Moore MG, Brigati DP, Crijns TJ, et al. - A total of 325 consecutive unilateral primary TKAs done on individuals completing the Perioperative Surgical Home preoperative optimization pathway within a single hospital system was retrospectively examined in order to recognize preoperatively ascertained factors related to hospital length of stay for same-day discharge (SDD) and inpatient TKA defined by Medicare’s 2-midnight rule benchmark. The cohort involved 32 SDD, 189 next-day discharges, and 104 inpatients. Lower BMI and fewer self-reported allergies were related to SDD. The SDD model exceeded the Risk Assessment and Prediction Tool (RAPT) alone. Elderly age, higher BMI, lower RAPT score, and later surgery start time were related to inpatient discharge. The inpatient model exceeded the RAPT alone. Hence, preoperatively ascertained factors correlated with SDD as BMI and allergies and inpatient TKA as age, BMI, RAPT score, and surgery start time were recognized. Moreover, hospitals, providers, patients, families, and payers could use this information for TKA episode planning.