Lo que no te contaron de las fracturas de fémur / What nobody told you about femur fractures

Introducción: Se relaciona la bibliografía con la experiencia de nuestros cirujanos frente a un instrumental defectuoso en el tratamiento de fracturas de fémur con osteosíntesis endomedulares. Objetivos: 1) Enumerar inconvenientes técnicos que se presentan en las cirugías de fémur, 2) comparar diferentes Centros y problemas afrontados, 3) estimar los canales de reclamo. Materiales y Métodos: 1) Estudio retrospectivo, de observación, descriptivo sobre historias clínicas y archivo radiológico, 2) encuesta en línea enviada a traumatólogos generales, 3) consulta con la ANMAT, el IRAM, los Ministerios de Salud de la Ciudad Autónoma de Buenos Aires y de la Nación. Resultados: 1) 31 pacientes con fracturas de fémur tratados con osteosíntesis endomedulares entre enero de 2008 y agosto de 2013. Dieciocho casos de fallas o defectos del instrumental de colocación en 14 pacientes. Los problemas más frecuentes fueron las guías y las mechas, 2) 270 respuestas, 19 provincias argentinas, respuestas de Colombia, Ecuador, Italia, Australia y Bolivia. Se obtuvieron 180 respuestas de Centros privados y 90 de Centros públicos, 3) cuatro vías de reclamo: ANMAT bajo el programa de Tecnovigilancia, IRAM por el incumplimiento de las Normas ISO 9001, Ministerio de Salud por incumplimiento de la resolución 255 y la Ley Básica de Salud N.º 153, art. 12 (ítems k y l) y AAOT, en la subcomisión de Implantes. Conclusiones: Queda explícita la diferencia entre Centros públicos y privados; sin embargo, el medio laboral solo definió la prevalencia de inconvenientes técnicos, pero los inconvenientes fueron los mismos. Existen formas para denunciar y enfrentar esta problemática.

Background: This paper intends to correlate data obtained from different orthopedic surgical teams and literature on faulty instrumentation during femoral fracture treatment with intramedullary nailing. Objectives: 1) To define technical problems arising during surgical procedures to treat femoral fractures; 2) to compare different centers and problems; 3) to analyze possible ways to find a solution. Methods: 1) A retrospective, descriptive, observational study on clinical records and radiologic files was performed; 2) an on-line survey was sent to orthopedic surgeons; 3) a query was sent to ANMAT, IRAM, and Ministerios de Salud de la Ciudad Autónoma de Buenos Aires y de la Nación. Results: 1) 31 intramedullary femoral nailing procedures were performed from January 2008 to August 2013. Eighteen cases of surgical tool deficiencies in 14 patients. More frequent problems were related to drill bits and guide wires; 2) 270 forms were filled up, from 19 provinces of Argentina, and from Colombia, Ecuador, Italy, Australia and Bolivia. We received answers from 180 private institutions and 90 public hospitals; 3) there are four possible ways to reach a solution: ANMAT with its Programa de Tecnovigilancia, IRAM for non-fulfillment of ISO 9001 rules, Ministerios de Salud for nonfulfillment of resolution 255 and Ley Básica de Salud N.º 153, art. 12, items k and l, and AAOT Implants Subcommittee. Conclusions: A clear-cut difference was established between public and private centers; however, the working place only defined the prevalence of technical problems, but problems themselves were the same. There are legal and administrative tools to deal with these problems.

Corrosion and microstructural characterization of martensitic stainless steels submitted to industrial thermal processes for use in surgical tools

INTRODUCTION: The mechanical properties and corrosion resistance of a material are dependent on its microstructure and can be modified by phase transformation. When a phase transformation occurs in a material it usually forms at least one new phase, with physical-chemical characteristics that differ from the original phase. Moreover, most phase transformations do not occur instantly. This paper presents an evaluation of the phase transformation of martensitic stainless steels ASTM 420A and ASTM 440C when submitted to different thermal processes. METHODS: Dilatometry tests were performed with several continuous heating and cooling rates in order to obtain the profiles of the continuous heating transformation (CHT) and continuous cooling transformation (CCT) diagrams for these two types of steel. Also, the temperature ranges for the formation of the different phases (ferrite and carbides; ferrite; austenite and carbides; non-homogeneous and homogeneous austenite phases) were identified. Rockwell hardness (HRC) tests were performed on all thermally treated steels. Anodic and cathodic potential dynamic polarization measurements were carried out through immersion in enzymatic detergent as an electrolyte for different samples submitted to the thermal processes in order to select the best routes for the heat treatment and to recommend steels for the manufacture of surgical tools. RESULTS: The martensitic transformation temperature tends to increase with increasing temperature for the initiation of cooling. The 440C steel had a higher hardness value than the 420A steel at the austenitizing temperature of 1100 °C. Above the austenitizing temperature of 1100 °C, the material does not form martensite at the cooling rate used, which explains the sharp decline in the hardness values. CONCLUSION: The study reported herein achieved its proposed objectives, successfully investigating the issues and indicating solutions to the industrial problems addressed, which are frequently encountered in the manufacture of surgical instruments.

Mathematical modeling of dilatometric behavior of 420A and 440C martensitic stainless steels used in surgical tools / Modelamento matemático de ensaio dilatométrico em aços inoxidáveis martensíticos 420A e 440C utilizados em ferramental cirúrgico

This research consisted of implementing and evaluating an empirical mathematical model to reproduce analytically the dilatometric behavior of ASTM 420A and ASTM 440C martensitic stainless steels, widely used for manufacturing surgical tools. Martensitic stainless steels can be subdivided into three subgroups: low-carbon, medium-carbon and high-carbon steels. The microstructure of each group is also characteristic as needlelike martensitic; very fine martensitic; and ultra-fine martensitic containing carbides. The proposed method was based on experimental data obtained from the dilatometric testing of the steel samples applying low heating rates. It was possible to determine the formation of phase fields near the equilibrium conditions. The method, being based on empirical data, ensured a greater approximation to the experimental values, verifying that it can be applied as a useful tool in the evaluation of industrial heat treatments for surgical tools.

O presente trabalho consistiu em implementar e avaliar um modelo matemático empírico que reproduz analiticamente o comportamento dilatométrico dos aços inoxidáveis martensíticos ASTM 420A e ASTM 440C, utilizados em ferramental cirúrgico. Aços inoxidáveis martensíticos podem ser subdivididos em três subgrupos, ou seja, baixo carbono; médio carbono e alto carbono. A microestrutura de cada grupo é caracterizada por martensita em forma de agulha; martensita fina e martensita ultra-fina contendo carbetos. A elaboração do método matemático se baseou em dados extraídos de ensaios dilatométricos sob baixas taxas de aquecimento. Foi possível determinar a formação dos campos de fase próximos às condições de equilíbrio. Os resultados obtidos garantiram boa aproximação com os valores experimentais, evidenciando que o modelo aplicado é um instrumento útil na avaliação dos tratamentos térmicos industriais para ferramental cirúrgico.