Abstract

Objectives: To develop and validate a nomogram model and simplified scoring system for predicting the risk of postoperative nausea and vomiting (PONV) following total knee arthroplasty (TKA) and total hip arthroplasty (THA), and to implement an online risk calculator to facilitate clinical application.

Methods: We retrospectively enrolled 925 patients who underwent primary TKA/THA at a tertiary hospital (January 2024–April 2025) and randomly classified them (7:3) into the training set (TS) and the internal validation set (IVS). Following initial screening with the least absolute shrinkage and selection operator (LASSO), multivariable logistic regression was utilized to determine the final predictors and develop a nomogram, which was further translated into a simplified point-based score. External prospective validation was conducted in 208 patients from three additional medical centers between May and September 2025. Model discrimination was quantified by the area under the receiver operating characteristic curve (AUC); calibration and clinical utility were examined using calibration plots and decision curve analysis, respectively.

Results: Seven predictors were identified, including six risk factors and one protective factor (prophylactic 5-HT3 receptor antagonist use). AUCs for the nomogram were 0.887 in the TS, 0.915 in the IVS, and 0.828 in the external validation set (EVS), indicating good discrimination; the model was well calibrated and showed clinical net benefit. The simplified score (0–13 points), based on the six risk factors, stratified patients into low-risk (LR) (0–5), intermediate-risk (IR) (6–8), and high-risk (HR) (9–13) groups, with corresponding PONV incidences of 15.7%, 44.4%, and 78.9%, respectively. Prophylactic 5-HT3 receptor antagonist use reduced risk classification by one category. The simplified score achieved AUCs of 0.792, 0.777, and 0.801.

Conclusion:

We constructed and prospectively validated practical prediction tools for PONV after primary TKA/THA. The simplified score and online calculator may facilitate rapid risk stratification and individualized antiemetic prophylaxis.