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The Effect of the Stiffness of the stem of the Modular Revision Prosthesis MRP Titan Depending on Stem Diameter
Author(s) -
Schuh A.,
Holzwarth U.,
Zeiler G.
Publication year - 2004
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.200400838
Subject(s) - implant , femur , stiffness , biomedical engineering , materials science , orthodontics , surgery , composite material , medicine
The MRP‐Titan revision stem has proved to be a very successful implant system in revision arthroplasty of the hip joint. With this revision system good and very good clinical and excellent radiographic results with spontaneous filling out of femur defects were published in studies. The observation, that an atrophy of the proximal femur could be recorded with stem diameters above 17 mm, lead us to carry out stiffness measurements on different diameters of the MRP‐Titan revision stem. To determine the static bending characteristics, the bent 200 mm MRP‐Titan revision stem was tested under axial stress in accordance with Euler´s buckling cases. Various diameters from 13 to 22 mm were tested with a calibrated hydraulic MTS 810 axial piston testing machine (MTS Systems, Minneapolis, Minnesota, USA). Each test was carried out five times, the mean average value of the respective deflexion for each stem diameter was listed in a diagram. It turned out that deflexion decreased disproportionately from a stem diameter of > 18 mm. This correlated directly with an increased stiffness of the stem. With the MRP‐Titan revision stem a reliable implant in revision arthroplasty has been made available. The clinical observation of a proximal femur atrophy with stem diameters > 17 mm could be correlated in the series of experiments with a corresponding exponential increase in stiffness. The aim of continuing development will be to reduce the stiffness of the individual implant, especially in larger stem diameters, through constructive and/or material science measures.