Planning and construction of mechanism for surface wear testing and fault analysis in quadril joint prosthetic tribosystem

The problems associated with prosthetic failures and revision surgeries have increased greatly since total joint replacement has also been applied to younger and more active patients, so the need to resolve or reduce wear-related problems is of paramount importance. Based on this premise, it was decided to design, manufacture, and validate a wear test machine of the orbital coupling type, capable of performing the total hip prosthesis (THP) wear test, according to load and movement parameters (flexion/extension, adduction/abduction), established by the Standard ABNT NBR ISO 14242-3. After validation, a sample composed of a 28 mm diameter femoral head of ASTM F138 stainless steel and conventional polyethylene acetabulum (UHMWPE) was performed. The assay lasted for one million cycles (approximately 12 days), equivalent to approximately 1 year of use of the prosthesis in vivo. Two mass and volume loss evaluations were performed throughout the trial, and the results of which were consistent with the results presented by other authors. The evaluation of the wear of the acetabular component (visual and microscopic analysis) and the morphological analysis of the particles generated by the wear, through MEV, provided important information to better interpret the mechanisms of wear (abrasion, adhesion and fatigue) that occurred during the tribological test. It is a fact that these wear mechanisms compromise the useful life of a hip joint prosthetic tribosystem, interfering in the longevity of the prosthetic joint or often leading to total implant failure, resulting in many cases in revision surgeries.