Modular cementless cup for total hip arthroplasty: results at 4-year follow-up.

The aim is to perform the assessment of a modular cementless acetabular cup with a tapered internal design for all bearing couplings. In 190 unselected consecutive patients, 207 total hip arthroplasties were implanted. The implants were clinically and radiographically evaluated. Follow-up was 49.7 ± 8.1 months. The average Harris hip score improved from 55.5 ± 5.7 to 94.7 ± 3.4 (P < 0.05). All cups were well-positioned and stable. The Kaplan-Maier cumulative survivorship was 98.5 ± 0.8%. No significant differences have been noted in dividing patients according to the different liner materials (P < 0.005). The study, whose rationale is the novelty of this kind of implant, suggests the efficacy of the Delta-PF acetabular cup.