[BIOMECH - Innocenti] Dynamic analysis of all-poly vs conventional tibial component in knee prosthesis
Context of the project:
Total knee arthroplasty (TKA) is a successful procedure with more than 600,000 surgeries performed
in the USA each year. Two types of tibial implants can be used today during TKA: a metal-backed
modular device or an all-poly tibial implant (Figure 1). Both systems have their advantages and
disadvantages. The all-poly solution presents three main benefits in comparison with the metalbacked.
First, it eliminates the insert-metal interface and may therefore reduce backside wear and,
consequently, risk of osteolysis. Second, the use of an all-poly component reduces the cost of TKA
surgeries by 20–50 %. Third, the implant can be used when patient is allergic to metal (in combination
with ceramic femoral components) .
While different clinical studies are present in the literature, with different and, sometimes,
controversial results, a full biomechanical investigation of the performance of all-poly is not currently
available. In the past, at the BEAMS department a preliminary study was accomplished .
The aim of this study is to improve the previous work, evaluating and comparing the metal-backed
and all-poly tibial components behaviour in a patient, during dynamic activities as walking and
squatting. Ligament strain, bone stress, together with the polyethylene stress and contact areas,
among the two designs will be compared, using finite element modelling, in this research activity.
 Jean Brihault, Alessandro Navacchia, Silvia Pianigiani, Luc Labey, Ronny DeCorte, Valerio Pascale, Bernardo Innocenti,
2016. All-polyethylene tibial components generate higher stress and micromotions than metal-backed tibial components in
total knee arthroplasty. KSSTA Journal, 24;8:2550-2559.