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Paul A Martineau - One of the best experts on this subject based on the ideXlab platform.
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proximal tibial fracture following anterior cruciate ligament reconstruction surgery a biomechanical analysis of the tibial tunnel as a Stress Riser
Knee Surgery Sports Traumatology Arthroscopy, 2017Co-Authors: Wassim Aldebeyan, Antony Liddell, Thomas Steffen, Lorne Beckman, Paul A MartineauAbstract:Purpose This is the first biomechanical study to examine the potential Stress Riser effect of the tibial tunnel or tunnels after ACL reconstruction surgery. In keeping with literature, the primary hypothesis tested in this study was that the tibial tunnel acts as a Stress Riser for fracture propagation. Secondary hypotheses were that the Stress Riser effect increases with the size of the tunnel (8 vs. 10 mm), the orientation of the tunnel [standard (STT) vs. modified transtibial (MTT)], and with the number of tunnels (1 vs. 2).
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peri anterior cruciate ligament reconstruction femur fracture a biomechanical analysis of the femoral tunnel as a Stress Riser
Orthopaedic Proceedings, 2012Co-Authors: Thomas Steffen, Yung Han, Zeeshan M Sardar, Scott Mcgrail, Paul A MartineauAbstract:Purpose Twelve case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential Stress Riser for fracture formation. The recent increase in double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the Stress Riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a Stress Riser to fracture and that this effect increases with the size of the tunnel (8mm versus 10mm) and with the number of tunnels (one versus two). Method Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7mm, 6 mm) were drilled in fourth generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels, were loaded to failure. Result All fractures occurred through the tunnels in the double tunnel group whereas fractures did not consistently occur through the tunnels in the single tunnel groups. The mean fracture load was 6145 N 471 N in the native group, 5691 N 198 N in the 8 mm single tunnel group, 5702 N 282 N in the 10 mm single tunnel group, and 4744 N 418 N in the double tunnel group. The mean fracture load for the double tunnel group was significantly different when compared to native, 8 mm single bundle, and 10 mm single bundle groups independently (p value = 0.0016, 0.0060, and 0.0038 respectively). No other statistically significant differences were identified. Conclusion An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a Stress Riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparcity of reported peri-ACL reconstruction femur fractures in single femoral tunnel techniques. However, the increased fracture risk in double bundle ACL reconstruction is a cause for concern and may impact patient selection.
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peri anterior cruciate ligament reconstruction femur fracture a biomechanical analysis of the femoral tunnel as a Stress Riser
Knee Surgery Sports Traumatology Arthroscopy, 2011Co-Authors: Thomas Steffen, Yung Han, Zeeshan M Sardar, Scott Mcgrail, Paul A MartineauAbstract:Purpose Sixteen case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential Stress Riser for fracture formation. Additionally, double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the significance of a Stress Riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a Stress Riser for fracture and that this effect increases with the size of the tunnel (8 mm vs. 10 mm) and with the number of tunnels (1 vs. 2).
Yung Han - One of the best experts on this subject based on the ideXlab platform.
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peri anterior cruciate ligament reconstruction femur fracture a biomechanical analysis of the femoral tunnel as a Stress Riser
Orthopaedic Proceedings, 2012Co-Authors: Thomas Steffen, Yung Han, Zeeshan M Sardar, Scott Mcgrail, Paul A MartineauAbstract:Purpose Twelve case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential Stress Riser for fracture formation. The recent increase in double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the Stress Riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a Stress Riser to fracture and that this effect increases with the size of the tunnel (8mm versus 10mm) and with the number of tunnels (one versus two). Method Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7mm, 6 mm) were drilled in fourth generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels, were loaded to failure. Result All fractures occurred through the tunnels in the double tunnel group whereas fractures did not consistently occur through the tunnels in the single tunnel groups. The mean fracture load was 6145 N 471 N in the native group, 5691 N 198 N in the 8 mm single tunnel group, 5702 N 282 N in the 10 mm single tunnel group, and 4744 N 418 N in the double tunnel group. The mean fracture load for the double tunnel group was significantly different when compared to native, 8 mm single bundle, and 10 mm single bundle groups independently (p value = 0.0016, 0.0060, and 0.0038 respectively). No other statistically significant differences were identified. Conclusion An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a Stress Riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparcity of reported peri-ACL reconstruction femur fractures in single femoral tunnel techniques. However, the increased fracture risk in double bundle ACL reconstruction is a cause for concern and may impact patient selection.
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peri anterior cruciate ligament reconstruction femur fracture a biomechanical analysis of the femoral tunnel as a Stress Riser
Knee Surgery Sports Traumatology Arthroscopy, 2011Co-Authors: Thomas Steffen, Yung Han, Zeeshan M Sardar, Scott Mcgrail, Paul A MartineauAbstract:Purpose Sixteen case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential Stress Riser for fracture formation. Additionally, double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the significance of a Stress Riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a Stress Riser for fracture and that this effect increases with the size of the tunnel (8 mm vs. 10 mm) and with the number of tunnels (1 vs. 2).
Nilesh Powar - One of the best experts on this subject based on the ideXlab platform.
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fatigue life prediction of corrosion damaged high strength steel using an equivalent Stress Riser esr model part ii model development and results
International Journal of Fatigue, 2009Co-Authors: D T Rusk, W Hoppe, William Braisted, Nilesh PowarAbstract:Abstract The fatigue life of metallic aircraft structural components can be significantly reduced by environmentally induced corrosion. However, there have historically been no analytical methods to quantify the specific fatigue life reduction of individual unfailed corroded components with any reasonable degree of confidence. As part of a NAVAIR high-strength steel corrosion–fatigue assessment program, methods were studied to predict the impact that corrosion-induced surface roughness has on the fatigue life of high-strength steel aircraft components. The steels of interest produce general corrosion in patches as well as localized material loss similar to pitting. In addition, this type of corrosion has characteristic features over a wide range of scales. Consequently, traditional finite element analysis approaches are not well suited to this problem, since the mesh required to accurately reflect the fine details distributed over the entire corrosion patch make computation unrealistic. Therefore, approximate methods were developed that allow localized regions of interest of high Stress to be identified. Subsequently, a simple notch metric formula is employed to approximate the Stress Riser in these regions of interest. Finally, an extension of Peterson’s fatigue notch sensitivity theory is applied to these small “notches” that has the result of suppressing the effect of smaller notches compared to larger notches in the prediction of life. Each region of interest is assigned a probability of crack initiation as a function of fatigue cycles, based on a probabilistic strain–life analysis using the predicted notch factor. The net life (to crack initiation) for the component is then the product of the survivabilities of all of the individual regions of interest on the component surface. Tests on corroded fatigue specimens have been conducted to both calibrate the parameters in the Peterson model as well as to test the life prediction capability of the approach. Predictions from the resulting model have demonstrated that an empirical approach to corrosion surface damage can be utilized to generate probabilistic life predictions that have substantial engineering value in assessing the residual fatigue life of corroded AF1410 steel components, and that the modeling technique can capture the significant corrosion features that cause fatigue cracking in most cases, especially for more severely corroded surfaces.
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fatigue life prediction of corrosion damaged high strength steel using an equivalent Stress Riser esr model part ii model development and results
International Journal of Fatigue, 2009Co-Authors: D T Rusk, W Hoppe, William Braisted, Nilesh PowarAbstract:Abstract The fatigue life of metallic aircraft structural components can be significantly reduced by environmentally induced corrosion. As part of a NAVAIR High Strength Steel Corrosion–Fatigue Assessment Program, methods were studied to predict the impact that corrosion-induced surface roughness has on the fatigue life of high-strength steel aircraft components. In order to adequately capture the corrosion damage features that cause fatigue cracking, a representative set of well-characterized corrosion–fatigue test results were generated to be used for model development. The test specimens fabricated for this program consisted of bare, unnotched AF1410 steel flat plates with a 25.4 mm diameter corrosion patch on one side. Two sets of test specimens were fabricated and tested, with one set abrasive blasted after heat treatment, and the other set hand polished after heat treatment. A method of growing corrosion in the laboratory was developed that consisted of filter paper soaked in a 3.5% NaCl solution and placed at the center of the test plate gage section, with a voltage applied across the filter paper to accelerate corrosion growth. High-resolution 3D surface topography data was collected from the corroded region on each test plate prior to fatigue testing using a commercial white-light interference microscope. Constant-amplitude fatigue tests were performed on corroded and uncorroded test plates at several different Stress levels, for three different corrosion exposure levels. Post-test fractographic analysis of the corroded specimens indicate that all of the critical cracks originated from small corrosion notches on the order of 10–200 μm in width, 10–120 μm in height and 2–100 μm in depth. These notches were not considered to be pits in that the depth dimension was less than the surface dimensions. The repeatability of the fatigue initiating mechanism for corrosion damaged surfaces in this material indicates that it should be possible to develop a single modeling approach that reasonably captures the effects of corrosion notches in reducing fatigue life.
Mark S Vrahas - One of the best experts on this subject based on the ideXlab platform.
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tibial plateau fracture following anterior cruciate ligament reconstruction
Knee Surgery Sports Traumatology Arthroscopy, 2004Co-Authors: Kai Mithofer, Thomas J Gill, Mark S VrahasAbstract:A case is presented of a tibial plateau fracture after previous anterior cruciate ligament reconstruction using patellar tendon autograft. The tibial plateau fracture occurred through the transosseous tibial tunnel and followed a torsional injury to the involved extremity. The Stress Riser effect of the transosseous tibial tunnel and the anatomic location of the cortical defect probably facilitated development of the fracture. Minimally invasive fixation of the fracture was effective in preserving knee stability without need for revision anterior cruciate ligament reconstruction.
Thomas Steffen - One of the best experts on this subject based on the ideXlab platform.
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proximal tibial fracture following anterior cruciate ligament reconstruction surgery a biomechanical analysis of the tibial tunnel as a Stress Riser
Knee Surgery Sports Traumatology Arthroscopy, 2017Co-Authors: Wassim Aldebeyan, Antony Liddell, Thomas Steffen, Lorne Beckman, Paul A MartineauAbstract:Purpose This is the first biomechanical study to examine the potential Stress Riser effect of the tibial tunnel or tunnels after ACL reconstruction surgery. In keeping with literature, the primary hypothesis tested in this study was that the tibial tunnel acts as a Stress Riser for fracture propagation. Secondary hypotheses were that the Stress Riser effect increases with the size of the tunnel (8 vs. 10 mm), the orientation of the tunnel [standard (STT) vs. modified transtibial (MTT)], and with the number of tunnels (1 vs. 2).
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peri anterior cruciate ligament reconstruction femur fracture a biomechanical analysis of the femoral tunnel as a Stress Riser
Orthopaedic Proceedings, 2012Co-Authors: Thomas Steffen, Yung Han, Zeeshan M Sardar, Scott Mcgrail, Paul A MartineauAbstract:Purpose Twelve case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential Stress Riser for fracture formation. The recent increase in double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the Stress Riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a Stress Riser to fracture and that this effect increases with the size of the tunnel (8mm versus 10mm) and with the number of tunnels (one versus two). Method Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7mm, 6 mm) were drilled in fourth generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels, were loaded to failure. Result All fractures occurred through the tunnels in the double tunnel group whereas fractures did not consistently occur through the tunnels in the single tunnel groups. The mean fracture load was 6145 N 471 N in the native group, 5691 N 198 N in the 8 mm single tunnel group, 5702 N 282 N in the 10 mm single tunnel group, and 4744 N 418 N in the double tunnel group. The mean fracture load for the double tunnel group was significantly different when compared to native, 8 mm single bundle, and 10 mm single bundle groups independently (p value = 0.0016, 0.0060, and 0.0038 respectively). No other statistically significant differences were identified. Conclusion An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a Stress Riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparcity of reported peri-ACL reconstruction femur fractures in single femoral tunnel techniques. However, the increased fracture risk in double bundle ACL reconstruction is a cause for concern and may impact patient selection.
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peri anterior cruciate ligament reconstruction femur fracture a biomechanical analysis of the femoral tunnel as a Stress Riser
Knee Surgery Sports Traumatology Arthroscopy, 2011Co-Authors: Thomas Steffen, Yung Han, Zeeshan M Sardar, Scott Mcgrail, Paul A MartineauAbstract:Purpose Sixteen case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential Stress Riser for fracture formation. Additionally, double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the significance of a Stress Riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a Stress Riser for fracture and that this effect increases with the size of the tunnel (8 mm vs. 10 mm) and with the number of tunnels (1 vs. 2).