AIM:To develop a new internal fixation device for comminuted, unstable fractures of the distal femur,and to offer a guide for management of these injuries based on biomechanical studies.METHODS:Ten fresh adult femurs ...AIM:To develop a new internal fixation device for comminuted, unstable fractures of the distal femur,and to offer a guide for management of these injuries based on biomechanical studies.METHODS:Ten fresh adult femurs of cadavers.All femurs were similarly made of the models of supracondylar intercondylar fractures,then double plating with a plate in combination with a polythene plate,and the conventional sigle plating was served as the control.The biomechanic tests (compression,bending,torsion) were performed.RESULTS:The bending and torsion tests demonstrated that the double plating groups were much stronger (P< 0.01) than the single plating groups in anti bending and anti torsion.During the tests loading to failure, the double plating groups failed at a mean peak load of 11 540 N in axial compression,700 N in anterior bending 1 082 N in posterior bending,593 N in medial bending,1 010 N in lateral bending.CONCLUSION: Double plating with a plate in combination with a polythene plate is an excellent technique and design modification for severely comminuted fractures of the distal femur,which may provide a high stability and solidness so that early mobilization and weight bearing are allowed.展开更多
By means of FEM, the physiologi cal blood flow in coronary bypass graft is simula ted. The stenosis in coronary artery is involved in the graft model, and the def ormation of graft end to allow the surgical suture wit...By means of FEM, the physiologi cal blood flow in coronary bypass graft is simula ted. The stenosis in coronary artery is involved in the graft model, and the def ormation of graft end to allow the surgical suture with a smaller diameter coron ary is taken into consideration. The flow pattern, secondary flow and wall shear stress in the vicinity of anastomosis are analyzed. It is shown that a zone of low wall stress and high wall stress gradient exists downstream the toe. The flo or opposed to the anastomosis is an area of high wall stress and high wall stres s gradient. Both the toe downstream and the anastomosis bottom floor are prone t o intimal hyperplasia.展开更多
文摘AIM:To develop a new internal fixation device for comminuted, unstable fractures of the distal femur,and to offer a guide for management of these injuries based on biomechanical studies.METHODS:Ten fresh adult femurs of cadavers.All femurs were similarly made of the models of supracondylar intercondylar fractures,then double plating with a plate in combination with a polythene plate,and the conventional sigle plating was served as the control.The biomechanic tests (compression,bending,torsion) were performed.RESULTS:The bending and torsion tests demonstrated that the double plating groups were much stronger (P< 0.01) than the single plating groups in anti bending and anti torsion.During the tests loading to failure, the double plating groups failed at a mean peak load of 11 540 N in axial compression,700 N in anterior bending 1 082 N in posterior bending,593 N in medial bending,1 010 N in lateral bending.CONCLUSION: Double plating with a plate in combination with a polythene plate is an excellent technique and design modification for severely comminuted fractures of the distal femur,which may provide a high stability and solidness so that early mobilization and weight bearing are allowed.
文摘By means of FEM, the physiologi cal blood flow in coronary bypass graft is simula ted. The stenosis in coronary artery is involved in the graft model, and the def ormation of graft end to allow the surgical suture with a smaller diameter coron ary is taken into consideration. The flow pattern, secondary flow and wall shear stress in the vicinity of anastomosis are analyzed. It is shown that a zone of low wall stress and high wall stress gradient exists downstream the toe. The flo or opposed to the anastomosis is an area of high wall stress and high wall stres s gradient. Both the toe downstream and the anastomosis bottom floor are prone t o intimal hyperplasia.
