New Zealand Joint Registry Surgeon-Level Feedback: The Influence of Reporting Timeframe on Distribution of Reasons for Revision Following Total Knee Arthroplasty.

Background: National joint registries have improved arthroplasty surgery by creating databases that monitor implant performance and recognize early implant failure. The New Zealand Joint Registry (NZJR) provides surgeon reports on individual revision rates, and outliers are identified using funnel plots. Historically, all-time revision rates were used; although reporting shorter timeframes is being considered. The purpose of this study was to evaluate the impact of reporting shorter timeframes on the distribution of reasons for revision following total knee arthroplasty (TKA).

Methods: Data was obtained from the NZJR for TKA performed from the registry's inception in 1998 to 31 December 2021. Distribution of reasons for revision for primary TKA was analyzed by postoperative year and reporting timeframe. Reporting timeframes of revision within 1, 2, 3, 5, and 10 years were evaluated.

Results: Infection accounted for 54.5% of reasons for revision in postoperative year one and a lower proportion over time, decreasing to 16.9% in year 10. Aseptic loosening accounted for 9.0% of reasons for revision in postoperative year one, increasing to 56.9% in year 10. Reporting revision within 2 years would result in a 60% increase in the proportion of reasons for revision attributed to deep infection (p < 0.001) and a 65% decrease in the proportion attributed to loosening (p < 0.001) compared with revision within 10 years.

Conclusions: Revision within 2 years would be a suitable shorter timeframe for reporting to surgeons. While this may ensure feedback reflects recent practice and increase responsiveness to changes in performance, the distribution of reasons for revision would change substantially compared to revision within 10 years, with a markedly higher proportion attributed to infection. Debate regarding the role of individual surgeons in causing deep infections will become increasingly important if this shorter timeframe is reported.