BACKGROUND: Oxidized zirconium (OxZr) was introduced as an alternative bearing for femoral components in total knee arthroplasty (TKA) in an attempt to reduce wear compared with conventional cobalt-chromium (CoCr) alloys. QUESTIONS/PURPOSES: The aim of this study was to compare matched pairs of retrieved OxZr and CoCr components using surface profilometry; specifically, we sought to compare the surface roughness of (1) retrieved OxZr TKA components with retrieved CoCr components; (2) the medial versus the lateral femoral condyles of retrieved components; and (3) unimplanted OxZr TKA components with unimplanted CoCr components. METHODS: Ten retrieved posterior-stabilized Genesis II TKA with OxZr femoral components were identified and matched to retrieved CoCr femoral components by duration of implantation, patient age, and body mass index. A noncontact white light interferometer was used to evaluate surface roughness. One pristine, unimplanted component of each design was analyzed as a control. RESULTS: The retrieved components showed significantly (p < 0.0001) lower roughness for the OxZr components than the CoCr components. CoCr retrievals showed a significantly greater average surface roughness on the medial condyle. No difference was found between the condyles of the OxZr components. The pristine CoCr implant had a significantly lower surface roughness than the pristine OxZr component. CONCLUSIONS: CoCr roughens significantly more in situ compared with OxZr components. CLINICAL RELEVANCE: Bearing surfaces are typically damaged in vivo. The extent of damage is variable between patients and implants; however, rougher surfaces should be associated with more wear. Whether the differences observed in our study prove meaningful requires long-term clinical data.
BACKGROUND: Oxidized zirconium (OxZr) was introduced as an alternative bearing for femoral components in total knee arthroplasty (TKA) in an attempt to reduce wear compared with conventional cobalt-chromium (CoCr) alloys. QUESTIONS/PURPOSES: The aim of this study was to compare matched pairs of retrieved OxZr and CoCr components using surface profilometry; specifically, we sought to compare the surface roughness of (1) retrieved OxZr TKA components with retrieved CoCr components; (2) the medial versus the lateral femoral condyles of retrieved components; and (3) unimplanted OxZr TKA components with unimplanted CoCr components. METHODS: Ten retrieved posterior-stabilized Genesis II TKA with OxZr femoral components were identified and matched to retrieved CoCr femoral components by duration of implantation, patient age, and body mass index. A noncontact white light interferometer was used to evaluate surface roughness. One pristine, unimplanted component of each design was analyzed as a control. RESULTS: The retrieved components showed significantly (p < 0.0001) lower roughness for the OxZr components than the CoCr components. CoCr retrievals showed a significantly greater average surface roughness on the medial condyle. No difference was found between the condyles of the OxZr components. The pristine CoCr implant had a significantly lower surface roughness than the pristine OxZr component. CONCLUSIONS:CoCr roughens significantly more in situ compared with OxZr components. CLINICAL RELEVANCE: Bearing surfaces are typically damaged in vivo. The extent of damage is variable between patients and implants; however, rougher surfaces should be associated with more wear. Whether the differences observed in our study prove meaningful requires long-term clinical data.
Authors: Shannon K T Puloski; Richard W McCalden; Steven J Macdonald; Robert B Bourne; Cecil H Rorabeck Journal: J Arthroplasty Date: 2003-10 Impact factor: 4.757
Authors: Raphael Malikian; Kunalan Maruthainar; John Stammers; Steve R Cannon; Richard Carrington; John A Skinner; Nimalan Maruthainar; George Dowd; Tim W R Briggs; Gordon W Blunn Journal: Knee Date: 2012-11-09 Impact factor: 2.199
Authors: Peter F Sharkey; William J Hozack; Richard H Rothman; Shani Shastri; Sidney M Jacoby Journal: Clin Orthop Relat Res Date: 2002-11 Impact factor: 4.176
Authors: Richard J Holleyman; Susan C Scholes; David Weir; Simon S Jameson; Jim Holland; Tom J Joyce; David J Deehan Journal: Knee Surg Sports Traumatol Arthrosc Date: 2014-08-07 Impact factor: 4.342
Authors: Mohamed E Moussa; Christina I Esposito; Marcella E Elpers; Timothy M Wright; Douglas E Padgett Journal: J Arthroplasty Date: 2014-11-11 Impact factor: 4.757