To compare the influence of two different cemented stems each made of different alloys on survival and outcome.
We analyzed 341 total hip replacements performed in 1998-2001. Two types of prostheses were implanted. Biomet Bi-Metric titanium stem, cobalt-chrome head and ultra high molecular weight all poly cup were implanted in 102 cases. Aesculap Centrament cobalt-chrome stem, head and ultra high molecular weight all poly cup were implanted in 239 cases. All prostheses were cemented; Palacos bone cement with gentamycin was used in all cases. Cementing technique was consistent in all cases. All data were collected prospectively. For every total hip replacement the form was filled in. The documental patients' data, implant type, cement type, cementing technique, intraoperative and postoperative complications were registered. All revision surgeries were registered; the patients' death dates were recorded from national register database up to December 31, 2004. Kaplan-Meier curves were used to calculate implant survival rates.
The total implant survival for Biomet Bi-metric prostheses was 98%, 7 years postoperatively. The total implant survival as Aesculap Centrament prostheses were used was 98%, 6 years postoperatively.
The mid-term implant survival of Biomet Bi-Metric titanium stems was the same as survival of Aesculap Centrament cobalt-chromium stems.