CRIS

Permanent URI for this communityhttps://investigadores.udd.cl/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 15

Some of the metrics are blocked by your
consent settings
Biomechanical Evaluation of Different Fixation Methods for Percutaneous Extracapsular Transverse Cervical Metatarsal Osteotomy in a Hallux Valgus Sawbone Model
(SAGE Publications, 2024-10)
WAGNER HITSCHFELD, PABLO
;
WAGNER HITSCHFFELD, EMILIO
;
Miguel Pinochet
;
David Salinas
;
Peter Lam
<jats:sec><jats:title>Background:</jats:title><jats:p> There is limited literature available that provide information about fixation methods for minimally invasive hallux valgus osteotomies. Our objective was to evaluate the strength of different fixation methods for a percutaneous extracapsular transverse cervical metatarsal (PTCM) osteotomy in a sawbone model. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Thirty solid foam sawbone foot models were used. Percutaneous extracapsular transverse cervical metatarsal osteotomies were performed and fixed in a standardized fashion in 6 different groups: (1) one 4.0-mm screw; (2) 2 (one 4.0-mm and one 3.0-mm) parallel screws; (3) 2 (one 4.0-mm and one 3.0-mm) divergent screws; (4) same as group 3, but with lateral metatarsal head cortex purchase with the 4.0-mm screw; (5) same as group 4, but with two 4.0-mm screws; (6) same as group 5, but with two 3.5-mm screws. Cyclic and load to failure testing were performed applying a plantar load to the metatarsal head. The measured variables were stiffness and force needed to create deformity using a Zwick Roell Universal Testing Machine. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> Group 1 failed as a result of rotational instability in cyclic testing. In load to failure testing, group 3 did not achieve difference compared with group 2 ( P = .09) (181 vs 131 N). Group 4 was stronger ( P = .02) (250 N) than groups 1-3. Group 5 did not show differences relative to group 4 ( P = .1) (223 N). Group 6 was stronger only than groups 1 and 2 ( P = .01) (193 N). </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> In this sawbones-based study, we found that the use of two 4.0-mm screws or use of a 3.0-mm screw and a 4.0-mm screw with lateral first metatarsal head cortical purchase was superior to other screw configurations. </jats:p></jats:sec>
2Scopus© Citations 1
Some of the metrics are blocked by your
consent settings
Polycaprolactone-based scaffolds for guided tissue regeneration in periodontal therapy: A systematic review
(2023)
Florencia Antunovic
;
Felipe Tolosa
;
Catherine Klein
;
René Ocaranza
<jats:sec><jats:title>Background:</jats:title><jats:p> Polycaprolactone (PCL) is a highly recognized synthetic polymer for its biocompatibility, ease of fabrication and mechanical strength in bone tissue engineering. Its applications have extended broadly, including regeneration of oral and maxillofacial lost tissues. Its usefulness has brought attention of researchers to regenerate periodontal lost tissues, including alveolar bone, periodontal ligament and cementum. The aim of this systematic review was to obtain an updated analysis of the contribution of PCL-based scaffolds in the alveolar bone regeneration process. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> This review adheres to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews. A computerized search of the PubMed, EBSCO, Scielo and Web of Science databases was performed, restricting literature search to published studies in English or Spanish between January 2002 and March 2023. Database search returned 248 studies which were screened based on title, author names and publication dates. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> Data from 17 studies were reviewed and tabulated. All studies combined PCL with other biomaterials (such as Alginate, hydroxyapatite, bioactive glass, poly (lactic-co-glycolic acid)), growth factors (BMP-2, rhCEMP1), and/or mesenchymal stromal cells (adipose-derived, bone marrow, periodontal ligament or gingiva mesenchymal stromal cells). PCL scaffolds showed higher cell viability and osteoinductive potential when combined with bioactive agents. Complementary, its degradation rates were affected by the addition or exposure to specific substances, such as: Dopamine, Cerium Oxide, PLGA and hydrogen peroxide. </jats:p></jats:sec><jats:sec><jats:title>Conclusions:</jats:title><jats:p> PCL is an effective biomaterial for alveolar bone regeneration in periodontally affected teeth. It could be part of a new generation of biomaterials with improved regenerative potential. </jats:p></jats:sec>
Scopus© Citations 15
Some of the metrics are blocked by your
consent settings
The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
(2023)
Joseph B. McCormick
;
Alexander S. Drusch
;
Darragh J. Lynch
;
Gesine H. Seeber
;
Katherine F. Wilford
<jats:sec id="background"> <jats:title>Background</jats:title> <jats:p>Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation.</jats:p> </jats:sec> <jats:sec id="hypothesispurpose"> <jats:title>Hypothesis/Purpose</jats:title> <jats:p>The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects.</jats:p> </jats:sec> <jats:sec id="study-design"> <jats:title>Study Design</jats:title> <jats:p>Controlled Laboratory Study</jats:p> </jats:sec> <jats:sec id="methods"> <jats:title>Methods</jats:title> <jats:p>Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey’s Post-Hoc tests identified the location of significant differences.</jats:p> </jats:sec> <jats:sec id="results"> <jats:title>Results</jats:title> <jats:p>Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p<0.001, ICL: p<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine.</jats:p> </jats:sec> <jats:sec id="conclusions"> <jats:title>Conclusions</jats:title> <jats:p>Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs.</jats:p> </jats:sec> <jats:sec id="level-of-evidence"> <jats:title>Level of Evidence</jats:title> <jats:p>Level 3</jats:p> </jats:sec>
1
Some of the metrics are blocked by your
consent settings
Evidence-Based Treatment Algorithm for Freiberg Disease
(2023)
Ichiro Yoshimura
;
Masato Takao
;
WAGNER HITSCHFFELD, EMILIO
;
Sjoerd Stufkens
;
Jari Dahmen
<jats:p> Freiberg disease is a type of osteonecrosis of the metatarsal head that predominantly occurs in young females and adolescents, although it may occur at any age. The pathophysiology is multifactorial and may involve trauma, altered foot biomechanics, systemic disorders, and arterial insufficiency. The most typical location is the second metatarsal head, but Freiberg disease may also occur in other lesser toes. Nonoperative treatment is best applied in the early stage of the disease; if this is ineffective, surgical treatment is recommended. Currently available surgical procedures include debridement, osteotomy, osteochondral grafting, microfracture, interposition arthroplasty, implant arthroplasty, and metatarsal shortening arthroplasty. In this article, we propose a treatment algorithm for Freiberg disease based on the current literature and expert opinion. </jats:p>
Scopus© Citations 9 1
Some of the metrics are blocked by your
consent settings
Acute Deltoid Injury in Ankle Fractures: A Biomechanical Analysis of Different Repair Constructs
(2023)
WAGNER HITSCHFFELD, EMILIO
;
WAGNER HITSCHFELD, PABLO
;
Mario I. Escudero
;
Florencia Pacheco
;
David-osvaldo Salinas-sanchez
<jats:sec><jats:title>Background:</jats:title><jats:p> The importance of the deltoid ligament in the congruency and coupling of the tibiotalar joint is well known. The current trend is to repair it in cases of acute injuries in the context of ankle fractures; however, there is limited information on how it should be reconstructed. The objective of this study was to compare different deltoid ligament repair types in an ankle fracture cadaveric model. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Sixteen cadaveric foot-ankle-distal tibia specimens were used. All samples were prepared as a supination external rotation ankle fracture model. Axial load and cyclic axial rotations were applied on every specimen using a specifically designed frame. This test was performed without deltoid injury, with deltoid injury, and after repair. The reconstruction was performed in 4 different ways (anterior, posterior, middle, and combined). Medial clear space (MCS) was measured for each condition on simulated weightbearing (WB) and gravity stress (GS) radiographs. Reflective markers were used in tibia and talus, registering the kinematics through a motion analysis system to record the tibiotalar uncoupling. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> After deltoid damage, in all cases the MCS increased significantly on GS radiographs, but there was no increase in the MCS on WB radiographs. After repair, in all cases, the MCS was normalized. Kinematically, after deltoid damage, the tibiotalar uncoupling increased significantly. All isolated repairs achieved a similar tibiotalar uncoupling value as its baseline condition. The combined repair resulted in a significant decrease in tibiotalar uncoupling. </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> Our results show that deltoid repair recovers the tibiotalar coupling mechanism in an ankle fracture model. Isolated deltoid repairs recovered baseline MCS and tibiotalar uncoupling values. Combined repairs may lead to overconstraint, which could lead to postoperative stiffness. Clinical studies are needed to prove these results and show clinically improved outcomes. </jats:p></jats:sec><jats:sec><jats:title>Clinical Relevance:</jats:title><jats:p> This study helps in finding the optimum deltoid repair to use in an acute trauma setting. </jats:p></jats:sec>
Scopus© Citations 4 8
Some of the metrics are blocked by your
consent settings
Modulation of the biophysical and biochemical properties of collagen by glycation for tissue engineering applications
(2023)
Mina Vaez
;
Meisam Asgari
;
Liisa Hirvonen
;
Gorkem Bakir
;
Emilie Khattignavong
5 1Scopus© Citations 21
Some of the metrics are blocked by your
consent settings
Posterolateral corner knee injuries: a narrative review
(2021)
FIGUEROA BERRIOS, FRANCISCO JAVIER
;
FIGUEROA POBLETE, DAVID HUMBERTO
;
Sven Putnis
;
Rodrigo Guiloff
;
Patricio Caro
<jats:p>Limited knowledge of the anatomy and biomechanics of the posterolateral corner (PLC) of the knee, coupled with poor patient outcomes with non-operative management, resulted in the PLC often being labelled as the ‘dark side’ of the knee. In the last two decades, extensive research has resulted in a better understanding of the anatomy and function of the PLC, and has led to the development of anatomic reconstructions that have resulted in improved patient outcomes. Despite considerable attention in the clinical orthopaedic literature (nearly 400 articles published in the last decade), a standardized algorithm for the diagnosis and treatment of the PLC is still lacking, and much controversy remains. Considering the literature review, there is not a reconstruction technique that clearly prevails over the others. As anatomic, biomechanical, and clinical knowledge of PLC injuries continues to progress, finding the balance between re-creating native anatomy and safely performing PLC reconstruction provides a big challenge. Treatment decisions should be made on a case-by-case basis.</jats:p><jats:p>Cite this article: EFORT Open Rev 2021;6:676-685. DOI: 10.1302/2058-5241.6.200096</jats:p>
16Scopus© Citations 23
Some of the metrics are blocked by your
consent settings
Review on Generation and Characterization of Copper Particles and Copper Composites Prepared by Mechanical Milling on a Lab-Scale
(2023)
Sebastián Salazar Sandoval
;
SILVA GONZALEZ, NATALY ROXANA
<jats:p>This review aims to expose mechanical milling as an alternative method for generating copper-based particles (copper particles (CuP) and copper composites (CuC)); more specifically, via a top-down or bottom-up approach, on a lab-scale. This work will also highlight the different parameters that can affect the size distribution, the type, and the morphology of the obtained CuP or CuC, such as the type of mechanical mill, ball-to-powder ratios (BPR), the milling speed, milling time, and the milling environment, among others. This review analyzes various papers based on the Cu-based particle generation route, which begins with a pretreatment step, then mechanical milling, its approach (top-down or bottom-up), and the post-treatment. Finally, the characterization methods of the resulting CuP and CuC through mechanical milling are also discussed.</jats:p>
3Scopus© Citations 7
Some of the metrics are blocked by your
consent settings
Progression of regional lung strain and heterogeneity in lung injury: assessing the evolution under spontaneous breathing and mechanical ventilation
(2020)
Daniel E. Hurtado
;
Benjamín Erranz
;
Felipe Lillo
;
Mauricio Sarabia-Vallejos
;
Pablo Iturrieta
<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Protective mechanical ventilation (MV) aims at limiting global lung deformation and has been associated with better clinical outcomes in acute respiratory distress syndrome (ARDS) patients. In ARDS lungs without MV support, the mechanisms and evolution of lung tissue deformation remain understudied. In this work, we quantify the progression and heterogeneity of regional strain in injured lungs under spontaneous breathing and under MV.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Lung injury was induced by lung lavage in murine subjects, followed by 3 h of spontaneous breathing (SB-group) or 3 h of low <jats:italic>V</jats:italic><jats:sub>t</jats:sub> mechanical ventilation (MV-group). Micro-CT images were acquired in all subjects at the beginning and at the end of the ventilation stage following induction of lung injury. Regional strain, strain progression and strain heterogeneity were computed from image-based biomechanical analysis. Three-dimensional regional strain maps were constructed, from which a region-of-interest (ROI) analysis was performed for the regional strain, the strain progression, and the strain heterogeneity.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>After 3 h of ventilation, regional strain levels were significantly higher in 43.7% of the ROIs in the SB-group. Significant increase in regional strain was found in 1.2% of the ROIs in the MV-group. Progression of regional strain was found in 100% of the ROIs in the SB-group, whereas the MV-group displayed strain progression in 1.2% of the ROIs. Progression in regional strain heterogeneity was found in 23.4% of the ROIs in the SB-group, while the MV-group resulted in 4.7% of the ROIs showing significant changes. Deformation progression is concurrent with an increase of non-aerated compartment in SB-group (from 13.3% ± 1.6% to 37.5% ± 3.1%), being higher in ventral regions of the lung.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Spontaneous breathing in lung injury promotes regional strain and strain heterogeneity progression. In contrast, low <jats:italic>V</jats:italic><jats:sub>t</jats:sub> MV prevents regional strain and heterogeneity progression in injured lungs.</jats:p> </jats:sec>
Scopus© Citations 43 1
Some of the metrics are blocked by your
consent settings
Biomechanical Cadaveric Evaluation of the Role of Medial Column Instability in Hallux Valgus Deformity
(2022)
WAGNER, EMILIO
;
WAGNER HITSCHFELD, PABLO
;
Florencia Pacheco
;
Mario López
;
Felipe Palma
<jats:sec><jats:title>Background:</jats:title><jats:p> Medial column instability is a frequent finding in patients with flatfeet and hallux valgus, within others. The etiology of hallux valgus is multifactorial, and medial ray axial rotation has been mentioned as having an individual role. Our objective was to design a novel cadaveric foot model where we could re-create through progressive medial column ligament damage some components of a hallux valgus deformity. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Ten fresh-frozen lower leg specimens were used, and fluorescent markers were attached in a multisegment foot model. Constant axial load and cyclic tibial rotation (to simulate foot pronation) were applied, including pull on the flexor hallucis longus tendon (FHL). We first damaged the intercuneiform (C1-C2) ligaments, second the naviculocuneiform (NC) ligaments, and third the first tarsometatarsal ligaments, leaving the plantar ligaments unharmed. Bony axial and coronal alignment was measured after each ligament damage. Statistical analysis was performed. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> A significant increase in pronation of multiple segments was observed after sectioning the NC ligaments. Damaging the tarsometatarsal ligament generated small supination and varus changes mainly in the medial ray. No significant change was observed in axial or frontal plane alignment after damaging the C1-C2 ligaments. The FHL pull exerted a small valgus change in segments of the first ray. </jats:p></jats:sec><jats:sec><jats:title>Discussion:</jats:title><jats:p> In this biomechanical cadaveric model, the naviculocuneiform joint was the most important one responsible for pronation of the medial column. Bone pronation occurs along the whole medial column, not isolated to a certain joint. Flexor hallucis longus pull appears to play some role in frontal plane alignment, but not in bone rotation. This model will be of great help to further study medial column instability as one of the factors influencing medial column pronation and its relevance in pathologies like hallux valgus. </jats:p></jats:sec><jats:sec><jats:title>Clinical Relevance:</jats:title><jats:p> This cadaveric model suggests a possible influence of medial column instability in first metatarsal pronation. With a thorough understanding of a condition’s origin, better treatment strategies can be developed. </jats:p></jats:sec>
20Scopus© Citations 7

CRIS

Browse

Filters

Settings

Sort By

Results per page

Search Results