La Russa Valentina, Skallerud Bjørn, Klaksvik Jomar, Foss Olav A
Norwegian Orthopaedic Implant Research Unit, NKSOI, Orthopaedic Department, St. Olavs Hospital, Trondheim University Hospital.
Proc Inst Mech Eng H. 2011 Mar;225(3):220-7. doi: 10.1177/2041303310392638.
The stability of an external ring fixator mainly depends on wire tension. Wire fixators should maintain the tension during both wire clamping to the ring and removal of the tensioner device. In the present study the loss in wire tension related to fixator clamping and wire tensioner removal using three different wire fixator designs was studied. The fixators were based on two different cannulated bolts and a washer. Effects from two different pretension levels in combination with three different bolt torque levels upon loss in wire tension were described. Emitted wire vibration frequency was used to assess the corresponding wire tension. Wire tension was determined after each wire fixator tightening and after the removal of the wire tensioner. Increased bolt torque led to a small decrease in tension for both pretension levels. A considerable higher tension loss was measured when removing the wire tensioner. In all cases, the combination of a new cannulated bolt and a washer maintained the highest tension.
外固定环的稳定性主要取决于钢丝张力。钢丝固定器在钢丝夹到环以及拆除张紧装置的过程中都应保持张力。在本研究中，研究了使用三种不同钢丝固定器设计时，与固定器夹紧和拆除钢丝张紧器相关的钢丝张力损失。这些固定器基于两种不同的空心螺栓和一个垫圈。描述了两种不同预紧水平与三种不同螺栓扭矩水平对钢丝张力损失的影响。通过发出的钢丝振动频率来评估相应的钢丝张力。在每次拧紧钢丝固定器后以及拆除钢丝张紧器后测定钢丝张力。对于两种预紧水平，螺栓扭矩增加都会导致张力略有下降。拆除钢丝张紧器时测得的张力损失要高得多。在所有情况下，新型空心螺栓和垫圈的组合保持的张力最高。
