Imaging Case of the Week 11

This 30 year old patient has had a fall on his outstretched hand and presents with pain and deformity of the forearm. Here are the x-rays.

a. What is your diagnosis?

b. What is technically wrong with the following x-ray ?

[peekaboo_link name=”Answer”]Answer[/peekaboo_link] [peekaboo_content name=”Answer”]

a. The x-ray shows Galeazzi fracture. There is fracture of the distal radial shaft at the junction of mid and distal third and subluxation of the distal radioulnar joint.

b. The x-ray does not show the joint above when there is a long bone shaft fracture. So, it is technically inadequate.

Galeazzi fracture:

Incidence : 3-7 % of all forearm fractures.

Mechanism : Axial loading injury on hyperpronated forearm. May occur secondary to direct blow to the dorsum of wrist.

Disruption of the interosseous membrane leads to obvious (classic) Galeazzi whereas disruption of the triangular fibrocartilage of the distal radioulnar joint only leads to subtle Galeazzi.

X-ray features :

  •  Widening of the distal radioulnar joint ( DRUJ) on AP view
  • There can be an associated ulnar styloid fracture
  • Shortening of radius more than 5 mm relative to the distal ulna as distal radius is pulled proximally by mechanical forces.

Clinical: patient presents with swelling and deformity over distal forearm. There will be tenderness over the DRUJ. The radial styloid will be felt at the level or above the ulnar styloid. Flexion and extension at the wrist may be unaffected (no radiocarpal injury) but pronation and supination will be painful.

Complications: As with any other fractures, associated neurovascular injury, tendon injury and compartment syndrome are possibilities.

An overlooked complication is anterior interosseous nerve palsy (no sensory deficit as the nerve has only motor component) causing inability to pinch between the thumb and index finger due to FPL and FDP involvement. Anterior interosseous nerve supplies FPL,lateral half of FDP and pronator quadratus.

The above patient needs his fracture fixed in the theatre. Subtle Galeazzi can be treated conservatively.

The counterpart injury, Monteggia fracture involves fracture of upper third of ulna with dislocation of superior radioulnar joint.