Metacarpal shaft fractures: operative fixation versus immediate unrestricted mobilization

The CARBO Study (metaCARpal Bone Osteosynthesis)

It tests whether immediate unrestricted mobilization (no surgery) provides similar one-year outcomes to operative fixation for adults with displaced spiral or oblique metacarpal shaft fractures.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 552 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Karolinska Institutet (other)
• Locations: 1 site (Stockholm, Stockholm County)
• Trial ID: NCT07357493 on ClinicalTrials.gov

What this trial studies

This is a multicenter randomized comparison enrolling adults with a single displaced spiral or oblique diaphyseal fracture of the second to fifth metacarpals to either non-operative treatment with immediate unrestricted mobilization or standard operative fixation. Participants are enrolled within 10 days of injury and followed for one year to compare recovery, complications, and need for additional procedures. The trial is led by Karolinska Institutet with collaborating sites at Uppsala University, Umeå University and the University of Oslo. The aim is to provide higher-quality multicenter randomized evidence to clarify whether non-operative management can match surgical outcomes.

Who should consider this trial

Good fit: Adults (≥18) with a single displaced spiral or oblique diaphyseal fracture of the second–fifth metacarpals within 10 days of injury, who had normal bilateral hand function before the injury and can give informed consent and access email.

Not a fit: Patients with open Gustilo–Anderson grade > I or pathological fractures, multiple or complex hand injuries, or those unable to adhere to follow-up or protocol requirements are unlikely to benefit from the nonoperative approach tested here.

Why it matters

Potential benefit: If successful, many patients could avoid surgery and recover with early mobilization while achieving similar function and potentially fewer surgery-related risks.

How similar studies have performed: Retrospective studies and one small randomized trial have reported comparable outcomes for nonoperative early mobilization versus surgery, but robust multicenter randomized evidence remains limited.

Eligibility criteria

Inclusion Criteria:

* 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).

Where this trial is running

Stockholm, Stockholm County

• Karolinska Institutet, Danderyd's hospital — Stockholm, Stockholm County, Sweden (RECRUITING)

Study contacts

• Study coordinator: Cecilia Mellstrand Navarro, Associate professor

Conditions: Metacarpal Shaft Fractures, Non-operative, operative, metacarpal, shaft, displaced, mobilization