[Translated article] Are frailty scores superior to the ASA score in predicting complications, hospital stay, and readmissions in total knee replacement? A comparative study between octogenarian and septuagenarian patients

BACKGROUND AND OBJECTIVE: Frailty scores have not been standardised for the preoperative assessment of patients undergoing total knee replacement (TKR). The aim of this study was to compare the efficacy of the American Society of Anesthesiology (ASA) score, the Charlson comorbidity index (ICC) and the simple frailty score (SSF) in predicting complications, hospital stay, readmissions and mortality after elective TKR. MATERIALS AND METHODS: We retrospectively studied 448 patients who underwent TKR for osteoarthritis at our institution between 2016 and 2019. They were divided into two groups: Group A (263 patients, <80 years) and Group B (185 patients, >80 years).). All were classified by ASA, ICC and SSF scores. RESULTS: The ICC was higher in Group B (median 5 [RI: 4-6] vs. 4 [RI: 3-5]; p<.001); however, it was not associated with a higher number of complications. When performing a logistic regression analysis we found, for complications: OR SSF=0.67; ICC=1.11; ASA 3 & 4=0.89 and age=1.04; while for readmissions: OR SSF=2.09; ICC=1.01; ASA 3 & 4=0.79 and age=1. CONCLUSIONS: The ICC and SSF scales showed no differences to the ASA scale in the prediction of readmissions, complications and hospital stay. However, the SSF seems to have a better correlation in predicting unplanned readmission.