Outpatient total knee arthroplasty leads to a higher number of complications: a meta-analysis

Background: Careful pre- and post-operative management can allow surgeons to perform outpatient TKA, making this a more affordable procedure. The aim of the present meta-analysis is to compare outpatient and inpatient TKA. Methods: A systematic search of the literature was performed in July 2020 on PubMed, Web of Science, Cochrane library, and on the grey literature databases. The papers collected were used for a meta-analysis comparing outpatient and inpatient TKA in terms of complication and readmission rates. Risk of bias and quality of evidence were defined according to Cochrane guidelines. Results: The literature search resulted in 4107 articles; of these, 8 articles were used for the meta-analysis. A total of 212,632 patients were included, 6607 of whom were TKA outpatients. The overall complication rate for outpatient TKAs was 16.1%, while inpatient TKAs had an overall lower complication rate of 10.5% (p = 0.003). The readmission rate was 4.9% in outpatient TKAs and 5.9% in inpatient TKAs. Only 3 studies reported the number of deaths, which accounted for 0%. The included studies presented a moderate risk of bias, and according to GRADE guidelines, the level of evidence for complications and readmissions was very low. Conclusions: This meta-analysis documented that outpatient TKA led to an increased number of complications although there were no differences in the number of readmissions. However, future high-level studies are needed to confirm results and indications for the outpatient approach, since the studies currently available have a moderate risk of bias and a very low quality of evidence.