The five times sit-to-stand test predicts same-day discharge for outpatients undergoing total joint arthroplasty

To examine whether a patient's pre-operatively administered five times sit-to-stand (FTSTS) test score, when used alone or when combined with previously established predictors, relates to same-day discharge (SDD) after total knee or hip arthroplasty.

This study utilized a multivariate, retrospective, observational design. Electronic medical record data for included participants were used to analyze the relationship between the patient factors (including the novel FTSTS variable) and the SDD outcome. Univariate and multiple variable regression modeling was undertaken to understand the strength of the relationship between the independent variables with the dependent variable. Receiver operating curve (ROC) analysis was performed to determine the area under the curve (AUC) for the novel model. Cut score analysis was performed to establish the score which has the greatest utility for stratifying patients based upon their likelihood of achieving SDD.

All independent variables related to the SDD outcome with varying effect sizes. The dichotomized FTSTS score related to the SDD outcome with medium effect (Exp(B) = 2.56). The score of 13.6 s was established as the point where the test was most highly sensitive and specific. The combined model including all included patient characteristics had a classification accuracy of 64.7% and an area under the curve score of .724.

The FTSTS score had higher predictive accuracy than all other stand-alone patient characteristics for the SDD outcome.