1 Department of Anaesthesia and Pain Medicine, Royal Surrey County Hospital NHS Foundation Trust, Guildford, United Kingdom.
2 Department of Surgery, School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
3 Gastrointestinal Surgery, Nottingham Digestive Diseases Centre, National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.
4 MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.