Blood Metal Ion Release After Primary Total Knee Arthroplasty: A Prospective Study

Abstract

Objectives:To investigate the course of in vivo blood metal ion levels in patients undergoing primary total knee arthroplasty (TKA) and to investigate potential risk factors associated with metal ion release in these patients. Methods:Twenty-five patients with indication for TKA were included in this prospective study. Whole blood metal ion analysis was performed pre-operatively and at 1 week, 6 weeks, 3 months, 6 months, and 12 months postoperatively. Clinical scores were obtained using the American Knee Society Score (AKSS) and the Oxford Knee Score (OKS) at each follow-up and patientsʼ activity levels were assessed by measuring the mean annual walking cycles at 12 months follow-up. Anteroposterior and lateral radiographs of the operated knee were evaluated postoperatively and at 12-month follow-up with regard to implant position and radiological signs of implant loosening. Correlation analysis using multivariate linear regression was performed to investigate the influence of different variables (age, gender, functional scores, number of walking cycles, and body mass index [BMI]) on blood cobalt ion concentrations.Results: Mean metal ion levels of cobalt, chromium, molybdenum, and titanium were 0.28 μg/L (SD, 0.14), 0.43 μg/L (SD, 0.49), 0.62 μg/L (SD, 0.45), and 1.96 μg/L (SD, 0.98), respectively at 12-month follow-up. Mean cobalt ion levels significantly increased 1-year after surgery compared to preoperative measurements. There was no statistically significant increase of mean metal ion levels of chromium, titanium, and molybdenum at 1-year follow-up. Overall, metal ion levels were low and no patient demonstrated cobalt ion levels above 1 μg/L. Postoperative radiographs demonstrated wellaligned TKAs in all patients and no signs of osteolysis or implant loosening were detected at 1-year follow-up. Both the AKSS and OKS significantly improved during the course of the study up to the final follow-up. Multivariate regression analysis did not show a statistically significant correlation between the tested variables and blood cobalt ion concentrations. Conclusion:A statistically significant increase of mean cobalt ion concentration at 1-year follow-up was found in this cohort of patients with well-functioning TKA, although overall blood metal ion levels were relatively low. Despite low systemic metal ion concentrations seen in this cohort, the local effects of increased metal ion concentrations in the periprosthetic environment on the long-term outcome of TKA should be further investigated.

Critically high metal ion levels found in metal-on-metal modular hinged knee arthroplasty

“…In TKA, wear-related problems have typically been reported in terms of damage to the PE insert. 5 although retrieval studies have recently demonstrated that abrasive and corrosive damage commonly occurs at the femoral component of tKas, little is known about metal ion exposure in patients with well-functioning TKAs. 21 no limit values for serum metal ion concentrations have been established for TKA, but ion concentrations above 2 μg/l are considered to be a potentially critical value for mom hip arthroplasty according to current guidelines.…”

“…4 However, few data have been published regarding metal ion concentrations following tKa, as metal ion concentrations seldom exceed 1 μg/l in primary TKA. 5 due to the constrained hinge mechanism and the resulting mechanical forces on the coupling, recent studies have shown increased serum levels of cobalt and chromium in the majority of patients receiving mom hinged knee designs combined with a modular revision knee system for the treatment of very large bone defects. [6][7][8] The implants examined in these studies were mostly modular tumour-or megaprostheses.…”

Die Anwendung antiallergisch beschichteter Knieendoprothesen ist mittelfristig sicher

“…Nach 5 Jahren zeigten jedoch alle Patienten unabhängig von der Beschichtung wieder Werte für Chrom von unter 2 μg/l. Für Kobalt, welches die Haupt- [15,33,36] und andere Arbeiten, die die Metallionenfreisetzung bei der Verwendung von Knieimplantaten untersucht haben, berichten über erhöhte Werte für Chrom und Kobalt bis zu 10 Jahre nach Implantation [7,17,27]. Für Nickel, das Metall, welches am häufigsten Hautallergien hervorruft (bis zu 20,1 % [28]) und daher in den Patientengesprächen oft benannt wird, wurden keine Änderungen der Konzentration bis zu 5 Jahre nach Operation in beiden Patientengruppen gemessen.…”

Metal wear debris generation in primary total knee arthroplasty: is it an issue?

“…The 10-year survival ratio of TKA is approximately 90 % (1). One of the major causes for revision is aseptic loosening, caused by wear debris, mainly polyethylene (1)(2)(3)(4). Wear debris is generated by biotribocorrosion, a process induced by mechanical No benefits or funds were received in support of this study.…”

“…Acta Orthopaedica Belgica, Vol. 87 -4 -2021 wear, which ruptures the passive film formed on the prosthesis surface and thus leaves the metallic surface exposed to corrosive media (2,5). However, the effects of metal wear debris (metal particles and ions), which is around 1/10 th of the total wear debris, have been underestimated.…”