A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Abstract

BackgroundMaterial wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only.MethodsA rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made.ResultsThe observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures.ConclusionsThe presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement implants.

Conventional and Highly Crosslinked Polyethylene in Total Knee Arthroplasty—A Design-Independent Wear Investigation

“…The predominant movement of the artificial knee in the sagital plane is a combination of a rollback of the femoral condyles upon the tibial plateau and a slidingmotion between these articulation partners [10]. As a consequence of these kinematics, the ISO 14243 standard describes adequate motion patterns [11].…”

“…Numerous test procedures have been designed and published addressing TKA materials, e.g., pin-on-disk (ASTM-standards), or knee simulators, mostly according to ISO 14243 [10,11,14].…”

“…Common design-independent material test procedures do not represent rolling-sliding movement at the human knee resembling loading patterns [15], while results of simulator studies always depend on the mounted TKA designs which have relevant influence on resulting wear [10]. Less commonly known are various rolling-sliding testing rigs that have successfully been introduced and published, but are not internationally standardized, providing substantial differences e.g., in rolling-sliding motion profiles and/or load sequences [10,16].…”

“…Less commonly known are various rolling-sliding testing rigs that have successfully been introduced and published, but are not internationally standardized, providing substantial differences e.g., in rolling-sliding motion profiles and/or load sequences [10,16]. In addition to the abovementioned testing setups, there is yet another testing rig which was used in this study.…”

A novel method for tribological evaluation of bearing materials in total knee replacements

“…These tests are time and money consuming in cause of the prototype fabrication of the new knee endoprosthesis. In 2010, Richter et al [1] described a new wear test for specimens of simplified geometry under simulated rolling-slidingmovements according to knee endoprostheses. However, the physiological loading of the knee joint was not considered during static load application.…”