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2.
Proc Inst Mech Eng H ; : 9544119211052377, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34686098

RESUMO

This study aims to evaluate the reconstructive stability for Paprosky III acetabular defects after total hip arthroplasty using three different reconstruction strategies with trabecular metal (TM) augments. The acetabular bone defects examined were located in the ilium, the sciatic ramus and the pubic ramus. Different scenarios of acetabular reconstructions were simulated, including the non-reconstruction model (NRM), the complete reconstruction model (CRM), the two-point reconstruction model (TRM) and the superior edge reconstruction model (SRM). A primary hip replacement model (HRM) was also investigated to compare the initial stability with different reconstruction models. The gait cycle was incorporated in the model to investigate the dynamic variation within the contact mechanics parameters. By comparing the SRM and the TRM, the acetabular cup translation was more pronounced when the superior defect on the acetabulum remained unfixed. Comparison of the acetabular cup displacement and the interface micromotion of both HRM and CRM demonstrated that the prosthetic implant provided good support for the reconstructed acetabulum. With the use of a press-fit cup, the cup displacement was reduced remarkably, while its Von-Mises stress increased significantly. The results show that the CRM was the best reconstruction option. In terms of acetabular defects, future improvements should focus on the reconstructive stability in stress concentration areas, to ensure no significant stress-shielding or other factors contributing to loosening of the prosthesis.

3.
Am J Transl Res ; 13(8): 9383-9394, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34540057

RESUMO

Charnley's low-friction principle of total hip arthroplasty (THA) is recognized as the gold standard. However, complications may arise, and one of the major reasons for revising THA is dislocation. Under such a background, Pr. Gilles Bousquet invented dual-mobility cups (DMC) in the 1970s to fight against hip instability. Despite the excellent clinical results of DMC compared with conventional implants, the clinical application of DMC is limited by concerns about the dual articulations, leading to rapid wear and the subsequent osteolysis and the wear on the retaining rim of the liner due to its contact with the femoral neck causing intraprosthetic dislocation (IPD). As a result, the original design of DMC has been upgraded by using highly cross-linked polyethylene, refining the geometry of the femoral neck, etc. After the improvement, the wear rate of the contemporary DMC liners has been largely reduced compared with the first generation DMC, and the IPD incidence rate has been controlled. However, with the increasing fretting corrosion damage found at the taper-trunnion interfaces in conventional implants, the contemporary DMC may face a similar problem. This is because the additional articulation and the larger head design of DMC gain the risk of articulation wear and taper-trunnion interface corrosion. Since there are still many potential DMC engineering issues that have not been extensively researched, future studies focusing on the wear and corrosion aspects are required. The purpose of this review article is to summarize both the clinical and engineering issues for DMC with possible directions for future research.

4.
Front Bioeng Biotechnol ; 9: 691450, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34291041

RESUMO

Anatomic total shoulder arthroplasty (ATSA) is widely used to treat the diseases of the glenohumeral (GH) joint. However, the incidence of rotator cuff tears after ATSA increases during follow-up. The effects of rotator cuff deficiencies after ATSA on the biomechanics of the GH joint are to be investigated. In this study, a musculoskeletal multibody dynamics model of ATSA was established using a force-dependent kinematics (FDK) method. The biomechanical effects were predicted during arm abduction under different rotator cuff deficiencies. The deltoid forces were increased under the rotator cuff deficiencies, the maximum deltoid forces were increased by 36% under the subscapularis deficiency and by 53% under the supraspinatus, infraspinatus, subscapularis, and teres minor deficiencies. The maximum GH contact forces were decreased by 11.3% under supraspinatus and infraspinatus deficiencies but increased by 24.8% under subscapularis deficiency. The maximum subscapularis force was decreased by 17% under only infraspinatus tear during arm abduction. The results suggested that the changes in the biomechanics of the GH joint induced by rotator cuff deficiencies after ATSA increase the deltoid muscle energy expenditure and joint instability, which result in postoperative less satisfactory clinical outcomes. The changes in rotator cuff muscle forces deserve more attention for understanding the evolution of rotator cuff tear after ATSA.

5.
Comput Methods Programs Biomed ; 206: 106122, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33979755

RESUMO

BACKGROUND AND OBJECTIVE: Investigating the biomechanics of cartilage could help to understand the unique load-bearing property of the cartilage and optimize the scaffold design in tissue-engineering. It is important to model the cartilage as a highly inhomogeneous fibril-reinforced biphasic material to represent its complex composition and structure. The depth-dependent and strain-dependent properties of the cartilage would also play an important role in its mechanical behaviour. However, the differences in representing the cartilage as a highly inhomogeneous model or as simplified models still remain unclear. Hence, in this study, a highly inhomogeneous fibril-reinforced biphasic cartilage model considering both the depth-dependent and strain-dependent properties was constructed; the effect of highly inhomogeneous properties on the mechanical behaviour of articular cartilage was investigated. METHODS: A finite element model of the cartilage was developed based on a flat-ended indentation test. Compressive forces were applied to four various inhomogeneous layered models through a porous indenter (Model 1: nine layers with strain-dependent permeability; Model 2: three layers with strain-dependent permeability; Model 3: single layer with strain-dependent permeability; Model 4: nine layers with constant permeability). RESULTS: Models 1 and 2 provided similar results with less than 3% difference in the peak effective stress, contact pressure, fluid pressure as well as fluid support ratio. However, Model 1 to Model 3 differed in stress and strain distribution patterns along depth over prolonged loads, which may provide an important insight into the highly inhomogeneous depth-dependent properties of cartilage. In addition, Model 1 with strain-dependent permeability demonstrated an enhanced capability on fluid pressurisation as compared with Model 4 which had constant permeability. CONCLUSIONS: A highly inhomogeneous fibril-reinforced biphasic model considering both depth-dependent and strain-dependent properties was developed in this study, in order to illustrate the effect of highly inhomogeneous properties on the mechanical behaviour of the articular cartilage. The number of layers in the models with depth-dependent properties should be selected according to the research questions and clinical demands. The model with strain-dependent permeability offers an enhanced capability on fluid pressurisation. In future studies, the proposed model could be adopted in cell-models to provide more in-depth information or in tissue-engineering to optimize the depth-dependent scaffold structure.


Assuntos
Cartilagem Articular , Fenômenos Biomecânicos , Elasticidade , Análise de Elementos Finitos , Modelos Biológicos , Pressão , Estresse Mecânico
6.
Proc Inst Mech Eng H ; 235(8): 861-872, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33913346

RESUMO

Unicompartmental knee arthroplasty has been shown to provide superior functional outcomes compared to total knee arthroplasty and have motivated development of advanced implant designs including bicruciate retaining knee arthroplasty. However, few validated frameworks are available to directly compare the effect of implant design and surgical techniques on ligament function and joint kinematics. In the present study, the subject-specific lower extremity models were developed based on musculoskeletal modeling framework using force-dependent kinematics method, and validated against in vivo telemetric data. The experiment data of two subjects who underwent TKA were obtained from the SimTK "Grand Challenge Competition" repository, and integrated into the subject-specific lower extremity model. Five walking gait trials and three different knee implant models for each subject were used as partial inputs for the model to predict knee biomechanics for unicompartmental, bicruciate retaining, and total knee arthroplasty. The results showed no significant differences in the tibiofemoral contact forces or angular kinematic parameters between three groups. However, unicompartmental knee arthroplasty demonstrated significantly more posterior tibial location between 0% and 40% of the gait cycle (p < 0.017). Significant differences in range of tibiofemoral anterior/posterior translation and medial/lateral translation were also observed between unicompartmental and bicruciate retaining arthroplasty (p < 0.017). Peak values of anterior cruciate ligament forces differed between unicompartmental and bicruciate retaining arthroplasty from 10% to 30% of the gait cycle. Findings of this study indicate that unicompartmental and bicruciate retaining arthroplasty do not have identical biomechanics and point to the complementary role of anterior cruciate ligament and articular geometry in guiding knee function. Further, the patient-specific musculoskeletal model developed provides a reliable framework for assessing new implant designs, and effect of surgical techniques on knee biomechanics following arthroplasty.


Assuntos
Artroplastia do Joelho , Prótese do Joelho , Ligamento Cruzado Anterior , Fenômenos Biomecânicos , Humanos , Articulação do Joelho/cirurgia , Amplitude de Movimento Articular
7.
Sci Rep ; 11(1): 3130, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542300

RESUMO

For pre-operative osteoarthritis (OA) patients with varus knee, previous studies showed inconsistent results. Therefore, we conducted this study to better identify the association of Hospital for Special Surgery (HSS) score and mechanical alignment. 44 patients (51 knees) with constitutional varus knee caused by combined deformities (LDFA (lateral distal femoral angle) > 90°and MPTA (medial proximal tibial angle) < 85°)) were selected and analyzed with a mean follow-up period of 14 months after total knee arthroplasty (TKA). From January 2015 to December 2016, patients were collected consecutively after primary TKA. After filtering, fifty-one knees (44patients) were analyzed with a mean follow-up period of 14 months. All patients were divided into two groups based on post-operative hip-knee-ankle (HKA) acute angle: varus mechanical alignment (VMA) group (HKA < - 3°) and neutral mechanical axis (NMA) group (- 3° ≤ HKA ≤ 3°). 30 knees were included in the NMA group, and 21 knees in the VMA group. Comparisons of HSS between NMA group and VMA group were performed. After adjusting for age and Body Mass Index (BMI) confounders, Compared with NMA group, the HSS score in VMA group decreased by 0.81 units (95% CI, - 3.37 to 1.75) p = 0.5370). For pre-operative constitutional varus knee caused by combined deformities in chinese populations, no significant association between post-operative lower limb mechanical alignment and HSS score was found.


Assuntos
Fêmur/cirurgia , Articulação do Joelho/cirurgia , Osteoartrite do Joelho/cirurgia , Pé Cavo/cirurgia , Tíbia/cirurgia , Fatores Etários , Idoso , Articulação do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/patologia , Artroplastia do Joelho/métodos , Índice de Massa Corporal , Feminino , Fêmur/diagnóstico por imagem , Fêmur/patologia , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/patologia , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/patologia , Radiografia , Estudos Retrospectivos , Pé Cavo/diagnóstico por imagem , Pé Cavo/patologia , Tíbia/diagnóstico por imagem , Tíbia/patologia , Resultado do Tratamento
8.
Proc Inst Mech Eng H ; 234(12): 1445-1456, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32741249

RESUMO

Bi-cruciate retaining total knee arthroplasty has several potential advantages including improved anteroposterior knee stability compared to contemporary posterior cruciate-retaining total knee arthroplasty. However, few studies have explored whether there is significant differences of knee biomechanics following bi-cruciate retaining total knee arthroplasty compared to posterior cruciate-retaining total knee arthroplasty. In the present study, subject-specific lower extremity musculoskeletal multi-body dynamics models for bi-cruciate retaining, bi-cruciate retaining without anterior cruciate ligament, and posterior cruciate-retaining total knee arthroplasty were developed based on the musculoskeletal modeling framework using force-dependent kinematics method and validated against in vivo telemetric data. The experiment data of two subjects who underwent total knee arthroplasty were obtained for the SimTK "Grand Challenge Competition" repository, and integrated into the musculoskeletal model. Five walking gait trials for each subject were used as partial inputs for the model to predict the knee biomechanics for bi-cruciate retaining, bi-cruciate retaining without anterior cruciate ligament, and posterior cruciate-retaining total knee arthroplasty. The results revealed significantly greater range of anterior/posterior tibiofemoral translation, and significantly more posterior tibial location during the early phase of gait and more anterior tibial location during the late phase of gait were found in bi-cruciate retaining total knee arthroplasty without anterior cruciate ligament when compared to the bi-cruciate retaining total knee arthroplasty. No significant differences in tibiofemoral contact forces, rotations, translations, and ligament forces between bi-cruciate retaining and posterior cruciate-retaining total knee arthroplasty during normal walking gait, albeit slight differences in range of tibiofemoral internal/external rotation and anterior/posterior translation were observed. The present study revealed that anterior cruciate ligament retention has a positive effect on restoring normal knee kinematics in bi-cruciate retaining total knee arthroplasty. Preservation of anterior cruciate ligament in total knee arthroplasty and knee implant designs interplay each other and both contribute to restoring normal knee kinematics in different types of total knee arthroplasty. Further evaluation of more demanding activities and subject data from patients with bi-cruciate retaining and posterior cruciate-retaining total knee arthroplasty via musculoskeletal modeling may better highlight the role of the anterior cruciate ligament and its stabilizing influence.


Assuntos
Artroplastia do Joelho , Ligamento Cruzado Posterior , Ligamento Cruzado Anterior/cirurgia , Fenômenos Biomecânicos , Marcha , Humanos , Articulação do Joelho/cirurgia , Ligamento Cruzado Posterior/cirurgia , Amplitude de Movimento Articular , Caminhada
9.
Proc Inst Mech Eng H ; 234(12): 1432-1444, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32741296

RESUMO

The motion capture and force plates data are essential inputs for musculoskeletal multibody dynamics models to predict in vivo tibiotalar contact forces. However, it could be almost impossible to obtain valid force plates data in old patients undergoing total ankle arthroplasty under some circumstances, such as smaller gait strides and inconsistent walking speeds during gait analysis. To remove the dependence of force plates, this study has established a patient-specific musculoskeletal multibody dynamics model with total ankle arthroplasty by combining a foot-ground contact model based on elastic contact elements. And the established model could predict ground reaction forces, ground reaction moments and tibiotalar contact forces simultaneously. Three patients' motion capture and force plates data during their normal walking were used to establish the patient-specific musculoskeletal models and evaluate the predicted ground reaction forces and ground reaction moments. Reasonable accuracies were achieved for the predicted and measured ground reaction forces and ground reaction moments. The predicted tibiotalar contact forces for all patients using the foot-ground contact model had good consistency with those using force plates data. These findings suggested that the foot-ground contact model could take the place of the force plates data for predicting the tibiotalar contact forces in other total ankle arthroplasty patients, thus providing a simplified and valid platform for further study of the patient-specific prosthetic designs and clinical problems of total ankle arthroplasty in the absence of force plates data.


Assuntos
Artroplastia de Substituição do Tornozelo , Caminhada , Tornozelo , Fenômenos Biomecânicos , Marcha , Humanos
10.
Artigo em Inglês | MEDLINE | ID: mdl-32224985

RESUMO

Flatfoot is linked to secondary lower limb joint problems, such as patellofemoral pain. This study aimed to investigate the influence of medial posting insoles on the joint mechanics of the lower extremity in adults with flatfoot. Gait analysis was performed on fifteen young adults with flatfoot under two conditions: walking with shoes and foot orthoses (WSFO), and walking with shoes (WS) in random order. The data collected by a vicon system were used to drive the musculoskeletal model to estimate the hip, patellofemoral, ankle, medial and lateral tibiofemoral joint contact forces. The joint contact forces in WSFO and WS conditions were compared. Compared to the WS group, the second peak patellofemoral contact force (p < 0.05) and the peak ankle contact force (p < 0.05) were significantly lower in the WSFO group by 10.2% and 6.8%, respectively. The foot orthosis significantly reduced the peak ankle eversion angle (p < 0.05) and ankle eversion moment (p < 0.05); however, the peak knee adduction moment increased (p < 0.05). The reduction in the patellofemoral joint force and ankle contact force could potentially inhibit flatfoot-induced lower limb joint problems, despite a greater knee adduction moment.


Assuntos
Pé Chato/fisiopatologia , Órtoses do Pé , Extremidade Inferior/fisiologia , Sapatos , Articulação do Tornozelo , Fenômenos Biomecânicos , Análise da Marcha , Articulação do Quadril , Humanos , Articulação do Joelho , Projetos Piloto , Caminhada , Adulto Jovem
11.
J Healthc Eng ; 2020: 8103523, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32257086

RESUMO

Dual mobility hip implants have been widely introduced to overcome dislocation in recent years. However, the potential influence of different gaits on kinematics and contact mechanics for dual mobility hip implants is still unclear. Furthermore, a large range of motion coupling with the implant position, especially high inclination or anteversion angle, may result in poor kinematics and contact mechanics. A previously developed dynamic finite element method was adopted in this study to examine the kinematics and corresponding stability of dual mobility hip implants under different gaits coupling with different inclinations or anteversion angles. The results showed only inner relative sliding under knee-bending for dual mobility hip implants under moderate inclination and anteversion angles, whereas an anteversion angle of 25° induced both impingement and consequent relative sliding of the outer articulation. However, the impingement (between the stem neck and the liner inner rim) indeed happened under stair-climbing and sitting-down/stand-up as well as combined movements when inclination and anteversion angles were set as 45° and 0°, respectively, and this finally led to relative sliding at the outer articulation. A high inclination angle did not worsen both the impingement and related outer sliding compared to modest inclination and anteversion angles of the liner, but a high anteversion angle prolonged the period of both the impingement and the outer relative sliding. The extreme motions and high anteversion angles are hardly inevitable, and they indeed lead to motions at both articulations for dual mobility hip implants.


Assuntos
Atividades Cotidianas , Prótese de Quadril , Desenho de Prótese , Fenômenos Biomecânicos , Marcha/fisiologia , Prótese de Quadril/normas , Humanos , Amplitude de Movimento Articular
12.
J Mech Behav Biomed Mater ; 104: 103629, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32174389

RESUMO

Ultra-low-wear polyethylene (ULWPE) is a new metallocene catalyzed high density polyethylene (HDPE)material. Previous studies have demonstrated that it has excellent biocompatibility and wear resistance, whereupon indicating great potential in the applications to artificial joints. However, as a newly developed material, its tribological behavior and wear resistance mechanism has not been well understood. In the current study, we experimentally evaluated the tribological behavior of ULWPE, and investigated its high wear resistance mechanism in terms of microstructure, crystallization properties, mechanical, physical, and chemical properties. ULWPE manifested the best tribological performance on pin-on-disc (POD) wear tests compared with the most widely used artificial joints materials, with a wear volume of 0.720 ± 0.032 mm3/million cycles (Mc) and 0.600 ± 0.027 mm3/Mc against cobalt-chromium (CoCr) alloy disc and zirconia toughened alumina (ZTA) ceramic disc, respectively. The results of the wear morphology analysis showed that the surface of ULWPE was the slightest, with no obvious surface damage, debris shedding and wear pits. We reveal that three major factors mainly contributed to its high wear resistance. First, ULWPE demonstrated a high crystallinity and a compact crystalline morphology comprised of long linear molecular chains, which contributed to its good mechanical performance. As confirmed by the mechanical test, ULWPE had a very high density, hardness, and tensile elongation at break. The high hardness and strength laid a solid foundation to a low wear volume, and its high ductility and hardness helped to endure abrasive and adhesive wear, resulting in excellent wear resistance. Second, the results of wettability analysis showed that the contact angle formed on the surface of ULWPE was the lowest and the surface energy was the highest. The hydrophilicity of ULWPE provided good lubrication conditions in body fluid. Third, it also had a lower oxidation index. The high hardness, high strength, high ductility and good wetting of ULWPE materials reduced the damage of the material to adhesion and abrasive wear, resulting in excellent wear resistance.


Assuntos
Polietileno , Polietilenos , Óxido de Alumínio , Ligas de Cromo , Dureza , Teste de Materiais , Propriedades de Superfície
13.
Environ Pollut ; 263(Pt A): 114419, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32220774

RESUMO

Fungi-associated phytoremediation is an environmentally friendly and cost-efficient approach to remove potential toxic elements (PTEs) from contaminated soils. Many fungal strains have been reported to possess PTE-biosorption behaviour which benefits phytoremediation performance. Nevertheless, most studies are limited in rich or defined medium, far away from the real-world scenarios where nutrients are deficient. Understanding fungal PTE-biosorption performance and influential factors in soil environment can expand their application potential and is urgently needed. This study applied attenuated total reflection Fourier-transform infrared (ATR-FTIR) coupled with phenotypic microarrays to study the biospectral alterations of a fungal strain Simplicillium chinense QD10 and explore the mechanisms of Cd and Pb biosorption. Both Cd and Pb were efficiently adsorbed by S. chinense QD10 cultivated with 48 different carbon sources and the biosorption efficiency achieved >90%. As the first study using spectroscopic tools to analyse PTE-biosorption by fungal cells in a high-throughput manner, our results indicated that spectral biomarkers associated with phosphor-lipids and proteins (1745 cm-1, 1456 cm-1 and 1396 cm-1) were significantly correlated with Cd biosorption, suggesting the cell wall components of S. chinense QD10 as the primary interactive targets. In contrast, there was no any spectral biomarker associated with Pb biosorption. Addtionally, adsorption isotherms evidenced a Langmuir model for Cd biosorption but a Freundlich model for Pb biosorption. Accordingly, Pb and Cd biosorption by S. chinense QD10 followed discriminating mechanisms, specific adsorption on cell membrane for Cd and unspecific extracellular precipitation for Pb. This work lends new insights into the mechanisms of PTE-biosorption via IR spectrochemical tools, which provide more comprehensive clues for biosorption behaviour with a nondestructive and high-throughput manner solving the traditional technical barrier regarding the real-world scenarios.


Assuntos
Cádmio , Chumbo , Adsorção , Biodegradação Ambiental , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Med Sci Monit ; 26: e919270, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32020914

RESUMO

BACKGROUND Anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) are effective treatments for cervical spondylotic myelopathy (CSM), but it is unclear which is better. In this study, we compared the biomechanical properties of 2-level ACDF and 1-level ACCF. MATERIAL AND METHODS An intact C3-C7 cervical spine model was developed and validated, then ACDF and ACCF simulation models were developed. We imposed 1.0 Nm moments and displacement-controlled loading on the C3 superior endplate. The range of motions (ROMs) of surgical and adjacent segments and von Mises stresses on endplates, fixation systems, bone-screw interfaces, and bone grafts were recorded. RESULTS ACDF and ACCF significantly reduced the surgical segmental ROMs to the same extent. ACCF induced much lower stress peaks in the fixation system and bone-screw interfaces and higher stress peaks on the bone graft. ACDF induced much lower stress peaks on the C4 inferior endplate and equivalent stress on the C6 superior endplate. There was no difference in the ROMs of surgical and adjacent segments and the intradiscal stress of adjacent levels between ACDF and ACCF. CONCLUSIONS Both ACDF and ACCF can provide satisfactory spinal stability. ACDF may be beneficial for subsidence resistance due to the lower stress peaks on the endplate. The ACCF may perform better in long-term stability and bone fusion owing to the lower stress peaks in the fixation system and bone-screw interfaces, and higher stress peaks in the bone graft.


Assuntos
Vértebras Cervicais/fisiopatologia , Vértebras Cervicais/cirurgia , Discotomia , Análise de Elementos Finitos , Espondilose/fisiopatologia , Espondilose/cirurgia , Adulto , Fenômenos Biomecânicos , Parafusos Ósseos , Transplante Ósseo , Humanos , Masculino , Placa Motora/patologia , Placa Motora/fisiopatologia , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Estresse Mecânico
15.
Proc Inst Mech Eng H ; 234(2): 210-222, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31752588

RESUMO

In vivo load and motion in the ankle joint play a key role in the understanding of the failure mechanism and function outcomes of total ankle arthroplasty. However, a thorough understanding of the biomechanics of the ankle joint in daily activities is lacking. The objective of this study was to develop a novel lower extremity musculoskeletal multibody dynamics model with total ankle arthroplasty considering the 6 degrees of freedom of the ankle joint motions and the deformable contact mechanics of the implant, based on force-dependent kinematics method. A patient who underwent total ankle arthroplasty surgery was considered. The walking gait data of the patient was measured in a gait laboratory and used as the input for the patient-specific musculoskeletal modeling. The predictions from the musculoskeletal model of total ankle arthroplasty included dorsiflexion-plantar flexion, inversion-eversion, internal-external rotation, anterior-posterior translation, inferior-superior translation, and medial-lateral translation of the tibiotalar joint, the ankle contact forces, the muscle activations, and the ligament forces. The magnitudes and tendencies of the predicted results were all within reasonable ranges, as compared with the data available in the literature. The predicted peak total ankle contact force was 6.55 body weight. In addition, the peak contact forces of the lateral and medial compartments were 4.22 body weight and 2.59 body weight, respectively. This study provides a potential new platform for the design of a better ankle prosthesis, the improvement of the operation techniques of the clinicians, and the accelerated postoperative recovery of the patients.


Assuntos
Articulação do Tornozelo , Tornozelo , Artroplastia de Substituição do Tornozelo , Músculo Esquelético/fisiologia , Tornozelo/diagnóstico por imagem , Tornozelo/fisiopatologia , Tornozelo/cirurgia , Articulação do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/fisiopatologia , Articulação do Tornozelo/cirurgia , Artrite/diagnóstico por imagem , Artrite/fisiopatologia , Artrite/cirurgia , Fenômenos Biomecânicos/fisiologia , Humanos , Prótese Articular , Ligamentos/fisiologia , Modelos Biológicos
16.
J Orthop Res ; 38(7): 1587-1595, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31876311

RESUMO

Using large femoral heads in total hip arthroplasty (THA) has been widely advocated to improve the function and longevity of the components. However, increasing the head size has been shown to accelerate polyethylene liner wear. Few studies have investigated the effect of other important structural parameters (such as polyethylene liner thickness, metal cup size, head-liner conformity, loading conditions, etc.) on the biomechanical functions of the THAs. In this study, an analytical model was used to evaluate the polyethylene liner wear characteristics of the THAs (defined using a biomechanical wear factor) with various structural parameters of the THAs and loading conditions. For all the THA systems examined in this study, under the same loading conditions, a larger head leads to increasing contact areas, lower contact stresses, and higher biomechanical wear factors. When the head size is fixed, a decrease in the polyethylene liner thickness or a decrease in the head-liner conformity leads to higher peak contact stresses and smaller contact areas and consequently, lower biomechanical wear factors. This study provides a parametric analysis tool for the optimal design/selection of the THA systems and for prediction of early effects of various structural parameters on the biomechanical function (such as contact stresses) and longevity (such as polyethylene liner wear) of the THA systems.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Modelos Teóricos , Polietileno , Desenho de Prótese , Humanos
17.
Sci Total Environ ; 697: 134148, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31479903

RESUMO

Phytoremediation is an effective approach to control soil heavy metal pollution. This study isolated a fungus strain from soils contaminated by cadmium (Cd) and lead (Pb) in Zhalong Wetland (China), which was identified as Simplicillium chinense QD10 via both genotypic and phenotypic analysis. The performance and mechanism of S. chinense QD10 in Cd and Pb adsorption was unraveled by morphological analysis and biosorption test, and its roles in ameliorating phytoremediation by Phragmites communis were tested in pot-experiments. Cd biosorption was attributed to the formation of Cd-chelate, whereas Pb was predominantly adsorbed by extracellular polymeric substances. Metal biosorption followed Langmuir isotherm, and the maximum biosorption capacity was 88.5 and 57.8 g/kg for Cd and Pb, respectively. Colonized in soils, such biosorption behavior of S. chinense QD10 can generate gradients of available Cr or Pb and drive their enrichment. Accordingly, S. chinense QD10 amendment significantly enhanced the phytoextraction of Cd and Pb by P. communis, possibly attributing to rhizospheric enrichment of Cd or Pb and defending effects on plants, explained by the significant removal of acid-extractable and reducible metals in soils and the increase of Cd and Pb content in P. communis tissues. The present study explored the mechanisms of S. chinense QD10 in Cd and Pb biosorption and proved its potential in ameliorating the phytoremediation performance at metal contaminated sites.


Assuntos
Biodegradação Ambiental , Metais Pesados/metabolismo , Poluentes do Solo/metabolismo , Cádmio/metabolismo , China , Fungos/metabolismo , Chumbo/metabolismo , Metais Pesados/análise , Microbiologia do Solo , Poluentes do Solo/análise
18.
J Biomech ; 94: 230-234, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31421809

RESUMO

Representation of realistic muscle geometries is needed for systematic biomechanical simulation of musculoskeletal systems. Most of the previous musculoskeletal models are based on multibody dynamics simulation with muscles simplified as one-dimensional (1D) line-segments without accounting for the large muscle attachment areas, spatial fibre alignment within muscles and contact and wrapping between muscles and surrounding tissues. In previous musculoskeletal models with three-dimensional (3D) muscles, contractions of muscles were among the inputs rather than calculated, which hampers the predictive capability of these models. To address these issues, a finite element musculoskeletal model with the ability to predict contractions of 3D muscles was developed. Muscles with realistic 3D geometry, spatial muscle fibre alignment and muscle-muscle and muscle-bone interactions were accounted for. Active contractile stresses of the 3D muscles were determined through an efficient optimization approach based on the measured kinematics of the lower extremity and ground force during gait. This model also provided stresses and strains of muscles and contact mechanics of the muscle-muscle and muscle-bone interactions. The total contact force of the knee predicted by the model corresponded well to the in vivo measurement. Contact and wrapping between muscles and surrounding tissues were evident, demonstrating the need to consider 3D contact models of muscles. This modelling framework serves as the methodological basis for developing musculoskeletal modelling systems in finite element method incorporating 3D deformable contact models of muscles, joints, ligaments and bones.


Assuntos
Marcha/fisiologia , Articulação do Joelho/fisiologia , Contração Muscular , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional , Joelho , Ligamentos/fisiologia , Extremidade Inferior/fisiologia , Modelos Anatômicos , Modelos Biológicos , Fibras Musculares Esqueléticas , Resistência à Tração
19.
Proc Inst Mech Eng H ; 233(9): 948-953, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31234760

RESUMO

Tibial locking mechanism design is adopted to limit the backside micromotion in fixed-bearing total knee replacement. However, the effect of the interference assembly of a tibial insert on the tibiofemoral contact mechanics was usually ignored. Finite element model of a fixed-bearing total knee replacement with full peripheral locking mechanism was established to simulate the interference assembly of the tibial insert, and the corresponding effects on the tibiofemoral contact mechanics were predicted. Due to the interference assembly of the tibial insert, a maximum Mises stress of 3.24 MPa was found for the tibial insert before loading. Furthermore, the contact stress was increased by 8.77%, and the contact area was decreased by 5.43% under peak load. The interference assembly of the tibial insert in a fixed-bearing total knee replacement changed the tibiofemoral contact mechanics. This study indicated that the level of interference fit should be cautiously designed for the tibial locking mechanism in fixed-bearing total knee replacement for balancing the articular surface wear and the backside wear of the modular tibial insert.


Assuntos
Artroplastia do Joelho , Fêmur , Fenômenos Mecânicos , Tíbia , Análise de Elementos Finitos , Desenho de Prótese , Estresse Mecânico , Suporte de Carga
20.
J Healthc Eng ; 2019: 8363128, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31191853

RESUMO

High tibial osteotomy becomes increasingly important in the treatment of cartilage damage or osteoarthritis of the medial compartment with concurrent varus deformity. HTO produces a postoperative valgus limb alignment with shifting the load-bearing axis of the lower limb laterally. However, maximizing procedural success and postoperative knee function still possess many difficulties. The key to improve the postoperative satisfaction and long-term survival is the understanding of the vital biomechanics of HTO in essence. This review article discussed the alignment principles, surgical technique, and fixation plate of HTO as well as the postoperative gait, musculoskeletal dynamics, and contact mechanics of the knee joint. We aimed to highlight the recent findings and progresses on the biomechanics of HTO. The biomechanical studies on HTO are still insufficient in the areas of gait analysis, joint kinematics, and joint contact mechanics. Combining musculoskeletal dynamics modelling and finite element analysis will help comprehensively understand in vivo patient-specific biomechanics after HTO.


Assuntos
Fenômenos Biomecânicos/fisiologia , Articulação do Joelho , Osteotomia , Tíbia , Idoso , Placas Ósseas , Análise da Marcha , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/fisiologia , Articulação do Joelho/cirurgia , Masculino , Pessoa de Meia-Idade , Osteotomia/instrumentação , Osteotomia/métodos , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Tíbia/cirurgia , Resultado do Tratamento
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