[1] Univ Copenhagen, Rigshosp, Sect Surg Pathophysiol, DK-2100 Copenhagen, Denmark
[2] Lundbeck Ctr Fast Track Hip & Knee Arthroplasty, Copenhagen, Denmark
[3] Univ Copenhagen, Glostrup Hosp, Dept Clin Neurophysiol, Danish Ctr Sleep Med,Ctr Healthy Ageing,Fac Hlth, DK-2100 Copenhagen, Denmark