tailieunhanh - báo cáo hóa học:" Biomechanical investigation of a novel ratcheting arthrodesis nail"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí sinh học quốc tế đề tài : Biomechanical investigation of a novel ratcheting arthrodesis nail | McCormick et al. Journal of Orthopaedic Surgery and Research 2010 5 74 http content 5 1 74 JOURNAL OF ORTHOPAEDIC SURGERY AND RESEARCH RESEARCH ARTICLE Open Access Biomechanical investigation of a novel ratcheting arthrodesis nail 1 I 1 1 2 3 Jeremy J McCormick Xinning Li Douglas R Weiss Kristen L Billiar John J Wixted Abstract Background Knee or tibiotalocalcaneal arthrodesis is a salvage procedure often with unacceptable rates of nonunion. Basic science of fracture healing suggests that compression across a fusion site may decrease nonunion. A novel ratcheting arthrodesis nail designed to improve dynamic compression is mechanically tested in comparison to existing nails. Methods A novel ratcheting nail was designed and mechanically tested in comparison to a solid nail and a threaded nail using sawbones models Pacific Research Laboratories Inc. . Intramedullary nails IM were implanted with a load cell Futek LTH 500 between fusion surfaces. Constructs were then placed into a servo-hydraulic test frame Model 858 Mini-bionix MTS Systems for application of 3 mm and 6 mm dynamic axial displacement n 3 group . Load to failure was also measured. Results Mean percent of initial load after 3-mm and 6-mm displacement was and for the solid nail and for the threaded nail and and for the ratcheting nail respectively. Stress-shielding as percentage of maximum load per test after 3-mm and 6-mm displacement averaged and solid nail and threaded nail and and ratcheting nail respectively. In the 6-mm trials statistically significant increase in initial load and decrease in stress-shielding for the ratcheting vs. solid nail p p and vs. threaded nail p p was observed. Load to failure for the ratcheting nail lbs threaded nail lbs and solid nail lbs. Conclusion With significantly increase of compressive load while decreasing stress-shielding at 6-mm of dynamic .