Mitchell, Natasha, Coleman, Elizabeth, Watson, Judith, Bell, Kerry, McDaid, Catriona, Barnett, Cleveland, Twiste, Martin, Jepson, Fergus, Salawu, Abayomi, Harrison, Dennis, Vanicek, Natalie, "Self-aligning prosthetic device for older patients with vascular-related amputations: protocol for a randomised feasibility study (the STEPFORWARD study)", BMJ Open, 2019