NORMALIZED AND PROPORTIONALIZED CEMENTED FEMORAL STEM DESIGNS - A 10-YEAR CLINICAL-STUDY

Two hundred fifteen cemented total hip arthroplasties were performed i n 184 patients using normalized and proportionalized femoral stems. No rmalization or stepped tapering of the stem minimizes development of t ensile hoop stresses by altering force transmission from the femoral s tem to the cement mantle. The pro proportionality of the stem was base d on an anatomic study that resulted in the development of a series of prostheses achieving a more complete femoral canal fill. Patients wer e followed clinically and radiographically from 8 to 12 years or until revision. Average hip scores (d'Aubigne and Postel) improved for pain (3.0-5.9), function (2.9-5.5), and motion (3.3-5.5). Radiographic res ults demonstrated a 4% incidence of loosening, a 16% incidence of cort ical hypertrophy, and no femoral stem fractures. Revision rate was 3%. These results support use of this device.