What is the Long-term Wear of a 5-Mrad Highly Crosslinked Polyethylene Liner? A 14-year RSA Study.

Background: Lower doses of irradiation (≤ 5 Mrad) during the manufacture of highly crosslinked polyethylene acetabular liners may result in less crosslinking and an increased wear rate. Radiostereometric analysis (RSA) studies have found that wear of more highly irradiated highly crosslinked polyethylene liners (7 to 10 Mrad) decreases at longer-term follow-up compared with earlier reports of the same cohorts. Although wear of 5-Mrad irradiated liners appears to increase at midterm follow-up, it is unclear whether that remains true at longer follow-up.

Large articulations do not increase wear rates of thin second-generation highly cross-linked polyethylene liners at ten years.

Aims: Radiostereometric analysis (RSA) is the most accurate radiological method to measure in vivo wear of highly cross-linked polyethylene (XLPE) acetabular components. We have previously reported very low wear rates for a sequentially irradiated and annealed X3 XLPE liner (Stryker Orthopaedics, USA) when used in conjunction with a 32 mm femoral heads at ten-year follow-up. Only two studies have reported the long-term wear rate of X3 liners used in conjunction with larger heads using plain radiographs which have poor sensitivity.