Acta Chir Orthop Traumatol Cech. 2009; 76(2):110-115 | DOI: 10.55095/achot2009/022

Mathematical Simulation of Stem/Cement/Bone Mechanical Interactions for Poldi-Čech, CF-30, MS-30 and PFC Femoral ComponentsOriginal papers

M. KOVANDA1, V. HAVLÍČEK1, J. HUDEC2
1 I. ortopedická klinika FN u sv. Anny, Brno
2 Katedra mechaniky těles, biotroniky a biomechaniky VUT Brno

PURPOSE OF THE STUDY:
The mid-term longevity of femoral components varies considerably, with some showing failure due to early aseptic loosening. Since the hip joint is subject to heavy mechanical loads, it can be assumed that the mechanical interaction of the implant, bone cement and femur will play a key role in the resultant reliability of an arthroplasty. This study was designed to examine this mechanical interaction in four femoral components different in construction (Poldi-Čech, CF-30, MS-30 and PFC) using mathematical simulation.

MATERIAL AND METHODS:
Four stem/cement/femur 3-D mathematical models, comparable in quality, infolving the Poldi-Čech, CF-30, MS-30 and PFC stems, respectively, were constructed. A 3-D model for each stem was created according to its real, middle-size femoral component. Each 3-D model of the cement mantle corresponded in shape to the mantle of the appropriate real stem, with its thickness based on the recommended values of 4-7 mm in the proximal and 1-3 mm in the distal part, and with the cement mantle reaching as far as 10 mm distal to the femoral stem tip. For simplicity's sake the outer surface of the cement mantle was simulated as smooth. A 3-D model involving the proximal epiphysis and the metaphysis of a femur was reconstructed, based on a series of CT cross-sections obtained periodically at 10.5-mm and 2.5-mm distances. The sten/cement/femur model with the MS-30 stem also included a centraliser.
The mechanical interaction of the stem, bone cement and bone tissue was examined by means of mathematical stimulation using ANSYS 5.7 software based on finite element analysis.

RESULTS:
For the sake of simplicity, only two key parameters are presented, namely, contact stress at the stem-cement interface and equivalent deformation in the stem/cement/femur system. The least satisfactory stress loading was in the CF-30 stem whose sharp edges showed the values of contact stress about six-times higher than on the mid-medial portion of the stem, with the sharp edges behaving as stress concentrators. A satisfactory stress loading was found in Poldi-Čech, MS-30 and PFC stems, in which contact stress was evenly distributed along the whole lenght of the stem and the values at the edges and on the mid-medial portion did not differ much.

DISCUSSION:
The distribution of contact stress is one of the most important factors for the long-term longevity of implants. It was found least satisfactory in the CF-30 stem whose sharp edges act as stress condenser adversely affecting not only the stem-cement interface, but also the resultant stress distribution within the femur. The most satisfactory results of stress distribution were recorded in the Poldi-Čech and MS-30 stems. The PFC stem also responded satisfactorily to the simulated stress loading. However, on loading whose substantial part would be torsion, the stem's circular or oval cross-section could interfere with rotation stability of the implant; but this was impossible to detect by the mathematical simulation used in this study.

CONCLUSIONS:
The results presented here show that, in the Poldi-Čech, CF-30, MS-30 and PFC femoral stems, a good agreement was achieved between the results of their clinical application and those of mathematical modelling of their mechanical properties. It can be concluded that mechanical interaction among the femoral stem, cement mantle and bone tissue plays the key role in the long-term longevity of such an implant.

Keywords: Poldi-Čech, CF-30, MS-30, PFC, mechanical interaction, contact stress

Published: April 1, 2009  Show citation

ACS AIP APA ASA Harvard Chicago Chicago Notes IEEE ISO690 MLA NLM Turabian Vancouver
KOVANDA M, HAVLÍČEK V, HUDEC J. Mathematical Simulation of Stem/Cement/Bone Mechanical Interactions for Poldi-Čech, CF-30, MS-30 and PFC Femoral Components. Acta Chir Orthop Traumatol Cech. 2009;76(2):110-115. doi: 10.55095/achot2009/022. PubMed PMID: 19439130.
Download citation

References

  1. BARTONÍČEK, J., D®UPA, V.: Problematika polyetylenu u totálních náhrad kyčelního kloubu. Acta Chir. orthop. Traum. čech., 66: 320-355, 1999.
  2. BECK, T. J., MOURTADA, F. A, RUFF, C. B., SCOTT, W. W. JR., KAO, G.: Experimental testing of a DEXA-derived curved beam model of the proximal femur. J. Orthop. Res., 16: 394-398, 1998. Go to original source... Go to PubMed...
  3. BLACK, J. HASTINGS, G.: Handbook of Biomaterial Properties. London, Chapman & Hall 1998. Go to original source...
  4. CODY, D. D., GROSS, G. J., HOU, F. J., SPENCER, H. J., GOLDSTEIN, S. A., FYHRIE, D. P.: Femoral strength is better predicted by finite element models than QCT and DXA. J. Biomech., 32: 1013-1020, 1999. Go to original source... Go to PubMed...
  5. ČECH, O., BEZNOSKA, S., KRBEC, M.: Hybridní náhrada kyčelního kloubu systémem Poldi-Čech. Acta Chir. orthop. Traum. čech., 59: 77-80, 1992.
  6. ČECH, O., D®UPA, V., SVATO©, F.: Necementovaná jamka endoprotézy kloubu CLS Spotorno - pětileté výsledky. Acta Chir. orthop. Traum. čech., 68: 10-17, 2001.
  7. ČECH, O., D®UPA, V.: Revizní operace náhrad kyčelního kloubu. Praha, Galén 2004.
  8. ČECH, O., PAVLANSKÝ, R.: Artroplastika kyčelního kloubu. Praha, Avicenum 1978.
  9. DOSTAL, W. F., ANDREWS, J. G.: A three-dimensional biomechanical model of hip musculature. J. Biomech., 14: 803-812, 1981. Go to original source... Go to PubMed...
  10. DUDA, G. N., HELLER, M., ALBINGER, J., SCHULTZ, O., SCHNEIDER, E., CLAES, L.: Influence of muscle forces on femoral strain distribution. J. Biomech., 31: 841-846, 1998. Go to original source... Go to PubMed...
  11. DUNGL, P. A KOLEKTIV: Ortopedie. Praha, Grada publishing 2005.
  12. GALLO, J., KAMÍNEK, P., ZAPLETALOVÁ, J., ČECHOVÁ, I., ©PIČKA, J., DITMAR, R.: Je osteolýza kolem stabilní TEP kyčelního kloubu asymptomatická? Acta Chir. orthop. Traum. čech., 71: 20-25, 2004.
  13. GALLO, J., HAVRÁNEK, V., ZAPLETALOVÁ, J., MANDÁT, D.: Měření otěru polyetylenových jamek TEP kyčelního kloubu univerzálním měřícím mikroskopem. Charakteristika měření. Acta Chir. orthop. Traum. čech., 73: 28-33, 2006. Go to original source...
  14. GRAICHEN, F., BERGMANN, G., ROHLMANN, A.: Hip endoprosthesis for in vivo measurement of joint force and temperature. J. Biomech., 32: 1113-1117, 1999. Go to original source... Go to PubMed...
  15. GRUEN,T. A., McNEICE, G. M., AMSTUTZ, H. C.: "Modes of failure" of cemented stem-type femoral components: radiographic analysis of loosening. Clin. Orthop., 141: 17-27, 1979. Go to original source...
  16. HARRIS, W. H.: Wear and Periprosthetic Osteolysis. The Problem. Clin. Orthop., 393: 66-70, 2001. Go to original source... Go to PubMed...
  17. HART R., ROZKYDAL, Z.: Dlouhodobé výsledky totální protézy kyčelního kloubu Poldi. Acta Chir. orthop. Traum. čech., 66: 139-145, 1999.
  18. HUDEC, J., KOVANDA, M.: Analýza mechanické interakce cementované endoprotézy s femurem se zaměřením na zpřesněné mechanické vlastnosti kostní tkáně. Výpočtová mechanika 2000, Nečtiny, 155-162, 2000.
  19. CHEAL, E., SPECTOR, M., HAYES, W.: Role of loads and prosthesis material properties on the mechanics of the proximal femur after total hip arthroplasty. J. Orthop. Res., 10: 405-422, 1992. Go to original source... Go to PubMed...
  20. INGHAM, E., FISCHER, J.: Biological Reactions to Wear Debris in Total Joint Replacement. Proc. Inst. Mech. Eng., Part H, 214: 21-37, 2000. Go to original source... Go to PubMed...
  21. JAHODA, D., NYČ, O., ©IM©A, J., KUČERA, E., HANEK, P., CHRZ, P., POKORNÝ, D., TAWA, N., LANDOR, I., SOSNA, A.: Výskyt pozdní hematogenní infekce kloubních náhrad v naąem souboru a návrh systému prevence. Acta Chir. orthop.Traum. čech., 74: 397-400, 2007. Go to original source...
  22. KOVANDA, M.: Totální náhrada kyčelního kloubu. Brno, atestační práce, 1994.
  23. KOVANDA, M.: Artroplastika. Brno, I. ortopedická klinika FN USA, Ph. D. Thesis, 2002.
  24. KOVANDA, M., HAVLÍČEK, V., HUDEC, J.: Předčasné aseptické uvolňování dříku CF-30. Acta Chir. orthop. Traum. čech., 74: 59-64, 2007. Go to original source...
  25. KRBEC, M., ČECH, O., D®UPA, V.: Reoperace cementované totální endoprotézy kyčle: I. Rtg-diagnostika a klasifikace uvolnění. Acta Chir. orthop. Traum. čech., 59: 23-26, 1992.
  26. LING, R. S.: The use of a collar and precoating on cemented femoral stem is unnecessary and detrimental. Clin. Orthop., 285: 73-83, 1992. Go to original source...
  27. LOTZ, J. C., GERHART, T. N., HAYES, W. C.: Mechanical properties of metaphysical bone in the proximalfemur. J. Biomech., 24: 317-329, 1991. Go to original source... Go to PubMed...
  28. POKORNÝ, D., ©LOUF, M., HORÁK, Z., JAHODA, D., ENTLICHER, G., EKLOVÁ, S., SOSNA, A.: Metodika sledování distribuce otěrových částic UHMWPE v okolních tkáních u TEP kyčelního kloubu. Acta Chir. orthop. Traum. čech., 73: 243-250, 2006. Go to original source...
  29. SOSNA, A., RADONSKÝ, T., POKORNÝ, D., VERGL, D., HORÁK, Z., JAHODA, D.: Polyetylenová nemoc. Acta Chir. orthop. Traum. čech., 70: 6-16, 2003.
  30. STOLK, J. VERDONSCHOT, N. HUISKES, R.: Hip-joint and abductor-muscle forces adequately represent invivo loading of a cemented total hip reconstruction. J. Biomech., 34: 917-926, 2001. Go to original source... Go to PubMed...
  31. ©TĚDRÝ, V., HAJNÝ, P.: Dlouhodobé výsledky TEP kyčelního kloubu Poldi. Acta. Chir. orthop. Traum. čech. 64: 282-291, 1997.
  32. TOMÁ©, T.: Infekce totální náhrady kloubu. Brno, disertační práce, 2005.
  33. VALENTA, J.: Biomechanika. Praha, Academia 1985.
  34. WEBER, B. G.: Pressurized Cement Fixation in Total Hip Arthroplasty. Clin. Orthop., 232: 87-95, 1988. Go to original source...
  35. WROBLEWSKI, B. M., SINEY, P. D., FLEMING, P. A., BOBAK, P.: The calcar femorale in cemented stem fixation in total hip arthroplasty. J. Bone Jt Surg., 82: 842-845, 2000. Go to original source...