Defining growth potential and barriers to same day discharge total knee arthroplasty

Outpatient arthroplasty programs are becoming well established. Adverse event rates have been demonstrated to be no worse than inpatient arthroplasty in the literature for selected patients. The purpose of this study was to determine our rate of outpatient total knee arthroplasty (TKA), examine justification for exclusions, and estimate the proportion of TKAs that can occur safely on an outpatient basis.

Retrospective case series of 400 consecutive TKAs from Oct 2014 to Mar 2017. Patient demographics, allocation to outpatient surgery vs standard admission, and reason for exclusion from outpatient surgery were recorded. Ninety-day Emergency department (ED) visits, readmission rates, and length of stay (LOS) were compared between groups using independent sample t test and Chi-squared test.

Outpatients were younger (p = 0.001), had lower BMI (p < 0.001), and ASA scores (p < 0.001) than inpatients. One hundred twenty-five (31%) TKAs were assigned to outpatient surgery and 123 achieved discharge on the same day. There was no difference in 90-day ED visits (p = 0.889) or readmission rates (p = 0.338) between groups. Reasons for exclusion from outpatient surgery included medical (absolute 43% and relative 31%), distance > one hour from hospital (18%), no help (7%), and other/unclear (10%). LOS was significantly longer for medical than non-medical exclusions (p < 0.001) and for the absolute compared to relative medical exclusions (p = 0.004).

Outpatient TKA is safe in selected patients, and inclusion can likely be broadened by addressing modifiable exclusions and narrowing medical exclusions. We found that 55% of our TKA population could be appropriate for outpatient surgery.