Definition
- Congenital failure of union of the clavicle, present from birth
Aetiology
- Cause unknown
- Leading theory is pressure from the adjacent subclavian artery
Epidemiology
- Almost always right sided
- Left sided cases occur with dextrocardia
- Bilateral cases are rare
Clinical Features
- Appears like a fracture
- Non tender midshaft mass without history of trauma
- Painless, with full shoulder function in most
- Prominence enlarges with growth
- Rarely thoracic outlet symptoms in older children
Investigations
- X-ray shows a midshaft gap with rounded, smooth ends
- No callus formation
Differential Diagnosis
- Birth fracture, which is tender and forms callus within weeks
- Cleidocranial dysostosis, with lateral clavicle deficiency and other skeletal features
- Neurofibromatosis
Management
- Observation if asymptomatic
- Surgery for pain, prominence, functional limitation or cosmesis
- ORIF with iliac crest graft around 4 years
- Plate fixation is now favoured
- Union rates with grafting and plating are high
Complications
- Hypertrophic scar
- Hardware prominence
- Neurovascular injury beneath the clavicle
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.