The tension property of aluminum-alloy sheet with different microstructures is measured, and the surface and tension fracture morphology of tension sample with and without orange peel are observed by using scanning el...The tension property of aluminum-alloy sheet with different microstructures is measured, and the surface and tension fracture morphology of tension sample with and without orange peel are observed by using scanning electron microscope （SEM）. Surface roughness and nano hardness of tension sample are measured. The results show that the average elongation of the samples with orange peel is lower than that without orange peel ; especially the r value of per- pendicular to the rolling direction is much lower than that without orange peel. The tension surface of the orange peel samples is very rough; various parameters of surface roughness are higher. Under the observation of SEM, a wider slid- ing band with a micro crack on the surface of orange peel sample can be found. The various parameters of surface rough- ness without orange peel sample are near to zero, the sliding band is narrow and without micro cracks. The dimple width in tensile fracture of orange peel sample is larger than that without orange peel sample, but shear lip is narrower. The nano hardness testing results show that samples with orange peel behave high elastic modulus, high hardness, and high maximum load, but low plastic deformation depth. These mentioned features can completely describe surface and frac- ture morphology of tension samt31es with oranze peel.展开更多
To explore biomechanic characteristics and clinical outcome of absorbable polydloxanone (PDS) treating patellar fractures.Methods The tensile strength test of PDS 0-0 or PDS 1-0 sutures were made in WDW305 electro-uni...To explore biomechanic characteristics and clinical outcome of absorbable polydloxanone (PDS) treating patellar fractures.Methods The tensile strength test of PDS 0-0 or PDS 1-0 sutures were made in WDW305 electro-universal tester.A total of 60 cases were classified randomly and equally into two groups:treatment group (treated with the absorbable PDS tension hand) and Kirschner wire metals tension band control group (control group).Anatomy reduction was performed with towel clip fixation during operation.Treatment group was managed with diameter 1.5 mm Kirschner wires drilling two pores on the near or distal segment of patellar fracture end are penetrating through two strands of absorbable PDS 0-0 or PDS 1-0 sutures for a satisfactory fracture fixation.Control group was treated with Kirschner wires (2.0 mm in diameter) and steel wire (1.0 mm in diameter) of type “8” tension band fixation.Results Tensile strength testing showed that the biggest tensile of a strand PDS 0-0 sutures was 71.50 N and that of PDS 1-0 97.48 N,when the length was three times more than the initial.Two groups were followed up and the mean fracture healing time was two months,without broken wire or dislocation.Treatment group showed excellent clinical results in 21 cases,good in six and fair in three;while control group showed excellent clinical results in 19 cases,good in seven and fair in four,with no statistical difference compared with treatment group (χ2=0.32,P>0.05).Conclusion Absorbable PDS tension band has better characteristics of mechanics and creepage in treating patellar fractures.It can avoid defects of secondary operation and complications like needle-tail pain and sharped skin resulted from metal tension band fixation.Meanwhile,it is economic and worthy of further clinical application.16 refs,4 figs.展开更多
Purpose： Tension band wiring is commonly used for fixation of simple transverse fractures. The popular configuration is parallel Kirschner wires （K-wires） and a stainless steel wire loop placed in a vertically orie...Purpose： Tension band wiring is commonly used for fixation of simple transverse fractures. The popular configuration is parallel Kirschner wires （K-wires） and a stainless steel wire loop placed in a vertically oriented figure-of-8. Methods： We used a wooden model of a patella with a midway transverse fracture and compared four different types of fixation. The first construct had a vertical figure-of-8 with one twist of wire. The second contained a vertical figure-of-8 with two twists of wire. The third was a vertical figure-of-8 with two twists of wire placed at adjacent corners while the last one had a horizontal figure-of-8 with two twists of wire placed at adjacent corners, lnterfragmentary compression at the point of wire breakage was measured for each construct as well as permanent displacement on cyclic loading. Results： Placement of the figure-of-eight in a horizontal orientation with two wire twists at the corner improved interfragmentary compression by 63% （p 〈 0.05, Tukey post ]hoc test）. On cyclic loading, all the constructs with vertical figure-of-eight but none with a horizontal construct failed （p = 0.01; Fisher＇s exact test）. Permanent fracture displacement after cyclic loading was ,57% lower with horizontal figure- of-eight constructs （p 〈 0.05; t test）. Conclusion： Placing wire twists at the corner and a horizontal placement of figure-of-8 improves stability of the construct.展开更多
文摘The tension property of aluminum-alloy sheet with different microstructures is measured, and the surface and tension fracture morphology of tension sample with and without orange peel are observed by using scanning electron microscope （SEM）. Surface roughness and nano hardness of tension sample are measured. The results show that the average elongation of the samples with orange peel is lower than that without orange peel ; especially the r value of per- pendicular to the rolling direction is much lower than that without orange peel. The tension surface of the orange peel samples is very rough; various parameters of surface roughness are higher. Under the observation of SEM, a wider slid- ing band with a micro crack on the surface of orange peel sample can be found. The various parameters of surface rough- ness without orange peel sample are near to zero, the sliding band is narrow and without micro cracks. The dimple width in tensile fracture of orange peel sample is larger than that without orange peel sample, but shear lip is narrower. The nano hardness testing results show that samples with orange peel behave high elastic modulus, high hardness, and high maximum load, but low plastic deformation depth. These mentioned features can completely describe surface and frac- ture morphology of tension samt31es with oranze peel.
文摘To explore biomechanic characteristics and clinical outcome of absorbable polydloxanone (PDS) treating patellar fractures.Methods The tensile strength test of PDS 0-0 or PDS 1-0 sutures were made in WDW305 electro-universal tester.A total of 60 cases were classified randomly and equally into two groups:treatment group (treated with the absorbable PDS tension hand) and Kirschner wire metals tension band control group (control group).Anatomy reduction was performed with towel clip fixation during operation.Treatment group was managed with diameter 1.5 mm Kirschner wires drilling two pores on the near or distal segment of patellar fracture end are penetrating through two strands of absorbable PDS 0-0 or PDS 1-0 sutures for a satisfactory fracture fixation.Control group was treated with Kirschner wires (2.0 mm in diameter) and steel wire (1.0 mm in diameter) of type “8” tension band fixation.Results Tensile strength testing showed that the biggest tensile of a strand PDS 0-0 sutures was 71.50 N and that of PDS 1-0 97.48 N,when the length was three times more than the initial.Two groups were followed up and the mean fracture healing time was two months,without broken wire or dislocation.Treatment group showed excellent clinical results in 21 cases,good in six and fair in three;while control group showed excellent clinical results in 19 cases,good in seven and fair in four,with no statistical difference compared with treatment group (χ2=0.32,P>0.05).Conclusion Absorbable PDS tension band has better characteristics of mechanics and creepage in treating patellar fractures.It can avoid defects of secondary operation and complications like needle-tail pain and sharped skin resulted from metal tension band fixation.Meanwhile,it is economic and worthy of further clinical application.16 refs,4 figs.
文摘Purpose： Tension band wiring is commonly used for fixation of simple transverse fractures. The popular configuration is parallel Kirschner wires （K-wires） and a stainless steel wire loop placed in a vertically oriented figure-of-8. Methods： We used a wooden model of a patella with a midway transverse fracture and compared four different types of fixation. The first construct had a vertical figure-of-8 with one twist of wire. The second contained a vertical figure-of-8 with two twists of wire. The third was a vertical figure-of-8 with two twists of wire placed at adjacent corners while the last one had a horizontal figure-of-8 with two twists of wire placed at adjacent corners, lnterfragmentary compression at the point of wire breakage was measured for each construct as well as permanent displacement on cyclic loading. Results： Placement of the figure-of-eight in a horizontal orientation with two wire twists at the corner improved interfragmentary compression by 63% （p 〈 0.05, Tukey post ]hoc test）. On cyclic loading, all the constructs with vertical figure-of-eight but none with a horizontal construct failed （p = 0.01; Fisher＇s exact test）. Permanent fracture displacement after cyclic loading was ,57% lower with horizontal figure- of-eight constructs （p 〈 0.05; t test）. Conclusion： Placing wire twists at the corner and a horizontal placement of figure-of-8 improves stability of the construct.
