284 press-fit Kinemax total knee arthroplasties followed for 10 years: Poor survival of uncemented prostheses

Background and purpose Our institution began using the Kinemax total knee arthroplasty system in 1988, both with and without cement fixation. We report 10–year survival figures.

Methods Theater records showed that 284 Kinemax total knee arthroplasties had been performed 1988 through 1993. Life-table survival estimates were used to determine the probability of survivorship 10 years after surgery for the total group and by age, sex, diagnosis, and mode of fixation. Median follow-up was 11 (0.8–15) years for unrevised knees in patients who were still alive.

Results The 10–year cumulative survivorship was higher (93%, 95% CI: 81–97) when both components had been cemented than if either, or both, were uncemented (77%, CI: 67–83; p < 0.001). There was an increased incidence of failure in patients who were less than 60 years of age at the time of surgery (p = 0.004).

Interpretation The smooth-backed Kinemax knee without cement was found to be associated with a high failure rate at 10 years. The 10–year cumulative survival results of the cemented prosthesis are acceptable.