A randomised, controlled clinical study on total hip arthroplasty using 4 different bearings: results after 10 years.

Purpose: To compare 4 different bearings in total hip arthroplasty (THA) in a randomised controlled clinical study on clinical performance.

Methods: 393 patients with osteoarthritis of the hip or avascular necrosis were included and allocated to 1 of the head-and-cup couples zirconia-on-polyethylene (group A), metal-on-metal (group B), zirconia-on-polyethylene with the liner moulded into the shell (group C), or alumina-on-alumina (group D). In the individual case the surgeon could choose other implants if indicated.