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Importance: Improving patients' health status is a key goal of treating tricuspid regurgitation (TR). The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a heart failure disease-specific health status measure used to capture the health status impact of TR and the benefit of transcatheter tricuspid valve intervention (TTVI), but its validity in this clinical setting is unknown., Objective: To evaluate the psychometric properties of the KCCQ in patients with TR., Design, Setting, and Participants: Data were pooled from patients with severe TR enrolled in 11 manufacturer-sponsored trials of TTVI. The data were transferred to the US Food and Drug Administration to harmonize and anonymize prior to analysis by an independent center. Data were collected from December 2015 to April 2023, and data analysis was performed from July to October 2023., Main Outcomes and Measures: Prespecified analyses included evaluation of internal consistency, reproducibility, responsiveness, construct validity, and predictive validity. Outcomes were determined using Cronbach α, score comparisons, intraclass correlation, Cohen d, Spearman correlations with best available reference measures, and association of scores and changes in scores with risk of subsequent clinical events., Results: The study cohort was composed of 2693 patients enrolled in either single-arm (n = 1517) or randomized (n = 1176) investigations of TTVI. Mean (SD) patient age was 78.6 (8.0) years, 1658 of 2693 patients (61.6%) were female, and the mean (SD) baseline KCCQ Overall Summary (KCCQ-OS) score was 50 (23). There was strong internal consistency within individual domains (Cronbach α, .77-.83). Among clinically stable patients between 1 and 6 months, there were small mean changes in KCCQ domain and summary scores (differences of -0.1 to 1.9 points), demonstrating reproducibility. In contrast, domain and summary scores of patients who underwent TTVI showed large improvements at 1 month after treatment (mean changes, 12.1-21.4 points), indicating excellent perceived responsiveness. Construct validity was moderately strong when domains were compared with best available reference measures (Spearman correlations, 0.47-0.69). In both cross-sectional and longitudinal analyses, the KCCQ-OS was associated with clinical events, with lower scores associated with an increased risk of mortality (hazard ratio, 1.34 per 10-point decrement; 95% CI, 1.22-1.47) and heart failure hospitalization (hazard ratio, 1.24 per 10-point decrement; 95% CI, 1.17-1.31)., Conclusions and Relevance: In this cohort study, the KCCQ had strong psychometric properties in patients with severe TR, including reliability, responsiveness, and validity. These data support use of the KCCQ in patients with severe TR as a measure of their symptoms, function, and quality of life and also for assessing the impact of interventions, such as TTVI, in rigorously controlled trials.

A visible-light-triggered ring opening/in situ SO 2 -capture/alkynylation sequence of cyclopropyl alcohols with alkynyl triflones using 4CzIPN as a triplet energy transfer photocatalyst is herein described. This metal-free protocol provides a straightforward and atom-economical approach to alkynyl-substituted γ-keto sulfones with a broad scope of substituents. In this transformation, alkynyl triflones could be used as both radical acceptors and SO 2 donors. Preliminary experimental mechanistic studies and synthetic utility are also demonstrated.

Background: The labeled sizes of surgical valve prostheses and their discordance with the physical internal valve orifice sizes has long been a controversy in the cardiac surgery community, leading many to believe it to be a contributing factor in prosthesis-patient mismatch following valvular replacement surgery. In an attempt to address this issue, the International Organization for Standardization (ISO) 5840-2:2021 standard for surgical valve prostheses recommends that a new sizing parameter, namely, the effective orifice diameter, be provided in labeling by all manufacturers as an indicator of the true flow-passing capacity of a prosthetic valve., Methods: The ISO Cardiac Valves Working Group conducted a multi-laboratory round-robin study to investigate whether the effective orifice diameter of a prosthetic surgical valve could be derived repeatably and reproducibly through steady forward-flow testing. A total of seven valve models, each with multiple sizes, were tested, including a mechanical heart valve and multiple biological heart valves., Results: The round-robin study confirmed that the steady forward-flow test had good intra-laboratory repeatability and inter-laboratory reproducibility in deriving the effective orifice diameters of surgical valve prostheses. On average, among the participating laboratories, the experimentally derived effective orifice diameter of a prosthetic heart valve was 3-12 mm smaller than its labeled size., Conclusions: The effective orifice diameter provides better characterization of the hydrodynamic characteristics of a surgical valve prosthesis and can be derived using a validated steady forward-flow test method. This new sizing parameter will soon be adopted by surgical valve manufacturers and provided in device labeling to inform valve selection by surgeons., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2024 Annals of Cardiothoracic Surgery. All rights reserved.)

Objective: This study aimed to investigate the prevalence of glaucoma with associated factors in the rural populations of 10 provinces in China., Design: A population-based cross-sectional study., Methods: All participants aged 6 years or older from 10 provinces completed visual acuity testing, slit-lamp examination, ophthalmoscopy and non-contact tonometry. Glaucoma suspects underwent fundus photography, Goldmann applanation tonometry, visual field testing and gonioscopy. Glaucoma was determined according to the International Society of Geographical and Epidemiological Ophthalmology classification scheme. Associations of demographics and medical factors with glaucoma were assessed using multiple logistic regression models., Results: From June 2017 to October 2018, 48 398 of 52 041 participants were included in the final analyses. The age-standardised prevalence of glaucoma was 1.7% (95% CI 1.55% to 1.78%) among the participants older than 6 years, which was 2.1% (95% CI 1.93% to 2.23%) in participants aged over 40 years. The constituent ratios of glaucoma were: 44.4% primary angle-closure glaucoma (PACG), 34.7% primary open-angle glaucoma, 2.6% congenital glaucoma and 18.3% other types of glaucoma. Increasing age, smoking, cerebral stroke, type 2 diabetes, higher education (college or more) and higher personal income were significant risk factors for PACG. The unilateral and bilateral blindness rates in the entire study population were 4.692% and 1.068%, respectively. A family history of glaucoma was a significant risk factor for the prevalence of glaucoma and blindness in at least one eye., Conclusions: Rural populations have a high prevalence of glaucoma, which should be included in chronic disease management programmes in China for long-term care., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Importance: Recent studies have produced inconsistent findings regarding the outcomes of the percutaneous microaxial left ventricular assist device (LVAD) during acute myocardial infarction with cardiogenic shock (AMICS)., Objective: To compare the percutaneous microaxial LVAD vs alternative treatments among patients presenting with AMICS using observational analyses of administrative data., Design, Setting, and Participants: This comparative effectiveness research study used Medicare fee-for-service claims of patients admitted with AMICS undergoing percutaneous coronary intervention from October 1, 2015, through December 31, 2019. Treatment strategies were compared using (1) inverse probability of treatment weighting to estimate the effect of different baseline treatments in the overall population; (2) instrumental variable analysis to determine the effectiveness of the percutaneous microaxial LVAD among patients whose treatment was influenced by cross-sectional institutional practice patterns; (3) an instrumented difference-in-differences analysis to determine the effectiveness of treatment among patients whose treatment was influenced by longitudinal changes in institutional practice patterns; and (4) a grace period approach to determine the effectiveness of initiating the percutaneous microaxial LVAD within 2 days of percutaneous coronary intervention. Analysis took place between March 2021 and December 2022., Interventions: Percutaneous microaxial LVAD vs alternative treatments (including medical therapy and intra-aortic balloon pump)., Main Outcomes and Measures: Thirty-day all-cause mortality and readmissions., Results: Of 23 478 patients, 14 264 (60.8%) were male and the mean (SD) age was 73.9 (9.8) years. In the inverse probability of treatment weighting analysis and grace period approaches, treatment with percutaneous microaxial LVAD was associated with a higher risk-adjusted 30-day mortality (risk difference, 14.9%; 95% CI, 12.9%-17.0%). However, patients receiving the percutaneous microaxial LVAD had a higher frequency of factors associated with severe illness, suggesting possible confounding by measures of illness severity not available in the data. In the instrumental variable analysis, 30-day mortality was also higher with percutaneous microaxial LVAD, but patient and hospital characteristics differed across levels of the instrumental variable, suggesting possible confounding by unmeasured variables (risk difference, 13.5%; 95% CI, 3.9%-23.2%). In the instrumented difference-in-differences analysis, the association between the percutaneous microaxial LVAD and mortality was imprecise, and differences in trends in characteristics between hospitals with different percutaneous microaxial LVAD use suggested potential assumption violations., Conclusions: In observational analyses comparing the percutaneous microaxial LVAD to alternative treatments among patients with AMICS, the percutaneous microaxial LVAD was associated with worse outcomes in some analyses, while in other analyses, the association was too imprecise to draw meaningful conclusions. However, the distribution of patient and institutional characteristics between treatment groups or groups defined by institutional differences in treatment use, including changes in use over time, combined with clinical knowledge of illness severity factors not captured in the data, suggested violations of key assumptions that are needed for valid causal inference with different observational analyses. Randomized clinical trials of mechanical support devices will allow valid comparisons across candidate treatment strategies and help resolve ongoing controversies.

Mitral regurgitation is the most common valvular disease and is estimated to affect over 5 million Americans. Real-world data collection contributes to safety and effectiveness evidence for the U.S. Food and Drug Administration, quality evaluation for the Centers for Medicare and Medicaid Services and hospitals, and clinical best practice research. We aimed to establish a minimum core data set in mitral interventions to promote efficient, reusable real-world data collection for all of these purposes. Two expert task forces separately evaluated and reconciled a list of candidate elements derived from: 1) 2 ongoing transcatheter mitral trials; and 2) a systemic literature review of high-impact mitral trials and U.S multicenter, multidevice registries. From 703 unique data elements considered, unanimous consensus agreement was achieved on 127 "core" data elements, with the most common reasons for exclusion from the minimum core data set being burden or difficulty in accurate assessment (41.2%), duplicative information (25.0%), and low likelihood of affecting outcomes (19.6%). After a systematic review and extensive discussions, a multilateral group of academicians, industry representatives, and regulators established and implemented into the national Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapies Registry 127 interoperable, reusable core data elements to support more efficient, consistent, and informative transcatheter mitral device evidence for regulatory submissions, safety surveillance, best practice development, and hospital quality assessments., Competing Interests: Funding Support and Author Disclosures Dr Vemulapalli has received grants/contracts from the American College of Cardiology, Society of Thoracic Surgeons, National Institutes of Health (R01 and SBIR), Food and Drug Administration (NEST cc), Abbott, Boston Scientific, and Cytokinetics; and is on the advisory board or is a consultant for Edwards Lifesciences, Medtronic, American College of Physicians, and Total CME. Ms Alu has received institutional research funding from Abbott and Edwards Lifesciences. Dr Shahim has received a research grant from the Stockholm county research council. Dr James has been a proctor for Medtronic. Dr Leon has received institutional grants for clinical research from Abbott, Boston Scientific, Edwards Lifesciences, and Medtronic. Dr Thourani has been an advisor for Abbott Vascular, ARtivion, Atricure, Boston Scientific, Edwards Lifesciences, Medtronic, and Shockwave. Dr Carroll has received institutional grants for clinical trials from Edwards Lifesciences, Medtronic, and Abbott; and has been a consultant for Abbott. Dr Krucoff has received grants from Abbott Vascular, Boston Scientific, Medtronic, Mitre Medical, OrbusNeich, and 4C Medical; and has been a consultant for Abbott Vascular, Boston Scientific, Medtronic, Mitre Medical, OrbusNeich, and 4C Medical., (Copyright © 2023 American College of Cardiology Foundation. All rights reserved.)

Objectives: There is still controversy about the effect of vitamin D supplementation on osteoarthritis (OA). The purpose of this study was to investigate the effects of vitamin D supplementation with Hyaluronic acid (HA) injection on OA., Methods: We investigated serum vitamin D levels and oxidative stress (OS) in synovial fluid from patients with OA who underwent total knee arthroplasty (grade IV, n = 24) and HA injection (grade II and III, n = 40). The effects of HA injection with or without oral vitamin D supplementation on synovial fluid OS and knee pain and function were then further investigated. Finally, patients underwent HA injection were divided into two groups according to vitamin D levels (vitamin D < or > 30 ng/ml), and the efficacy of the two groups were compared., Results: The results showed that the levels of glutathione peroxidase (GSH-PX) ( P < 0.05) in the synovial fluid were lower in patients with stage IV OA than that in patients with stage II-III OA, while the levels of malondialdehyde (MDA) ( P < 0.05) and lactate dehydrogenase (LDH) ( P < 0.01) were significantly higher. Moreover, we found that age, BMI and vitamin D levels were significantly associated with the levels of oxidants and/or antioxidants in synovial fluid, and that vitamin D was significantly negatively correlated with BMI ( R = -0.3527, p = 0.0043). Supplementation of HA injections with vitamin D significantly reduced the OS status in synovial fluid, attenuated knee pain and improved knee function in OA patients with vitamin D insufficiency., Conclusion: We conclude that maintenance of vitamin D sufficiency may be beneficial for the treatment of OA by improving OS in synovial fluid., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Shen, Lin, Lin, Xiao, Wu, Zheng, Wu, Lin, Chen and Liu.)

A virtual workshop was organized by the Heart Valve Collaboratory to identify areas of expert consensus, areas of disagreement, and evidence gaps related to bioprosthetic aortic valve hemodynamics. Impaired functional performance of bioprosthetic aortic valve replacement is associated with adverse patient outcomes; however, this assessment is complicated by the lack of standardization for labelling, definitions, and measurement techniques, both after surgical and transcatheter valve replacement. Echocardiography remains the standard assessment methodology because of its ease of performance, widespread availability, ability to do serial measurements over time, and correlation with outcomes. Management of a high gradient after replacement requires integration of the patient's clinical status, physical examination, and multimodality imaging in addition to shared patient decisions regarding treatment options. Future priorities that are underway include efforts to standardize prosthesis sizing and labelling for both surgical and transcatheter valves as well as trials to characterize the consequences of adverse hemodynamics., Competing Interests: Funding Support and Author Disclosures Dr Herrmann has received institutional research funding from Abbott, Boston Scientific, Edwards Lifesciences, Highlife, Medtronic, and WL Gore; has received consulting fees from Edwards Lifesciences, Medtronic, Wells Fargo, and WL Gore; and has equity in Holistick Medical and Microinterventional Devices. Dr Pibarot has received funding from Edwards Lifesciences, Medtronic, Pi-Cardia, and Cardiac Phoenix for echocardiography core laboratory analyses and research studies in the field of transcatheter valve therapies, for which he received no personal compensation. Dr Hahn has received speaker fees from Abbott Structural and Edwards Lifesciences; has institutional consulting contracts for which she receives no direct compensation with Abbott Structural, Boston Scientific, Edwards Lifesciences, Medtronic, and Novartis; has served on the Scientific Advisory Board for Novartis; and has equity in Navigate. Dr Tang is a physician proctor and consultant for Medtronic; has served as a consultant and physician advisory board member for Abbott Structural Heart; has served as a consultant for NeoChord; and has served as a physician advisory board member for JenaValve. Dr Abbas has received research grants and consulting fees from Edwards Lifesciences. Dr Playford has received investigator-initiated research funding from Edwards Lifesciences, Pfizer, Novartis, Actelion, Bayer, and GlaxoSmithKline; is Chief Medical Advisor for Echo IQ; and has been a physician advisory board member for Edwards Lifesciences and AstraZeneca. Dr Ruel is a physician proctor for Medtronic (MICS CABG) and for Edwards Lifesciences (MICS AVR); has served as a steering committee member for Cryolife (PROACT Xa trial); and is a recipient of research funds from Medtronic (MIST trial). Dr Jilaihawi is a consultant to Boston Scientific, Edwards Lifesciences, and Medtronic; and has received grant/research support from Abbott Vascular, Edwards Lifesciences, and Medtronic. Dr Sathananthan is a consultant for and has received institutional research funding from Edwards Lifesciences and Medtronic; and has received speaker fees from NVT. Dr Wood is a consultant for and his institution (CCI-CIC) receives grant support from Edwards Lifesciences, Abbott Vascular, and Medtronic. Dr Bax’s institution (Department of Cardiology, LUMC, the Netherlands) has received research grants from Medtronic, Biotronik, Edwards Lifesciences, and Boston Scientific. Dr Rodes-Cabau has received institutional research grants from Edwards Lifesciences, Medtronic, and Boston Scientific. Dr Del Nido is cofounder of Autus Valve Technologies, Inc. Dr Dweck is a consultant to Edwards Lifesciences and Medtronic; has received research funding from Edwards Lifesciences and Medtronic; and has received speaker fees from NVT. Dr Kaneko is a consultant for Edwards, Medtronic, Abbott, and 4C Medical. Dr Latib is a consultant for Medtronic, Edwards Lifesciences, Boston Scientific, and Abbott. Dr Moat is a full-time employee of Abbott Structural Heart, Inc. Dr Modine has received research grants from Edwards Lifesciences and Medtronic; and is a consultant for Abbott, Edwards Lifesciences, Medtronic, and Microport. Dr Popma is a full-time employee of Medtronic, Inc. Dr Smith has received institutional grants from Edwards Lifesciences, Medtronic, Abbott, and Cryolife; has received advisory board fees from Edwards Lifesciences; and has received speaking honoraria from Medtronic, Cryolife, Abbott, and Edwards Lifesciences. Dr Thomas is a full-time employee of Edwards Lifesciences. Dr Yoganathan is a Principal Consultant to CardioMed Device Consultants LLC in the Structural Heart Valve area; is on the Scientific Advisory Board of Foldax Inc; and has served as Educational Consultant to Boston Scientific, Edwards Lifesciences, Abbott Cardiovascular, and Livanova. Dr Mack has served as a co-principal investigator for clinical trials for Abbott and Edwards Lifesciences; and has served as study chair for a trial for Medtronic; all roles were uncompensated. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Bioprosthetic valve dysfunction (BVD) and bioprosthetic valve failure (BVF) may be caused by structural or nonstructural valve dysfunction. Both surgical and transcatheter bioprosthetic valves have limited durability because of structural valve deterioration. The main objective of this summary of experts participating in a virtual workshop was to propose standardized definitions for nonstructural and structural BVD and BVF following aortic or mitral biological valve replacement with the goal of facilitating research reporting and implementation of these terms in clinical practice. Definitions of structural BVF, based on valve reintervention or death, underestimate the true incidence of BVF. However, definitions solely based on the presence of high transprosthetic gradient at a given echocardiogram during follow-up overestimate the incidence of structural BVD and BVF. Definitions of aortic or mitral structural BVD must therefore include the confirmation by imaging of permanent structural changes to the leaflets alongside evidence of deterioration in valve hemodynamic function at echocardiography follow-up., Competing Interests: Funding Support and Author Disclosures Dr Pibarot has received funding from Edwards Lifesciences, Medtronic, Pi-Cardia, and Cardiac Phoenix for echocardiography core laboratory analyses and research studies in the field of transcatheter valve therapies, for which he received no personal compensation; and has received lecture fees from Edwards Lifesciences and Medtronic. Dr Herrmann has received institutional research funding from Abbott, Boston Scientific, Edwards Lifesciences, Highlife, Medtronic, and WL Gore; has received consulting fees from Edwards Lifesciences, Medtronic, Wells Fargo, and WL Gore; and has equity in Holistick Medical and Microinterventional Devices. Dr Hahn has received speaker fees from Abbott Structural, Edwards Lifesciences, and Philips Healthcare; has institutional consulting contracts for which she receives no direct compensation with Abbott Structural, Boston Scientific, Edwards Lifesciences, Medtronic and Novartis; and has equity in Navigate. Dr Abbas has received research grants and consulting fees from Edwards Lifesciences. Dr Dweck has served as a consultant to Edwards Lifesciences and Medtronic; has received research funding from Edwards Lifesciences and Medtronic; and has received speaking fees from NVT. Dr Leipsic has served as a consultant for Circle CVI and MVRX; and has received institutional funding for CT core laboratory analyses from Edwards Lifesciences, Neovasc, Abbott, Medtronic, Boston Scientific, PI Cardia, and Conformal. Dr Rogers has served as a consultant and physician proctor for Edwards Lifesciences and Medtronic; has served as an advisory board member for Medtronic; and holds equity interest in Transmural Systems. Dr Sathananthan has served as a consultant to Edwards Lifesciences and Medtronic; has received research funding from Edwards Lifesciences and Medtronic; and has received speaking fees from NVT. Dr Guerrero has received institutional research grant support from Edwards Lifesciences. Dr Ternacle has served as a consultant for Philips Healthcare and Abbott Medical. Dr Barbanti has served as a consultant for Edwards Lifesciences and Boston Scientific. Dr Généreux has served as a consultant and advisor for and received speaker fees from Abbott Vascular, Abiomed, BioTrace Medical, and Medtronic; has served as a consultant for Boston Scientific, GE Healthcare, iRhythm Technologies, Opsens, Siemens, and Teleflex; has served as a consultant, PI Eclipse Trial, for Cardiovascular System Inc; has served as a consultant, advisor, and proctor for and received speaker fees and research grant from Edwards LifeSciences for the PI EARLY-TAVR and PI PROGRESS trials; has served as a consultant for and has equity in Pi-Cardia, Puzzle Medical, Saranas, and Soundbite Medical Inc; has served as a consultant for and received speaker fees from Shockwave; and has served as a consultant for the PI Feasibility study for 4C Medical. Dr Kaneko has served as a consultant for Edwards Lifesciences, Medtronic, and Abbott Structural. Dr Wood has served as a consultant to and his institution (CCI-CIC) receives grant support from Edwards Lifesciences, Abbott Vascular, and Medtronic. Dr Gillam has served as a consultant to Philips and Bracco; is an advisory board member for Edwards Lifesciences; and has core lab contracts with Edwards Lifesciences, Medtronic, and Abbott for which she receives no direct compensation. Dr Reardon has served as a consultant for Medtronic, Boston Scientific, Abbott Medical, and Gore Medical; all fees for such are to his department. Dr Rodes-Cabau has received institutional research grants from Edwards Lifesciences, Medtronic, and Boston Scientific. Dr Thourani has performed consulting/research for Abbott Vascular, Boston Scientific, Cryolife, Edwards Lifesciences, Medtronic, and Shockwave. Dr Bax’s institution (Department of Cardiology, LUMC, the Netherlands) has received research grants from Medtronic, Biotronik, Edwards Lifesciences, and Boston Scientific. Dr Mack has served as a co-principal investigator for clinical trials for Abbott and Edwards Lifesciences; and has served as study chair for a trial for Medtronic; all roles were uncompensated. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Funding Support and Author Disclosures Baylor Scott & White Health Research Institute is a 501c3 not for profit institution in Dallas, Texas. Cardiovascular Research Foundation is a 501c3 not for profit institution in New York, New York. Dr Mack has received consulting fees from Gore; has served as a trial coprimary investigator for Edwards Lifesciences and Abbott; and has served as a study chair for Medtronic. Dr Leon has received grant support, paid to his institution, from Edwards Lifesciences, Medtronic, Abbott, and Boston Scientific; and has received advisory board fees from Medtronic, Abbott, Boston Scientific, Gore, and Meril Life Sciences. Drs Wu and Zuckerman are employees of the U.S. Food and Drug Administration.

Objective: The objective is to investigate the biomechanical conditions of the Posterior Vertebral Column Resection (PVCR) of the constructed scoliosis 3D finite element model., Methods: A patient with scoliosis was selected; before the PVCR orthopaedy, the patient was submitted to the radiography of normal and lateral full-length vertebral column scans and the total magnetic resonance imaging (MRI) scans; then, the idiopathic scoliosis model was constructed by the 3D finite element method, and the 3D finite element software utilized in the process of model construction included Mimics software, Geomagic Studio 12 software, and Unigraphic 8.0 (UG 8.0) software; in addition, PVCR orthopaedy was utilized to correct the scoliosis of the patient, and the biomechanical parameters, such as orthodontic force, vertebral body displacement, orthopedic rod stress, stress on the pin-bone interface of the vertebral body surface, and the stress on the intervertebral disc, were studied., Results: The 3D effective finite element model of scoliosis was successfully constructed by the Mimics software, the Geomagic Studio 12 software, and the UG 8.0 software, and the effectiveness was tested. PVCR orthopaedy could effectively solve the problem of scoliosis. The magnitude of the orthodontic force that a patient needed depended on the physical conditions and the personal orthodontic requirements of the patient. The maximum vertebral body displacement on the X-axis was the vertebral body L1, the maximum displacement on the Y-axis was the vertebral body T3, the maximum displacement on the Z-axis was the vertebral body T1, and the rang of orthopedic rod stress was 0.0050214e 7 MPa to 0.045217e 7 MPa, in which the maximum stress of 2 vertebral bodies in, above, and below the osteotomy area reached 0.045217e 7 MPa, the stress on the pin-bone interface of the T10 vertebral body surface reached 11.83 MPa, and the stress of T8/T9 intervertebral disc reached 13.84 MPa., Conclusion: The 3D finite element model based on 3D finite element software was highly efficient, and its numerical simulation was accurate, which was important for the subsequent biomechanical analysis of PVCR orthopaedy. In addition, the vertebral stress of PVCR orthopaedy was different in each body part, which was mainly affected by the applied orthodontic force and the sites of the orthodontic area., Competing Interests: The authors declared that there is no conflict of interest., (© 2019 The Author(s).)

Transcatheter aortic valves (TAV) are symmetrically designed, but they are often not deployed inside cylindrical conduits with circular cross-sectional areas. Many TAV patients have heavily calcified aortic valves, which often result in deformed prosthesis geometries after deployment. We investigated the effects of deformed valve annulus configurations on a surgical bioprosthetic valve as a model for TAV. We studied valve leaflet motions, stresses and strains, and analog hydrodynamic measures (using geometric methods), via finite element (FE) modeling. Two categories of annular deformations were created to approximate clinical observations: (1) noncircular annulus with valve area conserved, and (2) under-expansion (reduced area) compared to circular annulus. We found that under-expansion had more impact on increasing stenosis (with geometric orifice area metrics) than noncircularity, and that noncircularity had more impact on increasing regurgitation (with regurgitation orifice area metrics) than under-expansion. We found durability predictors (stress/strain) to be the highest in the commissure regions of noncircular configurations such as EllipMajor (noncircular and under-expansion areas). Other clinically relevant performance aspects such as leaflet kinematics and coaptation were also investigated with the noncircular configurations. This study provides a framework for choosing the most challenging TAV deformations for acute and long-term valve performance in the design and testing phase of device development., (Copyright © 2020 by ASME.)

Purpose: Hydrodynamic performance testing is one of the core in vitro assessments required by the ISO 5840 series of standards for all prosthetic heart valves. A round-robin study carried out in 2005 in accordance with ISO 5840:2005 revealed significant variabilities in prosthetic heart valve hydrodynamic performance measurements among the participating laboratories. In order to re-examine the inter-laboratory variability based on the "state-of-the-art" under ISO 5840-1 and 5840-2:2015, the ISO Cardiac Valve Working Groups decided in 2016 to repeat the round-robin study., Methods: A total of 13 international laboratories participated in the study. The test valves were chosen to be the St. Jude Medical Masters Series mechanical valves (19 mm aortic, 25 mm aortic, 25 mm mitral, and 31 mm mitral), which were circulated among the laboratories. The testing was conducted according to a common test run sequence, with prespecified flow conditions., Results: The study revealed improved, yet still significant variability among different laboratories as compared to the 2005 study. The coefficient of variation ranged from 7.7 to 21.6% for the effective orifice area, from 10.1 to 32.8% for the total regurgitant fraction, and from 14.7 to 45.5% for the mean transvalvular pressure gradient., Conclusions: The study revealed the ambiguities in the current versions of the ISO 5840 series of standards and the shortcomings of some participating laboratories. This information has allowed the ISO Working Group to incorporate additional clarifying language into the ISO 5840-1, -2, and -3 standards that are currently under revision to improve in vitro assessments. The results presented here can also be used by the testing laboratories to benchmark pulse duplicator systems and to train and certify testing personnel.

Background: The Transcatheter Valve Therapy (TVT) Coordinated Registry Network (CRN) supported 23 regulatory decisions and ensured evidence-based evaluation of the application of TVT technology. However, there are cost concerns that require value assessment of the TVT CRN compared with traditional study designs., Objectives: We aimed to determine the value created by the TVT CRN based on (1) Return on investment (ROI), (2) Time saved (TS) in conducting necessary regulatory studies., Methods: For both ROI and TS analyses, we compared studies that used the TVT CRN with those that would have been required if the registry did not exist (counterfactual studies). To estimate ROI, we accounted for the costs of investment and gain from investment. Both the counterfactual costs and length of studies were projected using design specifications determined by US Food and Drug Administration (FDA) reviewers., Results: We identified 21 studies using the TVT CRN (supporting 23 FDA decisions) that generated evidence on TVT for three device manufacturers. ROI is estimated to be greater than 550%. TS by using the CRN ranged from months to years., Conclusions: The CRN method to evidence generation creates value for manufacturers and the broader device ecosystem, demonstrated with this example of the TVT CRN. The public health benefits of evidence created by this CRN outweighs the difference in data quality between traditional clinical studies and the CRN method., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: This study aimed to compare the efficacy and safety of oral tranexamic acid (TXA) with intravenous (IV) TXA in reducing perioperative blood loss in total-knee arthroplasty (TKA) and total-hip arthroplasty (THA)., Methods: PubMed, Web of Science, Embase, and Cochrane Library were fully searched for relevant studies. Studies comparing the efficacy and safety of oral TXA with IV TXA in TKA and THA were included in this research. Odds ratio (OR) or risk difference (RD) was applied to compare dichotomous variables, while mean difference (MD) was used to compare continues variables., Results: A total of 7 studies (5 randomized controlled trials and 2 retrospective studies) were included into this study. As for patients undergoing TKA or THA, there were no obvious differences between oral TXA group and IV TXA group in hemoglobin (Hb) drop (MD = 0.06, 95% confidence interval [CI] = -0.01 to 0.13, P = .09), transfusion rate (OR = 0.78, 95% CI = 0.54-1.13, P = .19), total blood loss (MD = 16.31, 95% CI = -69.85 to 102.46, P = .71), total Hb loss (MD = 5.18, 95% CI = -12.65 to 23.02, P = .57), length of hospital stay (MD = -0.06, 95% CI = -0.30 to 0.18, P = .63), drain out (MD = 21.04, 95% CI = -15.81 to 57.88, P = .26), incidence of deep vein deep vein thrombosis (RD = 0.00, 95% CI = -0.01 to 0.01, P = .82) or pulmonary embolism (RD = 0.00, 95% CI = -0.01 to 0.01, P = .91). The sample size of this study was small and several included studies were with relatively low quality., Conclusion: Oral TXA is equivalent to IV TXA in reducing perioperative blood loss and should be recommended in TKA and THA. More high-quality studies are needed to elucidate this issue.

After implantation of a transcatheter bioprosthetic heart valve its original circular circumference may become distorted, which can lead to changes in leaflet coaptation and leaflets that are stretched or sagging. This may lead to early structural deterioration of the valve as seen in some explanted transcatheter heart valves. Our in vitro study evaluates the effect of leaflet deformations seen in elliptical configurations on the damage patterns of the leaflets, with circular valve deformation as the control. Bovine pericardial tissue heart valves were subjected to accelerated wear testing under both circular (N = 2) and elliptical (N = 4) configurations. The elliptical configurations were created by placing the valve inside custom-made elliptical holders, which caused the leaflets to sag or stretch. The hydrodynamic performance of the valves was monitored and high resolution images were acquired to evaluate leaflet damage patterns over time. In the elliptically deformed valves, sagging leaflets experienced more damage from wear compared to stretched leaflets; the undistorted leaflets of the circular valves experienced the least leaflet damage. Free-edge thinning and tearing were the primary modes of damage in the sagging leaflets. Belly region thinning was seen in the undistorted and stretched leaflets. Leaflet and fabric tears at the commissures were seen in all valve configurations. Free-edge tearing and commissure tears were the leading cause of valve hydrodynamic incompetence. Our study shows that mechanical wear affects heart valve pericardial leaflets differently based on whether they are undistorted, stretched, or sagging in a valve configuration. Sagging leaflets are more likely to be subjected to free-edge tear than stretched or undistorted leaflets. Reducing leaflet stress at the free edge of non-circular valve configurations should be an important factor to consider in the design and/or deployment of transcatheter bioprosthetic heart valves to improve their long-term performance.

Background: Transcatheter aortic valve replacement (TAVR) is a less invasive alternative approach to surgery. Individual randomized clinical trials evaluating the safety and efficacy of TAVR were mostly underpowered for conducting separate analyses for women and men. We pooled data from premarket TAVR clinical trials comparing short (30 days)- and long-term (∼2 years) outcomes by sex., Methods: Patient-level data from the TAVR arms of six clinical trials were pooled (2515 patients). Random-effects models for time-to-event outcomes (odds ratios [ORs] for 30-day outcomes and hazard ratios [HRs] for complete follow-up for mortality, ischemic stroke, kidney injury, major bleeding, myocardial infarction, and device migration) and dichotomous outcomes (ORs for reintervention, rehospitalization, and pacemaker implantation) were then fit to directly compare outcomes between women and men., Results: Overall, the pattern of individual comorbidities was more severe in men. There was no difference in mortality risk at 30 days (female-to-male OR = 1.00 [0.69-1.46]); however, at follow-up completion (∼2 years post-TAVR), women had a 24% lower mortality risk than men (HR = 0.76 [95% CI: 0.65-0.89]). Women also had a 30% lower risk of kidney injury at 30 days (OR = 0.70 [0.49-0.98]), which increased to 33% over the complete follow-up period (HR = 0.67 [0.51-0.87]). Major bleeding was more common in women compared to men at both 30 days (OR = 1.44 [1.19-1.76]) and long-term follow-up (HR = 1.22 [1.04-1.43]). For dichotomous outcomes, women had a 68% lower risk for reinterventions (OR = 0.32 [0.18-0.58]). We did not observe any difference in the risk of ischemic stroke, myocardial infarction, device migration, rehospitalizations, or pacemaker implantations between sexes., Conclusions: This patient-level data meta-analysis of six premarket clinical trials found that women who received TAVR had fewer comorbidities at baseline. Acute outcomes (30 day) with respect to mortality were similar. Women were observed to have a lower risk of kidney injury, but higher risk of major bleeding compared to men receiving TAVR at 30 days. At complete follow-up, statistically significant advantages for women emerged in improved survival and lower reintervention risk. No differences in ischemic stroke, pacemaker implantation, or rehospitalization were observed. That women are healthier at baseline and develop fewer postprocedural complications than men may explain their higher survival.

Objective: Accurate placement of cervical pedicle screws remains a surgical challenge. This study aimed to test the feasibility of using a novel three-dimensional (3D-)printed navigational template to overcome this challenge., Methods: Cervical spines were scanned using computed tomography (CT). A 3D model of the cervical spines was created. The screw trajectory was designed to pass through the central axis of the pedicle. Thereafter, a navigational template was designed by removing the soft tissue from the bony surface in the 3D model. A 3D printer was used to print the navigational template. The screws were then placed in the cadavers following CT scanning. The 3D model of the designed trajectory and the placed screws were registered. The coordinates of the entry and exit points of the designed trajectory and the actual trajectory were recorded. The numbers of qualified points that met the different degrees of accuracy were compared using a χ 2 test., Results: A total of 158 screws were placed. Five screws breached the pedicle cortex with a distance <2 mm. There was no significant difference between the pre- and postoperative entry points with a degree of accuracy ≥1.7 mm (P = 0.131). Meanwhile, there was no significant difference between the pre- and postoperative exit points with degrees of accuracy ≥6.4 mm (P = 0.071)., Conclusion: A navigational template can be designed by removing the soft tissue from the bony surface in a CT-generated 3D model. This guiding tool may effectively prevent intraoperative drifting and accurately places cervical pedicle screws.

Transcatheter aortic valve replacement (TAVR) is a safe and effective therapy for aortic valve replacement in patients ineligible for or at high risk for surgery. However, outcomes after TAVR based on an individual's sex remain to be fully elucidated. We searched PUBMED and EMBASE using the keywords: "transcatheter aortic valve replacement," "transcatheter aortic valve implantation," "sex differences," "gender," "sex characteristics" and collected information on baseline features, procedural characteristics, and postprocedural outcomes in women. Inclusion/exclusion resulted in 23 publications. Women had less preexisting comorbidities than men. Most studies reported better survival in women (range of hazard ratio [95% CI] = 0.27 [0.09-0.84] to 0.91 [0.75-1.10]). At 30 days, women also had more vascular complications (6-20% vs 2-14%) and higher bleeding rates (10-44% vs 8-25%). Stroke rates were similar at 30 days (women, 1-7%; men, 1-5%). This literature review showed better survival in women than men after TAVR. However, women had more vascular complications and bleeding; stroke rates were similar. These findings may partly be explained by fewer baseline comorbidities in women. These results should be interpreted with caution as most measures only include unadjusted percentages.

Purpose: To develop and validate the efficacy and accuracy of a three-dimensional (3D) computed tomography (CT) reconstructive rapid prototyping drill template for cervical pedicle screw placement., Methods: CT thin-layer scans were obtained from 12 adult cadaveric cervical specimens and reconstructed. The ideal screw channels were chosen by analyzing the cross sections of the reconstructed 3D images. The navigation templates were designed and printed based on the optimal screw channels. The pedicle screws were placed on the cadaver specimens under template guidance, and the cadaver specimens were scanned and reconstructed. The pre- and post-operative models were compared. Entry point and exit point data of these two models were collected and compared using the Chi-square test., Results: A total of 164 cervical pedicle screws were placed; among them, six punctured the cortical bone of the vertebral pedicle reaching an accuracy of 96.3%. Among the outside screws, all of the deviation distances were <2 mm. The Chi-square test results showed that when a deviation of 1.2 mm was used as a standard for the entry point, there was no difference between the two groups (χ 2  = 1.346, p = 0.248); when a deviation of 2.2 mm was used as a standard for the exit point, there was no difference between the two groups (χ 2  = 3.250, p = 0.061)., Conclusion: The 3D CT reconstructive rapid prototyping drill template combined with the screw tunnel design based on 3D cutting technique can help facilitate accurate cervical pedicle screw insertion.

Objective: To investigate the feasibility of the use of 3D-printed guiding templates for accurate placement of plates and screws for internal fixation of acetabular fractures., Methods: 3D models of the pelvises of 14 adult cadavers were reconstructed using computed tomography (CT). Twenty-eight acetabular fractures were simulated and placement positions for plates and screw trajectories were designed. Bending module was obtained by 3D cutting; guiding template was manufactured using 3D printing, and the plate was pre-bent according to the bending module. Plates and screws were placed in cadaveric pelvises using the guiding template, and 3D model was reconstructed using CT. The designed and real trajectories were matched using 3D registration including the coordinates (entry and exit points) of designed trajectory. The number of qualified points with different accuracy levels was compared using Chi-squared test., Results: Sixty-four plates and 339 screws were placed with no cortical breach. The absolute difference of the X, Y, and Z coordinates between the designed and real entry points were 0.52±0.45, 0.43±0.36, and 0.53±0.44mm, respectively. The corresponding values for the exit points were 0.83±0.67, 1.22±0.87, and 1.26±0.83mm, respectively. With an accuracy degree ≥1.9mm for the entry points and ≥3.8mm for the exit points, there was no significant difference between the designed and the real trajectories., Conclusion: The 3D-printed guiding template helped achieve accurate placement of plates and screws in the pelvis of adult cadavers., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A finite element model was used to compare the biomechanical properties of a novel anterior transpedicular screw artificial vertebral body system (AVBS) with a conventional anterior screw plate system (ASPS) for fixation in the lower cervical spine. A model of the intact cervical spine (C3-C7) was established. AVBS or ASPS constructs were implanted between C4 and C6. The models were loaded in three-dimensional (3D) motion. The Von Mises stress distribution in the internal fixators was evaluated, as well as the range of motion (ROM) and facet joint force. The models were generated and analyzed by mimics, geomagic studio, and ansys software. The intact model of the lower cervical spine consisted of 286,382 elements. The model was validated against previously reported cadaveric experimental data. In the ASPS model, stress was concentrated at the connection between the screw and plate and the connection between the titanium mesh and adjacent vertebral body. In the AVBS model, stress was evenly distributed. Compared to the intact cervical spine model, the ROM of the whole specimen after fixation with both constructs is decreased by approximately 3 deg. ROM of adjacent segments is increased by approximately 5 deg. Facet joint force of the ASPS and AVBS models was higher than those of the intact cervical spine model, especially in extension and lateral bending. AVBS fixation represents a novel reconstruction approach for the lower cervical spine. AVBS provides better stability and lower risk for internal fixator failure compared with traditional ASPS fixation.

Objective: To explore the feasibility and the effectiveness of the accurate placement of lumbar pedicle screws using three-dimensional (3D) printing navigational templates in Quadrant minimally invasive system., Methods: The L 1-5 spines of 12 adult cadavers were scanned using CT. The 3D models of the lumbar spines were established. The screw trajectory was designed to pass through the central axis of the pedicle by using Mimics software. The navigational template was designed and 3D-printed according to the bony surface where the soft tissues could be removed. The placed screws were scanned using CT to create the 3D model again after operation. The 3D models of the designed trajectory and the placed screws were registered to evaluate the placed screws coincidence rate. Between November 2014 and November 2015, 31 patients with lumbar instability accepted surgery assisted with 3D-printing navigation module under Quadrant minimally invasive system. There were 14 males and 17 females, aged from 42 to 60 years, with an average of 45.2 years. The disease duration was 6-13 months (mean, 8.8 months). Single segment was involved in 15 cases, two segments in 13 cases, and three segments in 3 cases. Preoperative visual analogue scale (VAS) was 7.59±1.04; Oswestry disability index (ODI) was 76.21±5.82; and the Japanese Orthopaedic Association (JOA) score was 9.21±1.64., Results: A total of 120 screws were placed in 12 cadavers specimens. The coincidence rate of placed screw was 100%. A total of 162 screws were implanted in 31 patients. The operation time was 65-147 minutes (mean, 102.23 minutes); the intraoperative blood loss was 50-116 mL (mean, 78.20 mL); and the intraoperative radiation exposure time was 8-54 seconds (mean, 42 seconds). At 3-7 days after operation, CT showed that the coincidence rate of the placed screws was 98.15% (159/162). At 4 weeks after operation, VAS, ODI, and JOA score were 2.24±0.80, 29.17±2.50, and 23.43±1.14 respectively, showing significant differences when compared with preoperative ones ( t =14.842, P =0.006; t =36.927, P =0.002; t =-36.031, P =0.001). Thirty-one patients were followed up 8-24 months (mean, 18.7 months). All incision healed by first intention, and no complication occurred. During the follow-up, X-ray film and CT showed that pedicle screw was accurately placed without loosening or breakage, and with good fusion of intervertebral bone graft., Conclusion: 3D-printing navigational templates in Quadrant minimally invasive system can help lumbar surgery gain minimal invasion, less radiation, and accurate placement.

Although generally manufactured as circular devices with symmetric leaflets, transcatheter heart valves can become non-circular post-implantation, the impact of which on the long-term durability of the device is unclear. We investigated the effects of five non-circular (EllipMajor, EllipMinor, D-Shape, TriVertex, TriSides) annular configurations on valve leaflet stresses and valve leaflet deformations through finite element analysis. The highest in-plane principal stresses and strains were observed under an elliptical configuration with an aspect ratio of 1.25 where one of the commissures was on the minor axis of the ellipse. In this elliptical configuration (EllipMinor), the maximum principal stress increased 218% and the maximum principal strain increased 80% as compared with those in the circular configuration, and occurred along the free edge of the leaflet whose commissures were not on the minor axis (i.e., the "stretched" leaflet). The D-Shape configuration was similar to this elliptical configuration, with the degree to which the leaflets were stretched or sagging being less than the EllipMinor configuration. The TriVertex and TriSides configurations had similar leaflet deformation patterns in all three leaflets and similar to the Circular configuration. In the D-Shape, TriVertex, and TriSides configurations, the maximum principal stress was located near the commissures similar to the Circular configuration. In the EllipMinor and EllipMajor configurations, the maximum principal stress occurred near the center of the free edge of the "stretched" leaflets. These results further affirm recommendations by the International Standards Organization (ISO) that pre-clinical testing should consider non-circular configurations for transcatheter valve durability testing.

Objective: To study the method of internal fixation by the navigation embedded plate from standard parts database for the distal femoral fractures based on digital design by Mimics software with 3D printing technology, and to explore its feasibility and accuracy., Methods: A total of 21 cases with distal femoral fractures admitted into the Department of Orthopedics, Affiliated Hospital of Putian University were included in this study. Dicom format data of lamellar CT scanning was imported into Mimics software for 3D anatomical modeling and virtual fracture reduction. The steel plates was chose from standard parts database for virtual internal fixation, and to design the navigation module with screw. 3D printing skeleton, steel plates, navigation module, internal fixation implants were simulated based on the printed bones model. Locations of steel plates and screws were determined by the navigation module. Then the sticking effects of navigation module, screws position and postoperative appearance were observed. After second CT scan and 3D reconstruction, 3D registration was performed to obtain the data of the three-dimensional coordinate values of screws entrance points and piercing points to analyze the results., Results: A total of 21 plates and 180 screws were placed with the assistance of navigation module. CT scanning and 3D reconstruction was performed in twenty-one cases of postoperative bone model. The position of plates was in high accordance with the digital design by Mimics software. There were no significant differences between spatial location of screw entrance points and piercing points. The real operation was quite consistent with preoperative design. Navigation module and the corresponding distal femur bony structure jointed closely. The sticking effects and stability of navigation module were good, which was able to guide placement of steel plates and screws., Conclusion: These methods can enhance the accuracy of internal fixation of the standard parts database steel plate in distal femur fractures, with the assistance of navigation module.

Objective: To explore the method and feasibility of digital internal fixation for proximal tibia fractures using standard parts database and three-dimensional (3D) printing technology., Methods: Ten adult lower extremity specimens were selected to take continuously thin-layer scanning. After Dicom image was imported into the Mimics software, the model of Schatzker II-VI types proximal tibia fracture was established, 2 cases each type. The virtual internal fixation was performed with plate and screw from standard parts database. The pilot hole of the navigation module design was printed by 3D printing technique. The plate and screw were inserted by the navigation module. X-ray film and CT were taken postoperatively to observe the position. Thirty patients with proximal tibia fracture underwent digital internal fixation using standard parts database and 3D printing technology (study group), and another 30 patients underwent traditional open reduction and internal fixation (control group). There was no significant difference in sex, age, side, causes, fracture classification, associated injury, and course of disease between 2 groups (P > 0.05). The preparative time, incision length, fracture healing time, operation time, and intraoperative blood loss were recorded. Follow up of imaging evaluation, clinical efficacy was evaluated by MacNab criteria., Results: The navigation models were designed to fit the bony structure of proximal tibia and to guide implant insertion. The parameters of orientation, length, diameter, and angle were consistent with the preoperative plan. No statistically significant difference was found in the preparative times of pre-operation between 2 groups (t = 1.393, P = 0.169). The incision length, wound healing time, blood loss, operation time, and the cost of treatment in study group were significantly less than those in control group (P < 0.05). All patients were followed up 12-16 months (mean, 13.5 months). The fracture healing time of study group was significantly shorter than that of control group (t = 4.070, P = 0.000). At 12 months postoperatively, there was no significant difference in the efficacy based on MacNab criteria between 2 groups (U = 377.000, P = 0.238)., Conclusion: Digital internal fixation for proximal tibia fractures using standard parts database and 3D printing technology has the advantages of short process, less blood loss, high safety and rapid fracture healing.

Study Design: Biomechanical in vitro study., Objective: To determine whether the peak pull-out force (PPF) of cervical anterior transpedicular screw (ATPS) fixed in osteoporotic vertebrae positively influence screw stability or not before and after fatigue., Summary of Background Data: Multilevel cervical spine procedures with osteoporosis can challenge the stability of current screw-and-plate systems. A second surgical posterior approach is coupled with potential risks of increased morbidity and complications. Hence, anterior cervical instrumentation that increases primary construct stability, while avoiding the need for posterior augmentation, would be valuable., Methods: Sixty formalin-fixed vertebrae at different levels were randomly selected. The vertebrae were divided into healthy controls (groups A1, A2), osteoporotic controls (B1, B2), healthy ATPS groups (C1, C2), osteoporotic ATPS groups (D1, D2), and osteoporotic restoration controls (E1, E2). The procedure of ATPS insertion was simulated with 2 pilot holes being drilled on each side of 20 vertebral bodies that were implanted with either vertebral screw or polymethylmethacrylate. Each side randomly received either instant PPF or PPF beyond fatigue (2.5 Hz; 20,000 times)., Results: The prefatigue PPFs were significantly higher than the postfatigue PPFs in all groups (group A: 366.06 ± 58.78 vs. 248.93 ± 57.21 N; group B: 275.58 ± 23.18 vs. 142.79 ± 44.78 N; group C: 635.99 ± 185.28 vs. 542.57 ± 136.58 N; group D: 519.22 ± 122.12 vs. 393.16 ± 192.07 N, and group E: 431.78 ± 75.77 vs. 325.74 ± 95.10 N). The postfatigue PPFs were reduced by 32.00% (group A), 48.19% (group B), 14.69% (group C), 24.28% (group D), and 24.72% (group E). The acute and postfatigue PPFs of both control groups were significantly lower than that of ATPS groups (P < 0.05). The cyclic osteoporosis ATPS group achieved the same PPF compared with the vertebral restoration screw group., Conclusion: The findings of this study suggest that instant PPF and fatigue resistance capability of an ATPS fixation were significantly better than other control groups, especially in the osteoporotic vertebrae.

To assess the short-term outcome of unilateral pedicle screw fixed intervertebral fusion surgery for degenerative disc disease via MAST QUADRANT minimally invasive system. Thirty patients with degenerative lumbar disease from September 2009 to September 2011 were enrolled and divided into two groups: (1) unilateral pedicle screw fixed intervertebral fusion via MAST QUADRANT system; and (2) conventional bilateral pedicle fixed intervertebral fusion via open surgery. The perioperative parameters (operation time, intraoperative blood loss, and length of stay) and the follow-up clinical curative effect parameters (VAS and ODI) were compared between two groups. All patients successfully completed surgery and were followed up for more than 1 year. The perioperative parameters of MAST QUADRANT system group were significantly better than the control group (P < 0.05). And the clinical curative effects were similar to conventional surgery (P > 0.05). Unilateral pedicle screw fixed intervertebral fusion via MAST QUADRANT system is a less invasive and safer surgical techniques. It offers a quick recovery and effective surgical option in the treatment of lumbar degenerative diseases.

The objective of this study is to evaluate the relationship between the g.27450A>T genetic variant of osteoprotegerin (OPG) gene and osteoporosis in Chinese postmenopausal women. A total of 886 subjects were enrolled in this study. The femoral neck hip, lumbar spine (L2-4), and total hip bone mineral density (BMD) were detected by dual-energy X-ray absorptiometry (DEXA). The genotyping of the g.27450A>T genetic variant of OPG gene was investigated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. Significant differences in the femoral neck hip, lumbar spine (L2-4), and total hip BMD among different genotypes were found, and the subjects with AA genotype were significantly higher than those of AT and TT genotypes (P<0.05). The allele-A could be a decreased risk factor for osteoporosis. Results from this study support that the g.27450A>T genetic variant of OPG gene has potential relationship with BMD and osteoporosis in Chinese postmenopausal women., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Study Design: An experimental study., Objective: To compare the peak pull-out force (PPF) of vertebral screws fixed in osteoporotic vertebrae versus polymethylmethacrylate (PMMA) used for augmentation or restoration, before and after fatigue., Summary of Background Data: Failure of screw fixation in anterior cervical interbody fusion remains a significant clinical problem. However, little is known of the biomechanical characteristics of cervical vertebral screws before and after restoration or augmentation, especially after fatigue., Methods: Fifty fresh cervical vertebrae, of which 40 were randomly selected, from 12 adult cadavers were used. The vertebrae were divided into healthy controls, osteoporotic controls, a PMMA restoration group, and a PMMA augmentation group. In each of the control groups, 2 pilot holes on each side of 20 vertebral bodies were implanted with vertebral screws (4 mm in diameter). Each side randomly received either acute PPF or PPF beyond fatigue that was ensured using cyclic loading (2 Hz; 20,000 times). In the PMMA groups, pilot holes were drilled parallel to the sagittal plane and injected with 0.6-1.0 mL PMMA before the vertebral screw was inserted. Each side of each vertebral body randomly received either PPF or PPF beyond fatigue that was ensured using cyclic loading (2 Hz; 20,000 times). A Bose3510-AT fatigue testing machine measured the PPF of vertebral screws with or without PMMA for all specimens before and after fatigue., Results: In all groups, the prefatigue PPF was significantly higher than the postfatigue PPF. Compared with the prefatigue PPF, postfatigue PPF was reduced by 37.40%, 43.10%, 32.08%, and 31.85% in the healthy controls, osteoporotic controls, PMMA restoration, and PMMA augmentation groups, respectively. The acute and postfatigue PPFs of the healthy controls were significantly higher from that of the osteoporotic controls. The acute and postfatigue PPFs of both control groups were significantly lower from that of both PMMA groups. There was no difference in acute and postfatigue PPFs between the PMMA restoration and augmentation groups., Conclusions: The results indicated that both PMMA augmentation and PMMA restoration could significantly increase cervical screw pull-out strength and antifatigue capability. The results provide a biomechanical justification for spine surgeons to use PMMA for augmentation or restoration in cases of surgeries with poor bone quality or osteoporotic vertebral bodies.

Background: Accurate placement of pedicle screw during Anterior Transpedicular Screw fixation (ATPS) in cervical spine depends on accurate anatomical knowledge of the vertebrae. However, little is known of the morphometric characteristics of cervical vertebrae in Chinese population., Methods: Three-dimensional reconstructions of CT images were performed for 80 cases. The anatomic data and screw fixation parameters for ATPS fixation were measured using the Mimics software., Findings: The overall mean OPW, OPH and PAL ranged from 5.81 to 7.49 mm, 7.77 to 8.69 mm, and 33.40 to 31.13 mm separately, and SPA was 93.54 to 109.36 degrees from C3 to C6, 104.99 degrees at C7, whereas, 49.00 to 32.26 degrees from C4 to C7, 46.79 degrees at C3 (TPA). Dl/rSIP had an increasing trend away from upper endplate with mean value from 1.87 to 5.83 mm. Dl/rTIP was located at the lateral portion of the anterior cortex of vertebrae for C3 to C5 and ipsilateral for C6 to C7 with mean value from -2.70 to -3.00 mm, and 0.17 to 3.18 mm. The entrance points for pedicular screw insertion for C3 to C5 and C6 to C7 were recommended -2∼-3 mm and 0-4 mm from the median sagittal plane, respectively, 1-4 mm and 5-6 mm from the upper endplate, with TPA being 46.79-49.00 degrees and 40.89-32.26 degrees, respectively, and SPA being 93.54-106.69 degrees and 109.36-104.99 degrees, respectively. The pedicle screw insertion diameter was recommended 3.5 mm (C3 and C4), 4.0 mm (C5 to C7), and the pedicle axial length was 21-24 mm for C3 to C7 for both genders. However, the ATPS insertion in C3 should be individualized given its relatively small anatomical dimensions., Conclusions: The data provided a morphometric basis for the ATPS fixation technique in lower cervical fixation. It will help in preoperative planning and execution of this surgery.

Objective: To compare the biomechanical properties of the anterior transpedicular screw-artificial vertebral body (AVB) and conventional anterior screw plate system (AP) in lower cervical spine by finite element study., Methods: CT images (C1-T1) were obtained from a 38-year-old female volunteer. The models of intact C(3-7) (intact group), AP fixation (AP group), and AVB fixation (AVB group) were established and analyzed by Mimics 14.0, Geomagic Studio 2013, and ANSYS 14.0 softwares. The axial force of 74 N and moment couple of 1 N x m were loaded on the upper surface and upper facet joint surfaces of C3. Under conditions of flexion, extension, lateral bending, and rotation, the Von Mises stress distribution regularity and maximum equivalent stree of AP and AVB groups were recorded, and the range of motion (ROM) was also analyzed of 3 groups., Results: The intact model of lower cervical spine (C(3-7)) was established, consisting of 286,382 elements and 414,522 nodes, and it was successfully validated with the previously reported cadaveric experimental data of Panjabi and Kallemeyn. The stress concentrated on the connection between plate and screw in AP group, while it distributed evenly in AVB group. Between AP and AVB groups, there was significant difference in maximum equivalent stress values under conditions of 74 N axial force, flexion, extension, and rotation. AVB group had smaller ROM of fixed segments and larger ROM of adjacent segments than AP group. Compared with intact group, whole ROM of the lower cervical spine decreased about 3 degrees, but ROM of C(3,4) and C(6,7) segments increased nearly 5 degrees in both AP and AVB groups., Conclusion: As a new reconstruction method of lower cervical spine, AVB fixation provides better stability and lower risk of failure than AP fixation.

The serine/threonine kinase Pim-1 was recently identified as a cardiomyocyte survival regulator downstream of Akt. The present study aims to examine Pim-1 activity and its association with the post MI remodeling myocardium in a clinically relevant large animal model. Apical myocardial infarction of approximately 25% left ventricular mass was created in an ovine model. Regional post-infarction deformation of the left ventricle was monitored by sonomicrometry and quantified using areal remodeling strain (i.e., areal expansion). Myocardial tissues were harvested at 12weeks from the adjacent and remote regions of the infarct for analysis of Pim-1 mediated survival signaling proteins as well as apoptotic activity. The cDNA coding sequences of two ovine Pim-1 kinase isoforms, 44 and 33kDa, were identified. Both isoforms were detected in heart tissue and the overall Pim-1 expression was found to be tightly controlled at multiple molecular levels. Pim-1 as well as the Pim-1 mediated survival signaling proteins Bcl-2, Bcl-xL, and phospho-Bad (Ser112) were upregulated in the adjacent region at 12weeks post-infarction and their expression correlated positively with the degree of the remodeling, which was accompanied by significant upregulations of the PP2A/BAD mediated apoptotic signaling proteins. However these upregulations were imbalanced, such that p-BAD (Ser112)/BAD decreased in the adjacent region of the infarcted hearts. Apoptotic activity also increased with remodeling strain. Despite an observed intrinsic upregulation of survival proteins, the imbalanced activation of apoptotic pathways resulted in evident apoptosis in the adjacent region., Ultramini-Abstract: Pim-1 mediated survival signaling in myocardial tissues from infarcted ovine hearts was studied. It was shown that the adjacent region of the infarct experienced higher remodeling strain and exhibited increased levels of Pim-1 and related anti-apoptotic proteins. Despite this elevation of survival activity, however, the imbalanced activation of PP2A/BAD mediated apoptotic pathway resulted in evident apoptosis in the adjacent region., (© 2013.)

Background: The underlying molecular mechanisms of the remodeling after myocardial infarction (MI) remain unclear. The purpose of this study was to investigate the role of a survival pathway (PI3K/Akt) and an apoptosis pathway (calcineurin/BAD) in the remodeling after MI in a large animal model., Methods: Ten Dorset hybrid sheep underwent 25% MI in the left ventricle (LV, n=10). Five sheep were used as sham control. The regional strain was calculated from sonomicrometry. Apoptosis and the activation of the PI3K/Akt and calcineurin/BAD pathways were evaluated in the non-ischemic adjacent zone and the remote zone relative to infarct by immunoblotting, immunoprecipitation, and immunofluorescence staining., Results: Dilation and dysfunction of LV were present at 12 weeks after MI. The regional strain in the adjacent zone was significantly higher than in the remote zone at 12 weeks (36.6 ± 4.0% vs 9.5 ± 3.6%, p<0.05). Apoptosis was more severe in the adjacent zone than in the remote zone. The PI3K/Akt and calcineurin/BAD pathways were activated in the adjacent zone. Dephosphorylation and translocation of BAD were evident in the adjacent zone. Regional correlation between the strain and the expression of calcineurin/BAD indicated that the activation was strain-related (R(2)=0.46, 0.48, 0.39 for calcineurin, BAD, mitochondrial BAD, respectively, p<0.05)., Conclusions: The PI3K/Akt survival and calcineurin/BAD apoptotic pathways were concomitantly activated in the non-ischemic adjacent zone after MI. The calcineurin/BAD pathway is strain related and its imbalanced activation may be one of the causes of progressive remodeling after MI., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Objectives: This study sought to demonstrate that short-term cardiac unloading with a left ventricular (LV) assist device (LVAD) after acute myocardial infarction (MI) can conserve calcium cycling and improve heart function., Background: Heart failure secondary to MI remains a major source of morbidity and mortality. Alterations in calcium cycling are linked to cardiac dysfunction in the failing heart., Methods: Adult Dorsett hybrid sheep underwent acute MI and were mechanically unloaded with an axial-flow LVAD (Impella 5.0) for 2 weeks (n = 6). Six sheep with MI only and 4 sham sheep were used as controls. All animals were followed for 12 weeks post-MI. Regional strains in the LV were measured by sonomicrometry. Major calcium-handling proteins (CHPs), including sarco-/endoplasmic reticulum calcium ATPase-2α (SERCA-2α), Na(+)-Ca(2+) exchanger-1, and phospholamban, and Ca(2+)-ATPase activity were investigated. The electrophysiological calcium cycling in single isolated cardiomyocytes was measured with the patch-clamp technique. The related ultrastructures were studied with electron microscopy., Results: LVAD unloading alleviated LV dilation and improved global cardiac function and regional contractility compared with the MI group. The regional myocardial strain (stretch) was minimized during the unloading period and even attenuated compared with the MI group at 12 weeks. Impaired calcium cycling was evident in the adjacent noninfarcted zone in the MI group, whereas CHP expression was normalized and Ca(2+)-ATPase activity was preserved in the LVAD unloading group. The electrophysiological calcium cycling was also conserved, and the ultrastructural damage was ameliorated in the unloaded animals., Conclusions: Short-term LVAD unloading may conserve calcium cycling and improve heart function during the post-infarct period., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Hemolysis caused by flow-induced mechanical damage to red blood cells is still a problem in medical devices such as ventricular assist devices (VADs), artificial lungs, and mechanical heart valves. A number of different models have been proposed by different research groups for calculating the hemolysis, and of these, the power law-based models (HI(%)=Ct(α)τ(β)) have proved the most popular because of their ease of use and applicability to a wide range of devices. However, within this power law category of models there are a number of different implementations. The aim of this work was to evaluate different power law-based models by calculating hemolysis in a specifically designed shearing device and a clinical VAD, and comparing the estimated results with experimental measurements of the hemolysis in these two devices. Both the Eulerian scalar transport and all the Lagrangian models had fairly large percentage of errors compared with the experiments (minimum Eulerian 91% and minimum Lagrangian 57%) showing they could not accurately predict the magnitude of the hemolysis. However, the Eulerian approach had large correlation coefficients (>0.99) showing that this method can predict relative hemolysis, which would be useful in comparative analysis, for example, for ranking different devices or for design optimization studies.

An understanding of the load transfer within spinal posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant such as artificial intervertebral disc and the dynamic spine stabilization systems. In this study, a new method has been developed for evaluating the load bearing of spinal posterior column by the surface strain of spinal pedicle response to the loading of spinal segment. Six cadaveric lumbar spine segments were biomechanically evaluated between levels L1 and L5 in intact condition and the strain gauges were pasted to an inferior surface of L2 pedicles. Multidirectional flexibility testing used the Panjabi testing protocol; pure moments for the intact condition with overall spinal motion and unconstrained intact moments of ±8 Nm were used for flexion-extension and lateral bending testing. High correlation coefficient (0.967-0.998) indicated a good agreement between the load of spinal segment and the surface strain of pedicle in all loading directions. Principal compressive strain could be observed in flexion direction and tensile strain in extension direction, respectively. In conclusion, the new method seems to be effective for evaluating posterior spinal column loads using pedicles' surface strain data collected during biomechanical testing of spine segments.

Objective: To evaluate the effect of polymethylmethacrylate (PMMA) augmentation on cervical stability after anterior cervical interbody fusion (ACIF) before and after fatigue., Methods: Twelve porcine cervical spines (C3-7) were subjected to testing angular displacement parameters, including the range of motion (ROM), neutral zone (NZ), and elastic zone (EZ), in nondestructive flexion and extension, right/left lateral bending, and left/right rotation on Motion Analysis motion capture system and MTS-858 servo-hydraulic testing machine. Intact cervical spines served as control group (group A); one-level discectomy and fusion was performed with anterior plate fixation based on group A as group B; flexion and extension, left/right lateral bending (5 000 cycles) fatigue testing based on group B as group C; the augmentation screw channel was used based on group C as group D; and flexion and extension, left/right lateral bending fatigue testing were performed based on group D as group E., Results: The ROM, NZ, and EZ in group A were significantly different from those in other groups (P < 0.05) at flexion/extension, left/right bending, and left/right rotation. The ROM, NZ, and EZ in group B were significantly smaller than those in group C (P < 0.05) in flexion/extension, left/right bending, and left/right rotation, but there was no significant difference when compared with group D (P > 0.05). The ROM and NZ in flexion/extension and the EZ in flexion in group B were significant smaller than those in group E (P < 0.05), but there was no significant difference in the other indexes (P > 0.05). The ROM, NZ, and EZ in group C in flexion and extension, left/right lateral bending, and left/right rotation were significantly higher than those in groups D and E (P < 0.05). The ROM and NZ in flexion and extension and left/right lateral bending, and the ROM in left/right rotation, and the EZ in flexion and extension, right bending, and left/right rotation in group D were significantly smaller than those in group E (P < 0.05), but there was no significant difference in the other indexes (P > 0.05)., Conclusion: PMMA augmentation can significantly increase the instant cervical stability and provide a biomechanics basis in cervical anterior plate fixation.

Submission of data regarding the cavitation potential of a mechanical heart valve is recommended by the U.S. Food and Drug Administration in the device-review process. An acoustic method has long been proposed for cavitation detection. However, the question as to whether such a method can differentiate the cavitation noise from the mechanical closing sound has not been sufficiently addressed. In this study, cavitation near a Medtronic Hall tilting disc valve was investigated in a pressurized pulsatile duplicator. The purpose of pressurizing the testing chambers was to prevent cavitation under a normally cavitating loading condition to isolate the mechanical closing sound. By comparing the sound signals before and after pressurization, some noticeable differences were found between them. In the time domain, the intensity of the sound under a cavitating condition was much higher. In the frequency domain, the energy distribution of a sound signal was distinctively different depending on whether cavitation occurred or not. The valve closing sound had a large amount of energy in the low-frequency range (less than about 25 kHz). When cavitation took place, the sound energy shifted toward the high-frequency range (from 25 to 500 kHz).

The two functional bundles of the anterior cruciate ligament (ACL), namely, the anteromedial (AM) and posterolateral (PL) bundles, must work in concert to control displacement of the tibia relative to the femur for complex motions. Thus, the replacement graft(s) for a torn ACL should possess similar tension patterns. The objective of the study was to examine whether a double-bundle ACL reconstruction with the semitendinosus-gracilis autografts could replicate the tension patterns of those for the intact ACL under controlled in vitro loading conditions. By means of a robotic/universal force moment sensor (UFS) testing system, the in situ force vectors (both magnitude and direction) for the AM and PL bundles of the ACL, as well as their respective replacement grafts, were determined and compared on nine human cadaveric knees. It was found that double-bundle ACL reconstruction could closely replicate the in situ force vectors. Under a 134-N anterior tibial load, the resultant force vectors for the intact ACL and the reconstructed ACL had a difference of 5 to 11 N (p > 0.05) in magnitude and 1 to 13 degrees (p > 0.05) in direction. Whereas, under combined rotatory loads of 10-N-m valgus and 5-N-m internal tibial torques, the corresponding differences were 10 to 16 N and 4 degrees to 11 degrees, respectively. Again, there were no statistically significant differences except at 30 degrees of flexion where the force vector for the AM graft had a 15 degrees (p < 0.05) lower elevation angle than did the AM bundle.

The porcine small intestine submucosa, an extracellular matrix-derived bioscaffold (ECM-SIS), has been successfully used to enhance the healing of ligaments and tendons. Since the collagen fibers of ECM-SIS have an orientation of +/- 30 degrees , its application in improving the healing of the parallel-fibered ligament and tendon may not be optimal. Therefore, the objective was to improve the collagen fiber alignment of ECM-SIS in vitro with fibroblast seeding and cyclic stretch. The hypothesis was that with the synergistic effects of cell seeding and mechanical stimuli, the collagen fibers in the ECM-SIS can be remodeled and aligned, making it an improved bioscaffold with enhanced conductive properties. Three experimental groups were established: group I (n = 14), ECM-SIS was seeded with fibroblasts and cyclically stretched; group II (n = 13), ECM-SIS was seeded with fibroblasts but not cyclically stretched; and group III (n = 8), ECM-SIS was not seeded with fibroblasts but cyclically stretched. After 5 days' experiments, the scaffolds from all the three groups (n = 9 for group I; n = 8 for groups II and III) were processed for quantification of the collagen fiber orientation with a small-angle light scattering (SALS) system. For groups I and II, in which the scaffolds were seeded with fibroblasts, the cell morphology and orientation and newly produced collagen fibrils were examined with confocal fluorescent microscopy (n = 3/group) and transmission electronic microscopy (n = 2/group). The results revealed that the collagen fiber orientation in group I was more aligned closer to the stretching direction when compared to the other two groups. The mean angle decreased from 25.3 degrees to 7.1 degrees (p < 0.05), and the associated angular dispersion was also reduced (37.4 degrees vs. 18.5 degrees , p < 0.05). In contrast, groups II and III demonstrated minimal changes. The cells in group I were more aligned in the stretching direction than those in group II. Newly produced collagen fibrils could be observed along the cells in both groups I and II. This study demonstrated that a combination of fibroblast seeding and cyclic stretch could remodel and align the collagen fiber orientation in ECM-SIS bioscaffolds. The better-aligned ECM-SIS has the prospect of eliciting improved effects on enhancing the healing of ligaments and tendons.

Objective: More than 200,000 aortic valve replacements are performed annually worldwide. We describe changes in the aortic valve replacement population during 10 years in a large registry and analyze outcomes., Methods: The Society of Thoracic Surgeons National Database was queried for all isolated aortic valve replacements between January 1, 1997, and December 31, 2006. After exclusion for endocarditis and missing age or sex data, 108,687 isolated aortic valve replacements were analyzed. Time-related trends were assessed by comparing distributions of risk factors, valve types, and outcomes in 1997 versus 2006. Differences in case mix were summarized by comparing average predicted mortality risks with a logistic regression model. Differences across subgroups and time were assessed., Results: There was a dramatic shift toward use of bioprosthetic valves. Aortic valve replacement recipients in 2006 were older (mean age 65.9 vs 67.9 years, P < .001) with higher predicted operative mortality risk (2.75 vs 3.25, P < .001); however, observed mortality and permanent stroke rate fell (by 24% and 27%, respectively). Female sex, age older than 70 years, and ejection fraction less than 30% were all related to higher mortality, higher stroke rate and longer postoperative stay. There was a 39% reduction in mortality with preoperative renal failure., Conclusions: Morbidity and mortality of isolated aortic valve replacement have fallen, despite gradual increases in patient age and overall risk profile. There has been a shift toward bioprostheses. Women, patients older than 70 years, and patients with ejection fraction less than 30% have worse outcomes for mortality, stroke, and postoperative stay.

The anterior cruciate ligament (ACL) is commonly injured. The stress distribution in the ACL is the key for understanding its function and injury mechanism, as well as for developing optimal surgical reconstruction protocols. In this study, a three-dimensional subject-specific finite element model of human ACL was developed. Bony geometries were reconstructed from CT scan images, while the geometry of the ACL and the orientation of its fiber bundles were measured via a mechanical digitizer. A transversely isotropic, hyperelastic, and nearly incompressible constitutive model was implemented to describe the mechanical properties of the ACL. A 134N anterior tibial load were applied to a cadaveric knee specimen at full extension, 30 degrees , and 60 degrees of flexion by a 6-DOF Robotic/Universal Force-moment Sensor (UFS) system, which was also used to measure the ACL resultant force. Knee kinematics was collected by digitizing two registration blocks attached to the femur and the tibia, respectively, and was input into the FE model as boundary conditions. The resultant force of the ACL calculated by the FE model was comparable to the experimental data, with the error within 10%, thus validated the model. The FE results showed that the average stress in the ACL was between the range 4.7-5.0MPa, with a peak stress between the range 9.8-10.9MPa, which shifted from the posterior lateral (PL) bundle to the anterior medial (AM) bundle as the knee flexed.

The anterior cruciate ligament (ACL) has irregular geometry and spirally oriented fiber bundle organization, which are closely related to its physiological function. In previous finite element (FE) models, however, these two features are neglected due to the difficulty of obtaining its complex geometry and spiral fiber bundle orientation. Based on a previously developed and validated FE model, this study performed parametric studies to evaluate the effects of geometry and fiber bundle orientation on the FE modeling of the ACL. To evaluate the effect of the geometry, two models were compared: 1) with realistic ACL geometry obtained by using digitizer; 2) with ACL geometry reconstructed by directly connecting the femur and tibia insertion sites as commonly used in previous studies. To evaluate the effect of fiber bundle orientation, another two models were compared: 1) with realistic fiber bundle orientation obtained by using digitizer (alpha=38 degrees ); 2) with unrealistic fiber bundle orientation (alpha=0 degrees ). The same kinematics obtained by a Robotic/Universal Force-moment Sensor (UFS) system was input into the models as boundary conditions. The resultant forces calculated by the models were compared to the experimental data. The model with unrealistic geometry had a 40% higher ACL resultant force compared to the experimental data, while the model with the realistic ACL geometry well predicted the ACL resultant force, with an error less than 10%. When evaluating the effect of fiber bundle orientation, the model with unrealistic fiber bundle orientation predicted similar ACL resultant forces and stress distribution as the model with realistic fiber bundle orientation. The results revealed that ACL geometry has a significant effect on the FE model while fiber orientation does not.