Multiple logistic regression demonstrated older age (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.34-2.77; P < .001), female gender (OR, 4.22; 95% CI, 2.35-7.57; P < .001), American Society of Anesthesiologists score 3 or 4 (OR, 2.00; 95% CI, 1.01-3.95; P = .046), atrial fibrillation (OR, 8.87; 95% CI, 1.81-43.47; P = .007), and prior TKA on the contralateral side (OR, 3.57; 95% CI, 1.27-10.05; P = .016) as significant preoperative characteristics correlating with the ≥2-day LOS group. The most significant hospital perioperative factor associated with longer stays was patients not ambulating on the day of surgery (OR, 4.09; 95% CI, 1.77-9.48; P = .001). Walking 150 ft (93% sensitive, 35% specific) on the day of surgery was predictive of patients in the 1-day LOS group. Hospital costs were US$1873 (P < .001) lower for patients in the 1-day group.