Lunate and Perilunate Dislocations

Lunate dislocation is an uncommon injury in which the lunate alone is dislocated while the rest of the carpals remain in place; perilunate dislocation (also uncommon) occurs when all carpals except the lunate dislocate posteriorly and usually occurs with FOOSH.

Causes

Perilunate Dislocations causes such as includes repeated stress on carpal ligaments renders them more prone to injury, especially in athletes. The carpal bones serve as a link between the hands and the upper body; a great deal of force is transmitted through them. Sports with increased force vectors, such as adult in-line skaters, commonly experience such injuries. One eg. of risks are falls from height; these occur in athletes such as gymnasts, among others. Although high energy is the common cause of injury, some reports describe low-energy trauma as the cause of carpal dislocation

Signs

• Swollen, tender wrist with decreased ROM and pain with axial
  compression of third metacarpal. Tenderness of the lunate itself should be examined. This is elicited by compression over the depression present just proximal to the third metacarpal, and is exacerbatedwhen the wrist is flexed, which brings the lunate up into the "empty space."

Treatment

Surgical options include the following:

• The closed reduction and casting
• Percutaneous pin fixation
• Open reduction, open ligamentous repair with internal fixation.

The surgical treatment of choice is open reduction and ligamentous repair with percutaneous pin fixation. If a distal radius styloid fracture or a carpal bone fracture accompanies the perilunate dislocation, internal fixation is preferred in most settings.