Using Illness Rating Systems to Predict Discharge Location Following Total Knee Arthroplasty.

Overview

PURPOSE: Total knee arthroplasty (TKA) is increasing in frequency and cost. Optimization of discharge location may reduce total expenditure while maximizing patient outcomes. Although preoperative illness rating systems-including the American Society for Anesthesiologists Physical Classification System (ASA), severity of illness scoring system (SOI), and Mallampati rating scale (MP)-are associated with patient morbidity and mortality, their predictive value for discharge location, length of stay (LOS), and total costs remains unclear. MATERIALS AND METHODS: We conducted a retrospective analysis of 677 TKA patients (550 primary and 127 revision) treated at a single institution. The influence of ASA, SOI, and MP scores on discharge locations, LOS, and total costs was assessed using multivariable regression analyses. RESULTS: None of the systems were significant predictors of discharge location following TKA. SOI scores of major or higher (β=2.08 days, p＜0.001) and minor (β=-0.25 days, p=0.009) significantly predicted LOS relative to moderate scores. Total costs were also significantly predicted by SOI scores of major or higher (β=$6,155, p=0.022) and minor (β=-$1,163, p=0.007). CONCLUSIONS: SOI scores may be harnessed as a predictive tool for LOS and total costs following TKA, but other mechanisms are necessary to predict discharge location.