Length of stay and inpatient mortality trends in primary and revision total joint arthroplasty in the United States, 2000-2014.

Retrospective review of the National Inpatient Sample was performed. LOS and IHM were assessed among TJA patients and assessed by comorbidity status. LOS among TJA patients decreased from 4.31 to 5.87 days to 2.83-4.49 days. Relative risk for prolonged LOS among high comorbidity patients ranged from 3.01-5.62. IHM per 1,000 was 5.1 for revision THA, 1.8 for revision TKA, 1.1 for primary THA, and 0.4 for primary TKA. Relative risk for IHM in high comorbidity patients ranged from 443.9-780.9 (p < 0.0001). LOS and IHM decreased significantly across all TJA procedures. LOS and IHM among the highest comorbidity groups are unacceptably high.