Twenty-Five-Years and Greater, Results After Nonmodular Cemented Total Knee Arthroplasty

Abstract

Background: Total knee arthroplasty (TKA) has been shown to be very successful with long-term follow-ups. But there are no reports showing prosthesis survival at 25-30 years. Here, we report the outcomes for 25-30 years using the Anatomic Graduated Component (Biomet, Warsaw, IN) TKA and elucidate the etiology and cause of failure of the components.

Methods: We reviewed the outcomes of 5649 primary total knee arthroplasties for 25-30 years using the Anatomic Graduated Component. Statistical analysis was performed by the Kaplan-Meier survival analysis. Clinical outcomes included the Knee Society Score and standardized radiographs to check for loosening of the implants. The reason for revision surgery was reviewed retrospectively. We compared our results with those at another institution with similar long-term follow-up.

Results: There were 112 failures, 48 with aseptic loosening and 25 with instability for an overall prosthesis survival rate of 94.2% at 25 years and 92.4% at 30 years follow-up. In the third decade after TKA, patients are substantially more likely to experience death than experience a failing prosthesis, with a 3811% greater risk of dying relative to failing (Risk ratio = 38.1, Odds ratio = 56.7, P < .0001).

Conclusion: There was a greater risk of dying than failing over time. The primary reason for revision knee surgery was due to aseptic loosening of the prosthesis followed by instability.

Keywords: AGC; failure; long-term follow-up; loosening; total knee arthroplasty.