or carpal ligamentous injury stage IV
– best viewed on the lateral Xray of the wrist, where there is disruption of the 3 Cs again, with the lunate (the “middle C”) displaced off the radius towards the palm
– on the PA view, the lunate has a triangular, “piece-of-pie” appearance
Look for signs of median nerve injury.
This injury also needs urgent Orthopaedics review. You can attempt to reduce it in ED:
– one person applying traction on the fingers
– another person hyperextends the wrist and attempts to “push” the lunate back in, from the volar aspect of the wrist towards the dorsum; gradually flex the wrist, repositioning the rest of the carpal bones on onto the lunate
– be patient – you might need to apply traction for up to 10 min before a succesful reduction
– it can be extremely difficult to reduce a lunate dislocation, especially if there are other associated carpal injuries – in this case, they need to go to theatre for ORIF
Immobilize in a long-arm splint with the wrist in volar flexion.
Even if the reduction is successful in ED, they need Orthopaedics review on the same day.