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Supplementary finite element analysis in experimental testing of total hip stems

Finite Elemente Analyse von Hüftendoprothesen-Stielen zur Unterstützung der experimentellen Prüfung
  • Daniel Kluess , Hans-E. Lange , Horst Heyer , Manuela Sander , Wolfram Mittelmeier and Rainer Bader
From the journal Materials Testing

Abstract

Before an implantable medical device passes market clearance, a number of mechanical tests need to be conducted in order to verify the mechanical safety of the product. With regard to total hip replacement stems, these are subject to fatigue tests both in the proximal region of the neck as well as in the distal region of the shaft. Despite these tests, we experienced two clinical fractures of the same product in our clinic. It was shown that these fractures were initiated by a laser engraving of the manufacturer with subsequent crack growth. The basic question raised in the present work was to find out why fracture may not have occurred during experimental preclinical testing. Hence, a supplementary finite element analysis was conducted considering the same hip stem under the prescribed conditions of the test standard in different variations. It was found that the choice of orientation and side (left or right leg) strongly influences stress in the hip stem which has not yet been prescribed in test standards. Depending on the side, only compressive stress may be acting in the experimental situation on the locations under risk, thereby inhibiting clinically relevant crack growth and concealing an actual fracture risk.

Kurzfassung

Bevor ein implantierbares Medizinprodukt die Marktzulassung erhält, muss eine Reihe von mechanischen Tests durchgeführt werden, um die Sicherheit des Produktes nachzuweisen. Hüftendoprothesen-Stiele unterliegen unter anderem Ermüdungsversuchen sowohl im proximalen Bereich des Halses als auch im distalen Bereich des Schaftes. Trotz dieser erforderlichen Tests traten in unserer Klinik zwei Brüche desselben Produkts auf. Es zeigte sich, dass diese Brüche durch eine Lasergravur des Herstellerlogos mit anschließendem Risswachstum initiiert wurden. Die grundlegende Frage für die vorliegende Arbeit war, weshalb diese Brüche während der experimentellen präklinischen Testung möglicherweise nicht aufgetreten sind. Daher wurde eine Finite-Elemente-Analyse durchgeführt, in welcher der gleiche Hüftstiel unter den vorgeschriebenen Bedingungen des Teststandards mit unterschiedlichen Variationen untersucht wurde. Im Ergebnis zeigte sich, dass die Belastung des Hüftstiels stark von der Wahl der Orientierung und Seite (linkes oder rechtes Bein) abhängt, welche in den Testbedingungen nicht ausdrücklich vorgeschrieben ist. Abhängig von der betrachteten Seite können in der experimentellen Prüfung an den gefährdeten Stellen nur Druckspannungen wirken, wodurch das klinisch relevante Risswachstum gehemmt werden kann. Ein tatsächliches Bruchrisiko kann dadurch letztendlich unentdeckt bleiben.


*Correspondence Address, Priv.-Doz. Dr.-Ing. habil. Daniel Kluess, Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, Rostock University Medical Center, Doberaner Strasse 142, D-18057 Rostock, Germany. E-mail:

Priv.-Doz. Dr.-Ing. Daniel Kluess was born in 1977 and studied biomechanical engineering at the University of Rostock, Germany with residences in Switzerland and the USA. He earned his doctorate in 2008 and became Privat-Dozent (associate professor) in 2014. He is working group leader at the Biomechanics and Implant Technology Research Laboratory of the Department of Orthopaedics, Rostock University Medical Center. He is also founder and CEO of INNOPROOF GmbH, Rostock.

Dipl.-Ing. Hans-Eckhard Lange was born in 1989 and earned his Master's degree in biomedical engineering at the University of Rostock, Germany in 2016. From 2013 to 2014, he studied abroad at Ghent University, Belgium. Since 2017, he has been research assistant at the Biomechanics and Implant Technology Research Laboratory of the Department of Orthopaedics, Rostock University Medical Center.

Dr.-Ing. Horst Heyer, born 1958, is working group leader at the Chair of Structural Mechanics at the Faculty of Mechanical Engineering and Ship Technology, University of Rostock, Germany. He earned his doctorate in 1990 and has been working as a research associate at the Chair of Structural Mechanics since 1992. From 1988 to 1990, he held a leading position at the VEB Shipyard ‘Neptun’ in Rostock.

Prof. Dr.-Ing. Manuela Sander was born in 1975 and has been Chair for Structural Mechanics at the Faculty of Mechanical Engineering and Ship Technology, University of Rostock, Germany since 2008. From 2004 to 2008, she was Senior Engineer at the Institute of Applied Mechanics, University of Paderborn, Germany. Currently, Prof. Sander is Dean of the Faculty of Mechanical Engineering and Ship Technology, University of Rostock.

Prof. Dr. med. Wolfram Mittelmeier, born 1959, has been Director of the Department of Orthopaedics, Rostock University Medical Center, since 2004. He studied human medicine in Leuven, Belgium, as well as in Giessen and Homburg/Saar, Germany. He was senior physician at the Orthopedic University Hospital Lübeck and then senior medical director of the Department of Orthopedics and Sports Orthopedics at the Technical University of Munich, Germany.

Prof. Dr. med. Dipl.-Ing. Rainer Bader was born in 1965 and studied human medicine as well as biomedical engineering in Ulm. He then worked as a research assistant at the Department of Orthopedics and Sports Orthopedics at the Technical University of Munich, Germany where he completed his doctorate in 2001. In In 2009 he was Professor for Biomechanics and Implantat Technology at the Medical Faculty of the University of Rostock. Since 2005 he has been head of the Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, Rostock University Medical Center, Germany.


References

1 Council Directive 93/42/EECof 14 June 1993 concerning medical devices, Journal referenceL169, 12.07.1993, pp. 143Search in Google Scholar

2 The Act on Medical Devices of 2nd August 1994 (Federal Law Gazette I, p. 1963), in the version of 7th August 2002 (Federal Law Gazette I, p. 3146), last amended by Article 12 of the Act of 24th July 2010 (Federal Law Gazette I, p. 983)Search in Google Scholar

3 ISO 7206-4: Implants for surgery, Partial and total hip joint prostheses, Part 4: Determination of endurance properties and performance of stemmed femoral components, ISO, Switzerland (2010)Search in Google Scholar

4 ISO 7206-6: Implants for surgery – Partial and total hip joint prostheses, Part 6: Endurance properties testing and performance requirements of neck region of stemmed femoral components, ISO, Geneva, Switzerland (2013)Search in Google Scholar

5 G.Garellick, J.Kärrholm, H.Lindahl, H.Malchau, C.Rogmark, O.Rolfson: The Swedish hip arthroplasty register – Annual report 2014, Gothenburg, Sweden (2015)Search in Google Scholar

6 D.Kluess, E.Steinhauser, M.Joseph, U.Koch, M.Ellenrieder, W.Mittelmeier, R.Bader: Laser engravings as reason for mechanical failure of titanium-alloyed total hip stems, Archives of orthopaedic and trauma surgery135 (2015), pp. 1027103110.1007/s00402-015-2225-7Search in Google Scholar

7 ISO 14630: Non-active surgical implants – General requirements. ISO copyright office, ISO, Geneva, Switzerland (2012)Search in Google Scholar

8 ASTM F983–86: Standard practice for permanent marking of orthopaedic implant components, Developed by Subcommittee: F04.21, Book of Standards Volume: 13.01, ASTM International, West Conshohocken, PA, USA (2013)Search in Google Scholar

9 R.Lass, A.Kolb, G.Skrbensky, G.Reinisch, B.Kubista, A.Giurea, R.Windhager, R.Kotz: A cementless hip system with a new surface for osseous integration, International orthopedics38 (2014), No. 4, pp. 70370910.1007/s00264-013-2135-7Search in Google Scholar

10 D. M.Brunette, P.Tengvail, M.Taxtor, P.Thomsen (Ed.): Titanium in Medicine: Material Science, Surface Science, Engineering, Biological Responses, and Medical Applications, Springer, Berlin, Germany (2001)10.1007/978-3-642-56486-4Search in Google Scholar

11 M. T.Raimondi, R.Pietrabissa: Modelling evaluation of the testing condition influence on the maximum stress induced in a hip prosthesis during ISO 7206 fatigue testing, Medical Engineering & Physics21 (1999), No. 5, pp. 35335910.1016/S1350-4533(99)00061-2Search in Google Scholar

12 K. K.Wang, L. J.Gustavson, J. H.Dumbleton: Microstructure and properties of a new beta titanium alloy, Ti-12Mo-6Zr-2Fe, developed for surgical implants, S. A.Brown (Ed.): Medical Applications of Titanium and its Alloys, The Material and Biological Issues, ASTM, West Conshohocken, PA, USA (1996)Search in Google Scholar

13 ASTM F 2996–13: Standard Practice for Finite Element Analysis (FEA) of Non-Modular Metallic Orthopaedic Hip Femoral Stems, F04.22, Book of Standards Volume: 13.02, ASTM International, West Conshohocken, PA, USA (2013)Search in Google Scholar

14 G.Bergmann, F.Graichen, A.Rohlmann: Hip joint loading during walking and running, measured in two patients, Journal of Biomechanics26 (1993), No. 8, pp. 96999010.1016/0021-9290(93)90058-MSearch in Google Scholar

15 O.Kayabasi, F.Erzincanli: Finite element modelling and analysis of a new cemented hip prosthesis, Advances in Engineering Software37 (2006), No. 7, pp. 47748310.1016/j.advengsoft.2005.09.003Search in Google Scholar

16 K. A.Mann, D. L.Bartel, T. M.Wright, A. R.Ingraffea: Mechanical characteristics of the stem-cement interface, Journal of Orthopaedic Research9 (1991), No.6, pp. 79880810.1002/jor.1100090605Search in Google Scholar

17 M.Niinomi: Mechanical properties of biomedical titanium alloys. Materials science and engineering243 (1998), No. 1–2, pp. 23123610.1016/S0921-5093(97)00806-XSearch in Google Scholar

18 G.Bergmann, A.Bender, J.Dymke, G.Duda, P.Damm: Standardized loads acting in hip implants, PLoS One19 (2016), No. 11, pp. e0155612 10.1371/journal.pone.0155612Search in Google Scholar PubMed PubMed Central

Published Online: 2018-11-15
Published in Print: 2018-05-26

© 2018, Carl Hanser Verlag, München

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