Gronbeck C, et al. - The American College of Surgeons National Surgical Quality Improvement Program (ACS–NSQIP) database between 2006 and 2015 was researched to ascertain a risk-stratifying nomogram to assess the necessity for inpatient admission among Medicare-aged cases experiencing primary total knee arthroplasty (TKA). Researchers estimated 61,284 inpatient and 26,066 outpatient admissions. They reported age > 80 years, simultaneous bilateral TKA, dependent functional status, metastatic cancer, and female gender as the greatest determinants related to the inpatient stay. Acceptable discrimination and excellent calibration were demonstrated in the resulting predictive model.