Assessment of Head Displacement and Disassembly Force With Increasing Assembly Load at the Head/Trunnion Junction of a Total Hip Arthroplasty Prosthesis.

Background: Most femoral components used now for total hip arthroplasty are modular, requiring a strong connection at assembly. The aim of this study was to assess the effect of assembly force on the strength of head-trunnion interface and to measure the initial displacement of the head on the trunnion with different assembly forces.

Methods: Three assembly load levels were assessed (A: 2 kN, B: 4 kN, C: 6 kN) with 4 implants in each group.

The effect of dynamic hip motion on the micromotion of press-fit acetabular cups in six degrees of freedom.

The hip joint is subjected to cyclic loading and motion during activities of daily living and this can induce micromotions at the bone-implant interface of cementless total hip replacements. Initial stability has been identified as a crucial factor to achieve osseointegration and long-term survival. Whilst fixation of femoral stems achieves good clinical results, the fixation of acetabular components remains a challenge.

Combining ageing and wear to assess the durability of zirconia-based ceramic heads for total hip arthroplasty.

The degradation of zirconia-based ceramic components for total hip arthroplasty (head and cup) has been the topic of many works. However, the correlation between what is measured in vivo and what is expected from in vitro simulations on hip simulators may be sometimes feeble, especially where zirconia component are concerned, mainly due to a lack of representativeness of in vitro experiments. The present study seeks to explore the combined effects of hydrothermal ageing and wear on zirconia components.