Received: 20 February 2019
Accepted: 4 June 2019
First Online: 27 June 2019
Ethics approval and consent to participate
: This study was based on a completely de-identified retrospective national database (National Readmissions Database), and only aggregate data were reported. Institutional Review Board approval was not required.
: Not applicable as only completely de-identified retrospective database from which only aggregate results were reported.
: AA & PT are employees of Smith & Nephew, Inc., and may own shares of Smith & Nephew.