Internship Master (Bachelor) student

Developing an advanced finite element model to investigate primary fixation of total knee implants


Total knee replacement (TKR) is the gold standard for treatment of patients suffering from osteoarthritis. However, early implant loosening still remains a problem, especially in younger patients, who have a longer life expectancy and a higher activity level. Instead of cemented fixation, press-fit implants have been introduced to provide long-term biological fixation for younger patients. Many studies have investigated the effect of the primary fixation on the long-term outcome, achieved by bone ingrowth into the porous implant surface. Primary fixation is affected by various parameters, including bone material properties, surgical technique, and implant design.

At the Orthopaedic Research Lab we are developing a patient-specific Finite Element (FE) model, based on different experimental and numerical studies, to investigate implant fixation [1-3]. We are currently working on improving the press-fit fixation between the implant and the bone in the FE model. Our goal is to account for complex phenomena that occur during implantation of the femoral component, such as bone plasticity, abrasion, crushing and viscoelastic behaviour. In this regard, the objective of this study is to develop an advanced FE model based on experimental data. This approach will lead to a better understanding of press-fit implants, which aides to further improve current implant designs, thereby improving patient outcome and satisfaction.

internship master / bachelor student orthopaedic research lab radboud university medical centre

Figure 1: Experimental steps to determine the fixation strength of a femoral knee implant.
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internship 2015 master / bachelor student orthopaedic research lab radboud university medical centre

Figure 2: Finite element model of three different implant designs to evaluate the effect of implant design and surgical variation on the primary stability of the femoral knee implant.
Click image to enlarge


We aim to develop a more realistic implant-bone interaction by introducing advanced material properties based on experimental data using finite element analysis.


This project can be done in a time frame of 4 to 6 months.

Learning objectives:

  • understanding the interaction between orthopaedic implants and bony tissue
  • learning finite element software and imaging software (mimics, dicom toolkit, etc,)
  • acquaintance with biomechanical testing

Contact details:

For any questions, contact Nico Verdonschot


[1] Berahmani S, Janssen D, van Kessel S, Wolfson D, de Waal Malefijt M, Buma P, et al.
An experimental study to investigate biomechanical aspects of the initial stability of press-fit implants.
Journal of the mechanical behavior of biomedical materials. 2015 Feb; 42:177-85.

[2] Berahmani S, Janssen D, Wolfson D, Rivard K, de Waal Malefijt M, Verdonschot N.
The Effect of Surface Morphology on the Primary Fixation Strength of Uncemented Femoral Knee Prosthesis: A Cadaveric Study
The Journal of Arthroplasty. 2015;30:300-7.

[3] Berahmani S, Janssen D, Wolfson D, de Waal Malefijt M, Fitzpatrick CK, Rullkoetter PJ, et al.
An FE analysis of the effects of simplifications in experimental testing on micromotions of uncemented femoral knee implants.
Journal of Orthopaedic Research: official publication of the Orthopaedic Research Society. 2015.

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