Design of an Advanced Bearing System for Total Knee Arthroplasty

• Published in: Lubricants Vol. 3; no. 2; pp. 475 - 492
• Main Authors: Morrison, Mark L, Jani, Shilesh, Parikh, Amit
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.06.2015
• Subjects: abrasion; Biomedical materials; crosslink density; Crosslinking; highly crosslinked UHMWPE; knee; Mechanical properties; oxidized zirconium; Polyethylenes; Reduction; Surgical implants; TKA; wear; Wear rate; Wear resistance
• ISSN: 2075-4442; 2075-4442
• DOI: 10.3390/lubricants3020475

The objective of this study was to develop an advanced-bearing couple for TKA that optimizes the balance between wear resistance and mechanical properties. The mechanical and structural properties of virgin and highly crosslinked, re-melted UHMWPE were evaluated, and tibial inserts manufactured from these UHMWPE materials were tested against either oxidized zirconium (OxZr) or CoCr femoral components on a knee simulator. This study confirmed that the wear resistance of crosslinked UHMWPE improves with increasing radiation dose but is accompanied by a concomitant reduction in mechanical properties. Compared to CoCr, the ceramic surface of OxZr allows the use of a lower irradiation dose to achieve equivalent reductions in wear rates. As a result, a given wear rate can be achieved without sacrificing the mechanical properties to the same extent that is necessary with a CoCr femoral component. The advantage of ceramic counter bearing surfaces extends to both pristine and microabrasive conditions.