Mechanisms of reduced implant stability in osteoporotic bone
- 316 Downloads
The determining factors for the fixation of uncemented screws in bone are the bone-implant interface and the peri-implant bone. The goal of this work was to explore the role of the peri-implant bone architecture on the mechanics of the bone-implant system. In particular, the specific aims of the study were to investigate: (i) the impact of the different architectural parameters, (ii) the effects of disorder, and (iii) the deformations in the peri-implant region. A three-dimensional beam lattice model to describe trabecular bone was developed. Various microstructural features of the lattice were varied in a systematic way. Implant pull-out tests were simulated, and the stiffness and strength of the bone-implant system were computed. The results indicated that the strongest decrease in pull-out strength was obtained by trabecular thinning, whereas pull-out stiffness was mostly affected by trabecular removal. These findings could be explained by investigating the peri-implant deformation field. For small implant displacements, a large amount of trabeculae in the peri-implant region were involved in the load transfer from implant to bone. Therefore, trabecular removal in this region had a strong negative effect on pull-out stiffness. Conversely, at higher displacements, deformations mainly localized in the trabeculae in contact with the implant; hence, thinning those trabeculae produced the strongest decrease in the strength of the system. Although idealized, the current approach is helpful for a mechanical understanding of the role played by peri-implant bone.
KeywordsImplant anchorage Peri-implant bone architecture Osteoporosis Finite element method Pull-out test
Unable to display preview. Download preview PDF.
- An Y, Draughn R (2000) Mechanical testing of bone and the bone-implant interface. CRC Press, Boca RatonGoogle Scholar
- Chen H, Zhou X, Shoumura S, Emura S, Bunai Y (2010) Age- and gender-dependent changes in three-dimensional microstructure of cortical and trabecular bone at the human femoral neck. Osteoporos Int 21: 227–236Google Scholar
- Gibson L, Ashby M (1997) Cellular solids: structure and properties. Cambridge University Press, CambridgeGoogle Scholar
- Matsunaga S, Shirakura Y, Ohashi T, Nakahara K, Tamatsu Y, Takano N, Ide Y (2010) Biomechanical role of peri-implant cancellous bone architecture. Int J Prosthodont 23: 333–338Google Scholar
- Peter B, Gauthier O, Laib S, Bujoli B, Guicheux J, Janvier P, van Lenthe G, Müller R, Zambelli P, Bouler J, Pioletti D (2006) Local delivery of bisphosphonate from coated orthopedic implants increases implants mechanical stability in osteoporotic rats. J Biomed Mater Res A 76(1): 133–143Google Scholar
- Stadlinger B, Pilling E, Huhle M, Mai R, Bierbaum S, Bernhardt R, Scharnweber D, Kuhlisch E, Hempel U, Eckelt U (2007) Influence of extracellular matrix coatings on implant stability and osseointegration: an animal study. J Biomed Mater Res B 83(1): 222–231Google Scholar
- Wirth A, Müller R, van Lenthe G (2010b) Computational analysis of small endosseous implants in osteoporotic bone. Eur Cells Mater 20: 58–71Google Scholar