(P 101) METAL ION MONITORING AFTER CUSTOM 3D-PRINTED IMPLANTS IN BONE TUMOR SURGERY: COMPARISON WITH MODULAR SYSTEMS AND EARLY OBSERVATIONS

Objective: To evaluate metal ion release following skeletal reconstruction using 3D-printed endoprostheses in bone tumor patients, compared to conventional modular tumor implants.

Methods: We prospectively monitored serum and drain concentrations of titanium (Ti), aluminum (Al), and vanadium (V) in 16 patients with custom 3D-printed Ti6Al4V implants and 3 patients with MUTARS® prostheses, all with ≥12-month follow-up. Serial measurements were analyzed for early and late-phase ion trends.

Results: Both groups showed an early postoperative peak in drain fluid, followed by a serum peak at 2–3 months. The 3D group included reconstructions in the pelvis (n=6), lower limb (n=8), and upper limb (n=3), with 6 patients having prior implants. Mean peak Ti, Al, and V in the 3D group were 47.6, 225.0, and 1.99 µg/L, respectively, compared to 9.4, 176.7, and 0.84 µg/L in the MUTARS® group. Postoperative Ti elevation was higher in 3D patients (ΔTi 37.6 vs. 9.8 µg/L), while Al and V were similar. A second ion peak was noted after 3 months in both groups, suggesting ongoing material interaction. Al levels did not correlate with Ti, but late Ti increases in the 3D group raise concerns about corrosion.

Conclusion: 3D-printed implants showed significantly higher Ti release compared to conventional systems, possibly due to surface roughness or lattice design. Late-phase re-elevation suggests potential long-term degradation. Al accumulation, a neurotoxic concern, was comparable between groups. Long-term surveillance and improved surface treatments are warranted.