Behring Jon K, Gjerdet Nils R, Mølster Anders
The Orthopaedic Biomaterials Project, University of Bergen and Haukeland University Hospital, Norway.
Clin Orthop Relat Res. 2002 Nov(404):368-72. doi: 10.1097/00003086-200211000-00054.
Cortical 3.5-mm stainless steel screws with hexagonal heads and corresponding screwdrivers from two manufacturers were investigated. Measurement of dimensions and torsional testing were done to study slippage between the screw and the driver bit. There were only small differences in dimensions between the manufacturers. Ultimate torque values obtained were at the level of 2.7 N-m where reaming of the screw socket took place. Additional rotation resulted in approximately (1/2) of the maximum torque. Subsequent torque testing in the opposite direction, corresponding to removal of the screw, revealed that the torque values were equally low in that direction. Additional insertion and removal of bone screws with hexagonal sockets are hampered after only one episode of slippage. It is justified to consider new shapes of drive bits and corresponding screw head sockets, such as a fluted multiedge configuration.
对来自两个制造商的带有六角头的3.5毫米皮质不锈钢螺钉及相应螺丝刀进行了研究。进行尺寸测量和扭转测试以研究螺钉与螺丝刀刀头之间的滑动情况。制造商之间的尺寸仅有微小差异。获得的极限扭矩值在2.7牛米水平，此时螺钉孔发生扩孔。额外旋转导致扭矩约为最大扭矩的(1/2)。随后在相反方向进行对应于拧出螺钉的扭矩测试，结果表明该方向的扭矩值同样较低。仅一次滑动后，带有六角孔的接骨螺钉的额外插入和拧出就会受到阻碍。考虑采用新形状的刀头和相应的螺钉头孔，如带槽多边缘结构是合理的。
