1 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, United Kingdom. Electronic address: thomas.hamilton@ndorms.ox.ac.uk.
2 Clinic of Orthopaedics and Traumatology, University of Udine, Italy.
3 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, United Kingdom.