PROSTHETIC JOINT INFECTION (PJI) CARE IN TRANSITION: TRACKING CHANGE IN A REGIONAL MEDICAL CENTRE

INTRODUCTION Single stage exchange (1SE) is displacing DAIR and Two-Stage Exchanges (2SE). Surgeons may “hedge their bets” with simpler constructs, in the event infection persists. METHODS PATIENTS Between April 2010 and May 2023, 84 knee prostheses were removed for PJI in a regional NZ public medical center. No cases were referred out. The 1SE and 2SE were separated. All 2SE were separated into Simple and Complex. Data were collected from the comprehensive national electronic records (includes radiographs) and the National Joint Registry. Outcomes reported by Musculoskeletal Infection Society (MSIS) Tiers. RESULTS 1SE in 9 cases (53-85 yrs mean 73) since 2022: no deaths. 08 (88.9%) Tier 1(Infection Control with no Suppressive Antibiotic Therapy-SAT) 01 (11.1)% Tier 2 (Control with SAT) Radiographs showed no constructs with maximal fixation. Simple 2SE 62 primary TKA removed 02 proceeded directly to amputation 27 (50%) Tier 1 (control no SAT) 03 (05.6) Tier 2 (control with SAT) 03 (05.6) Tier 3A (aseptic surgery >1 year) 02 (03.7) Tier 3B (septic surgery >1 year) 00 Tier 3C (aseptic surgery <1 year) 08 (14.8) Tier 3D (septic surgery <1 year) 04 (07.4) Tier 3E (Amputation, resection or fusion) 03 (05.6) Tier 3F (Retained spacer) 04 (07.4) Tier 4A (death<1 year) 11 Tier 4B (death> 1year) reported above as Tier at death. 06 did not meet MSIS definition of PJI, leaving 54 PJI (48-84yrs avg 66.8). Complex 2SE performed for septic failure of: 02 Two Stage Primaries 06 Aseptic Revisions (minus 1 did not meet definition) 05 2SE's Outcome: 06 (50%) Tier 1 02 (16.6) Tier 2, 01 (08.3) Tier 3D 02 (16.6) Tier 3E 01 (08.3) Tier 4A. Radiographs: All 2SE spacers transitioned from “none” to implants intended as 1SE. Second stage was required for poor function. DISCUSSION AND CONCLUSIONS 2SE results showed a high percent reimplantation, and 55.6% infection control without further surgery. Acceptance of 1SE is growing for selected cases with encouraging short term results. During transition, surgeons at this center used less robust fixation for 1SE, perhaps until confidence grows, and more functional “spacers” in 2SE, hoping that a 2nd stage may not be necessary. Mechanical failure for loosening may follow.