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Endurance habitual and peak loads in hip and knee arthroplasty : review and summary of aspects to be considered
Publikationstyp
Research Report
Date Issued
2023-05
Sprache
English
Author(s)
Schierjott, Ronja A.
Traina, Francesco
Larrainzar-Garijo, Ricardo
Start Page
56
End Page
58
Citation
1st EFORT European Consensus Medical & Scientific Research Requirements for the Clinical Introduction of Artificial Joint Arthroplasty Devices (2023)
Publisher
EFORT
Question: Mechanical component testing
How can be established from a clinical perspective that the implant will withstand the endurance habitual and peak loads that must
reasonably be expected (i.e. single implant parts as well as complete arthroplasty combination)?
Summary/Recommendation:
Presently catastrophic implant failure as the origin of clinical failure is rare as long as the implant is loaded according to its designed
purpose, especially with respect to the load transfer between implant and bone. Aspects to be considered are:
• The execution of established and standardized pre-clinical testing methods for the determination of strength and endurance
properties are the essential basis for successful pre-clinical assessment. These have to be performed under physiological conditions
(i.e. considering the pH-value in the body and potential corrosion processes, especially for implants with interfaces such
as modular implants – see also Consensus Statement 13: Modularities / Interfaces) and worst-case size combinations (e.g. based
on FEA).
• The combination matrix for implant systems (size range of component 1 compatible with size range of component 2) has to be
respected in the clinical application to avoid failure due to overloading (e.g. for TKA components to find suitable size combinations
and avoid failure of PE inserts due to mechanical overloading).
• Systematic analysis of retrieved implants from clinical studies and specific cases (even if the reason for retrieval was not mechanical
failure, the retrievals could be analyzed for potential signs of fatigue)
• Careful analysis of registry results (especially for combinations) and their association with patient characteristics and the respective
results from pre-clinical testing.
• If implants are used in a mix&match combination, which is typically not tested pre-clinically, the potential influence of this
combination on overall survival is difficult to assess since frequently not both manufacturers are notified of adverse events. This is
one more justification for public registries.
How can be established from a clinical perspective that the implant will withstand the endurance habitual and peak loads that must
reasonably be expected (i.e. single implant parts as well as complete arthroplasty combination)?
Summary/Recommendation:
Presently catastrophic implant failure as the origin of clinical failure is rare as long as the implant is loaded according to its designed
purpose, especially with respect to the load transfer between implant and bone. Aspects to be considered are:
• The execution of established and standardized pre-clinical testing methods for the determination of strength and endurance
properties are the essential basis for successful pre-clinical assessment. These have to be performed under physiological conditions
(i.e. considering the pH-value in the body and potential corrosion processes, especially for implants with interfaces such
as modular implants – see also Consensus Statement 13: Modularities / Interfaces) and worst-case size combinations (e.g. based
on FEA).
• The combination matrix for implant systems (size range of component 1 compatible with size range of component 2) has to be
respected in the clinical application to avoid failure due to overloading (e.g. for TKA components to find suitable size combinations
and avoid failure of PE inserts due to mechanical overloading).
• Systematic analysis of retrieved implants from clinical studies and specific cases (even if the reason for retrieval was not mechanical
failure, the retrievals could be analyzed for potential signs of fatigue)
• Careful analysis of registry results (especially for combinations) and their association with patient characteristics and the respective
results from pre-clinical testing.
• If implants are used in a mix&match combination, which is typically not tested pre-clinically, the potential influence of this
combination on overall survival is difficult to assess since frequently not both manufacturers are notified of adverse events. This is
one more justification for public registries.
DDC Class
610: Medicine, Health
620: Engineering