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Biotribological Testing and Analysis of Articular Cartilage Sliding against Metal for Implants
Published on: May 14, 2020
Hard-on-hard lubrication in the artificial hip under dynamic loading conditions
Robert Sonntag1, Jörn Reinders, Johannes S Rieger
1Laboratory of Biomechanics and Implant Research, Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Heidelberg, Germany. robert.sonntag@med.uni-heidelberg.de
Plos One
|August 14, 2013
Summary
Artificial hip joint lubrication is crucial for implant longevity. This study reveals that standard gait cycle simulations may not fully predict real-world performance, especially under demanding conditions.
Area of Science:
- Biomedical Engineering
- Tribology
- Orthopedics
Background:
- Artificial hip joint tribological performance significantly impacts implant success.
- Wear debris and poor lubrication leading to implant loosening are primary failure modes.
- Standardized models are essential for evaluating lubrication in hip implants.
Purpose of the Study:
- To verify the tribological relevance of the ISO 14242-1 gait cycle for total hip replacements.
- To compare lubrication under standardized conditions with real-world activities like walking and stair climbing.
- To evaluate lubrication regimes in hard-on-hard bearings under various loading conditions.
Main Methods:
- Extended a steady-state numerical model with dynamic experimental data.
- Utilized data from the Orthoload database and instrumented gait analysis.
- Investigated three loading conditions: normal walking, climbing stairs, and descending stairs.
Main Results:
- Ceramic-on-ceramic bearings exhibit superior lubrication compared to those with metal components.
- Lubrication regimes are highly dependent on activity kinematics and loading.
- ISO gait cycle outcomes do not fully align with normal walking data; challenging activities show poorer lubrication.
Conclusions:
- The ISO gait cycle may not adequately represent all functional conditions for artificial hip joints.
- Differences between in vitro predictions and clinical outcomes for hard-on-hard bearings might be explained by lubrication variations.
- Further research into diverse loading scenarios is needed for accurate tribological assessments.
