Knee. 2025 May 26;56:94-102. doi: 10.1016/j.knee.2025.05.014. Online ahead of print.
ABSTRACT
BACKGROUND: Patellar resurfacing during total knee arthroplasty (TKA) is debated. The reverse fragility index (RFI1) assesses study neutrality by determining the minimum number of events needed to change non-significant results, significant. This study determined the RFI for studies showing no difference in reoperation between TKAs with and without resurfacing.
METHODS: A systematic review of PubMed, Embase, and Web of Science databases was conducted to identify randomized controlled trials (RCT) showing no difference in reoperation rates between TKAs with and without patellar resurfacing. The number of reoperations and the number of patients lost to follow-up were included. The RFI was calculated for reoperation rate of each study with a threshold of P < 0.05.
RESULTS: Nineteen RCTs with 3,804 TKAs were included, 1,813 of which resurfaced the patella. The median (interquartile range [IQR2]) reoperation rate was 4.4% (0-9.1%) in resurfaced patellae, and 4.5% (0-8.3%) in retained patellae. The median RFI was five, indicating that only five patients would need the opposite outcome for the difference in reoperation rate to become significant. The median (IQR) loss to follow-up was eight (3-20) patients, and 63.2% (12 of 19) of studies had loss that exceeded their RFI.
CONCLUSION: Most RCTs showing no difference in reoperation rate between TKAs with or without patellar resurfacing are statistically fragile. Difference in rates can become significant with the reversal of only a few outcomes, and this number was less than a study’s loss to follow-up in most studies.
PMID:40424662 | DOI:10.1016/j.knee.2025.05.014
