Effect of sleeved ceramic femoral heads on titanium ion release.

INTRODUCTION

Metal ion release from wear and corrosion at the femoral head-stem taper junction can evoke local adverse reactions to metal debris (ARMD). In a specific large-diameter head (LDH) total hip arthroplasty (THA) system, ceramic femoral heads of 44 to 48 mm are available with a titanium (Ti) adaptor sleeve, while heads of 36- to 40-mm come without sleeves. The hypothesis of this study is that the Ti adaptor sleeve with LDH ceramic-on-ceramic (CoC) bearings will not cause wear or corrosion at the taper junction and, thus, will not generate high whole blood Ti ion levels.

METHODS

We compared whole blood Ti levels at minimum 1-year follow-up in 27 patients with unilateral primary LDH CoC THA with head sizes ranging from 36 to 48 mm using a Ti stem and acetabular component.

RESULTS

Although Ti ion levels in patients with 36- to 40-mm head diameters without Ti sleeve were found to be statistically significantly higher (2.3 μg/l: 1.6-3.1, SD 0.44) compared to those with a Ti sleeve (1.9 μg/l: 1.6-2.2, SD 0.19) (p = 0.020), the found difference has no clinical importance. No patients presented clinical signs of ARMD, and the clinical results in both groups were similar.

CONCLUSIONS

LDH CoC THA Ti levels were low and probably related to unavoidable passive corrosion of implant surfaces. Measurement of Ti in subjects with ceramic LDH, with or without Ti adaptor sleeve, did not disclose undirected signs of trunnionosis.