1. From the School of Health Sciences (C.S.), University of Birmingham, UK; the Oxford Centre for Enablement (D.T.W.), Nuffield Orthopaedic Centre, UK; the Department of Primary Health Care (D.M., J.C.A., P.Y., K.C., S.L.), University of Oxford, UK; and the Oxford Brookes University (V.B., K.R.), UK.