Johannesdottir, K.B., Kehlet, H., Petersen, P.B., Aasvang, E.K., Sørensen, H.B.D. and Jørgensen, C.C. 2022. Machine learning classifiers do not improve prediction of hospitalization > 2 days after fast-track hip and knee arthroplasty compared with a classical statistical risk model. Acta Orthopaedica. 93, (Jan. 2022), 117–123. DOI:https://doi.org/10.2340/17453674.2021.843.