PCP intoxication, jump from 3rd story

A young male presents to the emergency room with wrist pain after jumping from a 3rd story balcony while intoxicated with PCP. A wrist radiograph is obtained:

AP external rotation:

PA:

Lateral:


Go to the next page for the findings and diagnosis!


AP external rotation:

A fracture of the proximal pole of the scaphoid is probably best seen on this view. A radial styloid fracture is also present, better seen on the PA view.

PA:

Here we see a displaced radial styloid fracture. The scaphoid fracture is not well seen. On both the AP and PA views, there is a funny look to the lunate as well, taking on a kind of triangular or "piece of pie" shape. The lunate is best evaluated on the lateral, and this particular abnormality can be easily overlooked on AP views alone.

Lateral:

Now the lunate abnormality is far more obvious. The lunate is dislocated, with volar displacement and rotation, looking kind of like a "spilled teacup". The rest of the carpal bones remain in relatively normal position.

This injury could actually represent midcarpal dislocation rather than true lunate dislocation, as the carpal bones may be slightly displaced dorsally, however that appearance could be due to rotation as well. Any MSK radiologists feel free to comment!

This is a case of lunate dislocation with associated fractures of the proximal scaphoid and radial styloid. There is injury of all the perilunate ligaments and the lunate is freely displaced from the radius and carpals. Lunate dislocation is also known as stage IV perilunate instability.

Scaphoid fractures are commonly seen in conjuction with this injury. Fractures of the proximal scaphoid, as seen here, are the least common however carry the most concern for poor healing and development of avascular necrosis since the scaphoid blood supply is most robust distally, and least robust proximally.

More reading about lunate dislocation here.

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