THUMB CMC DISLOCATIONS

Question 1

Most common direction for thumb CMC dislocations

Answer 1

Dorsal dislocations are most common

Question 2

Mechanism of injury for thumb CMC dislocations

Answer 2

Axial load with thumb in flexion

Question 3

Pathoanatomy of thumb CMC dislocations

Answer 3

• Dorsoradial ligament must be disrupted for dorsal CMC dislocations
• Beak ligament is often stripped off thumb MC but remains continuous

Question 4

Management of thumb CMC dislocations

Answer 4

Closed reduction and assess stability

1. If stable (Beak ligament intact) = thumb spica 4-6 wks
2. If unstable (Beak ligament torn)
   - CR and temporary pinning
   - reconstruction of dorsal capsuloligamentous structures and temporary pinning
   - better abduction ROM and pinch with reconstruction