[Assessment of the level of metal ions in the blood of patients after hip resurfacing--preliminary report].

Abstract

Introduction: Metal-on-metal bearings characterize lower wear than metal-poly, lower fracture risk than ceramics and they allow for the manufacturing of large diameter heads. The metal ion release from the bearings is the the major concern of these articulations.

Material: The study group consisted of 16 patients who underwent hip resurfacing with Durom implant and had minimum 1 year follow-up period. Blood from the patients was collected 4 times: before the surgery, 2, 6 and 12 months postoperatively.

Methods: Clinical examination was done according to HHS, Radiographic image was used to measure the cup inclination, evaluation of chromium and cobalt ion blood levels was performed using graphite furnace atomic absorbtion spectrometry (GFAAS).

Results: The levels of cobalt and chromium increased postoperatively significantly to decrease slightly at 6 months. At 1 year cobalt levels increased to the similar level like at at 2 months. The chromium level decresed to the values as low as preoperatively. The mean cup inclination angle measured on X-rays was 48 degrees(range 39 degrees - 56 degrees). The mean HHS result was 89.86 (range 64.43 to 98.73). The mean activity level measured with UCLA scale was 6 (range 3-9).

Conclusions: The metal ion blond levels increase sigficantly in the period 2-6 months following hip replacement with large diameter metal-on-metal articulation. In further examinations at 1 year post-op ion levels decrease.