The 5-year postoperative metal ion levels plateaued in cases having 28-mm metal-on-metal hip bearings but continued to increase for 36-mm metal-on-metal bearings, according to a recently presented prospective study involving 120 patients.
“This was a prospective randomized trial with three arms: a 28-mm polyethylene liner, 28-mm metal-on-metal (MoM) and a 36-mm [MoM],” C. Anderson Engh Jr., MD, said at the American Academy of Orthopaedic Surgeons 2012 Annual Meeting, in San Francisco. “The same stem and cup were utilized. We looked at serum, erythrocyte and, at 5 years, whole blood ion levels,” he said.
Of the 120 patients enrolled, 105 patients were eligible for the study at the time of surgery and randomized into three groups. The first group underwent metal-on-polyethylene (MoP) total hip arthroplasty (THA), while the second and third groups underwent 28-mm MoM THA and 36-mm MoM THA, respectively, Engh reported.