Alternative Wear Couples 49
Clinical Performance of a Highly Crosslinked Polyethylene at Four to Five Years In Total Hip Arthroplasty: A Randomized Prospective Trial
J. M. Martell J. J. Verner and S. J. Incavo
Introduction
Highly crosslinked polyethylene demonstrates 80-90% wear reduction by hip sinnulator testing, however clinical data on this new polyethylene has been limiited. We report the tour to five-year results tor a prospective randomized trial comparing highly crosslinked to standard polyethylene.
Methods
88 hips were available for radiographic analysis. All cases were performed using the Secur-Fit^'' HA acetabular component and the Secur-Fit^'^ or Secur-Fit Plus^'^ HA femoral components (Stryker/Howmedica/Osteonics). Femoral bearings were 28 mm cobalt chrome with low friction ion treatment (L-Fit). The polyethylene insert was randomized at the time of implantation to highly crosslinked polyethylene (Crossfire^'^), or standard polyethylene that was gamma sterilized and packaged in nitrogen (N2/Vac^^). Polyethylene wear rates were measured based on AP and lateral pelvis radiographs at six weeks and yearly intervals using a validated computer assisted edge detection method. Wear rotes between the two groups were compared using the non-parametric Mann- Whitney U-test at the 95% level.
Results
There were no device related failures in this group. The 2D volumetric wear rate was 61% lower in the highly crosslinked group (19.8 mmVyr.), than in the standard group (61.5 mmVyr.).
Conclusions
This follow-up on highly crosslinked polyethylene shows no device related failures and a 61% wear reduction compared to standard (N2-Vac) polyethylene.
Follow-up beyond five years will be needed to determine whether in-vivo oxidation impacts wear performance in the long term.
At this time these results are encouraging, given the widespread use of highly crosslinked polyethylene.
