Department of Traumatology and Reconstructive Surgery, University Hospital Carl-Gustav-Carus, Fetscherstrasse 74, 01309 Dresden, Germany.
Foot Ankle Int. 2011 Mar;32(3):307-13. doi: 10.3113/FAI.2011.0307.
The aim of this biomechanical cadaver study of calcaneal fractures was to investigate whether a locking calcaneal plate provides more stiffness in osteoporotic bone compared to a non-locking plate.
Sixteen fresh frozen bone mineral density (BMD)-matched cadaver feet were tested in a four-part model of a Sanders Type IIB calcaneal fracture. The fractures were fixed either with a non-locking AO (Sanders) plate or an interlocking AO plate (Synthes, Paoli, PA) to the lateral calcaneal wall with six screws. Specimens were subjected to cyclic loading which was increased stepwise to full body weight. Displacement of the posterior facet fragment was measured with an optical tracking system in the sagittal and transverse planes.
No statistically significant differences were observed between the non-locking and the locking plates with respect to number of cycles to failure or 1-mm displacement of the posterior facet. The initial stiffness was significantly higher for non-locking plates.
In osteoporotic bone, the greater stiffness of the screw-locking-plate construct was offset by the smaller diameter of the screw threads and the lower friction between the plate and bone when a locking plate was used. In clinical practice, the plate should first be compressed to osteoporotic bone with cancellous screws and at least two screws should be placed in the anterior process and in the tuberosity of the calcaneus.
本生物力学尸体研究旨在探讨跟骨骨折时，锁定跟骨板是否比非锁定板在骨质疏松骨中提供更高的刚度。
将十六个新鲜冷冻骨密度（BMD）匹配的尸体足在 Sanders IIB 型跟骨骨折的四部分模型中进行测试。骨折通过外侧跟骨壁的非锁定 AO（Sanders）板或锁定 AO 板（Synthes，Paoli，PA）用六根螺钉固定。标本接受逐步增加至全体重的循环加载。用光学跟踪系统测量后关节面碎片在矢状面和横断面上的位移。
在失败的循环次数或后关节面 1 毫米位移方面，非锁定板和锁定板之间没有观察到统计学上的显著差异。非锁定板的初始刚度显著更高。
在骨质疏松骨中，使用锁定板时，由于螺钉锁定板结构的螺纹直径较小且板与骨之间的摩擦力较低，因此更大的刚度被抵消了。在临床实践中，应先用松质骨螺钉将板压缩至骨质疏松骨，并且至少应将两个螺钉放置在前突和跟骨结节中。
