1 Introduction topenlarge
This is a rare injury.
If there is diagnostic doubt, screening by image intensification can be useful.
For fractures that are unstable after reduction, a single K-wire usually provides sufficient stability.
2 Reduction topenlarge
Indirect reduction by forearm rotation
Reduction maneuver is by forearm rotation and direct pressure over the distal ulna.
Posteriorly displaced fractures are reduced by forearm pronation.
Anteriorly displaced fractures are reduced by forearm supination.
Closed reduction is usually successful and if stable will not require fixation.
Direct reduction using K-wire
For irreducible fractures, a K-wire can be inserted into the fracture site (through a stab incision) and used as a lever to facilitate reduction of the ulna.
Note: This technique applies pressure to the already compromised growth plate and should be used only exceptionally and with great care.
3 Skin incision topenlarge
A small skin incision is made.
Care should be taken to avoid the dorsal sensory branch of the ulnar nerve.
The incision is deepened to the bone using a blunt artery forceps and a protective sleeve is inserted.
4 K-wire insertion topenlarge
The fracture is stabilized using a single smooth 1.6 mm K-wire through the ulnar styloid, across the physis, engaging the lateral cortex of the ulnar diaphysis.
Continued care should be taken to avoid the dorsal sensory branch of the ulnar nerve during insertion of the K-wire.
The wire should be inserted with an oscillating drill, cooled with saline solution to prevent thermal injury, or by hand using a T-handle.
Ideally, wire insertion is done using image intensification control, in order to check the trajectory of the wire and to ensure engagement of the far diaphyseal cortex without penetration of soft tissues.
The K-wire is left protruding through the skin, bent and cut. The skin is protected with sterile padding prior to application of a cast.
The illustration demonstrates the use of a small section of plastic tubing over the cut end of the protruding wire. This adds further protection for the skin.
Note: Excessive pressure between dressing and skin should be avoided to prevent skin necrosis.
5 Long arm cast topenlarge
Once the fracture displacement has been reduced and fixed with a K-wire, the arm is splinted in a reduced position with a long arm cast to control forearm rotation.
The purpose of the cast is to maintain reduction by preventing forearm rotation and protect the fixation.
The long arm cast is applied according to standard procedure:
Splitting of the cast
If a complete cast is applied in the acute phase after injury, it should be split over the full length of the cast. The split of the cast must be full thickness and expose the underlying skin.