Okuizumi H, Harada A, Iwata H, Konishi N
Department of Orthopaedic Surgery, Chubu National Hospital, Obu, Aichi, Japan.
J Bone Miner Res. 1998 Dec;13(12):1940-5. doi: 10.1359/jbmr.1998.13.12.1940.
To reduce hip fractures during falls, we devised a new hip fracture preventive system to attenuate impact on the greater trochanteric region and studied the effects of the system on the femur. Twelve coupled, embalmed, cadaveric femora were used. Right femora were fractured without protection as a control and compared with left femora covered by the protection system, which consisted of a silicone gel pad or the silicone gel pad combined with a resin cover. The impact of a fall was simulated by mounting a femur in the horizontal plane and dropping an 8.4 kg mass on its greater trochanteric region. The impact load and time were measured using a load cell within the mass. The maximum strain during impact at the inferior side of the femoral neck was determined from an attached strain gauge. Trochanteric fractures were produced in 18 of the 24 femora (75%). The mean impact load for a drop height of 25 cm was reduced from 3117 N to 2176 N by silicone gel (p < 0.01) and to 1681 N by the addition of the resin cover (p < 0.01). The mean maximum strain was similarly reduced from 2276 microvarepsilon to 1872 microvarepsilon (p = 0.15) and to a mean 1559 microvarepsilon (p < 0. 05). The mean impact time was prolonged from 13 ms to 20 ms (p < 0. 01) and 22 ms (p < 0.01), respectively. The effect of the cover became more conspicuous as height increased. We concluded that the silicone gel pad provided effective impact attenuation, and the addition of the rigid cover was even more effective for impact reduction. This system was thought to be clinically useful in preventing hip fractures.
为减少跌倒时的髋部骨折，我们设计了一种新的髋部骨折预防系统，以减轻对大转子区域的撞击，并研究了该系统对股骨的影响。使用了12对防腐处理的尸体股骨。右侧股骨在无保护的情况下造成骨折作为对照，与覆盖有保护系统的左侧股骨进行比较，该保护系统由硅胶垫或硅胶垫与树脂外壳组成。通过将股骨安装在水平面上并在其大转子区域落下一个8.4千克的重物来模拟跌倒的撞击。使用重物内的测力传感器测量撞击力和时间。通过附着的应变片测定股骨颈下侧撞击时的最大应变。24根股骨中有18根（75%）发生了转子骨折。对于25厘米的跌落高度，硅胶使平均撞击力从3117牛降低到2176牛（p<0.01），添加树脂外壳后降低到1681牛（p<0.01）。平均最大应变同样从2276微应变降低到1872微应变（p=0.15），平均降低到1559微应变（p<0.05）。平均撞击时间分别从13毫秒延长到20毫秒（p<0.01）和22毫秒（p<0.01）。随着高度增加，外壳的效果变得更加明显。我们得出结论，硅胶垫提供了有效的撞击衰减，添加刚性外壳对减少撞击甚至更有效。该系统被认为在预防髋部骨折方面具有临床实用性。
