Hutchinson D T, Savory K M, Bachus K N
Department of Orthopaedics, University of Utah School of Medicine, Salt Lake City 84132, USA.
J Biomed Mater Res. 1997 Oct;37(1):94-9. doi: 10.1002/(sici)1097-4636(199710)37:1<94::aid-jbm11>3.0.co;2-q.
Silastic small joint spacers for the metacarpophalangeal joint fail catastrophically at a reported rate ranging from 2 to 26%. Although the exact cause of this problem is not known, it is speculated that failure is due to the propagation of flaws generated in the material surface. In addition to wear secondary to bony impingement, these flaws can be introduced through manufacturing, surgical handling, and in vivo frictional wear. In an effort to identify an elastomeric material that will function similarly to Silastic as a self-hinging joint spacer but provide an increased functional life, we have investigated and compared the crack-growth properties of two polyurethanes, ChronoFlex and Medicaflex, and a thermoplastic elastomer, Santoprene, with those of Silastic. The materials were evaluated after sterilization by either ethylene oxide or gamma irradiation in an ASTM standard flexing machine under conditions of high humidity and body temperature both before and after artificially aging. In each case, the materials investigated presented significantly lower crack-growth rates than Silastic (p < 0.001).
用于掌指关节的硅橡胶小关节间隔器的灾难性失败率据报道在2%至26%之间。尽管这个问题的确切原因尚不清楚，但据推测，失败是由于材料表面产生的缺陷扩展所致。除了骨撞击引起的磨损外，这些缺陷可通过制造、手术操作和体内摩擦磨损引入。为了确定一种与硅橡胶功能相似的弹性体材料作为自铰链关节间隔器，但能延长其功能寿命，我们研究并比较了两种聚氨酯（ChronoFlex和Medicaflex）以及一种热塑性弹性体（山都平）与硅橡胶的裂纹扩展特性。在通过环氧乙烷或伽马射线灭菌后，在ASTM标准弯曲试验机中，于高湿度和体温条件下，在人工老化前后对这些材料进行了评估。在每种情况下，所研究的材料的裂纹扩展速率均显著低于硅橡胶（p < 0.001）。
