TECHNICAL ARTICLE—PEER-REVIEWED Premature Failure in Orthopedic Implants: Analysis of Three Different Cases C. Barbosa Æ J. L. do Nascimento Æ I. M. V. Caminha Æ I. C. Abud Submitted: 3 September 2008 / in revised form: 30 October 2008 / Published online: 22 November 2008 Ó ASM International 2008 Abstract The increasing lifetime of the population on a world-wide scale over the last decades has led to a sig- nificant growth in the use of surgical implants for replacement of bones and teeth in affected patients. Other factors, such as scientific-technological development and more frequent exposure of individuals to trauma risk, have also contributed to this general trend. Metallic materials designed for applications in surgical implants, no matter whether orthopedic or dental, must show a group of properties in which biocompatibility, mechanical strength, and resistance to degradation (by wear or corrosion) are of primary importance. In order to reach these aims, ortho- pedic materials must fulfill certain requirements, usually specified in standards. These requirements include chemi- cal composition, microstructure, and even macrographic appearances. In the present work, three cases of implant failure are presented. These cases demonstrate the most frequent causes of premature failure in orthopedic implants: inadequate surgical procedures and processing/ design errors. Evaluation techniques, including optical and scanning electron microscopy (SEM), were used to evalu- ate macroscopic and microstructural aspects of the failed implants, and the chemical composition of each material was analyzed. These evaluations showed that design errors and improper surgical procedures of outright violation of standards were the cause of the failures. Keywords Failure analysis Á Implant degradation Á Microscopy Introduction Orthopedic implants can be defined as devices that are used to replace bones or to help the fixation of fractured bones. They can be manufactured using different types of mate- rials. Some metallic materials, such as cobalt-chromium alloys, stainless steels, and titanium and its alloys are particularly suitable for this kind of application, because of an optimum combination of biocompatibility, corrosion resistance, mechanical strength (both under static and cyclic loading), and cost effectiveness [1, 2]. Although the use of titanium and its alloys has experienced a significant increase in the last decades [3], 316 L austenitic type stainless steel continues to be used in orthopedic surgical implants in many situations, and research efforts have led to the development of new austenitic stainless steels with lower nickel and higher manganese and nitrogen contents to minimize adverse allergic reactions typically associated with a sensitivity to nickel [4]. Since the average human life expectation has increased significantly in the past decades and is supposed to keep increasing in the near future [4], more and more implants are being used. In addition, the increased trauma risk as a consequence of more frequent exposure of many individ- uals to different types of accidents has precipitated a growing need for high-performance implants capable of withstanding severe loads for a longer time. For this rea- son, metallic materials designed for applications in surgical implants, whether orthopedic or dental, must show a group of properties that include biocompatibility, mechanical strength, and resistance to degradation (by wear or corro- sion) outstanding. In order to reach these aims, such materials must fulfill certain requirements, usually speci- fied in standards, that specify chemical composition, microstructure, and even macrographic appearance [1–4]. C. Barbosa (&) Á J. L. do Nascimento Á I. M. V. Caminha Á I. C. Abud Instituto Nacional de Tecnologia (INT), Avenida Venezuela, 82, Rio de Janeiro 20081-312, Brazil e-mail: cassiob@int.gov.br 123 J Fail. Anal. and Preven. (2009) 9:67–73 DOI 10.1007/s11668-008-9192-z