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Why Total Knees Fail and Re-Fail: An Analysis of 20,568 Revision Cases From the Swiss Implant Registry
Randa Elsheikh1, Felix Amsler2, Yuma Onoi1
1University Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland, Bruderholz, Switzerland; Department of Clinical Research, Research Group Michael T. Hirschmann, Regenerative Medicine & Biomechanics, University of Basel, Basel, Switzerland.
Background:
Despite advances in total knee arthroplasty (TKA), revision procedures represent a major clinical challenge and are expected to rise with growing primary volumes. This study aimed to analyze trends in first and repeated revisions over the past decade, focusing on timing, causes, and patient-related factors.
Methods:
A registry-based cohort study was conducted using data from a national arthroplasty registry (2015 to 2024). A total of 20,568 revision TKAs were analyzed. Revision number (first versus repeated), patient demographics, comorbidities, and revision causes were analyzed. Temporal trends in revision indications were assessed using logistic regression, estimating annual percentage changes across the 10-year period. Comparisons between first and repeated revisions and between early (less than two years) and later (≥ two years) failures were conducted using cross-tabulations and Chi-square tests. The mean age at revision was 69 years (range, 13 to 99); 58.3% were women, and the mean body mass index was 29.7 (range, 11.7 to 100.8).
Results:
The first revisions accounted for 79.2% and rerevisions for 20.8% of cases. The annual number of revisions increased by 59% over the decade, with 42% occurring within two years of primary TKA. Patellar complications represented the most frequent indication for revision (29%; 35.8 per 1,000 primary TKAs), followed by aseptic loosening (23.5%; 29), infection (21%; 26), and instability (20.3%; 24.7). Infection dominated rerevision, rising from 15% in first to nearly 65% in fourth or higher revisions. Over time, patellar problems, instability, and infection increased significantly (P < 0.01), whereas aseptic loosening and pain of unclear origin declined. Infection risk was highest in men and high-body mass index patients (P < 0.001).
Conclusions:
Nationwide data show a growing burden of TKA revisions. While patellar problems represent the predominant indication for first revisions, infections emerge as the main driver of rerevisions and early failures, underscoring the need for targeted prevention strategies to reduce preventable failures and improve implant longevity.
Level Of Evidence:
Level III.
