignored. The biomaterials specificity and limitations to clinical application point to the current need for developing safer products with better interactions with the biological microenvironments.展开更多
Athletes and military recruits are often afflicted by stress fractures. Rigorous training programs consisting of increased repetitive mechanical loading may contribute to the high incidence of tibia stress fracture in...Athletes and military recruits are often afflicted by stress fractures. Rigorous training programs consisting of increased repetitive mechanical loading may contribute to the high incidence of tibia stress fracture in the athletic and army populations. The purpose of this study was to assess the effect of incremented height on tibia bone strains and strain rates during landing. Seven healthy college males performed drop-landing tasks from 26 cm, 39 cm, and 52 cm, respectively. Tibia bone strains and strain rates were obtained through subject-specific multi-body dynamic computer simulations and finite element analyses. One-way repeated measures ANOVAs were conducted. Both 39 cm and 52 cm conditions resulted in larger tibia bone strains and strain rates than the 26 cm condition. The 52 cm condition also resulted in greater bone strains and strain rates than the 39 cm condition. A dose-response relationship exists between incremented landing height and bone strains and strain rates. Activities consisting of high impact landings are associated with increased risk of developing tibia stress fracture. When designing training programs involved high impact activities, athletes and military recruits should consider the effect of impact loading on tibia bone health and giving enough time for bones to adapt to new trainings.展开更多
AIM: To analyse bone remodeling in regard to the age of scaphoid non-unions(SNU) with immunohistochemistry.METHODS: Thirty-six patients with symptomatic SNU underwent surgery with resection of the pseudarthrosis. The ...AIM: To analyse bone remodeling in regard to the age of scaphoid non-unions(SNU) with immunohistochemistry.METHODS: Thirty-six patients with symptomatic SNU underwent surgery with resection of the pseudarthrosis. The resected material was evaluated histologically after staining with hematoxylin-eosin(HE), tartrate resistant acid phosphatase(TRAP), CD 68, osteocalcin(OC) and osteopontin(OP). Histological examination was performed in a blinded fashion.RESULTS: The number of multinuclear osteoclasts in the TRAP-staining correlated with the age of the SNU and was significantly higher in younger SNU(P = 0.034; r = 0.75). A higher number of OP-immunoreactive osteoblasts significantly correlated with a higher number of OC-immunoreactive osteoblasts(P = 0.001; r = 0.55). Furthermore, a greater number of OP-immunoreactive osteoblasts correlated significantly with a higher number of OP-immunoreactive multinuclear osteoclasts(P = 0.008; r = 0.43). SNU older than 6 mo showed a signifi-cant decrease of the number of fibroblasts(P = 0.04). Smoking and the age of the patients had no influence on bone remodeling in SNU.CONCLUSION: Multinuclear osteoclasts showed a significant decrease in relation to the age of SNU. However, most of the immunhistochemical findings of bone remodeling do not correlate with the age of the SNU. This indicates a permanent imbalance of bone formation and resorption as indicated by a concurrent increase in both osteoblast and osteoclast numbers. A clear histological differentiation into phases of bone remodeling in SNU is not possible.展开更多
BACKGROUND Fibrous hamartoma of infancy(FHI)is a rare disease of infancy with unknown etiology.The disease mainly involves soft tissue,has no specific clinical manifestations,and is difficult to diagnose.At present,th...BACKGROUND Fibrous hamartoma of infancy(FHI)is a rare disease of infancy with unknown etiology.The disease mainly involves soft tissue,has no specific clinical manifestations,and is difficult to diagnose.At present,the diagnosis is mainly confirmed by histopathological examination,and the main treatment is surgical resection of the pathological tissue,which is prone to recurrence.CASE SUMMARY A five-month-old female patient was admitted to our hospital with swelling in the right calf.Two biopsies were performed in our hospital and another hospital,respectively,confirming the diagnosis as fibrous hamartoma.After exclusion of surgical contraindications,resection was performed with clear margins of 1 cm.Radiographic examination showed tumor recurrence more than four months after the operation,and surgery was performed again to extend the resection margins to 1.5 cm.The patient is recovering well,and after a follow-up of 36 mo,shows no signs of recurrence.CONCLUSION Our case report demonstrates that FHI should be considered in the differential diagnosis for a lower extremity mass with bone destruction.For FHI with bone destruction and unclear boundaries,excision margins of 1.5 cm could be superior to margins of 1 cm.展开更多
Microdamage is produced in bone tissue under the long-termeffects of physiological loading,as well as age,disease and other factors.Bone remodeling can repair microdamage,otherwise this damage will undermine bone qual...Microdamage is produced in bone tissue under the long-termeffects of physiological loading,as well as age,disease and other factors.Bone remodeling can repair microdamage,otherwise this damage will undermine bone quality and even lead to fractures.In this paper,the damage variable was introduced into the remodeling algorithm.The new remodeling algorithm contains a quadratic term that can simulate reduction in bone density after large numbers of loading cycles.The model was applied in conjunction with the 3Dfinite elementmethod(FEM)to the remodeling of the proximal femur.The results showed that the initial accumulation of fatigue damage led to an increase in density but when the damage reached a certain level,the bone density decreased rapidly until the femur failed.With the accumulation of damage,bone remodeling was coupled with fatigue damage to maintain the function of bone.When the accumulation of damage reached a certain level,bone remodeling failed to repair the accumulated fatigue damage in time,and continued cyclic loading significantly weakened the loadbearing capacity of the bone.The new mathematical model not only predicts fatigue life,but also helps to further understand the compromise between damage repair and damage accumulation,which is of great significance for the prevention and treatment of clinical bone diseases.展开更多
Gap bone defect is a major challenge. Its treatment has evolved over the years from amputation to limb reconstruction through vascularised graft, distraction osteogenesis and use of customised implants. Availability a...Gap bone defect is a major challenge. Its treatment has evolved over the years from amputation to limb reconstruction through vascularised graft, distraction osteogenesis and use of customised implants. Availability and affordability of these innovative techniques have always been an additional challenge in the developing resource poor countries. We report the use of Tibialization of Ipsilateral fibula first suggested by Hahns in 1884 to bridge a gap of 12 cm in an 8 year old male, with segmental tibia loss from chronic osteomyelitis. We did an end to end transposition of the ipsilateral fibular into the tibia gap defect in a one stage procedure. This was after eradication of the infective process of osteomyelitis. He commenced partial weight bearing ambulation in cast at 3 months and out of cast ambulation at 18 months post surgery. The transposed fibula was 75% tibialized at 18 months post surgery. Conclusion: Fibular is a useful armamentarium in filling segmental bone defect.展开更多
Live bone inherently responds to applied mechanical stimulus by altering its internal tissue composition and ultimately biomechanical properties, structure and function. The final formation may structurally appear inf...Live bone inherently responds to applied mechanical stimulus by altering its internal tissue composition and ultimately biomechanical properties, structure and function. The final formation may structurally appear inferior by design but complete by function. To understand the loading response, this paper numerically investigated structural remodeling of mature sheep femur using evolutionary structural optimization method (ESO). Femur images from Computed Tomography scanner were used to determine the elastic modulus variation and subsequently construct finite element model of the femur with stiffest elasticity measured. Major muscle forces on dominant phases of healthy sheep gait were imposed on the femur under static mode. ESO was applied to progressively alter the remodeling of numerically simulated femur from its initial to final design by iteratively removing elements with low strain energy density (SED). The computations were repeated with two different mesh sizes to test the convergence. The elements within the medullary canal had low SEDs and therefore were removed during the optimization. The SEDs in the remaining elements varied with angle around the circumference of the shaft. Those elements with low SED were inefficient in supporting the load and thus fundamentally explained how bone remodels itself with less stiff inferior tissue to meet load demand. This was in line with the Wolff’s law of transformation of bone. Tissue growth and remodeling process was found to shape the sheep femur to a mechanically optimized structure and this was initiated by SED in macro-scale according to traditional principle of Wolff’s law.展开更多
Medial tibial stress syndrome(MTSS) is a debilitating overuse injury of the tibia sustained by individuals whoperform recurrent impact exercise such as athletes and military recruits. Characterised by diffuse tibial a...Medial tibial stress syndrome(MTSS) is a debilitating overuse injury of the tibia sustained by individuals whoperform recurrent impact exercise such as athletes and military recruits. Characterised by diffuse tibial anteromedial or posteromedial surface subcutaneous periostitis, in most cases it is also an injury involving underlying cortical bone microtrauma, although it is not clear if the soft tissue or cortical bone reaction occurs first. Nuclear bone scans and magnetic resonance imaging(MRI) can both be used for the diagnosis of MTSS, but the patient's history and clinical symptoms need to be considered in conjunction with the imaging findings for a correct interpretation of the results, as both imaging modalities have demonstrated positive findings in the absence of injury. However, MRI is rapidly becoming the preferred imaging modality for the diagnosis of bone stress injuries. It can also be used for the early diagnosis of MTSS, as the developing periosteal oedema can be identified. Retrospective studies have demonstrated that MTSS patients have lower bone mineral density(BMD) at the injury site than exercising controls, and preliminary data indicates the BMD is lower in MTSS subjects than tibial stress fracture(TSF) subjects. The values of a number of tibial geometric parameters such as cross-sectional area and section modulus are also lower in MTSS subjects than exercising controls, but not as low as the values in TSF subjects. Thus, the balance between BMD and cortical bone geometry may predict an individual's likelihood of developing MTSS. However, prospective longitudinal studies are needed to determine how these factors alter during the development of the injury and to find the detailed structural cause, which is still unknown. Finite element analysis has recently been used to examine the mechanisms involved in tibial stress injuries and offer a promising future tool to understand the mechanisms involved in MTSS. Contemporary accurate diagnosis of either MTSS or a TSF includes a thorough clinical examination to identify signs of bone stress injury and to exclude other pathologies. This should be followed by an MRI study of the whole tibia. The cause of the injury should be established and addressed in order tofacilitate healing and prevent future re-occurrence.展开更多
A novel reconstructive prosthesis was designed with topological optimization(TO)and a lattice structure to enhance biomechanical and biological properties in the proximal tibia.The biomechanical performance was valida...A novel reconstructive prosthesis was designed with topological optimization(TO)and a lattice structure to enhance biomechanical and biological properties in the proximal tibia.The biomechanical performance was validated through finite element analysis(FEA)and biomechanical tests.The tibia with inhomogeneous material properties was reconstructed according to computed tomography images,and different components were designed to simulate the operation.Minimum compliance TO subject to a volume fraction constraint combined with a graded lattice structure was utilized to redesign the prosthesis.FEA was performed to evaluate the mechanical performances of the tibia and implants after optimization,including stress,micromotion,and strain energy.The results were analyzed by paired-samples t tests,and p<0.05 was considered significant.Biomechanical testing was used to verify the tibial stresses.Compared to the original group(OG),the TO group(TOG)exhibited lower stress on the stem,and the maximum von Mises stresses were 87.2 and 53.1 MPa,respectively,a 39.1%reduction(p<0.05).Conversely,the stress and strain energy on the tibia increased in the TOG.The maximum von Mises stress values were 16.4 MPa in the OG and 22.9 MPa in the TOG with a 39.6%increase(p<0.05),and the maximum SED value was 0.026 MPa in the OG and 0.042 MPa in the TOG,corresponding to an increase of 61.5%(p<0.05).The maximum micromotions in the distal end of the stem were 135μm in the OG and 68μm in the TOG,almost a 50%reduction.The stress curves of the biomechanical test coincided well with the FEA results.The TO approach can effectively reduce the whole weight of the prosthesis and improve the biomechanical environment of the tibia.It could also pave the way for next-generation applications in orthopedics surgery.展开更多
基金supported by National Natural Science Foundation of China (32172759)Shaanxi Provincial Science and Technology Department (2022QFY11-05,2021KJXX-97,2021TD-30).
文摘Background Body phosphorus metabolism exhibits a circadian rhythm over the 24-h daily cycle.The egg laying behavior makes laying hens a very special model for investigating phosphorus circadian rhythms.There is lack of information about the impact of adjusting phosphate feeding regimen according to daily rhythm on the phosphorus homeostasis and bone remodeling of laying hens.Methods and results Two experiments were conducted.In Exp.1,Hy-Line Brown laying hens(n=45)were sampled according the oviposition cycle(at 0,6,12,and 18 h post-oviposition,and at the next oviposition,respectively;n=9 at each time point).Diurnal rhythms of body calcium/phosphorus ingestions and excretions,serum calcium/phosphorus levels,oviduct uterus calcium transporter expressions,and medullary bone(MB)remodeling were illustrated.In Exp.2,two diets with different phosphorus levels(0.32%and 0.14%non-phytate phosphorus(NPP),respectively)were alternately presented to the laying hens.Briefly,four phosphorus feeding regimens in total(each included 6 replicates of 5 hens):(1)fed 0.32%NPP at both 09:00 and 17:00;(2)fed 0.32%NPP at 09:00 and 0.14%NPP at 17:00;(3)fed 0.14%NPP at 09:00 and 0.32%NPP at 17:00;(4)fed 0.14%NPP at both 09:00 and 17:00.As a result,the regimen fed 0.14%NPP at 09:00 and 0.32%NPP at 17:00,which was designed to strengthen intrinsic phosphate circadian rhythms according to the findings in Exp.1,enhanced(P<0.05)MB remodeling(indicated by histological images,serum markers and bone mineralization gene expressions),elevated(P<0.05)oviduct uterus calcium transportation(indicated by transient receptor potential vanilloid 6 protein expression),and subsequently increased(P<0.05)eggshell thickness,eggshell strength,egg specific gravity and eggshell index in laying hens.Conclusions These results underscore the importance of manipulating the sequence of daily phosphorus ingestion,instead of simply controlling dietary phosphate concentrations,in modifying the bone remodeling process.Body phosphorus rhythms will need to be maintained during the daily eggshell calcification cycle.
基金Thailand Science Research and Innovation(TSRI).Contract No.FRB650059/NMA/10the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(grant number B05F640092).
文摘This study aims to solve the nonlinear fractional-order mathematical model(FOMM)by using the normal and dysregulated bone remodeling of themyeloma bone disease(MBD).For themore precise performance of the model,fractional-order derivatives have been used to solve the disease model numerically.The FOMM is preliminarily designed to focus on the critical interactions between bone resorption or osteoclasts(OC)and bone formation or osteoblasts(OB).The connections of OC and OB are represented by a nonlinear differential system based on the cellular components,which depict stable fluctuation in the usual bone case and unstable fluctuation through the MBD.Untreated myeloma causes by increasing the OC and reducing the osteoblasts,resulting in net bone waste the tumor growth.The solutions of the FOMM will be provided by using the stochastic framework based on the Levenberg-Marquardt backpropagation(LVMBP)neural networks(NN),i.e.,LVMBPNN.The mathematical performances of three variations of the fractional-order derivative based on the nonlinear disease model using the LVMPNN.The static structural performances are 82%for investigation and 9%for both learning and certification.The performances of the LVMBPNN are authenticated by using the results of the Adams-Bashforth-Moulton mechanism.To accomplish the capability,steadiness,accuracy,and ability of the LVMBPNN,the performances of the error histograms(EHs),mean square error(MSE),recurrence,and state transitions(STs)will be provided.
基金Scientific Research Project of Hainan Provincial Department of Education (No.Hnky2018ZD-7)。
文摘Dental implant is an effective method in the treatment of missing teeth.The process of osseointegration of implant teeth involves the coordinated operation of immune system and bone system.The interaction between cells is closely related to bone formation and repair.Exosomes are important intercellular communication molecules.They were originally found in the supernatant of sheep erythrocytes cultured in vitro.They are micro vesicles with a diameter of 40~150 nm.They exist in a variety of cells and body fluids.They enter the target cells by endocytosis and transport,affecting the expression of cell genes and changing the fate of cells.It has an important regulatory function in the microenvironment of implant bone binding.It plays a role in bone remodeling through small molecular RNA,specific proteins and other growth factors secreted by different cells.This article reviews the role of bone derived cellderived exosomes in bone remodeling and their function in implant osseointegration.
基金supported by grants from the Science and Technology Fund of Sichuan Province (Grant No. 2011SZ0096)the National Natural Science Foundation of China (Grant No. 31470904)
文摘Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that micro RNAs(mi RNAs), known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression,and growing numbers of novel mi RNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis,and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of mi RNAs in regulating bone remodeling as well as novel applications for mi RNAs in biomaterials for therapeutic purposes.
基金supported by National Institutes of Health Grant DK083350 to M. W
文摘Lipoprotein receptor-related protein 6 (LRP6) plays a critical role in skeletal development and homeostasis in adults. However, the role of LRP6 in mesenchymal stem cells (MSCs), skeletal stem cells that give rise to osteoblastic lineage, is unknown. In this study, we generated mice lacking LRP6 expression specifically in nestin+ MSCs by crossing nestin-Cre mice with LRP6 flox mice and investigated the functional changes of bone marrow MSCs and skeletal alterations. Mice with LRP6 deletion in nestin+ cells demonstrated reductions in body weight and body length at I and 3 months of age. Bone architecture measured by microCT (uCT) showed a significant reduction in bone mass in both trabecular and cortical bone of homozygous and heterozygous LRP6 mutant mice. A dramatic reduction in the numbers of osteoblasts but much less significant reduction in the numbers of osteoclasts was observed in the mutant mice. Osterix+ osteoprogenitors and osteocalcin+ osteoblasts significantly reduced at the secondary spongiosa area, but only moderately decreased at the primary spongiosa area in mutant mice. Bone marrow MSCs from the mutant mice showed decreased colony forming, cell viability and cell proliferation. Thus, LRP6 in bone marrow MSCs is essential for their survival and proliferation, and therefore, is a key positive regulator for bone formation during skeletal growth and remodeling.
文摘A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model. Not only can the model compare reasonably well with these ex- perimental results such as the increase percentage of final values of bone mineral content (BMC) and bone fracture en- ergy (BFE) among different loading schemes (which proves the validity of the model), but also predict the realtime devel- opment pattern of BMC and BFE, as well as the dynamics of osteoblasts (OBA), osteoclasts (OCA), nitric oxide (NO) and prostaglandin E2 (PGE2) for each loading scheme, which can hardly be monitored through experiment. In conclusion, the model is the first of its kind that is able to provide an in- sight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechan- ical stimulus in order to start resorption/formation of bone mass. More importantly, this model has laid a solid foun- dation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimu- lus can be investigated. The to-be identified control mecha- nism will help to develop effective drugs and combined non- pharmacological therapies to combat bone loss pathologies. Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.
文摘Bone loss associated with type 1 diabetes mellitus(T1DM)begins at the onset of the disease,already in childhood,determining a lower bone mass peak and hence a greater risk of osteoporosis and fractures later in life.The mechanisms underlying diabetic bone fragility are not yet completely understood.Hyperglycemia and insulin deficiency can affect the bone cells functions,as well as the bone marrow fat,thus impairing the bone strength,geometry,and microarchitecture.Several factors,like insulin and growth hormone/insulin-like growth factor 1,can control bone marrow mesenchymal stem cell commitment,and the receptor activator of nuclear factor-κB ligand/osteoprotegerin and Wnt-b catenin pathways can impair bone turnover.Some myokines may have a key role in regulating metabolic control and improving bone mass in T1DM subjects.The aim of this review is to provide an overview of the current knowledge of the mechanisms underlying altered bone remodeling in children affected by T1DM.
文摘Mesenchymal stem cells(MSCs)have been widely exploited as promising candidates in clinical settings for bone repair and regeneration in view of their self-renewal capacity and multipotentiality.However,little is known about the mechanisms underlying their fate determination,which would illustrate their effectiveness in regenerative medicine.Recent evidence has shed light on a fundamental biological role of autophagy in the maintenance of the regenerative capability of MSCs and bone homeostasis.Autophagy has been implicated in provoking an immediately available cytoprotective mechanism in MSCs against stress,while dysfunction of autophagy impairs the function of MSCs,leading to imbalances of bone remodeling and a wide range of aging and degenerative bone diseases.This review aims to summarize the up-to-date knowledge about the effects of autophagy on MSC fate determination and its role as a stress adaptation response.Meanwhile,we highlight autophagy as a dynamic process and a double-edged sword to account for some discrepancies in the current research.We also discuss the contribution of autophagy to the regulation of bone cells and bone remodeling and emphasize its potential involvement in bone disease.
基金supported by National Natural Science Foundation of China(NSFC Nos.81601930 and U1613224)Natural Science Foundation of Guangxi(2016JJB140050)+1 种基金Research Grant Council of Hong Kong(HKU715213 and 17206916)Shenzhen Peacock Project
文摘Type 2 diabetes (T2D) is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis (OA). Accordingly, we investigated alterations in subchondral bone remodeling, microstructure and strength in knees from T2D patients and their association with cartilage degradation. Tibial plateaus were collected from knee OA patients undergoing total knee arthroplasty and divided into non-diabetic (n---70) and diabetes (n = 51) groups. Tibial plateaus were also collected from cadaver donors (n = 20) and used as controls. Subchondral bone microstructure was assessed using micro-computed tomography. Bone strength was evaluated by micro-finite-element analysis. Cartilage degradation was estimated using histology. The expression of tartrate-resistant acidic phosphatase (TRAP), osterix, and osteocalcin were calculated using immunohistochemistry. Osteoarthritis Research Society International (OARSI) scores of lateral tibial plateau did not differ between non-diabetic and diabetes groups, while higher OARSI scores on medial side were detected in diabetes group. Lower bone volume fraction and trabecular number and higher structure model index were found on both sides in diabetes group. These microstructural alterations translated into lower elastic modulus in diabetes group. Moreover, diabetes group had a larger number of TRAP~ osteoclasts and lower number of Osterix~ osteoprogenitors and Osteocalcin~ osteoblasts. T2D knees are characterized by abnormal subchondral bone remodeling and microstructural and mechanical impairments, which were associated with exacerbated cartilage degradation. In regions with intact cartilage the underlying bone still had abnormal remodeling in diabetes group, suggesting that abnormal bone remodeling may contribute to the early pathogenesis of T2D-associated knee OA.
文摘The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.
基金The Beijing Scholar 2015and the National Natural Science Foundation of China,No.61931013,No.81701644,and No.61801311.
文摘BACKGROUND Pulsatile tinnitus(PT)is a potentially disabling symptom that has received increasing attention.Multiple causes of PT have been confirmed by targeted treatment.However,dynamic changes of related structures in PT patients with multiple causes after stenting for ipsilateral transverse sinus stenosis(TSS)have not been previously reported.We report such a case and present postoperative computed tomography venography(CTV)follow-up findings to demonstrate the decreased sigmoid sinus diverticulum and bone remodeling.CASE SUMMARY A 45-year-old man suffered from left-sided PT for 15 years that was occasionally accompanied by headache and dizziness.Pre-operative CTV revealed left-sided sigmoid sinus wall anomalies(SSWAs),TSS,outflow dominance,large posterior condylar emissary vein,and an empty sella turcica.A cerebrospinal fluid pressure of 270 mmH2O was further detected.The sound disappeared immediately after stenting for ipsilateral TSS,with no recurrence during 2 years of follow-up.After the procedure,the patient underwent four consecutive CTV examinations.The diverticulum decreased 6 mo after the procedure with new bone remodeling.The density of the remodeled bone was further increased 1 year later,and a hardened edge was formed 2 years later.CONCLUSION PT associated with SSWAs,TSS,and idiopathic intracranial hypertension can be cured by stenting for TSS alone.And bone remodeling around SSWAs is a more significant finding.
基金We thank the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico(CNPq)Coordenacao de Aperfeicoamento de Pessoal Docente(CAPES-Edital Nanobiotecnologia 2008) Fundacao de AmparoaPesquisa do Estado do Rio de Janeiro(FAPERJ)for the financial support and fellowships.
文摘Presently, several different graft materials are employed in regenerative or corrective bone surgery. However current misconceptions about these biomaterials, their use and risks may compromise their correct application and development. To unveil these misconceptions, this work briefly reviewed concepts about bone remodeling, grafts classification and manufacturing processes, with a special focus on calcium phosphate materials as an example of a current employed biomaterial. Thus a search on the last decade was performed in Medline, LILACS, Scielo and other scientific electronic libraries using as keywords biomaterials, bone remodeling, regeneration, biocompatible materials, hydroxyapatite and therapeutic risks. Our search showed not only an accelerated biotechnological development that brought significant advances to biomaterials use on bone remodeling treatments but also several therapeutic risks that should not be ignored. The biomaterials specificity and limitations to clinical application point to the current need for developing safer products with better interactions with the biological microenvironments.
文摘Athletes and military recruits are often afflicted by stress fractures. Rigorous training programs consisting of increased repetitive mechanical loading may contribute to the high incidence of tibia stress fracture in the athletic and army populations. The purpose of this study was to assess the effect of incremented height on tibia bone strains and strain rates during landing. Seven healthy college males performed drop-landing tasks from 26 cm, 39 cm, and 52 cm, respectively. Tibia bone strains and strain rates were obtained through subject-specific multi-body dynamic computer simulations and finite element analyses. One-way repeated measures ANOVAs were conducted. Both 39 cm and 52 cm conditions resulted in larger tibia bone strains and strain rates than the 26 cm condition. The 52 cm condition also resulted in greater bone strains and strain rates than the 39 cm condition. A dose-response relationship exists between incremented landing height and bone strains and strain rates. Activities consisting of high impact landings are associated with increased risk of developing tibia stress fracture. When designing training programs involved high impact activities, athletes and military recruits should consider the effect of impact loading on tibia bone health and giving enough time for bones to adapt to new trainings.
文摘AIM: To analyse bone remodeling in regard to the age of scaphoid non-unions(SNU) with immunohistochemistry.METHODS: Thirty-six patients with symptomatic SNU underwent surgery with resection of the pseudarthrosis. The resected material was evaluated histologically after staining with hematoxylin-eosin(HE), tartrate resistant acid phosphatase(TRAP), CD 68, osteocalcin(OC) and osteopontin(OP). Histological examination was performed in a blinded fashion.RESULTS: The number of multinuclear osteoclasts in the TRAP-staining correlated with the age of the SNU and was significantly higher in younger SNU(P = 0.034; r = 0.75). A higher number of OP-immunoreactive osteoblasts significantly correlated with a higher number of OC-immunoreactive osteoblasts(P = 0.001; r = 0.55). Furthermore, a greater number of OP-immunoreactive osteoblasts correlated significantly with a higher number of OP-immunoreactive multinuclear osteoclasts(P = 0.008; r = 0.43). SNU older than 6 mo showed a signifi-cant decrease of the number of fibroblasts(P = 0.04). Smoking and the age of the patients had no influence on bone remodeling in SNU.CONCLUSION: Multinuclear osteoclasts showed a significant decrease in relation to the age of SNU. However, most of the immunhistochemical findings of bone remodeling do not correlate with the age of the SNU. This indicates a permanent imbalance of bone formation and resorption as indicated by a concurrent increase in both osteoblast and osteoclast numbers. A clear histological differentiation into phases of bone remodeling in SNU is not possible.
基金Supported by Youth Science and Technology Foundation of Gansu Province,No.20JR5RA588Youth Science and Technology Foundation of Gansu Province,No.21JR7RA014Key RESEARCH and Development Program of Gansu Province,No.21YF5FA154。
文摘BACKGROUND Fibrous hamartoma of infancy(FHI)is a rare disease of infancy with unknown etiology.The disease mainly involves soft tissue,has no specific clinical manifestations,and is difficult to diagnose.At present,the diagnosis is mainly confirmed by histopathological examination,and the main treatment is surgical resection of the pathological tissue,which is prone to recurrence.CASE SUMMARY A five-month-old female patient was admitted to our hospital with swelling in the right calf.Two biopsies were performed in our hospital and another hospital,respectively,confirming the diagnosis as fibrous hamartoma.After exclusion of surgical contraindications,resection was performed with clear margins of 1 cm.Radiographic examination showed tumor recurrence more than four months after the operation,and surgery was performed again to extend the resection margins to 1.5 cm.The patient is recovering well,and after a follow-up of 36 mo,shows no signs of recurrence.CONCLUSION Our case report demonstrates that FHI should be considered in the differential diagnosis for a lower extremity mass with bone destruction.For FHI with bone destruction and unclear boundaries,excision margins of 1.5 cm could be superior to margins of 1 cm.
基金This research was funded by National Natural Science Foundation of China(Grant No.11972247).
文摘Microdamage is produced in bone tissue under the long-termeffects of physiological loading,as well as age,disease and other factors.Bone remodeling can repair microdamage,otherwise this damage will undermine bone quality and even lead to fractures.In this paper,the damage variable was introduced into the remodeling algorithm.The new remodeling algorithm contains a quadratic term that can simulate reduction in bone density after large numbers of loading cycles.The model was applied in conjunction with the 3Dfinite elementmethod(FEM)to the remodeling of the proximal femur.The results showed that the initial accumulation of fatigue damage led to an increase in density but when the damage reached a certain level,the bone density decreased rapidly until the femur failed.With the accumulation of damage,bone remodeling was coupled with fatigue damage to maintain the function of bone.When the accumulation of damage reached a certain level,bone remodeling failed to repair the accumulated fatigue damage in time,and continued cyclic loading significantly weakened the loadbearing capacity of the bone.The new mathematical model not only predicts fatigue life,but also helps to further understand the compromise between damage repair and damage accumulation,which is of great significance for the prevention and treatment of clinical bone diseases.
文摘Gap bone defect is a major challenge. Its treatment has evolved over the years from amputation to limb reconstruction through vascularised graft, distraction osteogenesis and use of customised implants. Availability and affordability of these innovative techniques have always been an additional challenge in the developing resource poor countries. We report the use of Tibialization of Ipsilateral fibula first suggested by Hahns in 1884 to bridge a gap of 12 cm in an 8 year old male, with segmental tibia loss from chronic osteomyelitis. We did an end to end transposition of the ipsilateral fibular into the tibia gap defect in a one stage procedure. This was after eradication of the infective process of osteomyelitis. He commenced partial weight bearing ambulation in cast at 3 months and out of cast ambulation at 18 months post surgery. The transposed fibula was 75% tibialized at 18 months post surgery. Conclusion: Fibular is a useful armamentarium in filling segmental bone defect.
文摘Live bone inherently responds to applied mechanical stimulus by altering its internal tissue composition and ultimately biomechanical properties, structure and function. The final formation may structurally appear inferior by design but complete by function. To understand the loading response, this paper numerically investigated structural remodeling of mature sheep femur using evolutionary structural optimization method (ESO). Femur images from Computed Tomography scanner were used to determine the elastic modulus variation and subsequently construct finite element model of the femur with stiffest elasticity measured. Major muscle forces on dominant phases of healthy sheep gait were imposed on the femur under static mode. ESO was applied to progressively alter the remodeling of numerically simulated femur from its initial to final design by iteratively removing elements with low strain energy density (SED). The computations were repeated with two different mesh sizes to test the convergence. The elements within the medullary canal had low SEDs and therefore were removed during the optimization. The SEDs in the remaining elements varied with angle around the circumference of the shaft. Those elements with low SED were inefficient in supporting the load and thus fundamentally explained how bone remodels itself with less stiff inferior tissue to meet load demand. This was in line with the Wolff’s law of transformation of bone. Tissue growth and remodeling process was found to shape the sheep femur to a mechanically optimized structure and this was initiated by SED in macro-scale according to traditional principle of Wolff’s law.
文摘Medial tibial stress syndrome(MTSS) is a debilitating overuse injury of the tibia sustained by individuals whoperform recurrent impact exercise such as athletes and military recruits. Characterised by diffuse tibial anteromedial or posteromedial surface subcutaneous periostitis, in most cases it is also an injury involving underlying cortical bone microtrauma, although it is not clear if the soft tissue or cortical bone reaction occurs first. Nuclear bone scans and magnetic resonance imaging(MRI) can both be used for the diagnosis of MTSS, but the patient's history and clinical symptoms need to be considered in conjunction with the imaging findings for a correct interpretation of the results, as both imaging modalities have demonstrated positive findings in the absence of injury. However, MRI is rapidly becoming the preferred imaging modality for the diagnosis of bone stress injuries. It can also be used for the early diagnosis of MTSS, as the developing periosteal oedema can be identified. Retrospective studies have demonstrated that MTSS patients have lower bone mineral density(BMD) at the injury site than exercising controls, and preliminary data indicates the BMD is lower in MTSS subjects than tibial stress fracture(TSF) subjects. The values of a number of tibial geometric parameters such as cross-sectional area and section modulus are also lower in MTSS subjects than exercising controls, but not as low as the values in TSF subjects. Thus, the balance between BMD and cortical bone geometry may predict an individual's likelihood of developing MTSS. However, prospective longitudinal studies are needed to determine how these factors alter during the development of the injury and to find the detailed structural cause, which is still unknown. Finite element analysis has recently been used to examine the mechanisms involved in tibial stress injuries and offer a promising future tool to understand the mechanisms involved in MTSS. Contemporary accurate diagnosis of either MTSS or a TSF includes a thorough clinical examination to identify signs of bone stress injury and to exclude other pathologies. This should be followed by an MRI study of the whole tibia. The cause of the injury should be established and addressed in order tofacilitate healing and prevent future re-occurrence.
基金National Natural Science Foundation of China[Grant Numbers 81802174,81900726&82072456]Department of Science and Technology of Jilin Province,P.R.C[Grant Numbers 20200404202YY,20200403086SF&20200201453JC]+8 种基金Jilin Province Development and Reform Commission,P.R.C[Grant Number 2018C010]Education Department of Jilin Province,P.R.C[GrantNumber JJKH20180106KJ]Administration of Traditional Chinese Medicine of Jilin Province P.R.C[Grant Number 2018115]10th Youth Project of the First Hospital of Jilin University[Grant Number JDYY102019025]Department of Finance in Jilin Province[Grant Number 2019SCZT046]Undergraduate Teaching Reform Research Project of Jilin University[Grant Number 4Z2000610852]Key training plan for outstanding young teachers of Jilin University[Grant Number 419080520253]Bethune plan of Jilin University[Grant Number 470110000692]The major participant is Qing Han.
文摘A novel reconstructive prosthesis was designed with topological optimization(TO)and a lattice structure to enhance biomechanical and biological properties in the proximal tibia.The biomechanical performance was validated through finite element analysis(FEA)and biomechanical tests.The tibia with inhomogeneous material properties was reconstructed according to computed tomography images,and different components were designed to simulate the operation.Minimum compliance TO subject to a volume fraction constraint combined with a graded lattice structure was utilized to redesign the prosthesis.FEA was performed to evaluate the mechanical performances of the tibia and implants after optimization,including stress,micromotion,and strain energy.The results were analyzed by paired-samples t tests,and p<0.05 was considered significant.Biomechanical testing was used to verify the tibial stresses.Compared to the original group(OG),the TO group(TOG)exhibited lower stress on the stem,and the maximum von Mises stresses were 87.2 and 53.1 MPa,respectively,a 39.1%reduction(p<0.05).Conversely,the stress and strain energy on the tibia increased in the TOG.The maximum von Mises stress values were 16.4 MPa in the OG and 22.9 MPa in the TOG with a 39.6%increase(p<0.05),and the maximum SED value was 0.026 MPa in the OG and 0.042 MPa in the TOG,corresponding to an increase of 61.5%(p<0.05).The maximum micromotions in the distal end of the stem were 135μm in the OG and 68μm in the TOG,almost a 50%reduction.The stress curves of the biomechanical test coincided well with the FEA results.The TO approach can effectively reduce the whole weight of the prosthesis and improve the biomechanical environment of the tibia.It could also pave the way for next-generation applications in orthopedics surgery.