Brain structure and function in patients after metal-on-metal hip resurfacing

Hip prostheses that use a metal-on-metal articulation expose the brain to elevated metal concentrations that, in acute excess due to prosthesis malfunction, is associated with neurologic damage, including visual and hearing loss and motor deficits. Here, we examined whether chronic exposure to lower elevated metal levels, typical of well-functioning prostheses, also affects brain structure and function. We compared brain volumes, metal deposition, and gray matter attenuation by MR imaging and clinical neurologic function in patients 8 years after receiving a metal-on-metal hip resurfacing versus a matched group of patients with the same duration exposure to a conventional hip prosthesis. Twenty-nine patients (25 men; mean, age 59±7 years) after metal-on-metal hip resurfacing and 29 patients (25 men; 59±8 years) after total hip arthroplasty were compared. Whole blood cobalt and chromium concentrations were 5-10 times higher in the metal-on-metal hip resurfacing group (P