Comparative Analysis of Frailty Indices on Complication Risk Following Septic Revision Total Hip and Knee Arthroplasty.

Background: Frailty is an established risk factor for adverse outcomes following total joint arthroplasty, including higher rates of prosthetic joint infection (PJI), reoperation rates, and readmission, which may be greater in the setting of revision. The purpose of this study is to compare the association of frailty indices with mortality and complications following septic revision arthroplasty. Methods: A query from The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) was performed for adult patients undergoing revision total knee or hip arthroplasty between 2015 and 2020, which records perioperative data (30 days postoperatively) for over 700 centers nationwide. PJI cases without revision arthroplasty were excluded. The RAI-rev and mFI-5 frailty scores were calculated for each patient. Outcomes included major complications, mortality, non-home discharge (NHD), DVT, readmission within 30 days, wound complications, pulmonary complications, cardiac complications, and postoperative infection. T-test and binary logistic regression assessed associations with frailty scores and outcomes. Predictability was evaluated through multivariate regression analysis, and its discriminative accuracy was measured using receiver operating curve (ROC) analysis and C-statistics. Results: A total of 4395 patients were included (median age: 66 [IQR 59-73]). Within the cohort, 46.44% were female and 38.02% exhibited NHD. RAI-rev demonstrated increased association compared to mFI-5 with mortality (OR: 1.20 vs 1.10, CI: 95%) and NHD (OR: 1.15 vs 1.05, CI: 95%). RAI-Rev demonstrated significantly superior discriminatory accuracy when compared to mFI-5 for NHD (Cs: 0.670 vs 0.602, Conclusions: Frailty may have a distinct association with mortality and NHD following septic rTJA, especially when assessed by the revised Risk Analysis Index. This understanding is important to educate the patient and their family and provide insight into the necessary resources and surveillance needed to manage frail patients undergoing septic revision total joint arthroplasty.