Sandborn P M, Cook S D, Kester M A, Haddad R J
Clin Orthop Relat Res. 1987 Sep(222):249-54.
A unicompartmental knee implant was retrieved after 11 years in situ. The cast stainless steel femoral component had fractured approximately 1 cm from the anterior tip. The implant and clinical tolerance were analyzed to ascertain the factors associated with the mechanical failure. Increased tensile stresses owing to poor surgical placement and wear on the weight-bearing surface of the component, together with the quality of implant material, influenced the mechanical failure. Examination of the fracture surface revealed fatigue to be the mode of failure. Microscopic analysis of sections through the specimens showed a high inclusion content and inhomogeneous grain size, typical of the cast stainless steel from which the femoral component was fabricated.
一个单髁膝关节植入物在原位使用11年后被取出。铸造不锈钢股骨部件在距前端约1厘米处发生骨折。对该植入物和临床耐受性进行了分析，以确定与机械故障相关的因素。手术放置不当导致的拉伸应力增加以及部件承重表面的磨损，再加上植入材料的质量，影响了机械故障。对骨折表面的检查显示疲劳是失效模式。对标本切片的显微镜分析显示夹杂物含量高且晶粒尺寸不均匀，这是制造股骨部件所用铸造不锈钢的典型特征。
