The incidence of total hip replacements in OECD countries is >300/100.000 inhabitants. Due to the demographic challenge, more than 400.000 total knee and hip arthroplasties are implanted each year (incidence 400/100.000 inhabitants) with numbers being expected to increase. About 5% of these patients are in need of revision surgery due to prosthesis loosening within 10 years.
One main factor contributing to aseptic hip prosthesis loosening is corrosion at the head-neck junction.
Wear and corrosion at this modular junction have been recognized to induce early failure of hip replacements. There have been a number of reports on the occurrence of taper corrosion and/or fretting with some of them conjecturing a link to the occurrence of adverse local tissue reaction specifically with respect to total hip replacement. Factors like manufacturing tolerances, surgical technique, non-axial alignment, material combination, high frictional torque, and high bending moment were identified to affect the failure process.
The objective of this PhD project is to elucidate the effects and contributions mentioned above, aiming for technical improvements to reduce the risk factors. Therefore, this study will mainly focus on the evaluation of the tribological properties and contributing factors.
Damage analysis of explants and simulation of worst case scenarios using test implants will be performed.
To improve the current standard, different material combinations will be investigated to understand relevant (e.g. crevice and bimetallic) corrosion processes. The investigation of biological reactions between tissue and wear particles generated by damaged implants makes up another important part of this sub-project.
This interaction will be analysed in cooperation with the laboratory for experimental orthopedics.
Several analytical methods (e.g. SEM, cell culture, hip simulator testing) will be applied to examine and clarify the interplay of implant wear and human tissue.