1 Introduction topenlarge
These fractures are often caused by direct blow. The direction of displacement is determined by the direction of the blow.
2 Reduction topenlarge
If closed reduction is not possible, this may be due to soft tissue interposition with structures including the ulnar nerve, flexor carpi ulnaris or rarely extensor carpi ulnaris.
Open reduction may be necessary with a direct approach to the subcutaneous surface of the ulna.
Care should be taken to avoid the dorsal sensory branch of the ulnar nerve.
For irreducible fractures, initially, any soft tissue structures that are preventing reduction are identified and cleared.
Reduction is performed under direct vision.
This may require using a K-wire either as a joystick or as a lever.
Posteriorly displaced fractures are reduced with forearm pronation. Anteriorly displaced fractures are reduced with forearm supination.
3 K-wire fixation topenlarge
A single smooth 1.6 mm K-wire is inserted through a protective sleeve into the ulnar styloid, through the physis, then engaging the lateral cortex of the ulnar diaphysis.
The wire should be inserted with an oscillating drill and cooled with saline solution to prevent thermal injury.
The wire may also be inserted by hand using a T-handle.
Ideally, wire insertion is monitored using image intensification in order to check the trajectory of the wire and to ensure engagement of far 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 should be avoided between dressing and skin to prevent skin necrosis.
4 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.