Complication Rates Are Not Higher After Outpatient Versus Inpatient Fast-Track Total Knee Arthroplasty: A Propensity-Matched Prospective Comparative Study.

Background: This prospective study aimed to compare the complication rates and clinical outcomes of propensity-matched patients who received fast-track total knee arthroplasty (FT TKA) in outpatient versus inpatient settings.

Methods: Patients (n = 629) who received FT TKA at various outpatient (n = 176) and inpatient (n = 462) surgery rates were prospectively followed until 90 days after surgery. The decision between inpatient versus outpatient FT TKA was made on a case-by-case basis, depending on consultation between the surgeon and patient. Complications were collected to distinguish between intraoperative complications, complications with no readmission, complications with readmission, and complications with reoperation. Propensity scores based on age, sex, body mass index, and the American Society of Anesthesiologists score were used to match outpatient to inpatient FT TKA. A cumulative incidence function was computed by taking the time to diagnose any postoperative complication in the first 90 days as the end point.

Results: Propensity score matching (1:2 ratio) for comparison resulted in 173 outpatient FT TKAs and 316 inpatient FT TKAs. No significant differences were observed between outpatient versus inpatient FT TKA for intraoperative complication rates (2% in both groups). At 90-day follow-up, no significant differences were observed between outpatient versus inpatient FT TKA for total complications with no readmission (8.0 versus 7.9%), complications with readmission but no reoperation (1.1 versus 0.6%), and complications with reoperation (4.0 versus 4.4%). A comparison of postoperative complication diagnosis time using the cumulative incidence function revealed no significant differences between outpatient versus inpatient FT TKA.

Conclusions: The present study revealed that there were no differences in 90-day postoperative complication rates between outpatient and inpatient FT TKA and that there were also no differences in rates of intraoperative complications, readmissions, or reoperations. These findings may encourage hesitant surgeons to move toward outpatient TKA pathways, as there is no greater risk of early postoperative complications that could be more difficult to manage after discharge.

Level Of Evidence: Level II.