OBJECTIVES: To compare the difference in length of stay (LOS) and discharge status for total knee arthroplasty (TKA) patients who received an ATTUNE^®or Triathlon™ Knee System.    METHODS: A retrospective cohort design using the Premier Perspective^® hospital billing database was used. Patients undergoing elective primary unilateral TKA in US inpatient hospitals from 2013-2014 with an ATTUNE or Triathlon™ Knee were included in the cohort.  The study was restricted to patients with a diagnosis of osteoarthritis and hospitals that used both devices. Patient, provider, and procedure characteristics were included in generalized estimating equation (GEE) models to explore the impact of device on LOS and discharge status after accounting for clustering within hospitals.  A 1:1 propensity score matching sensitivity analysis was also conducted.  RESULTS: Overall, 1,178 patients received an ATTUNE Knee while 5,707 patients received Triathlon™ in the study period. ATTUNE Knee patients were more likely to be older, single, covered by insurance other than Medicare/Commercial, and treated in the West region.  Unadjusted mean (SD) LOS for ATTUNE Knee patients was 2.82 days (0.98) and 3.14 days (1.25) for Triathlon™ patients. Adjusted mean LOS for ATTUNE Knee patients was 0.19 days shorter than for Triathlon™ patients (p<0.001). Overall, 18.9% of ATTUNE Knee patients were discharged to a skilled nursing facility (SNF) or other inpatient facility compared to 34.4% of Triathlon™ patients.  The adjusted odds of ATTUNE Knee patients being discharged to a SNF were 39% lower than for Triathlon™ patients (OR= 0.61; 95% CI: 0.50-0.75; p<.001). Consistent findings were obtained from the propensity matched sub cohort of 2,044 patients, which was balanced on baseline covariates between devices (standardized differences were ≤ 8%).  CONCLUSIONS: Patients who received TKA with ATTUNE were 39% less likely to be discharged to a SNF versus those who received TKA with Triathlon™.