Length of Stay after Joint Arthroplasty is Less than Predicted Using Two Risk Calculators

Abstract Introduction Predicting the length of stay (LOS) after total joint arthroplasty (TJA) has become more important with their recent removal from inpatientonly designation. The American College of Surgeons (ACS) NSQIP Surgical Risk Calculator and the CMS’ Diagnosis Related Groups (DRGs) calculator are two common LOS predictors. The aim of our study was to determine how our actual LOS compared to those predicted by both the ACS and DRG. Methods 99 consecutive TJA (49 hips and 50 knee procedures) were reviewed in Medicare-eligible patients from four fellowship-trained arthroplasty surgeons. Predicted LOS was calculated using the DRG and ACS risk calculators for each patient using demographics, medical histories and comorbidities. LOS was compared between the predicted and the actual LOS for both total hip and total knee arthroplasty (THA, TKA) using paired t-tests. Results Actual LOS was shorter in the THA group versus the TKA group (1.29 days vs 1.46 days, p Discussion We found the actual LOS was significantly shorter than that predicted by both the DRG and ACS risk calculators. Current risk calculators may not be accurate for contemporary fast-track protocols and newer tools should be developed.