Thiele O C, Eckhardt C, Linke B, Schneider E, Lill C A
AO Research Institute, Clavadelerstrasse CH-7270, Davos Platz, Switzerland.
J Bone Joint Surg Br. 2007 May;89(5):701-5. doi: 10.1302/0301-620X.89B5.18504.
We investigated several factors which affect the stability of cortical screws in osteoporotic bone using 18 femora from cadavers of women aged between 45 and 96 years (mean 76). We performed bone densitometry to measure the bone mineral density of the cortical and cancellous bone of the shaft and head of the femur, respectively. The thickness and overall bone mass of the cortical layer of the shaft of the femur were measured using a microCT scanner. The force required to pull-out a 3.5 mm titanium cortical bone screw was determined after standardised insertion into specimens of the cortex of the femoral shaft. A significant correlation was found between the pull-out strength and the overall bone mass of the cortical layer (r(2) = 0.867, p < 0.01) and also between its thickness (r(2) = 0.826, p < 0.01) and bone mineral density (r(2) = 0.861, p < 0.01). There was no statistically significant correlation between the age of the donor and the pull-out force (p = 0.246), the cortical thickness (p = 0.199), the bone mineral density (p = 0.697) or the level of osteoporosis (p = 0.378). We conclude that the overall bone mass, the thickness and the bone mineral density of the cortical layer, are the main factors which affect the stability of a screw in human female osteoporotic cortical bone.
我们使用了18具年龄在45至96岁（平均76岁）女性尸体的股骨，研究了影响骨质疏松性骨中皮质骨螺钉稳定性的几个因素。我们分别进行了骨密度测量，以测量股骨骨干和股骨头皮质骨与松质骨的骨矿物质密度。使用微型CT扫描仪测量股骨骨干皮质层的厚度和整体骨量。在将3.5毫米钛质皮质骨螺钉标准化插入股骨干皮质标本后，测定拔出该螺钉所需的力。发现拔出强度与皮质层的整体骨量之间存在显著相关性（r(2)=0.867，p<0.01），其厚度（r(2)=0.826，p<0.01）与骨矿物质密度之间也存在显著相关性（r(2)=0.861，p<0.01）。供体年龄与拔出力（p=0.246）、皮质厚度（p=0.199）、骨矿物质密度（p=0.697）或骨质疏松程度（p=0.378）之间无统计学显著相关性。我们得出结论，皮质层的整体骨量、厚度和骨矿物质密度是影响人类女性骨质疏松性皮质骨中螺钉稳定性的主要因素。
