Article

Aseptic tibial component loosening remains a major cause of total
knee arthroplasty failure. The cementation technique used to achieve fixation may
play a major role in loosening. Despite this, the optimum technique remains
unanswered. This study aims to investigate stress and strain distributions in the
proximal tibia for full cementation and surface cementation of the Genesis II
tibial component. METHODS: Principal cortical bone strains were measured
experimentally in intact, surface cemented and fully cemented synthetic tibiae
using strain gauges. Both axial and 15 degrees flexion loading were considered.
Finite element models were used to assess both cortical and cancellous bone
stresses and strains. Using a bone remodeling algorithm potential sites of bone
formation and resorption were identified post-implantation. FINDINGS: Principal
cortical bone strain results demonstrate strong correlations between the
experimental and finite element analyses (R(2)>/=0.81, RMSE(%)</=17.5%). Higher
cortical strains are measured for surface cementation, as full cementation
creates a stiffer proximal tibial structure. Simulations reveal that both
cementation techniques result in lower cancellous stresses under the baseplate
compared to the intact tibia, with greater reductions being computed for full
cementation. The surface cementation model displays the closest cancellous stress
distribution to the intact model. In addition, bone remodeling simulations
predict more extensive bone resorption under the baseplate for full cementation
(43%) than for surface cementation (29%). INTERPRETATION: Full cementation
results in greater stress reduction under the tibial baseplate than surface
cementation, suggesting that surface cementation will result in less proximal
bone resorption, thus reducing the possibility of aseptic loosening.
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Langue : ANGLAIS