Capitate fractures are an uncommon carpal fracture. They rarely occur in isolation and are often associated with greater arc injuries.
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Epidemiology
Capitate fractures account for 1-2% of all carpal fractures 1,2. It is the second most common carpal bone injury in children 1.
Pathology
Capitate fractures are most commonly due to high-energy, hyperextension forces 2.
Radiographic features
Capitate fractures will rarely occur in isolation, they can be subtle due to boney overlap, and are most commonly transverse body fractures. These can be subtle on projectional radiography and best appreciated on cross-sectional imaging
Treatment and prognosis
In general, conservative management is warranted for fractures that are non-displaced, fractures that display a high level of displacement require surgical fixation 1.
Like the scaphoid, there is a risk of avascular necrosis at the proximal pole given its poor vascularity due to a retrograde blood supply 1,2.
Complications
In very rare circumstances, during a scaphoid and capitate fracture, the proximal aspect of the capitate can rotate 90 degrees into the sagittal plane, this is known as scaphocapitate syndrome 3, which could be better described as a trans-scaphoid, trans-capitate peri-lunar fracture-dislocation that reduces to result in an inversion of the proximal aspect of the capitate.