1. From the Department of Anesthesiology, Copenhagen University Hospital, Hvidovre, Copenhagen, Denmark (T.H.L.); The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen, Denmark (T.H.L., T.B.H., P.W.K., T.L., H.K.); Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark (V.G.F.); University C