Search

Your search keyword '"Ferreira Louis"' showing total 556 results
Start Over Author "Ferreira Louis"
556 results on '"Ferreira Louis"'

2. Assessing Methodological Uncertainty of In-Vitro Digital Volume Correlation Bone Strain Measurements in Total Shoulder Arthroplasties

Author

Targosinski, Jakub, Kusins, Jonathan, Martensson, Nicole, Nelson, Andrew, Knowles, Nikolas, Ferreira, Louis, Tavares, João Manuel R. S., Series Editor, Jorge, Renato Natal, Series Editor, Cohen, Laurent, Editorial Board Member, Doblare, Manuel, Editorial Board Member, Frangi, Alejandro, Editorial Board Member, Garcia-Aznar, Jose Manuel, Editorial Board Member, Holzapfel, Gerhard A., Editorial Board Member, Hughes, Thomas J.R., Editorial Board Member, Kamm, Roger, Editorial Board Member, Li, Shuo, Editorial Board Member, Löhner, Rainald, Editorial Board Member, Nithiarasu, Perumal, Editorial Board Member, Oñate, Eugenio, Editorial Board Member, Perales, Francisco J., Editorial Board Member, Prendergast, Patrick J., Editorial Board Member, Tamma, Kumar K., Editorial Board Member, Vilas-Boas, Joao Paulo, Editorial Board Member, Weiss, Jeffrey, Editorial Board Member, Zhang, Yongjie Jessica, Editorial Board Member, Bourauel, Christoph, editor, Geris, Liesbet, editor, and Vander Slote, Jos, editor

Published
2023
Full Text
View/download PDF

4. A comparison of two headless compression screws for operative treatment of scaphoid fractures

Author

Johnson Jim, Ferreira Louis, Sauder David, Assini Joseph, Grewal Ruby, and Faber Kenneth

Subjects
Orthopedic surgery, RD701-811, Diseases of the musculoskeletal system, RC925-935
Abstract

Abstract Purpose The purpose of this study was to compare the interfragmentary compression force across a simulated scaphoid fracture by two commonly used compression screw systems; the Acutrak 2 Standard and the 3.0 mm Synthes headless compression screw. Methods Sixteen (8 pairs; 6 female, 2 male) cadaver scaphoids were randomly assigned to receive either the Acutrak 2 or Synthes screw with the contralateral scaphoid designated to receive the opposite. Guide wires were inserted under fluoroscopic control. Following transverse osteotomy, the distal and proximal fragments were placed on either side of a custom load cell, to measure interfragmentary compression. Screws were placed under fluoroscopic control using the manufacturer's recommended surgical technique. Compressive forces were measured during screw insertion. Recording continued for an additional 60s in order to measure any loss of compression after installation was complete. The peak and final interfragmentary compression were recorded and paired t-tests performed. Results The mean peak compression generated by the Acutrak 2 Standard was greater than that produced by the Synthes compression screw (103.9 ± 33.2 N vs. 88.7 ± 38.6 N respectively, p = 0.13). The mean final interfragmentary compression generated by the Acutrak 2 screw (68.6 ± 36.4 N) was significantly greater (p = 0.04) than the Synthes screw (37.2 ± 26.8 N). Specimens typically reached a steady state of compression by 120-150s after final tightening. Conclusion Peak interfragmentary compression observed during screw installation was similar for both screw systems. However, the mean interfragmentary compression generated by the Acutrak 2 Standard was significantly greater. Our study demonstrates that the Synthes headless compression screw experienced a greater loss of interfragmentary compressive force from the time of installation to the final steady state compression level. The higher post-installation compression of the Acutrak 2 Standard may be attributable to the greater number of threads throughout the entire length of the screw. The clinical significance of these results, are, at this point uncertain. We do demonstrate that a fully threaded design offers a more reliable compression that may translate to more predictable bony union.

Published
2011
Full Text
View/download PDF

8. An in vitro study of glenoid implant peripheral peg interface mechanics during eccentric loading and lift‐off.

Author

Targosinski, Jakub, Kusins, Jonathan, Athwal, George, Nelson, Andrew, and Ferreira, Louis

Subjects
ECCENTRIC loads, CYCLIC loads, ARTHROPLASTY, MICROMECHANICS, IN vitro studies
Abstract

Glenoid implants used in anatomic total shoulder arthroplasties typically incorporate peripheral pegs as a design feature to support eccentric loads. These peripheral pegs and the implant‐cement‐bone interface undergo substantial cyclic tensile‐compressive loads during normal activity. Therefore, these pegs are of interest in translating the micromechanics of local implant fixation failure to the biomechanics of gross anatomic failure of the glenoid implant after total shoulder arthroplasty. This study used an in vitro peg‐cement‐bone construct which incorporated bone tissue acquired from osteoarthritic patients undergoing total shoulder arthroplasty. Strain distributions in the peripheral peg‐cement‐bone interfaces were analyzed under loading conditions emulating glenoid implant edge displacements. It was found that tensile strains in the interfaces were highest near the backside‐peg junction and were greater in magnitude than compressive strains. Notably, strains near the peg's fixation channels were relatively low. These results suggest that cracks may initiate around the peg near the backside and travel downward to cause broader fixation failure. [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results