Physical Therapy on Postoperative Day Zero Following Total Knee Arthroplasty: A Randomized, Controlled Trial of 394 Patients

Surgeons have increasingly emphasized early mobilization as a way to facilitate discharge following total knee arthroplasty (TKA). The purpose of this study was to determine whether starting formal physical therapy (PT) the afternoon of postoperative day (POD) 0, instead of starting PT the morning of POD 1, could shorten hospital length of stay (LOS). Patients undergoing elective TKA with a planned minimum 1-night hospital stay were randomized to start formal PT the afternoon following surgery or the morning of POD 1. LOS in hours was the primary outcome. An a priori sample size calculation suggested that 394 patients were required to show a 4-hour difference between groups. Out of 394 patients enrolled and randomized, 378 (95.9%) completed the study. The observed difference in hospital LOS was not large enough to be of clinical significance (intention-to-treat analysis: median of 32.0 hours for POD 0 PT vs 31.0 hours for POD 1 PT, P = .65; as-treated analysis: median of 31.0 hours for POD 0 PT vs 32.0 hours for POD 1 PT, P = .12). Similarly, the observed differences in satisfaction with inpatient PT (10.0 vs 10.0, P = .77), patient-reported readiness for discharge at time of discharge (10.0 vs 10.0, P = .97), and POD 0 pain (3.3 vs 4.0, P = .79) were not large enough to be of clinical significance. While PT on the day of surgery has been suggested as one method to facilitate discharge following TKA, this randomized trial did not demonstrate clinically meaningful differences in hospital LOS or patient satisfaction when PT is initiated on the day of surgery vs on the morning after surgery.