The Long-Term Results of Total Hip Arthroplasty With a Cemented β-Titanium Stem

Abstract

BackgroundWe report on the outcomes of a double-tapered cemented stem made of β-titanium alloys (Ti-15Mo-5Zr-3Al) at least 10 years after total hip arthroplasty. MethodsWe retrospectively analyzed 148 consecutive, primary total hip arthroplasties using this stem performed in 130 patients between January 2004 and August 2008. The patients’ mean age was 59.6 years (range, 24-79). Implant survival was evaluated using Kaplan-Meier curves with the primary end point being stem revision for any reason and the secondary end point being stem revision for aseptic stem loosening. We also clinically and radiologically followed 140 hips (in 123 patients) for an average of 12.2 years (range, 10-15). ResultsThe only revisions were for 2 stems with deep infection. Ten-year survival was 99.3% (95% confidence interval, 95.4%-99.9%) and 100% for the primary and secondary end point, respectively. The mean Japanese Orthopaedic Association hip score improved from 51.4 preoperatively to 88.7 at the last follow-up. Radiolucent lines at the stem-cement interface were seen in 14 hips (10.0%). None of the hips met the criteria of radiological stem loosening. Nineteen stems (13.6%) subsided by around 1 mm between 2 and 8 years after surgery. Distal femoral cortical hypertrophy occurred in 24 hips (17.0%), mostly with valgus alignment. ConclusionThe clinical outcomes of the femoral stems were excellent with survival at 10 years. Stem subsidence and distal femoral cortical hypertrophy did not affect the results. Long-term use of β-titanium alloy stems is safe and effective.