Oxidised zirconium versus cobalt alloy bearing surfaces intotal knee arthroplasty 3D laser scanning of retrieved polyethylene inserts

• Published in: Journal of bone and joint surgery. British volume Vol. 99-B; no. 6; pp. 793 - 798
• Main Authors: Anderson, F L, Koch, C N, Elpers, M E, Haas, S B, Heyse, T J
• Format: Journal Article
• Language: English
• Published: London British Editorial Society of Bone & Joint Surgery 01-06-2017
• Subjects: Joint surgery; Polyethylene
• ISSN: 2049-4394; 2049-4408
• DOI: 10.1302/0301-620X.99B6.BJJ-2016-1281.R1

AimsWe sought to establish whether an oxidised zirconium (OxZr) femoralcomponent causes less loss of polyethylene volume than a cobaltalloy (CoCr) femoral component in total knee arthroplasty.Materials and MethodsA total of 20 retrieved tibial inserts that had articulated withOxZr components were matched with 20 inserts from CoCr articulationsfor patient age, body mass index, length of implantation, and revisiondiagnosis. Changes in dimensions of the articular surfaces were comparedwith those of pristine inserts using laser scanning. The differencesin volume between the retrieved and pristine surfaces of the twogroups were calculated and compared.ResultsThe loss of polyethylene volume was 122 mm3 (standarddeviation (sd) 87) in the OxZr group and 170 mm3 (sd 96)in the CoCr group (p = 0.033). The volume loss in the OxZr group wasalso lower in the medial (72 mm3 (sd 67) versus 92mm3 (sd 60); p = 0.096) and lateral (49 mm3 (sd 36) versus 79mm3 (sd 61); p = 0.096) compartments separately,but these differences were not significant.ConclusionOur results corroborate earlier findings from in vitro testingand visual retrieval analysis which suggest that polyethylene volumeloss is lower with OxZr femoral components. Since both OxZr andCoCr are hard surfaces that would be expected to create comparable amountsof polyethylene creep, the differences in volume loss may reflectdifferences in the in vivo wear of these inserts.Cite this article: Bone Joint J 2017;99-B:793–8.