Journal Published Online: 24 July 2019
Volume 49, Issue 3

A Proposition to Standardize the Microstructural Grain Size Measurements of Hip Stems

CODEN: JTEVAB

Abstract

Femoral stem fractures in total hip arthroplasty (THA) are a problem in clinical practice that results in great morbidity and high cost of revision hip surgery. Stem fractures are multifactorial events that are usually related to a combination of factors that increase the mechanical stress on the stem or decrease the mechanical strength of the implant. Failure analyses of hip prosthesis have identified that the presence of inadequate grain size may lead to implant failure. The aim of this article is to develop a rational to set specific sites to perform grain size measurements along stems used in THA as well as appropriate procedures to evaluate the heterogeneity of the microstructure related to the grain size distribution. In the present study, nonmodular femoral stems from three manufacturers with different wrought materials were chosen: stainless steel ISO 5832-1 (Manufacturer I), high nitrogen stainless steel ISO 5832-9 (Manufacturer II), and cobalt-chromium-molybdenum alloy ISO 5832-12 (Manufacturer III). The results of this study showed a great variability of grain size number depending on the cross section and fields evaluated. Therefore, the current technical standards for evaluating THA stems need to be modified. Analyses of grain sizes at different cross sections and inside each cross section of the stem is necessary to ensure the safety of hip stems.

Author Information

Cubillos, Patricia O.
Laboratory of Biomechanical Engineering (LEBm) of University Hospital, Federal University of Santa Catarina, Florianópolis, SC, Brazil
dos Santos, Claudio T.
National Institute of Technology (INT), Rio de Janeiro, RJ, Brazil
dos Santos, Vinícius O.
Laboratory of Biomechanical Engineering (LEBm) of University Hospital, Federal University of Santa Catarina, Florianópolis, SC, Brazil
Caminha, Ieda M. V.
National Institute of Technology (INT), Rio de Janeiro, RJ, Brazil
da Rosa, Edison
Laboratory of Biomechanical Engineering (LEBm) of University Hospital, Federal University of Santa Catarina, Florianópolis, SC, Brazil
Roesler, Carlos R. M.
Laboratory of Biomechanical Engineering (LEBm) of University Hospital, Federal University of Santa Catarina, Florianópolis, SC, Brazil
Pages: 11
Price: $25.00
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Stock #: JTE20190038
ISSN: 0090-3973
DOI: 10.1520/JTE20190038