Search

Your search keyword '"Richards, R Geoff"' showing total 502 results
Start Over Author "Richards, R Geoff"
502 results on '"Richards, R Geoff"'

7. Alginate microbeads and hydrogels delivering meropenem and bacteriophages to treat Pseudomonas aeruginosa fracture-related infections

Author

Chen, Baixing, Benavente, Luis Ponce, Chittò, Marco, Wychowaniec, Jacek K., Post, Virginia, D'Este, Matteo, Constant, Caroline, Zeiter, Stephan, Feng, Wenli, Moreno, Mercedes González, Trampuz, Andrej, Wagemans, Jeroen, Onsea, Jolien, Richards, R. Geoff, Lavigne, Rob, Moriarty, T. Fintan, and Metsemakers, Willem-Jan

Published
2023
Full Text
View/download PDF

14. Fracture-related infection

Author

Moriarty, T. Fintan, Metsemakers, Willem-Jan, Morgenstern, Mario, Hofstee, Marloes I., Vallejo Diaz, Alejandro, Cassat, James E., Wildemann, Britt, Depypere, Melissa, Schwarz, Edward M., and Richards, R. Geoff

Published
2022
Full Text
View/download PDF

23. Impact of Perioperative Dexamethasone Administration on Infection and Implant Osseointegration in a Preclinical Model of Orthopedic Device-Related Infection.

Author

Burch, Marc-Antoine, Keshishian, Aron, Wittmann, Charlotte, Nehrbass, Dirk, Thompson, Keith, Arens, Daniel, Richards, R. Geoff, Mdingi, Vuysa, Chitto, Marco, Morgenstern, Mario, Moriarty, T. Fintan, and Eijer, Henk

Subjects
OSSEOINTEGRATION, ANIMAL models in research, PROSTHESIS-related infections, LABORATORY rats, DEXAMETHASONE, ARTIFICIAL joints, SUMATRIPTAN
Abstract

Glucocorticoids may be given prior to major orthopedic surgery to decrease postoperative nausea, vomiting, and pain. Additionally, many orthopedic patients may be on chronic glucocorticoid therapy. The aim of our study was to investigate whether glucocorticoid administration influences Orthopedic-Device-Related Infection (ODRI) in a rat model. Screws colonized with Staphylococcus epidermidis were implanted in the tibia of skeletally mature female Wistar rats. The treated groups received either a single shot of dexamethasone in a short-term risk study, or a daily dose of dexamethasone in a longer-term interference study. In both phases, bone changes in the vicinity of the implant were monitored with microCT. There were no statistically significant differences in bacteriological outcome with or without dexamethasone. In the interference study, new bone formation was statistically higher in the dexamethasone-treated group (p = 0.0005) as revealed by CT and histopathological analysis, although with relatively low direct osseointegration of the implant. In conclusion, dexamethasone does not increase the risk of developing periprosthetic osteolysis or infection in a pre-clinical model of ODRI. Long-term administration of dexamethasone seemed to offer a benefit in terms of new bone formation around the implant, but with low osseointegration. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

26. Non-union bone fractures

Author

Wildemann, Britt, Ignatius, Anita, Leung, Frankie, Taitsman, Lisa A., Smith, R. Malcolm, Pesántez, Rodrigo, Stoddart, Martin J., Richards, R. Geoff, and Jupiter, Jesse B.

Published
2021
Full Text
View/download PDF

30. Valgus malalignment causes increased forces on a medial collateral ligament reconstruction under dynamic valgus loading: A biomechanical study.

Author

Peez, Christian, Deichsel, Adrian, Zderic, Ivan, Richards, R. Geoff, Gueorguiev, Boyko, Kittl, Christoph, Raschke, Michael J., and Herbst, Elmar

Subjects
COLLATERAL ligament, DYNAMIC loads, EXTERNAL fixators, KNEE, TENDONS
Abstract

Purpose: To investigate the forces on a medial collateral ligament (MCL) reconstruction (MCLR) relative to the valgus alignment of the knee. Methods: Eight fresh‐frozen human cadaveric knees were subjected to dynamic valgus loading at 400 N using a custom‐made kinematics rig. After resection of the superficial medial collateral ligament, a single‐bundle MCLR with a hamstring tendon autograft was performed. A medial opening wedge distal femoral osteotomy was performed and fixed with an external fixator to gradually adjust the alignment in 5° increments from 0° to 10° valgus. For each degree of valgus deformity, the resulting forces acting on the MCLR were measured through a force sensor and captured in 15° increments from 0° to 60° of knee flexion. Results: Irrespective of the degree of knee flexion, increasing valgus malalignment resulted in significantly increased forces acting on the MCLR compared to neutral alignment (p < 0.05). Dynamic loading at 5° valgus resulted in increased forces on the MCLR at all flexion angles ranging between 16.2 N and 18.5 N (p < 0.05 from 0° to 30°; p < 0.01 from 45° to 60°). A 10° valgus malalignment further increased the forces on the MCLR at all flexion angles ranging between 29.4 N and 40.0 N (p < 0.01 from 0° to 45°, p < 0.05 at 60°). Conclusion: Valgus malalignment of the knee caused increased forces acting on the reconstructed MCL. In cases of chronic medial instabilities accompanied by a valgus deformity ≥ 5°, a realigning osteotomy should be considered concomitantly to the MCLR to protect the graft and potentially reduce graft failures. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

31. Treatment of Metaphyseal Defects in Plated Proximal Humerus Fractures with a New Augmentation Technique—A Biomechanical Cadaveric Study

Author

Zhelev, Daniel, primary, Hristov, Stoyan, additional, Zderic, Ivan, additional, Ivanov, Stoyan, additional, Visscher, Luke, additional, Baltov, Asen, additional, Ribagin, Simeon, additional, Stoffel, Karl, additional, Kralinger, Franz, additional, Winkler, Jörg, additional, Richards, R. Geoff, additional, Varga, Peter, additional, and Gueorguiev, Boyko, additional

Published
2023
Full Text
View/download PDF

40. Anterior column acetabulum fracture fixation with a screw-augmented acetabular cup-a biomechanical feasibility study

Author

Berk, Till; https://orcid.org/0000-0001-9582-1810, Zderic, Ivan; https://orcid.org/0000-0003-0484-887X, Schwarzenberg, Peter; https://orcid.org/0000-0002-8747-6786, Pfeifer, Roman; https://orcid.org/0000-0003-1543-3995, Pastor, Tatjana, Halvachizadeh, Sascha; https://orcid.org/0000-0003-1393-3232, Richards, R Geoff; https://orcid.org/0000-0002-7778-2480, Gueorguiev, Boyko; https://orcid.org/0000-0001-9795-115X, Pape, Hans-Christoph; https://orcid.org/0000-0002-2059-4980, Berk, Till; https://orcid.org/0000-0001-9582-1810, Zderic, Ivan; https://orcid.org/0000-0003-0484-887X, Schwarzenberg, Peter; https://orcid.org/0000-0002-8747-6786, Pfeifer, Roman; https://orcid.org/0000-0003-1543-3995, Pastor, Tatjana, Halvachizadeh, Sascha; https://orcid.org/0000-0003-1393-3232, Richards, R Geoff; https://orcid.org/0000-0002-7778-2480, Gueorguiev, Boyko; https://orcid.org/0000-0001-9795-115X, and Pape, Hans-Christoph; https://orcid.org/0000-0002-2059-4980

Abstract

BACKROUND: The beneficial effects of unrestricted postoperative full weight bearing for elderly patients suffering hip fractures have been demonstrated. However, there is still existing disagreement regarding acetabular fractures.The aim of this biomechanical study was to evaluate the initial load bearing capabilities of different fixation constructs of anterior column fractures (ACFs) in osteoporotic bone. METHODS: Artificial pelvises with ACFs were assigned to three groups (n = 8) and fixed with either a 7.3 mm partially threaded antegrade cannulated screw (group AASS), an anteriorly placed 3.5 mm plate (group AAPF), or a press-fit acetabular cup with screw augmentation (group AACF). All specimens underwent ramped loading from 20 N preload to 200 N at a rate of 18 N/s, followed by progressively increasing cyclic testing at 2 Hz until failure performed at a rate of 0.05 N/cycle. Relative displacements of the bone fragments were monitored by motion tracking. FINDINGS: Initial stiffness (N/mm) was 118.5 ± 34.3 in group AASS, 100.4 ± 57.5 in group AAPF, and 92.9 ± 44.0 in group AACF, with no significant differences between the groups, p = 0.544. Cycles to failure were significantly higher in groups AACF (8364 ± 2243) and AAPF (7827 ± 2881) compared to group AASS (4440 ± 2063), p ≤ 0.041. INTERPRETATION: From a biomechanical perspective, the minimally invasive cup fixation with screw augmentation demonstrated comparable stability to plate osteosynthesis of ACFs in osteoporotic bone. The results of the present study do not allow to conclusively answer whether immediate full weight bearing following cup fixation shall be allowed. Given its similar performance to plate osteosynthesis, this remains rather an utopic wish and a more conservative approach deems more reasonable.

Published
2023

41. Evaluation of cannulated compression headless screws as an alternative implant for superior pubic ramus fracture fixation: a biomechanical study

Author

Berk, Till; https://orcid.org/0000-0001-9582-1810, Zderic, Ivan, Schwarzenberg, Peter; https://orcid.org/0000-0002-8747-6786, Pastor, Tatjana, Lesche, Felix, Halvachizadeh, Sascha; https://orcid.org/0000-0003-1393-3232, Richards, R Geoff, Gueorguiev, Boyko; https://orcid.org/0000-0001-9795-115X, Pape, Hans-Christoph; https://orcid.org/0000-0002-2059-4980, Berk, Till; https://orcid.org/0000-0001-9582-1810, Zderic, Ivan, Schwarzenberg, Peter; https://orcid.org/0000-0002-8747-6786, Pastor, Tatjana, Lesche, Felix, Halvachizadeh, Sascha; https://orcid.org/0000-0003-1393-3232, Richards, R Geoff, Gueorguiev, Boyko; https://orcid.org/0000-0001-9795-115X, and Pape, Hans-Christoph; https://orcid.org/0000-0002-2059-4980

Abstract

BACKGROUND/PURPOSE: Pubic ramus fractures account for the most common types of pelvic fractures. The standard surgical approach for superior pubic ramus fractures (SPRF) is a minimally invasive percutaneous screw fixation. However, percutaneous closed reduction and internal fixation of anterior pelvic ring injuries have high failure rates of up to 15%. The aim of this biomechanical study was to evaluate the stability of SPRF following stabilization with retrograde placed cannulated compression headless screw (CCHS) versus conventional fully and partially threaded screws in an artificial pelvic bone model. METHODS: SPRF type II as described by Nakatani et al. was created by means of osteotomies in eighteen anatomical composite hemi-pelvises. Specimens were stratified into three groups of six specimens each (n = 6) for fixation with either a 7.3 mm partially threaded cannulated screw (group RST), a 7.3 mm fully threaded cannulated screw (group RSV), or a 7.5 mm partially threaded cannulated CCHS (group CCS). Each hemi-pelvic specimen was tested in an inverted upright standing position under progressively increasing cyclic axial loading. The peak load, starting at 200 N, was monotonically increased at a rate of 0.1 N/cycle until 10 mm actuator displacement. RESULTS: Total and torsional displacement were associated with higher values for RST versus CCS and RSV, with significant differences between RST and CCS for both these parameters (p ≤ 0.033). The differences between RST and RSV were significant for total displacement (p = 0.020), and a trend toward significance for torsional displacement (p = 0.061) was observed. For both failure criteria 2 mm total displacement and 5° torsional displacement, CCS was associated with significantly higher number of cycles compared to RST (p ≤ 0.040). CONCLUSION: CCHS fixation presented predominantly superior stability to the standard surgical treatment and could therefore be a possible alternative implant for retrograde SPRF screw fi

Published
2023

46. A doxycycline-loaded polymer-lipid encapsulation matrix coating for the prevention of implant-related osteomyelitis due to doxycycline-resistant methicillin-resistant Staphylococcus aureus

Author

Metsemakers, Willem-Jan, Emanuel, Noam, Cohen, Or, Reichart, Malka, Potapova, Inga, Schmid, Tanja, Segal, David, Riool, Martijn, Kwakman, Paulus H.S., de Boer, Leonie, de Breij, Anna, Nibbering, Peter H., Richards, R. Geoff, Zaat, Sebastian A.J., and Moriarty, T. Fintan

Published
2015
Full Text
View/download PDF

49. Helical Plating Of Proximal Third Humeral Shaft Fractures. A Biomechanical Comparative Study

Author

Zderic, Ivan, Pastor, Torsten, van Knegsel, Kenneth P., Richards, R. Geoff, Gueorguiev, Boyko, and Knobe, Matthias

Subjects
humerus, unstable fracture, Medicine and health, artificial, helical plating, biomechanics
Abstract

Objectives: Proximal humeral shaft fractures are commonly treated with long straight plates or intramedullary nails. Helical plates might overcome the downsides of these techniques as they are able to avoid the radial nerve distally. The aim of this study was to investigate in an artificial bone model: [for full text, please go to the a.m. URL]

Published
2022
Full Text
View/download PDF

50. Multiple hypervirulent methicillin-sensitiveStaphylococcus aureuslineages contribute towards poor patient outcomes in orthopedic device-related infections

Author

Post, Virginia, primary, Pascoe, Ben, additional, Mourkas, Evangelos, additional, Calland, Jessica K., additional, Hitchings, Matthew D., additional, Erichsen, Christoph, additional, Fischer, Julian, additional, Morgenstern, Mario, additional, Richards, R. Geoff, additional, Sheppard, Samuel K., additional, and Moriarty, T. Fintan, additional

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results