Abstract Background Traumatic injuries, defined as physical injuries with sudden onset, are a major cause of distress and disability, with far-reaching societal consequences. A significant proportion of trauma survivors report persistent symptoms and difficulties after the injury, and studies show unmet health care needs. Self-management programs delivered in the sub-acute phase after traumatic injuries are scarcely evaluated. The aim of the present study is to evaluate the effectiveness of a self-management program (SEMPO), delivered 3–4 months after moderate-to-severe traumatic injury. Methods This study protocol describes a pragmatic randomized controlled trial (RCT) with two classical RCT arms (intervention and control) and an explorative self-selection arm. 220 patients will be recruited from Oslo University Hospital, the largest Trauma Referral Centre in Norway. Patients aged 18–72 years residing in the south-east region of Norway, admitted to the Trauma Centre directly or within 72 h after having sustained a moderate to severe traumatic injury, defined as a New Injury Severity Score > 9, having at least 2 days hospital stay, and reporting injury-related symptoms and impairment at discharge from the acute hospital will be included. Patients will be randomly assigned to either a classical RCT randomization arm (intervention or control arm) or to a self-selection arm. In the randomization arm, participants are further randomized into intervention or control group. Participants allocated to the self-selection arm will choose to partake either in the intervention or control arm. The primary outcome is the level of self-efficacy in trauma coping assessed 6 months after completion of the intervention, with a similar time point for the control group. Secondary outcomes include symptom burden, physical functioning and disability, return to work and health care utilization, health-related quality of life, and communication competency. In addition, patients will be asked to nominate one domain-related measurement as their preferred outcome measure. Discussion This RCT will determine the effect of a self-management program tailored to patients with moderate to severe physical trauma, and the self-selection arm incorporates the potential influence of patient treatment preferences on intervention results. If the intervention proves effective, cost-effectiveness and cost-utility analyses will be performed and thereby provide important information for clinicians and policy makers. Trial registration The study is registered in Clinical Trials with the identifier: NCT06305819. Registered on March 05, 2004.
