What is your diagnosis?

Perilunate dislocation 

• Pearl: Lateral x-ray will show a "tea-cup sign" as if the tea cup remains upright and contents would not spill out(compared to a "spilled tea-cup sign" whereas the tea cup is tipped over and contents would spill out in a lunate dislocation). This is more so referring to the angle at which the tea-cup sits [4]. 

• Pearl: Exam findings of sensation deficits are suggestive of median nerve entrapment or acute carpal tunnel syndrome. Additionally, this injury is often associated with ligamentous injury and carpal instability [3]. 

What is your management in the ED?

Identify the injury, detailed neurovascular exam to determine Median Nerve involvement (aka acute carpal tunnel syndrome), and immediate attempt at closed reduction with volar splint placement. **We recognize that the initial scenario does not present this way, but other nerve entrapments are possible, the initial presentation represents a real case**

• Pearl: Closed reduction may be accomplished using traction, wrist flexion, dorsal pressure applied over the lunate [3]. 

What is your disposition?

Consult Ortho and likely OR for ORIF. Closed reduction is rarely definitive management given ligamentous injury and high likelihood for recurrent instability [1,2].

• Pearl: If closed reduction is successful, ORIF may be urgent, not emergent [1]. 

Do you consult orthopaedics emergently?

Yes, especially if there is evidence of acute carpal tunnel syndrome. 

Additional reading about perilunate dislocations can be found here