Metal ion trend in patients with metal-on-metal total hip arthroplasty: a 10-year prospective study

Abstract

Introduction: There have been reported adverse reactions in patients with large head metal-on-metal hip arthroplasty, therefore metal particle debris are a cause for concern. The aim of this study was to evaluate the release trend of metal ions and the correlated variables. Methods: 54 patients were prospectively enrolled into the study from 2004 to 2006. All patients had 36-mm metal head, Pinnacle acetabular component, Summit stem and Ultamet CoCr alloy liner (Depuy Inc.), and underwent clinical and radiological management. The haematic concentration of Cr-Co at 0, 6, 12, 24, 60 and 120 months after the implantation was analysed in a sub-cohort of 34 patients. Results: 10-year revision rate for each case was 8.9%. The average concentration of Co at 120 months was 3.12 μg/L (median 2.20) with 53% values >2 μg/L and 1 >7 μg/L. After 6 months the median levels of Cr and Co were higher than time 0 (p < 0.0001); no significant differences were found between 6 and 24 months; while Co had significant increase between 60 and 120 months (p = 0.002). Overweight, University of California at Los Angeles (UCLA) >9 and <50 years old patients have significantly higher circulating metal ions. Discussion: This is 1 of the few prospective studies on the argument. The revision rate is conforming to records. Our data shows ionic concentration is not predictive of revision or adverse reaction to metals. We described a 3-phase trend for Co probably due to the loss of integrity of the surfaces.

Outcomes after the conversion of metal-on-metal hip resurfacing arthroplasty to ceramic-on-ceramic total hip arthroplasty: A retrospective observational study with a mean 10-year follow-up

“…Earlier studies have shown that the serum metal ion levels, mainly for chromium ions, remain at moderate to high levels after conversion CoC-THA in the elderly population [34,35]. The return to exceptionally low or unnoticeable levels could take more than 3 years [36], which is in accordance with our follow-up outcomes that serum chromium ion levels remain moderately high in a majority of patients 3 years after conversion.…”

15-year follow-up of MoM 36-mm THA: clinical, laboratory, and radiological (CT and MRI) prospective assessment

“…To simplify statistical analysis, patients were stratified according to Cr or Co levels into low; (<2 μg/L), medium; (⩾2 and <7 μg/L) and high-risk; (⩾7 μg/L) for ALTR. 5,15,25 At 15-year follow-up the study protocol was implemented and every patient (both symptomatic and nonsymptomatic, irrespectively of ion levels) underwent a hip sonography, an MRI and a CT ( Figure 1). Sonographic results were classified according to Nishii et al, 26 developed as a qualitative screening of the soft tissue findings in MoM THA.…”

“…According to our results and previous literature, ALTR develops in the long term, leading to rTHA up to 10-15 years after MoM THA. 12,14,15,38 In the present study, all patients who underwent rTHA for ALTR were symptomatic; the 4 patients revised for ALTR were studied preoperatively with MRI and CT, however not previously with MAVRIC and O-MAR protocols. During surgery only the bearing couple was revised (MoM to CoP), with excision of affected soft tissues.…”

“…As expected, patients with bilateral MoM had higher ions levels. 12,15,39,42 It is known that Cr and Co concentrations show different trends. Blood Cr values are lower than Co values, due to Cr's greater tendency to settle in periprosthetic tissue, as opposed to Co, that tends to remain in the bloodstream.…”

“…7,8 Due to limited knowledge of the long-term results (>10 years) of MoM THA, particularly concerning clinical outcomes, adverse local tissue reaction (ALTR), Cr-Co ions level and revision rate, [9][10][11] long-term data could help in defining the course and best management for these patients. 1,[12][13][14][15][16][17][18] The purpose of this study was to investigate clinical outcomes, Co and Cr ions levels and describe radiological findings including computed tomography (CT) and magnetic resonance imaging (MRI) findings in 36-mm MoM THA.…”