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Retrieval Analysis Of Cross-linked Acetabular Bearings
Collier, J. P., Mayor, M. P., Currier, B. H., Wittmann, M. W.
Abstract
A number of cross-linked polyethylene acetabular components are currently available for clinical use. While the maximum time of implantation of these components is still less than five years, a number have been removed and sent to our laboratory for examination. Each component has been photographed, analyzed using a scanning electron microscope, sectioned, and tested for oxidation level. Where possible, free radical concentration and mechanical properties were measured. Six retrieved components, all with implantation durations of less than two years, were analyzed. All showed considerable evidence of scratching with some removal of the original machining marks. The oxidation levels of the components were low. There was no evidence of gross cracking or delamination, although microdamage to the raised portion of the machining marks was not uncommon. These components indicate that cross-linked materials are not immune to damage nor are they highly oxidized after short periods in vivo. Long term performance of these devices cannot be determined from these short-term retrievals.
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