Journal of Biomechanical Engineering-Transactions of the Asme最新文献

{"title":"Magnetic Resonance Imaging-Based Cohesive Extended Finite Element Modeling of Atypical Femoral Fracture.","authors":"Ashkan Sedigh, Nada Kamona, Brandon C Jones, Brian-Tinh Vu, Chet Friday, Brendan Stoeckl, Christiana L Cottrell, Alyssa Rosen, Chamith S Rajapakse, Ani Ural","doi":"10.1115/1.4070711","DOIUrl":"10.1115/1.4070711","url":null,"abstract":"<p><p>Atypical femoral fracture (AFF) is a rare fracture associated with prolonged bisphosphonate (BP) treatment that occurs in the subtrochanter and midshaft of the femur. The association of AFF with BP treatment suggests alterations in femoral material properties with treatment. Femoral geometry has also been identified as a potential contributor to AFF. This study aims to demonstrate the novel integration of high-resolution magnetic resonance imaging (MRI) with cohesive extended finite element method (XFEM) to assess AFF. Using this approach, we quantified the independent contributions of femoral geometry and material property distribution to fracture resistance at the AFF site. MRI-based finite element models of female donor femurs incorporating homogeneous and specimen-specific heterogeneous material properties derived from MRI-based bone volume fraction (BVF) were evaluated. To assess the predictive capability of the models, experimental testing of the femur under stance loading was performed. Simulation results showed that when only geometrical properties of the femur were considered anterior bowing angle and neck shaft angle showed negative and positive correlations with fracture load, respectively. Fracture load increased with increasing specimen-specific means BVF. Simulation femoral stiffness and lateral strains where AFF occurs correlated significantly with experimental values. Our findings demonstrate that MRI-based cohesive XFEM can assess crack formation in AFF and highlight the need for considering both geometrical and material properties when assessing AFF risk. This study lays the foundation for MRI-based AFF assessment, which can be extended to MRI-specific measurements that cannot be quantified by other imaging modalities.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145795567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age-Related Increases in Graft Tendon Size and Stiffness During Skeletal Growth Enhance Anterior Cruciate Ligament Graft Function and Joint Stability in an Early Adolescent Porcine Model.","authors":"Yukun Zhang, Kaan Gurbuz, Joshua Chavez-Arellano, Logan Opperman, Jeffrey T Spang, Matthew B Fisher","doi":"10.1115/1.4070647","DOIUrl":"10.1115/1.4070647","url":null,"abstract":"<p><p>Anterior cruciate ligament (ACL) reconstruction in pediatric patients has a higher graft failure rate compared to adults. Restoring joint stability and reducing graft failure is essential. However, how graft biomechanical properties change with age and affect reconstruction outcomes remains unclear. This study investigated the biomechanical development of porcine flexor tendons across skeletal growth and evaluated how graft size and stiffness influence knee biomechanics in a pediatric porcine model. Flexor tendons (n = 57) were harvested from pigs at 0.5, 1.5, 5, and 9 months of age to measure cross-sectional area (CSA), stiffness, and failure load. ACLs in nine early adolescent porcine knees were reconstructed using both 1.5- and 5-month-old (1.5 mo and 5 mo) grafts and tested under anterior-posterior, compressive, and varus-valgus (VV) loading at 40 deg of flexion using a robotic testing system. ACL and graft forces were calculated, and in situ properties were derived from force-displacement curves. Tendon CSA, stiffness, and failure load increased with age, and stiffness associated with CSA. The CSA of 5 mo tendons was 57% greater than that of 1.5 mo tendons, but stiffness increased only 20%. ACL reconstruction with 5 mo grafts resulted in 29% less anterior-posterior tibial translation and 44% higher graft force compared to 1.5 mo grafts. In situ stiffness of 5 mo grafts was 51% higher than 1.5 mo grafts. These findings highlight the differences between tendon size and biomechanical development, which together contribute to the improvements in joint function following ACL reconstruction.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12849221/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145745829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Compartment Injury Risk in High-Rate Non-Penetrating Blunt Thoracic Impacts.","authors":"Juliette Caffrey, Fang-Chi Hsu, F Scott Gayzik","doi":"10.1115/1.4071003","DOIUrl":"https://doi.org/10.1115/1.4071003","url":null,"abstract":"<p><p>The occurrence of blunt abdominal injuries resulting from thoracic high-rate non-penetrating impacts (NPBIs) are often missed and associated with increased mortality and morbidity. Diagnosis of penetrating gunshot wounds successfully predicts injury locations using bullet trajectory, but no similar correlation has been applied for blunt impacts. Historically, thoracic NPBIs have been studied on ovine subjects and have reported thoracic only and thoracoabdominal injuries for impacts at the same location. The purpose of this study is to investigate if the finite element ovine thorax model (FE-OTM) can indicate changes in multi-compartment injury risk based on impact angle and determine a method for measuring this change. Twelve thoracic NPBIs were run over six impact angles (0 - 25°). Tissue directly under the impactor and along the path of impact, was analyzed for changes in composition and strain. Tissue composition analysis identified abdominal, lung, and liver as key tissue types. Cumulative volume analysis was used to determine a combine strain - volume metric for regions of interest. Within each region, Spearman's rank correlation was used to determine the strength of the relationship between this metric and impact angle. The key tissues experienced very strong correlations with impact angles and directionalities that corresponded to their change in volume. In conclusion, the FE-OTM can be used to indicate changes to multi-compartment injury risk based on impact angle. A 1st principal strain-volume based metric in the key tissue types is recommended.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":"1-18"},"PeriodicalIF":1.7,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146107883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid Flow Analysis of Pulmonary Hypertension in End-Stage Renal Disease: A Novel Alternative Methods-Driven Case Study.","authors":"Fatemeh Bahmani, Daniel Pearce, Kaitlin Southern, Kenechukwu Nwadiaro, Veeranna Maddipati, Stephanie M George","doi":"10.1115/1.4070760","DOIUrl":"10.1115/1.4070760","url":null,"abstract":"<p><p>Pulmonary hypertension (PH) is a serious condition affecting patients with end-stage renal disease (ESRD), yet the hemodynamic mechanisms underlying development remain poorly understood. Novel alternative methods (NAMs), such as computational fluid dynamics (CFD), provide a powerful and ethical approach to investigate vascular physiology using patient-specific data. We developed a CFD model of the pulmonary artery (PA) informed by noninvasive magnetic resonance imaging (MRI) from an ESRD patient to characterize flow dynamics and wall shear metrics relevant to PH. Simulations were performed using image-based geometry, and velocity fields, wall shear stress (WSS), time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were quantified. Results demonstrated physiologically consistent flow distributions, with higher velocities localized near outlet regions and lower velocities in branches. Spatially averaged TAWSS was approximately 9 dyn/cm2, in agreement with previously reported ranges. OSI values were low across the pulmonary vasculature, suggesting limited flow reversal. Together, these results highlight the feasibility of using patient-specific CFD to capture PA hemodynamics in ESRD and demonstrate consistency with published physiological values. This framework demonstrates the utility of NAMs to provide insight into complex biomechanical systems and a foundation for future studies seeking to clarify mechanistic links between ESRD development, arteriovenous fistula (AVF) creation, and eventual PH development, ultimately informing development of patient-specific diagnostic and therapeutic strategies. As NAMs gain regulatory and scientific traction, approaches like this will play an important role in reducing reliance on animal models while enabling ethically responsible, patient-specific discovery in cardiovascular research.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145901664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Special Issue: NAMs in Biomechanical Engineering-What's in a NAM?","authors":"Laurel Kuxhaus, Nathan J Sniadecki","doi":"10.1115/1.4070652","DOIUrl":"10.1115/1.4070652","url":null,"abstract":"","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145745771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical Modeling of Cardiac Fibrosis With Explicit Spatial Representation of Cellular Structure and Collagen Alignment.","authors":"Åshild Telle, Mary M Maleckar, Samuel T Wall, Joseph D Powers, Christoph M Augustin, Joakim Sundnes, Patrick M Boyle","doi":"10.1115/1.4070346","DOIUrl":"10.1115/1.4070346","url":null,"abstract":"<p><p>Cardiac fibrosis is a pathological condition involving remodeling that impairs cardiac function. Common forms include replacement fibrosis, where damaged myocytes are substituted by collagenous tissue, and interstitial fibrosis, involving matrix expansion between the myocytes. These occur alongside other remodeling processes, including myocardial stiffening and collagen alignment. The mechanical impact of each process remains an active area of investigation. In this work, we used a computational model with explicit myocyte and collagen geometries to study the microscale mechanical effects of fibrotic remodeling. Replacement fibrosis was simulated by substituting myocytes with extracellular matrix, while interstitial fibrosis was modeled by increasing transverse spacing between the cells. These geometric changes were combined with increased matrix and myocyte stiffness and collagen alignment to assess individual and combined effects during contraction and stretch. Structural changes alone led to substantially higher myocyte stresses during contraction (53.9 kPa for increased interstitial space and 35.4 kPa for myocyte replacement, versus 30.9 kPa at baseline). Collagen alignment and myocyte stiffening mitigated increased stress levels. Stretch experiments showed less structural differences in resulting tissue-level load values, which combined with stiffening were slightly higher for increased interstitial space. Individual and combined analyzes attributed total tissue stiffening more to myocyte than matrix stiffening. Our findings suggest that fibrotic remodeling leads to elevated stress in surviving myocytes. Myocyte stiffening and collagen alignment may serve compensatory roles, while also increasing tissue-level stiffness. Integrating microscale modeling with experimental data in future studies may offer deeper insights into the mechanical consequences of fibrotic remodeling.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12755171/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145472428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dystrophin Loss in Engineered Heart Tissues Recapitulates Clinically Relevant Aspects of Dystrophic Cardiomyopathy.","authors":"Alex J Goldstein, Thomas P Leahy, David L Mack, Nathan J Sniadecki","doi":"10.1115/1.4070408","DOIUrl":"10.1115/1.4070408","url":null,"abstract":"<p><p>Heart failure is the leading cause of death in patients with Duchenne muscular dystrophy (DMD), but the mechanisms underlying the associated dilated cardiomyopathy (DCM) are not fully understood. To address this gap, we generated engineered heart tissues (EHTs) using CRISPR-edited human induced pluripotent stem cell-derived cardiomyocytes that lack dystrophin. These dystrophic EHTs reproduced aspects of systolic and diastolic dysfunction seen in DMD-related DCM as they showed impaired contractile function and slower kinetics. Increased beat rate variability was also observed in dystrophic EHTs. Accompanying these facets of the DMD pathology were attenuated Ca2+ transients and delayed kinetics. Lastly, histological analysis of EHTs revealed that dystrophin-null cardiomyocytes had reduced size and shorter sarcomere lengths when compared to isogenic controls. Together, these findings demonstrate that EHTs provide a physiologically relevant human model of DMD-associated DCM and may serve as a valuable platform for mechanistic studies and therapeutic testing.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12755164/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145524214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Directed Cell Self-Assembly to Form Tendon and Muscle Models for Studying Early Stages of Musculoskeletal Tissue Formation.","authors":"Tabitha R Stephenson, Colin R Marchus, Alonna G Clair, Manu M Lama, Peter J Wieber, Nathan R Schiele","doi":"10.1115/1.4070403","DOIUrl":"10.1115/1.4070403","url":null,"abstract":"<p><p>Nonanimal models (NAMs) provide an important platform for studying musculoskeletal tissue formation under controlled conditions while reducing reliance on vertebrate animal models. In this study, we advanced a simple, scaffold-free three-dimensional (3D) NAM system to guide the self-assembly of murine C3H/10T1/2 mesenchymal stem cells (MSCs) and C2C12 myoblast progenitor cells into neotendon and neomuscle structures. Custom 3D-printed molds and biologically inert agarose were used to form nonadherent wells that promoted high cell density and directed cell-cell adhesion without exogenous extracellular matrix (ECM) or biomaterial scaffolds. Transforming growth factor (TGF)β2 treatment enhanced actin cytoskeleton alignment in neotendons, with initial collagen fibril formation observed by day 7. C2C12 myoblasts exhibited progressive actin alignment, myotube formation, and desmin production by day 14. A custom bioreactor was used to apply cyclic tensile loading to the neotendons early in their development. Co-cultures of C3H/10T1/2 MSCs and C2C12 myoblasts formed cohesive structures, with aligned cytoskeletal organization and desmin distribution throughout, suggesting potential interactions at the developing myotendinous junction. This scaffold-free NAM system enables the evaluation of key biochemical and mechanical cues that regulate early musculoskeletal tissue formation in vitro. By recapitulating features of the embryonic environment, this approach refines current in vitro methods and establishes a simple, versatile platform to ultimately reduce the need for vertebrate animal models in developmental studies.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12755166/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145523880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Probabilistic Method to Model Progressive Metatarsal Displacement and Stiffness During Fatigue Testing.","authors":"Christopher H Nguyen, Andrew R Wilzman, Karen L Troy","doi":"10.1115/1.4070501","DOIUrl":"10.1115/1.4070501","url":null,"abstract":"<p><p>To better understand the mechanisms of bone stress injuries (BSI) in metatarsals, we developed an algorithm that adapts finite element (FE) models of metatarsals to simulate fatigue displacements through progressive stiffness loss. Twenty-two human metatarsals were imaged using computed tomography (CT) and then cyclically loaded in uniaxial compression until failure. CT images were used to generate specimen-specific FE models, and a custom program was developed to iteratively simulate cyclic loading and progressive stiffness loss associated with microdamage accumulation. Probability was incorporated into microdamage accumulation through a Weibull distribution. Simulations were able to accurately represent experimental trends in how metatarsal stiffness and displacement changed throughout the mechanical testing. Simulated displacement at failure was not significantly different from experimentally measured displacement. Simulated fatigue life, displacement, and rate of stiffness loss were significantly affected by (1) the Weibull scatter variable, m, and (2) the critical strain value, describing whether damage occurred before or after yielding. These simulations represent a novel alternative method that is significant because it helps us better understand the factors that influence fatigue life and observed mechanical behavior during fatigue testing in whole bones. Advanced adaptive simulations such as the one described here can be leveraged to reduce the reliance on physical testing, generate and test hypotheses regarding damage accumulation in materials, and eventually, be deployed in predictive algorithms with clinical applications.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12755163/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145607374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heart Scar-In-A-Dish: Tissue Culture Platform to Study Myocardial Injury and Mechanics In Vitro.","authors":"M J Potter, J D Heywood, S J Coeyman, W J Richardson","doi":"10.1115/1.4070123","DOIUrl":"10.1115/1.4070123","url":null,"abstract":"<p><p>Myocardial Infarction (MI) occurs when blood flow is blocked to a portion of the left ventricle and leads to necrosis and scar formation. Many therapies are under development to improve infarct healing, and three-dimensional engineered heart tissues (EHTs) offer an in vitro drug screening option to help reduce, refine, and potentially replace animal testing. Unfortunately, existing EHTs oversimplify cardiac mechanics and neglect the spatial variations of the infarcted ventricle in vivo, wherein the passive infarct zone is cyclically stretched under tension as the remote zone cyclically contracts with every heartbeat. We present an in vitro three-dimensional tissue culture platform focused on mimicking the heterogeneous mechanical environment of postinfarct myocardium. Herein, EHTs were subjected to a cryo-wound injury to induce localized cell death in a central portion of beating tissues composed of neonatal rat cardiomyocytes and fibroblasts. After injury, the remote zone continued to contract (i.e., negative strains) while the wounded zone was cyclically stretched (i.e., positive tensile strains) with intermediate strains in the border zone. We also observed increased tissue stiffnesses in the wounded zone and border zone following injury, while the remote zone did not show the same stiffening. Collectively, this work establishes a novel in vitro platform for characterizing myocardial mechanics after injury with both spatial and temporal resolution, contributing to a deeper understanding of MI and offering insights for potential therapeutic approaches.</p>","PeriodicalId":54871,"journal":{"name":"Journal of Biomechanical Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12755167/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145281943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}