Study: Arthroplasty implants linked to metal accumulation in cerebrospinal fluid

Editor's Note

Arthroplasty implants may release metals that accumulate in the central nervous system (CNS), potentially contributing to neurotoxic effects, according to a study published March 28 in JAMA Network Open. Researchers found that patients with large joint replacements had significantly higher levels of cobalt, chromium, titanium, niobium, and zirconium in both blood and cerebrospinal fluid (CSF) compared to individuals without implants.

The NeuroWear pilot study, conducted at Charité–Universitätsmedizin Berlin, was a cross-sectional analysis involving 204 patients. The cohort included 103 patients with large joint replacements and 101 age- and sex-matched controls without implants. Blood and CSF samples were collected from each participant to measure metal concentrations. Key findings include:

• Cobalt levels were significantly elevated in both blood and CSF among implant patients compared to controls.
• Cobalt levels in CSF strongly correlated with cobalt levels in blood (r=0.82) and serum (r=0.72), suggesting cobalt-specific transport mechanisms across neural barriers.
• Other metals, including chromium, titanium, niobium, and zirconium, were also significantly elevated in the blood of implant patients, with some accumulating in CSF.
• Patients with implants containing cobalt-chromium-molybdenum had notably higher levels of cobalt and chromium in both CSF and blood.
• Those reporting joint pain exhibited higher CSF cobalt levels than those without pain.
• In contrast, no significant increases were observed for aluminum, despite its presence in many implant alloys.

While cobalt and chromium are known to cross neural barriers, the study indicates that titanium, niobium, and zirconium may also accumulate in the CNS under certain conditions.

Authors emphasize the need for further research to assess whether elevated CSF metal levels correlate with neurological symptoms, particularly in patients experiencing new or worsening neurological conditions following joint replacement surgery. Future studies should explore the long-term health implications of metal exposure from arthroplasty implants, they write.