Three- to six-year results with the ultima metal-on-metal hip articulation for primary total hip arthroplasty

One hundred seventy-one primary total hip arthroplasties were evaluated in a prospective, randomized study. Ninety-five involved a metal-backed cup with an all-metal liner and 76 involved a metal-backed polyethylene cup that was used as the control. All were implanted with an S-ROM cementless femoral component with a 28 mm head. The mean follow-up period was 3.7 years (range, 3.0–5.7). The average postoperative Harris hip score was 95.4 (range, 65–100) for the metal-on-metal group and 96.1 (range, 65–100) for the metal-on-polyethylene group. Radiographic results were not statistically different between the 2 groups. Early results show the metal-on-metal articulation has been successful to date and justify continued clinical use.