Wyss Urs P
Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB, Canada.
Department of Mechanical Engineering, Queen's University, Kingston, ON, Canada.
Front Med (Lausanne). 2019 Mar 26;6:56. doi: 10.3389/fmed.2019.00056. eCollection 2019.
Implanted and non-implanted medical devices, including artificial joints, are widely accepted to improve the quality of life of patients. While implant survival rates of over 80% can be accepted for artificial joints, there is still a large need to achieve higher survival rates at 15 years or longer to reduce the need for revisions due to implant failure before the end of the patient's life. Therefore, artificial joints are constantly improved with design changes and new designs, including modified or new materials. Most of these improvements perform as expected, but there are still cases where previously unknown failures occur, requiring premature revisions. A few examples of such unsuccessful improvements in the last 20 years are mentioned in this technical case report. The main focus of this paper is on an acetabular cup that was recalled due to unexpected revisions after a few weeks to a few months . The main reason for the revisions were small amounts of an oily residue containing endotoxins trapped inside the porous coating applied to the cup to facilitate bone ingrowth. The cup was recalled within 4 months after the company become aware of the problem, and prior to knowing exactly why the cups were failing early. The root cause analysis took several more months to complete. The lessons learned during the analysis are discussed so that similar events in other implantable medical devices can be avoided. The acetabular cup case aims to highlight that a timely root cause analysis, triggered by very few unexplained revisions, will benefit patients and improve the quality of life.
包括人工关节在内的植入式和非植入式医疗器械被广泛认可用于改善患者生活质量。虽然人工关节的植入存活率超过80%是可以接受的，但仍迫切需要在15年或更长时间内实现更高的存活率，以减少患者生命结束前因植入失败而进行翻修的需求。因此，人工关节不断通过设计变更和新设计进行改进，包括改良材料或采用新材料。这些改进大多如预期那样发挥作用，但仍有一些情况会出现此前未知的故障，需要提前进行翻修。本技术案例报告列举了过去20年中此类改进未成功的一些例子。本文的主要关注点是一种髋臼杯，该髋臼杯在几周至几个月后因意外翻修而被召回。翻修的主要原因是涂覆在髋臼杯上以促进骨长入的多孔涂层内部截留了少量含有内毒素的油性残留物。该公司在意识到问题后4个月内召回了该髋臼杯，且当时并不确切知道髋臼杯为何过早出现故障。根本原因分析又花费了几个月才完成。文中讨论了分析过程中吸取的经验教训，以便避免其他可植入医疗器械出现类似事件。髋臼杯案例旨在强调，由极少无法解释的翻修引发的及时根本原因分析将造福患者并提高生活质量。
