PERFORMANCE OF THE CENATOR AND EPF ACETABULAR COMPONENTS AT THREE YEARS.

Abstract

Introduction: NICE guidelines (2000) stipulated three-year follow-up data compatible with satisfactory performance at 10 years as a minimum requirement for hip implants. We reviewed the performance of two devices in use in our department which fell outside these requirements. The Cenator cup (Corin Medical) is a cemented device, and the EPF cup (Plus Orthopedics) is uncemented (equatorially expanded, screw option, polished inside, porous HA coated).

Patients and Methods: 117 Cenator and 110 EPF cups inserted during the period 12/09/2000–28/01/2003 were assessed at 3 years by the following: Oxford Hip Score, satisfaction (visual analogue scale), details of femoral component, age, sex, BMI and any complications. Radiological assessment included Charnley Grade, concentricity, superior cover, cup inclination, migration, radiolucent lines, and linear wear at 3 years. Statistical associations with radiolucent lines or linear wear were calculated.

Results: The mean age of patients with Cenator cups was 81 (range 61–102) and EPF cups 67 (39–86). Oxford Hip Scores averaged 10 (0–41)(Cenator) and 7 (0–29)(EPF). Cup inclination range was 30–65° (mean 47). Linear wear > 1mm was observed in 18 Cenator and 53 EPF cups. Early radiolucent lines behind EPF cups closed (all cases), and superior cover improved in 8%. Progressive radiolucencies > 1mm were seen behind 37 Cenator cups. One of each type was revised for deep sepsis. Four other minor reoperations occurred. Statistical association was demonstrated between superior cover and progressive radiolucencies (Cenator), and between sex, cup size and inclination and linear wear (EPF).

Discussion: Crucial markers of prognosis were observed (progressive radiolucencies and linear wear) but survivorship at three years for aseptic loosening was 100%. Our results indicate satisfactory performance at three years in accordance with NICE guidelines, and suggest acceptability of both devices. Our methods may be applicable to similar implants currently in use but not yet endorsed by suitable published outcome data.