Abstract
Appropriate estimation of the risk of failure after debridement, antibiotics, and implant retention (DAIR) may provide useful prognostic information in patients with prosthetic joint infection (PJI). We aimed to externally validate the Kidney, Liver, Index surgery, Cemented prosthesis, C-reactive protein (KLIC) score and to develop and internally validate a new prediction model based on variables available before DAIR. We conducted a retrospective multicentre cohort study using medical record data from adults with PJI treated with DAIR across eight Spanish centres between 2006 and 2023, with a minimum 12-month follow-up. Predictors were analysed using a generalized linear mixed-effects model, with assessment of discrimination, calibration, and bootstrap internal validation. Among 224 patients, 121 (54 %) experienced DAIR failure. The final model retained revision prosthesis, Charlson Comorbidity Index ≥ 3, C-reactive protein > 150 mg L
−1
, longer time from index arthroplasty to DAIR, and Gram-negative bacilli or polymicrobial infection. The model showed good discrimination (Areas under the receiver operating characteristic curve (AUC-ROC) 0.85; 95 % confidence interval (CI) 0.79–0.90) and satisfactory calibration; the optimism-corrected AUC-ROC was 0.83. The derived clinical score showed an AUC-ROC of 0.81 (95 % CI 0.75–0.87) and identified groups with observed failure rates of 25.5 %, 45.6 %, and 87.9 %. The KLIC score did not demonstrate discriminative ability beyond chance (AUC-ROC 0.53; 95 % CI 0.44–0.64). Excluding microbiological aetiology reduced discrimination to 0.81 for the multivariable model and 0.77 for the corresponding reduced score. The new model showed good discrimination and calibration in this cohort, but external validation in independent PJI-DAIR populations is required before clinical implementation can be recommended.