No Detectable Polyethylene Wear 15 Years After Implantation of a Mobile–Bearing Total Knee Arthroplasty With Electron Beam–Irradiated Polyethylene

Abstract

BackgroundThe present study was designed to evaluate the risk of significant polyethylene (PE) wear 10 years or more after implantation of a total knee arthroplasty (TKA) using electron beam–irradiated highly cross-linked PE component. MethodsAll patients operated between 2001 and 2004 for implantation of this particular TKA in the two participating centers were eligible for this study. All patients were contacted after the 10-year follow-up for repeat clinical examination and radiological evaluation. The occurrence of a revision prior to the final evaluation and its reason were recorded. The thickness of the PE piece was measured on plain X-rays. ResultsFive hundred seventy-eight TKAs were implanted during the study time-frame. One hundred sixteen patients deceased prior to the 10-year follow-up (20%). An additional 121 patients were lost to follow-up prior to the 10-year follow-up (21%). Complete follow-up at 10 years or more (including death or revision) was obtained for 448 cases (78%). Ten prosthetic revisions were performed for mechanical reasons during the follow-up time (2%). One single revision was performed because PE wear after 13 years. No significant PE wear was detected at the final radiographic evaluation for nonrevised cases. The 10-year survival rate for mechanical revision only was 98.0% and decreased to 96.2% at 15 years. ConclusionThe use of electron beam–irradiated PE was associated with an extremely low incidence of wear. This technology may be considered as safe regarding PE behavior for TKA after more than 10 years. Further improvement of PE manufacturing may be not required.