The critical size of a defect in the glenoid causing anterior instability of the shoulder after a Bankart repair, under physiological joint loading

2019 ◽  
Vol 101-B (1) ◽  
pp. 68-74 ◽  
Author(s):  
C. Klemt ◽  
D. Toderita ◽  
D. Nolte ◽  
E. Di Federico ◽  
P. Reilly ◽  
...  
Keyword(s):  
Bone Grafting ◽  
Critical Size ◽  
Computational Study ◽  
Bankart Repair ◽  
Anterior Dislocation ◽  
Loading Conditions ◽  
Anterior Instability ◽  
Physiological Loading ◽  
Osseous Defect

Aims Patients with recurrent anterior dislocation of the shoulder commonly have an anterior osseous defect of the glenoid. Once the defect reaches a critical size, stability may be restored by bone grafting. The critical size of this defect under non-physiological loading conditions has previously been identified as 20% of the length of the glenoid. As the stability of the shoulder is load-dependent, with higher joint forces leading to a loss of stability, the aim of this study was to determine the critical size of an osseous defect that leads to further anterior instability of the shoulder under physiological loading despite a Bankart repair. Patients and Methods Two finite element (FE) models were used to determine the risk of dislocation of the shoulder during 30 activities of daily living (ADLs) for the intact glenoid and after creating anterior osseous defects of increasing magnitudes. A Bankart repair was simulated for each size of defect, and the shoulder was tested under loading conditions that replicate in vivo forces during these ADLs. The critical size of a defect was defined as the smallest osseous defect that leads to dislocation. Results The FE models showed a high risk of dislocation during ADLs after a Bankart repair for anterior defects corresponding to 16% of the length of the glenoid. Conclusion This computational study suggests that bone grafting should be undertaken for an anterior osseous defect in the glenoid of more than 16% of its length rather than a solely soft-tissue procedure, in order to optimize stability by restoring the concavity of the glenoid.

Determination of Real Time In-Vivo Cartilage Contact Deformation in the Ankle Joint

2007 ◽  
Author(s):  
Guoan Li ◽  
Lu Wan ◽  
Michal Kozanek
Keyword(s):  
Computational Models ◽  
Ex Vivo ◽  
Loading Conditions ◽  
Contact Deformation ◽  
Normal Cartilage ◽  
Physiological Loading ◽  
Contact Data ◽  
Biomechanical Responses

Knowledge of in-vivo articular cartilage contact deformation is critical for understanding normal cartilage function and the etiology of osteoarthritis (2,8). This knowledge is also instrumental for design of ex-vivo experiment to investigate the chondrocyte mechanotransductions under physiological loading conditions (7). Further, in-vivo cartilage contact data is necessary for validation of 3D computational models used to predict biomechanical responses of the articular joints (1,5). However, due to the complexity of in-vivo joint loading conditions as well as the complicated joint geometry, little information is available on in-vivo cartilage deformation in literature (9). In-vivo cartilage deformation as a function of loading history has not been delineated.

scholarly journals Pore Geometry Optimization of Titanium (Ti6Al4V) Alloy, for Its Application in the Fabrication of Customized Hip Implants

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Sandipan Roy ◽  
Debojyoti Panda ◽  
Niloy Khutia ◽  
Amit Roy Chowdhury
Keyword(s):  
Mechanical Response ◽  
Geometry Optimization ◽  
Combined Loading ◽  
Hip Implants ◽  
Loading Conditions ◽  
Mechanical Responses ◽  
Porous Ti ◽  
Physiological Loading ◽  
Solid Implants

The present study investigates the mechanical response of representative volume elements of porous Ti-6Al-4V alloy, to arrive at a desired range of pore geometries that would optimize the reduction in stiffness necessary for biocompatibility with the stress concentration arising around the pore periphery, under physiological loading conditions with respect to orthopedic hip implants. A comparative study of the two is performed with the aid of a newly defined optimizing parameter called pore efficiency that takes into consideration both the stiffness quantity and the stress localization around pores. To perform a detailed analysis of the response of the porous structure over the entire spectrum of loading conditions that a hip implant is subjected toin vivo, the mechanical responses of 3D finite element models of cubic and rectangular parallelepiped geometries, with porosities varying over a range of 10% to 60%, are simulated under representative compressive, flexural as well as combined loading conditions. The results that are obtained are used to suggest a range of pore diameters that lower the effective stiffness and modulus of the implant to around 60% of the stiffness and modulus of dense solid implants while keeping the stress levels within permissible limits.

scholarly journals Open Bankart Repair: Where do We Stand Now?

2019 ◽  
Vol 7 (11_suppl6) ◽  
pp. 2325967119S0044
Author(s):  
Erica Kholinne ◽  
In-Ho Jeon
Keyword(s):  
Meta Analysis ◽  
Bankart Repair ◽  
Anterior Dislocation ◽  
Anterior Shoulder Dislocation ◽  
Anterior Instability ◽  
Shoulder Stabilization ◽  
The Past ◽  
Open Versus ◽  
Recurrent Anterior Dislocation

The operative treatment for recurrent traumatic anterior shoulder dislocation is classified as an anatomical or non-anatomical technique. The anatomical technique was first described for more than 80 years ago by Dr. Arthur. S. B. Bankart. [Table: see text] Up to date, Bankart repair still is the most common procedure performed to treat recurrent anterior dislocation of the shoulder joint with Bankart lesion, the anterior-inferior labral disruption, namely as the most common pathology observed in 85% of those patients.2 At the earlier year, many orthopedic surgeons favored the open Bankart procedure for its reliable long term follow up result. Hence, open Bankart has been historically considered the gold standard in the treatment of shoulder instability. Open Bankart repair was previously a standard care, resulting in recurrence rates below 10%.3 Advocates of open Bankart surgery argue that a more anatomic and secure repair is reliably accomplished. However, arthroscopic shoulder stabilization methods have also evolved significantly during the past 25 years. Initially, there was an early disappointment for the high failure rates for arthroscopic Bankart repair as great as 49% for its trans-glenoid suturing and 23% for its bio-absorbable tack fixation.4 However, suture anchor came or should I say “save the day” and reduce the failure rates to 8 – 11% combined with capsular plication.5 United States’s data showed that arthroscopic Bankart repairs are increasingly used, from 71.2% of all cases in 2004 to 89% in 2009.6 Given the ceiling effect of a surgical learning curve in the last decade, the recurrence and failures rate should have been substantially decreased. These numbers have led to the suggestion that, could it be that arthroscopic Bankart repair with suture anchors is our ”blue ribbon” in this “competition”? Should we say ”abandon ship” now to open Bankart repair? A recent meta-analysis of open versus arthroscopic shoulder stabilization comparing 2 recent decades (the past 20 years) demonstrated there was no significant difference in improvements achieved for clinical outcomes and external rotation deficits.7 The recurrence rate for open Bankart surgery remained resolutely consistent at 10.7% (at the past 20 years) and 10.6% (at the past 10 years). The glory of arthroscopic surgery that has been taught for generations in orthopedic surgery is the ability to recon the additional intra-articular pathology with lower surgical morbidity, improved cosmesis and decreased pain. However, the earlier one can be mostly encountered by the advanced imaging system used these days. Hence, I would like to say, open Bankart surgery is considered not a history lesson and may be worthy to revisit. References Bankart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint. British Journal of Surgery 1938; 26: 7. DOI: 10.1002/bjs.18002610104. Rowe CR, Patel D and Southmayd WW. The Bankart procedure: a long-term end-result study. J Bone Joint Surg Am 1978; 60: 1-16. 1978/01/01. Rowe CR, Zarins B and Ciullo JV. Recurrent anterior dislocation of the shoulder after surgical repair. Apparent causes of failure and treatment. J Bone Joint Surg Am 1984; 66: 159-168. 1984/02/01. Freedman KB, Smith AP, Romeo AA, et al. Open Bankart repair versus arthroscopic repair with transglenoid sutures or bioabsorbable tacks for Recurrent Anterior instability of the shoulder: a meta-analysis. Am J Sports Med 2004; 32: 1520-1527. 2004/08/18. DOI: 10.1177/0363546504265188. Brophy RH and Marx RG. The treatment of traumatic anterior instability of the shoulder: nonoperative and surgical treatment. Arthroscopy 2009; 25: 298-304. 2009/02/28. DOI: 10.1016/j.arthro.2008.12.007. Zhang AL, Montgomery SR, Ngo SS, et al. Arthroscopic versus open shoulder stabilization: current practice patterns in the United States. Arthroscopy 2014; 30: 436-443. 2014/02/25. DOI: 10.1016/j.arthro.2013.12.013. Hohmann E, Tetsworth K and Glatt V. Open versus arthroscopic surgical treatment for anterior shoulder dislocation: a comparative systematic review and meta-analysis over the past 20 years. J Shoulder Elbow Surg 2017; 26: 1873-1880. 2017/07/10. DOI: 10.1016/j.jse.2017.04.009.

scholarly journals An Extrudable Partially Demineralized Allogeneic Bone Paste Exhibits a Similar Bone Healing Capacity as the “Gold Standard” Bone Graft

2021 ◽  
Vol 9 ◽  
Author(s):  
Pierre Tournier ◽  
Jérôme Guicheux ◽  
Arnaud Paré ◽  
Joëlle Veziers ◽  
Ana Barbeito ◽  
...  
Keyword(s):  
Bone Healing ◽  
Gold Standard ◽  
Bone Grafting ◽  
Critical Size ◽  
Bone Grafts ◽  
Allogeneic Bone ◽  
Clinical Model ◽  
Critical Size Defects ◽  
Grafting Technique

Autologous bone grafts (BGs) remain the reference grafting technique in various clinical contexts of bone grafting procedures despite their numerous peri- and post-operative limitations. The use of allogeneic bone is a viable option for overcoming these limitations, as it is reliable and it has been widely utilized in various forms for decades. However, the lack of versatility of conventional allogeneic BGs (e.g., blocks, powders) limits their potential for use with irregular or hard-to-reach bone defects. In this context, a ready- and easy-to-use partially demineralized allogeneic BG in a paste form has been developed, with the aim of facilitating such bone grafting procedures. The regenerative properties of this bone paste (BP) was assessed and compared to that of a syngeneic BG in a pre-clinical model of intramembranous bone healing in critical size defects in rat calvaria. The microcomputed tridimensional quantifications and the histological observations at 7 weeks after the implantation revealed that the in vivo bone regeneration of critical-size defects (CSDs) filled with the BP was similar to syngeneic bone grafts (BGs). Thus, this ready-to-use, injectable, and moldable partially demineralized allogeneic BP, displaying equivalent bone healing capacity than the “gold standard,” may be of particular clinical relevance in the context of oral and maxillofacial bone reconstructions.

Design, Synthesis, Anticonvulsant Activity, Preclinical Study and Pharmacokinetic Performance of N-{[3-(4-chlorophenyl)-4-oxo-3, 4-dihydroquinazolin- 2-yl] methyl}, 2-[(2-isopropyl-5-methyl) 1-cyclo Hexylidene] Hydrazinecarboxamide

2019 ◽  
Vol 19 (1) ◽  
pp. 31-45
Author(s):  
Meena K. Yadav ◽  
Laxmi Tripathi
Keyword(s):  
Anticonvulsant Activity ◽  
Computational Study ◽  
Plasma Concentrations ◽  
Elimination Rate ◽  
Area Under The Curve ◽  
Preclinical Study ◽  
In Vivo Studies ◽  
Maximum Plasma ◽  
Seizure Models

Background: N-{[3-(4-chlorophenyl)-4-oxo-3, 4-dihydroquinazolin-2-yl] methyl}, 2-[(2- isopropyl-5-methyl) 1-cyclohexylidene] hydrazinecarboxamide QS11 was designed by computational study. It possessed essential pharmacophoric features for anticonvulsant activity and showed good docking with iGluRs (Kainate) glutamate receptor. Methods: QSAR and ADMET screening results suggested that QS11 would possess good potency for anticonvulsant activity. QS11 was synthesised and evaluated for its anticonvulsant activity and neurotoxicity. QS11 showed protection in strychnine, thiosemicarbazide, 4-aminopyridine and scPTZ induced seizure models and MES seizure model. QS11 showed higher ED50, TD50 and PI values as compared to the standard drugs in both MES and scPTZ screen. A high safety profile (HD50/ED50 values) was noted and hypnosis, analgesia, and anaesthesia were only observed at higher doses. No considerable increase or decrease in the concentration of liver enzymes was observed. Optimized QS11 was subjected to preclinical (in-vivo) studies and the pharmacokinetic performance of the sample was investigated. The result revealed that the pharmacokinetic performance of QS11 achieved maximum plasma concentrations (Cmax) of 0.315 ± 0.011 µg/mL at Tmax of 2.0 ± 0.13 h, area under the curve (AUC0-∞) value 4.591 ± 0.163 µg/ml x h, elimination half-life (T1/2) 6.28 ± 0.71 h and elimination rate constant was found 0.110 ± 0.013 h-1. Results and Conclusion: Above evidences indicate that QS11 could serve as a lead for development of new antiepileptic drugs.

Computational study for suppression of CD25/IL-2 interaction

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Moein Dehbashi ◽  
Zohreh Hojati ◽  
Majid Motovali-bashi ◽  
Mazdak Ganjalikhani-Hakemi ◽  
Akihiro Shimosaka ◽  
...  
Keyword(s):  
Small Molecules ◽  
Cancer Progression ◽  
Immune Escape ◽  
De Novo ◽  
Computational Study ◽  
Treg Cells ◽  
Homology Search ◽  
Small Interfering Rnas

AbstractCancer recurrence presents a huge challenge in cancer patient management. Immune escape is a key mechanism of cancer progression and metastatic dissemination. CD25 is expressed in regulatory T (Treg) cells including tumor-infiltrating Treg cells (TI-Tregs). These cells specially activate and reinforce immune escape mechanism of cancers. The suppression of CD25/IL-2 interaction would be useful against Treg cells activation and ultimately immune escape of cancer. Here, software, web servers and databases were used, at which in silico designed small interfering RNAs (siRNAs), de novo designed peptides and virtual screened small molecules against CD25 were introduced for the prospect of eliminating cancer immune escape and obtaining successful treatment. We obtained siRNAs with low off-target effects. Further, small molecules based on the binding homology search in ligand and receptor similarity were introduced. Finally, the critical amino acids on CD25 were targeted by a de novo designed peptide with disulfide bond. Hence we introduced computational-based antagonists to lay a foundation for further in vitro and in vivo studies.

scholarly journals Pharmacoinformatics and UPLC-QTOF/ESI-MS-Based Phytochemical Screening of Combretum indicum against Oxidative Stress and Alloxan-Induced Diabetes in Long–Evans Rats

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4634
Author(s):  
Md. Shaekh Forid ◽  
Md. Atiar Rahman ◽  
Mohd Fadhlizil Fasihi Mohd Aluwi ◽  
Md. Nazim Uddin ◽  
Tapashi Ghosh Roy ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Immune Modulation ◽  
Computational Study ◽  
Density Lipoprotein ◽  
Control Group ◽  
Esi Ms ◽  
Long Evans ◽  
Antidiabetic Effects

This research investigated a UPLC-QTOF/ESI-MS-based phytochemical profiling of Combretum indicum leaf extract (CILEx), and explored its in vitro antioxidant and in vivo antidiabetic effects in a Long–Evans rat model. After a one-week intervention, the animals’ blood glucose, lipid profile, and pancreatic architectures were evaluated. UPLC-QTOF/ESI-MS fragmentation of CILEx and its eight docking-guided compounds were further dissected to evaluate their roles using bioinformatics-based network pharmacological tools. Results showed a very promising antioxidative effect of CILEx. Both doses of CILEx were found to significantly (p < 0.05) reduce blood glucose, low-density lipoprotein (LDL), and total cholesterol (TC), and increase high-density lipoprotein (HDL). Pancreatic tissue architectures were much improved compared to the diabetic control group. A computational approach revealed that schizonepetoside E, melianol, leucodelphinidin, and arbutin were highly suitable for further therapeutic assessment. Arbutin, in a Gene Ontology and PPI network study, evolved as the most prospective constituent for 203 target proteins of 48 KEGG pathways regulating immune modulation and insulin secretion to control diabetes. The fragmentation mechanisms of the compounds are consistent with the obtained effects for CILEx. Results show that the natural compounds from CILEx could exert potential antidiabetic effects through in vivo and computational study.

scholarly journals Antioxidant Properties of Ergosterol and Its Role in Yeast Resistance to Oxidation

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1024
Author(s):  
Sebastien Dupont ◽  
Paul Fleurat-Lessard ◽  
Richtier Gonçalves Cruz ◽  
Céline Lafarge ◽  
Cédric Grangeteau ◽  
...  
Keyword(s):  
Computational Study ◽  
Antioxidant Properties ◽  
Beneficial Effects ◽  
Tert Butyl Hydroperoxide ◽  
Resistance To Oxidation ◽  
Specific Accumulation ◽  
The Subject

Although the functions and structural roles of sterols have been the subject of numerous studies, the reasons for the diversity of sterols in the different eukaryotic kingdoms remain unclear. It is thought that the specificity of sterols is linked to unidentified supplementary functions that could enable organisms to be better adapted to their environment. Ergosterol is accumulated by late branching fungi that encounter oxidative perturbations in their interfacial habitats. Here, we investigated the antioxidant properties of ergosterol using in vivo, in vitro, and in silico approaches. The results showed that ergosterol is involved in yeast resistance to tert-butyl hydroperoxide and protects lipids against oxidation in liposomes. A computational study based on quantum chemistry revealed that this protection could be related to its antioxidant properties operating through an electron transfer followed by a proton transfer mechanism. This study demonstrates the antioxidant role of ergosterol and proposes knowledge elements to explain the specific accumulation of this sterol in late branching fungi. Ergosterol, as a natural antioxidant molecule, could also play a role in the incompletely understood beneficial effects of some mushrooms on health.

The Effect of Muscle Loading on Internal Mechanical Parameters of the Lumbar Spine: A Finite Element Study

2011 ◽  
Author(s):  
Benjamin C. Gadomski ◽  
John Rasmussen ◽  
Christian M. Puttlitz
Keyword(s):  
Annulus Fibrosus ◽  
Critical Role ◽  
Complex Loading ◽  
Tissue Level ◽  
Mechanical Parameters ◽  
Loading Conditions ◽  
Additional Stability ◽  
Muscle Loading ◽  
Pure Moment

The human spine experiences complex loading in vivo; however, simplifications to these loading conditions are commonly made in computational and experimental protocols. Pure moments are often used in cadaveric preparations to replicate in vivo loading conditions, and previous studies have shown this method adequately predicts range of motion behavior (1, 2). It is unclear what effect pure moment loading has on the tissue-level internal mechanical parameters such as stresses in the annulus fibrosus and facet contact parameters. Recent advances in musculoskeletal modeling have elucidated previously unknown quantities of the musculature recruitment patterns such as times, forces, and directions. The advancements are especially relevant in cases of surgical intervention because the spinal musculature has been reported to play a critical role in providing additional stability to the spine when defects such as discectomy and nucleotomy are involved (2). Thus, the aim of the study was to determine the importance of computational loading conditions on the resultant global ranges of motion, as well as the tissue-level predictions of annulus fibrosus stresses, and facet contact pressures, forces, and areas.

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