Short-term Outcomes With a Second-Generation Uncemented Stem in Total Hip Arthroplasty

An uncemented stem has been used successfully in total hip arthroplasty for 2 decades, and some implants have been updated. The authors have used second-generation uncemented proximal porous coating stems, the Echo Bi-Metric Full Proximal Profile stem (Echo FPP; Biomet, Warsaw, Indiana) and the Echo Reduced Proximal Profile stem (Echo RPP; Biomet). This article reports short-term outcomes with these stems compared with their predecessor, the Bi-Metric stem (Biomet). The authors reviewed 1280 Echo FPP stems, 366 Echo RPP stems, and 1497 Bi-Metric stems. With more than 5 years of follow-up, both the Echo FPP and the Echo RPP stems had 100% survivorship with stem revision as the endpoint, and the Bi-Metric stems also had 100% survivorship for more than 20 years. Average Harris Hip Scores for the Echo FPP, the Echo RPP, and the Bi-Metric stems were 53.3, 49.7, and 51.5 preoperatively, 93.8, 94.6, and 95.2 at 1 year, and 94.0, 95.8, and 95.4 at 3 years postoperatively, respectively. Dislocation after surgery was significantly lower with the Echo FPP and the Echo RPP stems than with the Bi-Metric stems, but this was more relevant to the surgical approach and head size. All radiographs of the Echo FPP, the Echo RPP, and the Bi-Metric stems showed proximal femoral remodeling consistent with osseous ingrowth. Distal cortical hypertrophy around the implanted stem and spot-welding were comparably observed in all 3 cohorts. The short-term outcomes of the updated uncemented stems were as excellent as the previously used stem regarding survivorship, complications, and radiographic assessment.