Thorkildsen is a specialist in cancer orthopedics and have worked for 13 years at Radiumhospitalet in OUS as a surgeon in the interdisciplinary sarcoma group. He is an active researcher and have a PhD in epidemiology related to a rare cancer called chondrosarcoma. He now work as an assistant subject director in Medicine and Health Sciences – Vestre Viken HF where lead the medicines committee and develop their virtual hospital unit.