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Purpose: Measurement of serum metal ion levels is used to determine systemic exposure to implant-derived metal debris that may be generated by processes of wear and corrosion. The aim of this study is to investigate predictors of serum metal ion levels in children undergoing instrumented spinal arthrodesis using a titanium alloy, focusing on implant characteristics and instrumentation construct design variables., Methods: This prospective longitudinal cohort study involved 33 children. Serum samples were obtained preoperatively:and at five defined interval periods over the first:two post-operative years. Samples were analysed using high resolution:inductively coupled plasma mass spectrometry to measure titanium, niobium and aluminium concentrations. Instrumentation characteristics were catalogued and construct surface area (SA) measurements calculated using an implant-specific software algorithm tool., Results: Significantly elevated levels of serum titanium and niobium were observed (p< 0.0001), with >95 % of post-operative levels abnormally elevated. Significant predictors of serum titanium and niobium levels included time since surgery, surgical procedure (posterior or anterior fusion), number of levels fused, number of pedicle screws inserted, total rod length, total metal SA, total exposed metal SA and total metal-on-metal SA. All significant instrumentation variables were highly correlated., Conclusions: There is a strong relationship between implant SA and both serum titanium and niobium levels. The direct clinical implications of these findings for patients are uncertain, but remain of concern. Surgeons should be aware of the strong correlation between implant surface area of the chosen construct and the subsequent serum metal ion levels.

Study Design: A prospective cohort study., Objective: To determine serum titanium, niobium, and aluminum levels in pediatric patients within the first postoperative year after instrumented spinal arthrodesis., Summary of Background Data: Instrumented spinal arthrodesis is a common procedure to correct scoliosis and kyphosis. Titanium-based instrumentation is increasingly favored due to enhanced biomechanical properties, but concerns have arisen regarding metal debris release and the potential for local and systemic complications., Methods: The pattern of systemic metal release over time was evaluated by measuring serum titanium, niobium, and aluminum levels preoperatively and 1 week, 1 month, 6 months, and 12 months after instrumented spinal arthrodesis using a titanium alloy. Serum metal levels were measured using high-resolution inductively coupled plasma mass spectrometry., Results: Thirty-two patients were included in the study group. Mean age at surgery was 14.7 years. Preoperative and postoperative concentrations of serum titanium and niobium were significantly different (P = 0.0001). Median postoperative serum concentrations of titanium and niobium were elevated 2.4- and 5.9-fold above the normal range respectively with 95% and 99% of samples elevated postoperatively. A significant and rapid rise in serum titanium and niobium levels was observed within the first postoperative week, after which elevated serum levels persisted up to 12 months., Conclusion: We report abnormally elevated serum titanium and niobium levels in patients with titanium-based spinal instrumentation up to 12 months. The long-term systemic consequences of debris generated by wear and corrosion of spinal instrumentation is unclear but concerning, particularly as these implants inserted into the pediatric population may remain in situ for beyond 6 decades.

Ions are released from all metals after implantation in the body through processes of corrosive and mechanical wear. The aim of this study was to investigate whether serum metal ion levels are raised in patients following total knee arthroplasty. Serum levels of chromium, cobalt, aluminium, molybdenum and zirconium were measured in two groups of patients at a minimum of 3 years after knee arthroplasty. Twenty three patients had a cobalt-chromium femoral component and 14 patients had an oxidized zirconium femoral component, acting as a control group as this femoral component is free from cobalt and chromium. All patients had the same titanium tibial base plates, and no patellae were resurfaced. Despite the lack of cobalt and chromium in the prostheses used in the control group, no statistically significant differences in serum cobalt and chromium ion levels were found between the groups. On the basis of these results there does not appear to be any significant rise in serum metal ion levels following total knee arthroplasty several years after implantation.