Canet Fanny, Duke Kajsa, Bourgeois Yan, Laflamme G-Yves, Brailovski Vladimir, Petit Yvan
Hôpital du Sacré-Coeur, Montréal, Canada.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:5749-52. doi: 10.1109/IEMBS.2011.6091423.
The purpose of this study was to evaluate cable tension during installation, and during loading similar to walking in a cable grip type greater trochanter (GT), reattachment system. A 4th generation Sawbones composite femur with osteotomised GT was reattached with four Cable-Ready® systems (Zimmer, Warsaw, IN). Cables were tightened at 3 different target installation forces (178, 356 and 534 N) and retightened once as recommended by the manufacturer. Cables tension was continuously monitored using in-situ load cells. To simulate walking, a custom frame was used to apply quasi static load on the head of a femoral stem implant (2340 N) and abductor pull (667 N) on the GT. GT displacement (gap and sliding) relative to the femur was measured using a 3D camera system. During installation, a drop in cable tension was observed when tightening subsequent cables: an average 40+12.2% and 11 ± 5.9% tension loss was measured in the first and second cable. Therefore, retightening the cables, as recommended by the manufacturer, is important. During simulated walking, the second cable additionally lost up to 12.2+3.6% of tension. No difference was observed between the GT-femur gaps measured with cables tightened at different installation forces (p=0.32). The GT sliding however was significantly greater (0.9 ± 0.3 mm) when target installation force was set to only 178 N compared to 356 N (0.2 ± 0.1 mm); p<0.001. There were no significant changes when initial tightening force was increased to 534 N (0.3 ± 0.1 mm); p=0.11. In conclusion, the cable tightening force should be as close as possible to that recommended by the manufacturer, because reducing it compromises the stability of the GT fragment, whereas increasing it does not improve this stability, but could lead to cable breakage.
本研究的目的是评估在安装过程中以及在加载过程中（类似于在缆索握持型大转子（GT）重新附着系统中行走时）的缆索张力。使用带有截骨大转子的第4代Sawbones复合股骨，通过四个Cable-Ready®系统（Zimmer，华沙，印第安纳州）进行重新附着。缆索在3种不同的目标安装力（178、356和534 N）下收紧，并按照制造商的建议重新收紧一次。使用原位测力传感器持续监测缆索张力。为了模拟行走，使用定制框架对股骨柄植入物头部施加准静态载荷（2340 N），并对大转子施加外展肌拉力（667 N）。使用3D摄像系统测量大转子相对于股骨的位移（间隙和滑动）。在安装过程中，收紧后续缆索时观察到缆索张力下降：第一根和第二根缆索的张力损失平均分别为40 + 12.2%和11±5.9%。因此，按照制造商的建议重新收紧缆索很重要。在模拟行走过程中，第二根缆索的张力额外损失高达12.2 + 3.6%。在不同安装力下收紧缆索时测量的大转子 - 股骨间隙之间未观察到差异（p = 0.32）。然而，当目标安装力仅设置为178 N时，大转子滑动明显更大（0.9±0.3 mm），而设置为356 N时为（0.2±0.1 mm）；p < 0.001。当初始收紧力增加到534 N时（0.3±0.1 mm）没有显著变化；p = 0.11。总之，缆索收紧力应尽可能接近制造商推荐的值，因为降低它会损害大转子碎片的稳定性，而增加它并不能提高这种稳定性，但可能导致缆索断裂。
