Five-Year Experience of Vitamin E-Diffused Highly Cross-Linked Polyethylene Wear in Total Hip Arthroplasty Assessed by Radiostereometric Analysis

Background: Vitamin E-diffused highly cross-linked polyethylene (VEPE) was developed to reduce oxidation without compromising mechanical strength. The purpose of this study was to evaluate VEPE in vivo using radiostereometric analysis (RSA) and patient-reported outcome measures (PROMs). Methods: Fifty-one hips were enrolled. Each patient received a VEPE liner, a porous titanium shell, and an uncemented stem with a 32-mm cobalt-chrome femoral head. Tantalum beads were inserted into the VEPE to measure femoral head penetration using RSA. RSA radiographs and PROMs were obtained preoperatively immediately after surgery, 6 months, 1, 2, 3, and 5 years after surgery. Results: Forty-seven hips returned at 3 years, and 42 hip at 5 years. The mean +/- standard error of the mean proximal head penetration into the polyethylene was 0.06 +/- 0.01 at 5 years. The amount of head penetration did not change significantly with increasing time in vivo. The mean +/- standard error of the mean Harris Hip Score was 58 +/- 2 preoperatively, which improved significantly to 93 +/- 2 at 5 years (P < .001). Conclusion: The head penetration into VEPE liners was low compared with non-VEPE at 5 years. After settling of the liners in the early period, no significant head penetration occurred from 2- to 5-year follow-up. All PROMs improved significantly from preoperative to postoperative and remained very favorable at 5 years. This study documents the longest-term evaluation of in vivo wear performance of VEPE. (C) 2015 Elsevier Inc. All rights reserved.