In a cross-sectional study, researchers from the United Kingdom found higher total body bone mineral density but “potentially deleterious effects” in the left ventricular function of patients with a metal-on-metal hip resurfacing compared to patients with conventional hip replacements at mean of 8 years after surgery.
“Our data suggest that the cross-sectional study designs required of manufacturers by the FDA, and the clinical follow-up of asymptomatic patients with elevated metal levels, should prioritize these organ systems,” J. Mark Wilkinson, MB, ChB, PhD, FRCS, and colleagues wrote in their study.
Wilkinson and colleagues compared 35 asymptomatic patients with a metal-on-metal hip resurfacing who were matched for age and gender with 35 patients with total hip replacement (THR). While bone turnover in the surfacing group was 14% lower, body bone mineral density was 5% higher than in the THR group. The investigators noted in the abstract that the cardiac ejection fraction was 7% lower and the left ventricular end-diastolic diameter was 6% larger in the resurfacing group vs. the THR group.
Both groups had similar results for neuropsychological function, hospital anxiety, depression, serum electrolytes, creatinine clearance and markers for renal tubular damage. Patients in the hip resurfacing group showed fractionary excretion of cobalt and chromium; however their creatinine levels were normal. In a subgroup of hip resurfacing patients, five patients were given diuretics, which was associated with a 40% fractionary excretion increase compared to patients not given the diuretics.
Disclosure: The authors have no relevant financial disclosures.