TEN-YEAR RESULTS WITH THE MORSCHER PRESS-FIT CUP

Abstract

Objective: The Morscher press-fit cup is a cementless, porous-coated acetabular component. The objective of this study was to assess clinical and radiological outcomes, patient satisfaction and complications at 10 years.

Methods: Prospective cohort study including all consecutive primary THAs with the Morscher cup operated by multiple surgeons of a University hospital between March 1996 and April 1998. Patients were evaluated at 120 months (±7.2 months) with clinical and radiological follow-up, patient satisfaction and questionnaire assessment, using the Harris Hip Score (HHS), WOMAC and SF-12. Follow-up examination was done by two physicians who had not performed the operations.

Results: 421 THAs were performed in 389 patients (54.6% women; mean age 69.3, range 28–98). In 80% the diagnosis was primary osteoarthritis. All stems were cemented except for 18 patients (4.3%). One-hundred-twenty-two patients (29.0%) had died, 27 (6.4%) were lost-to follow-up, 24 (5.7%) were unable to attend because of poor general health and 27 (6.4%) refused, thus leaving 221 hips, for which 176 x-rays were available.

None of the patients required cup revision for aseptic loosening. Complications included 12 dislocations and 3 deep infections resulting in 2 total revisions. In 3 patients the stem was revised for aseptic loosening at a mean of 63 months. At 10-years the survivorship was 98.6% (95% CI 96.7; 99.4) with endpoint revision for any cause.

Mean total wear was 0.89 mm (±0.5). 32 cups (18.8%) with a cup inclination > 45° had a mean wear of 1.06 mm (±0.5), whereas 138 cups (81.2%) with inclination < 45° had a mean wear of 0.86 mm (±0.5), p=0.036. In 16 cases osteolytic defects around the stem were present. The outcome scores at 10 years were: HHS 85.9 (±14.1), WOMAC pain 70.7 (±24.7), WOMAC function 68.8 (±24.5), SF-12 physical score 40.3 (±9.2) and mental score 47.0 (±10.4). Ninety-four percent of the patients were satisfied or very satisfied.

Conclusions: The Morscher acetabular replacement cup provides excellent results at 10 years. None of the patients had to be revised for aseptic loosening of the cup, patient satisfaction was high, and clinical results were very good.