The CARBO CARBON Study

Inclusion Criteria for the CARBO trial: Age ≥18 years. Access to a valid e-mail. Injury within 10 days prior to inclusion. Normal bilateral hand function prior to injury. Ability and willingness to provide written informed consent Single, displaced spiral or oblique diaphyseal fracture of the second to fifth metacarpals with definition of diaphysis as described by AO 2018 (AO/OTA as 77.2-5.2A) (Meinberg et al., 2018). Fracture line length at least twice the diameter of the bone at the level of the fracture. Fractures with at least 2 mm of radiological displacement and/or malrotation of injured finger compared to uninjured side regardless of fracture displacement. Exclusion Criteria: The patient is not expected to have difficulty adhering to the study protocol (e.g., due to insufficient language proficiency, dementia, substance abuse, or other reasons). The patient does not have an open fracture (Gustilo-Anderson grade \> I) or a pathological fracture. The patient does not have an ipsilateral fracture of the upper extremity, polytrauma, or generalized joint dysfunction (e.g., rheumatoid arthritis).