Diagnostic Imaging for Third Metacarpal Injuries

Imaging Protocol

The American College of Radiology recommends obtaining minimum 3-view radiographs (posteroanterior, lateral, and 45° semipronated oblique) for third metacarpal injuries, as 2-view examination is inadequate 1, 2
An internally rotated oblique projection should be added to standard externally rotated oblique to increase diagnostic yield for metacarpal fractures 1, 2
CT imaging is usually not indicated during acute injury unless there is concern for complex articular involvement 2
MRI without IV contrast is ideal for evaluating tendon injuries and surgical planning when radiographs are negative but clinical suspicion remains high 3, 1

Operative fixation is necessary when there is >2 mm of residual articular surface step-off to prevent long-term osteoarthritis 4

Active finger motion exercises should be initiated immediately following diagnosis and treatment to prevent stiffness, which is the most common functionally disabling complication 2
Wrist motion does not need early mobilization following stable fracture fixation 2
Vitamin C supplementation should be considered for prevention of disproportionate pain 2
The duration of external fixation should be limited to reduce complications 2

Failure to obtain adequate radiographic views (minimum 3 views with both oblique projections) can lead to missed CMC dislocations 1
Delayed diagnosis due to negative initial radiographs can lead to functional impairment; consider repeat radiographs in 10-14 days or proceed to MRI if clinical suspicion remains high 1