Introduction

Fast-track procedures after total knee arthroplasty (TKA) are currently validated and considered as the standard postoperative procedure. Outpatient procedures are still marginal today, and reticence focuses on the safety of these procedures and the risk of complications and unscheduled readmission. The objective of this study was to measure and compare this risk after the two procedures immediately after the introduction of the outpatient procedure in a university department. The tested hypothesis was that the complication and readmission rates were higher after the outpatient procedure.

MATERIAL

Methods

Two successive series were analyzed prospectively. The control group followed an exclusive fast-track procedure (183 cases), the study group either fast-track or outpatient procedure (143 cases). There were 159 men and 168 women, with a mean age of 67 years, operated on for elective implantation of TKA. The postoperative procedure was standardized, with walking within 3 hours after the procedure, the only difference was the discharge date. All patients were followed for three months.
91 fast-track cases (control group) and 91 out-patient cases (study group) were matched after propensity score calculation. The primary endpoint was the occurrence of a complication within three months after the TKA. The secondary criteria were the severity of complications according to the Clavien-Dindo classification, the need for readmission and re-intervention within three months of the TKA.

Results

There was no significant differences between the two groups in the preoperative data, except for the presence of renal failure. No patient was lost of follow-up and there was no missing data.
The complication rate was not significantly higher in the study group (15% versus 11%) (p=0.38), with an OR of 1.47 (95% confidence interval: 0.62 - 3.51). The readmission rate was not significantly higher in the study group (15% versus 9%) (p=0.17), with an OR of 1.89 (95% confidence interval: 0.75 - 4.75). The reoperation rate was not significantly higher in the study group (14% versus 9%) (p=0.25), with an OR of 1.73 (95% confidence interval: 0.68 - 4.40). The severity of the complications was not higher in the study group (mean score 2.9 ± 0.5 points versus 2.6 ± 0.8 points) (p=0.27).
The most frequent complication was a delayed rehabilitation requiring manipulation under anesthesia.

Discussion

The hypothesis has not been confirmed. The rates of complication, unscheduled readmission and unscheduled reoperation were not higher after the outpatient procedure than after the fast-track procedure in comparable populations. The reservations about the safety of outpatient procedures for TKA do not seem to be well founded.