Randomized comparison between 3 surface treatments of a single anteverted stem design: 84 hips followed for 5 years

80 consecutively patients with non-inflammatory osteoarthritis scheduled to undergo 84 total hip arthroplasty (THA) using the anteverted cobalt-chromium collarless femoral stem (Lubinus SP2; Waldemar Link, Hamburg, Germany) were randomized into 3 groups each with a different surface coating of the femoral stem polished, cemented matte or polymethyl-methacrylate coating. At the 5 year study conclusion, the collarless and polished SP2 stem did not result in significant changes in the BMD, VAS and Harris Hip Scores, as compared to other surface finishes. The polished stems were observed to subside within the cement mantle by 0.1 to 0.2 mm more at 6 months and 0.3 to 0.4 mm more at 5 years than the matte and pre-coated finished stems.