Background: Anatomic single bundle is a widely accepted technique for anterior cruciate ligament (ACL) reconstruction. The research question: are transverse pins safe to fix the ACL graft on the femoral side in anatom...Background: Anatomic single bundle is a widely accepted technique for anterior cruciate ligament (ACL) reconstruction. The research question: are transverse pins safe to fix the ACL graft on the femoral side in anatomic single bundle ACL reconstruction? Material and Methods: Ten cadaveric femoral dry bones were tested in this study. Thirty mm long sockets were prepared in the center of the anatomic ACL footprints. Transverse pin guide for soft tissue graft was used to prepare pin sites through the femoral sockets using three different positions. The positions (A) and (B) had a lateral entry point and differ in their inclination in relation to the joint line;while (A) has a 15° open laterally plane, (B) has a 15° closed laterally. The last position (C) had a medial entry point for the transverse pins. The relations of the transverse pins to the anatomic landmarks (lateral epicondyle and articular cartilage) in addition to the path of the pins within the femoral sockets were recorded. Results: Pins inserted while the guide in position (A) crossed the center of the femoral sockets and were fully seated within the bone of the distal femur. Distal pins inserted through inclination (B) were found to penetrate the posterior cortex of the distal femur proximal to the lateral femoral condyle. Pins inserted from the medial side (C) achieved central position through the femoral tunnel. The entry point for transverse pins through lateral entry points was very close to the attachment of the lateral collateral ligament at the lateral epicondyle while medial entry point avoided important structures. Conclusion: Transverse pins inserted through the lateral entry point carry the risk of penetrating the posterior cortex of the femur and/or damage the attachment of the lateral collateral ligament. Medial entry point may give a safer approach but needs further adjustments of the guides and clinical trials of the technique.展开更多
To enhance the thermo-hydraulic performance of cooling channels,this investigation examines the influence of distinct cross-sectional shapes(i.e.,triangular,rectangular,and hexagonal)of twisted pin fins and their arra...To enhance the thermo-hydraulic performance of cooling channels,this investigation examines the influence of distinct cross-sectional shapes(i.e.,triangular,rectangular,and hexagonal)of twisted pin fins and their arrangements in straight and cross rows.An ambient air cooling test platform was established to numerically and experimentally investigate the flow and heat transfer characteristics of 360°twisted pin fins at Re=15200-22800.The findings reveal that straight rows exhibit higher Nu values than cross rows for triangular and rectangular twisted pin fins,and Nu increases with Re.In contrast,for hexagonal twisted pin fins,only straight rows at Re=19000 exhibit superior overall thermal performance compared to cross rows.Notably,the heat transfer performance of the cooling channel with hexagonal twisted fins surpasses both triangular and rectangular configurations,especially at high Reynolds numbers(Re=22800).Although the heat transfer coefficient of the cooling channel with hexagonal twisted fins is significantly enhanced by 132.71%compared to the flat channel,it also exhibits the highest thermal resistance and relative friction among the three types of twisted fins,the maximum of which are 2.14 and 16.55.Furthermore,the hydrothermal performance factor(HTPF)of the cooling channels with different types of twisted pin fins depends on the Reynolds number and arrangement modes.At Re=15200,the highest HTPF achieved for the cross-row hexagonal twisted pin fins is 0.99.展开更多
文摘Background: Anatomic single bundle is a widely accepted technique for anterior cruciate ligament (ACL) reconstruction. The research question: are transverse pins safe to fix the ACL graft on the femoral side in anatomic single bundle ACL reconstruction? Material and Methods: Ten cadaveric femoral dry bones were tested in this study. Thirty mm long sockets were prepared in the center of the anatomic ACL footprints. Transverse pin guide for soft tissue graft was used to prepare pin sites through the femoral sockets using three different positions. The positions (A) and (B) had a lateral entry point and differ in their inclination in relation to the joint line;while (A) has a 15° open laterally plane, (B) has a 15° closed laterally. The last position (C) had a medial entry point for the transverse pins. The relations of the transverse pins to the anatomic landmarks (lateral epicondyle and articular cartilage) in addition to the path of the pins within the femoral sockets were recorded. Results: Pins inserted while the guide in position (A) crossed the center of the femoral sockets and were fully seated within the bone of the distal femur. Distal pins inserted through inclination (B) were found to penetrate the posterior cortex of the distal femur proximal to the lateral femoral condyle. Pins inserted from the medial side (C) achieved central position through the femoral tunnel. The entry point for transverse pins through lateral entry points was very close to the attachment of the lateral collateral ligament at the lateral epicondyle while medial entry point avoided important structures. Conclusion: Transverse pins inserted through the lateral entry point carry the risk of penetrating the posterior cortex of the femur and/or damage the attachment of the lateral collateral ligament. Medial entry point may give a safer approach but needs further adjustments of the guides and clinical trials of the technique.
基金sponsored by the China Postdoctoral Science Foundation(2023M732569)the Fundamental Research Program of Shanxi Province,China(202203021212263)+3 种基金Shanxi Scholarship Council of China(2023-055,2023-143)Chunhui Project Foundation of the Education Department of China(202200075)Science and Technology Innovation Project of Colleges and Universities in Shanxi Province(2022L061)financially supported by the Shanxi Provincial Key Laboratory ofHigh Efficiency Heat Storage and Low Carbon Heat Supply,Taiyuan Boiler Group Co.,Ltd。
文摘To enhance the thermo-hydraulic performance of cooling channels,this investigation examines the influence of distinct cross-sectional shapes(i.e.,triangular,rectangular,and hexagonal)of twisted pin fins and their arrangements in straight and cross rows.An ambient air cooling test platform was established to numerically and experimentally investigate the flow and heat transfer characteristics of 360°twisted pin fins at Re=15200-22800.The findings reveal that straight rows exhibit higher Nu values than cross rows for triangular and rectangular twisted pin fins,and Nu increases with Re.In contrast,for hexagonal twisted pin fins,only straight rows at Re=19000 exhibit superior overall thermal performance compared to cross rows.Notably,the heat transfer performance of the cooling channel with hexagonal twisted fins surpasses both triangular and rectangular configurations,especially at high Reynolds numbers(Re=22800).Although the heat transfer coefficient of the cooling channel with hexagonal twisted fins is significantly enhanced by 132.71%compared to the flat channel,it also exhibits the highest thermal resistance and relative friction among the three types of twisted fins,the maximum of which are 2.14 and 16.55.Furthermore,the hydrothermal performance factor(HTPF)of the cooling channels with different types of twisted pin fins depends on the Reynolds number and arrangement modes.At Re=15200,the highest HTPF achieved for the cross-row hexagonal twisted pin fins is 0.99.
