PhD Position F/M Modeling the dynamic behavior of implants used in total hip arthroplasty

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Contract type : Fixed-term contract

Level of qualifications required : Graduate degree or equivalent

Fonction : PhD Position

About the research centre or Inria department

The Inria centre at Université Côte d'Azur includes 42 research teams and 9 support services. The centre's staff (about 500 people) is made up of scientists of different nationalities, engineers, technicians and administrative staff. The teams are mainly located on the university campuses of Sophia Antipolis and Nice as well as Montpellier, in close collaboration with research and higher education laboratories and establishments (Université Côte d'Azur, CNRS, INRAE, INSERM ...), but also with the regiona economic players.

With a presence in the fields of computational neuroscience and biology, data science and modeling, software engineering and certification, as well as collaborative robotics, the Inria Centre at Université Côte d'Azur  is a major player in terms of scientific excellence through its results and collaborations at both European and international levels.

Context

The funding of this PhD thesis is granted by the ANR project “MoDyBe” (Modeling the Dynamic Behavior of implants used in total hip arthroplasty), which also involves the Multiscale modeling and simulation laboratory (CNRS, Paris-Est Créteil University), together with clinical partners from the department of orthopaedic (Henri Mondor hospital).

Assignment

Description of the project:

Cementless implants are increasingly used in clinical practice. They are inserted in the host bone using impacts performed with an orthopaedic hammer (press-fit procedure). However, the rate of revision surgery is still high, which is a public health issue of major importance.
The press-fit phenomenon occurring at implant insertion induces biomechanical effects in the bone tissues, which should ensure implant primary stability (that is, the stability of the implant during the surgery). Despite a routine clinical use, implant failures, which may have dramatic consequences, still occur and are difficult to anticipate.
Just after surgery, the implant fixation relies on the pre-stressed state of bone tissue around the implant. In order to avoid aseptic loosening, a compromise must be found by the surgeon. On the one hand, sufficient primary stability can be ensured by minimizing micromotion at the bone-implant interface in order to promote osteointegration phenomena. On the other hand, excessive stresses in bone tissue around the implant must be avoided, as they may lead to bone necrosis or fractures.
This raises the following mathematical issues:
– What is the appropriate mechanical model of the implant insertion process into the bone?
– What are the suitable high-performance computing methods to accurately solve the above modelling equations for the bone-implant interaction subject to dynamic excitations?
– Which robust inversion approaches can be employed to retrieve the quantities of interest of the bone-implant interaction such as the bone-implant contact area?
During the PhD thesis, after a bibliographical review, the successful candidate will investigate possible dynamic models described by partial differential equations and their possible simplifications. Inversion aspects of the problem will be considered such as reconstruction of the material (bone) parameters and estimation of the stability characteristics of the implant. Anticipating the need for real-time performance, reduced order modelling aspects should be studied.

Main activities

Research, transfer.

Skills

Required skills:

Interest in applied mathematics and modelling in physics or life sciences, basic numerical methods and their implementation.

Benefits package

  • Subsidized meals
  • Partial reimbursement of public transport costs
  • Leave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)
  • Possibility of teleworking (after 6 months of employment) and flexible organization of working hours
  • Professional equipment available (videoconferencing, loan of computer equipment, etc.)
  • Social, cultural and sports events and activities
  • Access to vocational training
  • Contribution to mutual insurance (subject to conditions)

Remuneration

Duration: 36 months
Location: Sophia Antipolis, France
Gross Salary per month: 2200€ (2025) 2300€ (2026)