Metal-on-Metal Hip Joint Prostheses: a Retrospective Case Series Investigating the Association of Systemic Toxicity with Serum Cobalt and Chromium Concentrations

Abstract

Introduction There have been concerns about prosthesis failure and the potential for systemic toxicity due to release of cobalt and chromium from metal-on-metal hip joint prostheses (MoM-HP). There is conflicting evidence on whether there is a correlation between higher cobalt and chromium concentrations and systemic toxicity. Methods We undertook a retrospective review of consecutive patients with MoM-HP referred for outpatient review in toxicology clinics in London, UK, and in the USA recorded in the Toxicology Investigators Consortium (ToxIC) Registry from June 2011 to June 2015. Results Thirty-one cases were identified; the median (IQR) serum cobalt concentration was 10.0 (3.8-32.8) mcg/L, and the median (IQR) serum chromium concentration was 6.9 (3.7-18.7) mcg/L. Twenty-three (74.2%) had symptoms, most commonly lethargy, hearing loss, and tinnitus. The odds ratios of symptomatic/asymptomatic patients for metal ion concentrations above/below 7 mcg/L were 1.87 (95% CI 0.37-9.57, p = 0.45) and 0.60 (95% CI 0.10-3.50, p = 0.57) for cobalt and chromium, respectively. Two (6.5%) patients with systemic cobalt toxicity had median (IQR) serum cobalt concentrations significantly higher than those without systemic features (630.4 [397.6-863.2] mcg/L versus 9.8 [2.9-16.4] mcg/L; p = 0.017). However, overall, there were no differences between cobalt (p = 0.38) or chromium (p = 0.92) concentrations between symptomatic and asymptomatic patients and no clinical features or investigation results correlated with cobalt or chromium concentration. Conclusion Two (6.5%) of 31 individuals referred for assessment of MoM-HP were diagnosed with systemic cobalt toxicity. However, despite a high prevalence of reported symptoms, neither symptoms nor investigation results correlated with serum cobalt or chromium concentrations.

Haemodynamic instability during hip prothesis removal due to metallosis: An acute chrome/cobalt intoxication? A case report

“…Despite our patient showed high chromium concentration, no clinical manifestations of chrome intoxication were present [2] . This is consistent with the findings of Ho J et al who studied the association of systemic toxicity with normal serum cobalt and chromium concentrations in patients with metal-on-metal (MOM) hip prostheses [10] . They found no direct correlation between the occurrence of symptoms and plasma concentration of these metals, as in our case.…”

Metal Ion Release, Clinical and Radiological Outcomes in Large Diameter Metal-on-Metal Total Hip Arthroplasty at Long-Term Follow-Up

“…This was because the study started after awareness of the safety concerns related to higher revision rates and adverse reactions of some MoM hip implants. Moreover, the present work involved a small sample size, even if the number is in line with the majority of published studies [ 44 , 48 , 53 , 68 , 69 ], limiting the possibility to highlight more correlations between metal ion levels and clinical and radiological scores evaluated. The impact of titanium release cannot be excluded as we did not measure its levels.…”

Prosthetic hip-associated cobalt toxicity: a systematic review of case series and case reports

“…tinnitus, vertigo, deafness, blindness, convulsions, headaches and peripheral neuropathy), cardiotoxicity and thyroid toxicity ( 14 ). Nausea, anorexia and unexplained weight loss have also been described ( 6 , 15 , 16 , 17 ). Initially, there were concerns that high cobalt and chromium concentrations increased the risk of cancer; however, this was not proven in large comparative studies ( 18 , 19 ).…”