Introduction A trend has evolved towards rib fixation for flail chest although evidence is limited. Little is known about rib fixation for multiple rib fractures without flail chest. The aim of... Show moreIntroduction A trend has evolved towards rib fixation for flail chest although evidence is limited. Little is known about rib fixation for multiple rib fractures without flail chest. The aim of this study is to compare rib fixation with nonoperative treatment for both patients with flail chest and patients with multiple rib fractures.Methods and analysis In this study protocol for a multicentre prospective cohort study, all patients with three or morerib fractures admitted to one of the five participating centres will be included. In two centres, rib fixation is performed and in three centres nonoperative treatment is the standard-of-care for flail chest or multiple rib fractures. The primary outcome measures are intensive care unit length of stay and hospital length of stay for patients with a flail chest and patients with multiple rib fractures, respectively. Propensity score matching will be used to control for potential confounding of the relation between treatment modality and length of stay. All analyses will be performed separately for patients with flail chest and patients with multiple rib fractures without flail chest.Ethics and dissemination The regional Medical Research Ethics Committee UMC Utrecht approved a waiver of consent (reference number WAG/mb/17/024787 and METC protocol number 17-544/C). Patients will be fully informed of the purpose and procedures of the study, and signed informed consent will be obtained in agreement with the General Data Protection Regulation. Study results will be submitted for peer review publication.Trial registration number NTR6833 Show less