JOA - 2026-06-18 - Journal Article
Why Total Knees Fail and Re-Fail: An Analysis of 20,568 Revision Cases from the Swiss Implant Registry.
Elsheikh R, Amsler F, Onoi Y, Brand C, Christen B, Nowakowski AM, Hirschmann MT
Topics
Key Takeaway
Patellar complications are the leading cause of first TKA revision (29%, 35.8/1,000 primaries), while infection drives re-revision, escalating from 15% of first revisions to nearly 65% of fourth-or-higher revisions.
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Summary
This Swiss national registry study analyzed 20,568 revision TKAs from 2015–2024 to characterize indications, timing, and trends across first and repeated revisions. Patellar complications (29%), aseptic loosening (23.5%), infection (21%), and instability (20.3%) were the leading first-revision indications; 42% of all revisions occurred within two years of primary TKA. Infection increased significantly over the decade (P<0.01) and dominated re-revision burden, while aseptic loosening and pain of unclear origin declined.
Key Limitation
The registry does not capture primary TKA surgical variables (patellar resurfacing rate, alignment technique, implant design), making it impossible to attribute the high patellar complication rate to specific modifiable intraoperative decisions.
Original Abstract
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 (BMI) was 29.7 (range, 11.7 to 100.8).
RESULTS
The first revisions accounted for 79.2% and re-revisions 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 re-revision, 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 BMI patients (P < 0.001).
CONCLUSION
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 re-revisions and early failures, underscoring the need for targeted prevention strategies to reduce preventable failures and improve implant longevity.