DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 118
Metal ions and lymphocyte counts in the bedding-in
period. An RCT between Resurfacing (RHA) and
ceramic on poly THA
Jeanentte Østergaard Penny, Jens-Erik Varmarken, Ole Ovesen,
Christian Nielsen, Søren Overgaard
Dept. of Orthopedic Surgery and Traumatology,
Odense University Hospital, Dept. of Orthopedics, Naestved
Background: Metal on metal articulations produce chromium (Cr) and
cobalt (Co) debris, particularly when the articulations are worn in. High
ion levels in the peripheral blood are indicative of excess wear, and may
have local and systemic affects.
Purpose: The present RCT investigates metal ion concentrations and the
relationship of Co Cr ions and lymphocyte counts during the bedding in
period.
Methods: Following randomization to RHA or THA we obtained whole
blood (wb), and serum (s) at baseline, 8 weeks, 6 months and 1 year. We
measured Co and Cr concentrations, total lymphocyte count and sub
populations. Inclination and anteversion angles of the cup were obtained
from X-rays.
Findings: Nineteen patients in each group. Mean Age 57.0 y (RHA) and
54.9 y (THA) For RHA only: Mean head size: 51.7 mm, inclination:
46.0°, anteversion: 20.4° Median ions stayed below 0.2 ppb for THAs.
For RHAs the ions generally were elevated at 8 weeks, followed by a
slower ascent up to 1 year to 1.02 (wb Co), 1.34 (s Co), 1.31 (wb Cr) and
1.71 ppb (s Cr) (p