Comparison of surgical treatments for hip and knee periprosthetic joint infections using the desirability of outcome ranking in a prospective multicentre study

<b>Introduction</b>: In periprosthetic joint infection (PJI), there is a paucity of prospective data comparing debridement, antibiotics and implant retention (DAIR) with two-stage revision while also accounting for time since the initial arthroplasty. Additionally, comparisons often lack patient-centred measures. A desirability of outcome ranking for PJI (DOOR-PJI) unifies joint function, infection cure and mortality into one outcome. We aimed to describe the DOOR-PJI distribution in a large patient cohort and use it to compare DAIR and two-stage revision. <b>Methods</b>: Adults with a newly diagnosed hip or knee PJI from the prospective Prosthetic joint Infection in Australia and New Zealand Observational (PIANO) study were analysed. Patients from 27 hospitals were included. PJI was classified as "early" or "late". The primary outcome was the novel DOOR-PJI at the 2-year follow-up. Results were expressed using win ratio (WR) values. A WR <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>></mml:mo></mml:math> 1.0 indicates that two-stage revision was superior to DAIR. <b>Results</b>: A DOOR was available for 533 patients. The most common treatments were DAIR (297 patients, 56 %) and two-stage revision (139 patients, 26 %). In early PJI, DAIR was superior to two-stage revision (WR 0.51, 95 % confidence interval (CI) [0.30-0.86], <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi> <mml:mo>=</mml:mo></mml:mrow> </mml:math> 0.012). In late PJI, two-stage revision was superior to DAIR (WR 1.61, 95 % CI [1.11-2.33], <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi> <mml:mo>=</mml:mo></mml:mrow> </mml:math> 0.012). These findings persisted following stratification by comorbidities, affected joint, symptom duration and a sensitivity analysis applying the initial (rather than the main) surgical strategy at day 90. <b>Conclusions</b>: In the first application of a DOOR in orthopaedics, DAIR was superior to two-stage revision for early PJI. Conversely, two-stage revision was superior compared with DAIR for late PJI. These findings were independent of comorbidities and symptom duration.