Can a safe level for metal ions in patients with metal-on-metal total hip arthroplasties be determined?

The single most significant obstacle preventing a broader application of metal-on-metal hip arthroplasties continues to be the concerns regarding elevated metal ion levels in the blood and urine of patients with this bearing. A safe level for metal ions has yet to be defined for patients with metal-on-metal hip arthroplasties. A review of occupational exposure data gives some insight; however, longitudinal studies of large numbers of patients with metal-on-metal implants will ultimately be required to answer specific clinical concerns.