Executive Editor: Peter Trafton

Authors: Kodi Kojima, Steve Velkes

Proximal forearm 21-B3.3 ORIF

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Glossary

1 Preliminary remark top

Elbow instability is a frequent problem with 21-B3.3 injuries. With complex proximal ulnar fractures, both olecranon and coronoid, if involved, must be reduced and fixed. If the radial neck fracture is simple, and easy to reduce, it might be fixed initially, to guide reduction of the ulnar fractures.

Anatomical reduction and stable fixation of both fractures are desirable for 21-B3.3 fractures. Begin by exposing both fractures.  Difficulty in reducing either fracture may be caused by malreduction of the fracture in the other bone.

Stability of the elbow must be confirmed at the conclusion of reduction and fixation. If instability remains, supplementary external fixation may be necessary.

2 Principles top

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Lag screw principles

In oblique fractures of the radial neck, fixation is achieved by lag screws. Longer oblique fractures allow two screws. This is more secure, and should be preplanned.

The thread pulls the opposite bone fragment towards the head of the screw, placing the fracture ends under compression. The portion of the thread in the gliding hole does not purchase in the surrounding bone. Insert the lag screw(s) as perpendicularly to the fracture plane as possible.

Note
Lag screw fixation may prove unsatisfactory for short oblique fractures of the radialneck. If so, plate fixation may be required.


Choice of implant

Mini fragment 1.5 mm, 2.0 mm, or 2.7 mm screws are used.

3 Reduction and provisional fixation top

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Expose the fracture ends with minimal soft tissue dissection off the bone. Remove hematoma and irrigate.

Reduction is direct, aided by supination-pronation of the forearm. Reduce and provisionally fix the fracture with the help of small pointed reduction forceps.

Difficulty with reduction may be due to the ulna’s being malreduced, or because the radial head is dislocated from the capitellum, perhaps with interposed annular ligament.

4 Lag screw insertion top

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Drilling

Drill a gliding hole (sized according to chosen screw size, see fig.) for the lag screw into the proximal fragment.

Insert the appropriate drill sleeve into the gliding hole until it reaches the far cortical bone.

Now drill the far cortex with the appropriate drill bit.


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Measuring

Measure the depth of the hole with the hook of the depth gauge pointing distally. Tap the far cortex with the appropriate cortical tap, using the protection sleeve.

Note
Always tap after measuring in order not to destroy the thread.


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Lag screw insertion

Closely observe the compression effect on the fracture line while tightening the lag screw.

The reduction forceps should be removed just before the final tightening of the screw.


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Second lag screw

If the fracture configuration allows the insertion of a second lag screw, it can be inserted now, using the same technique as described above.

5 Final assessment top

Following repair of fractures and ligaments, elbow stability should be assessed through a full range of flexion-extension. Radiocapitellar and ulnohumeral joints should remain located.

Also check supination and pronation. Fixation should be stable. Crepitus or restricted motion should be absent. Check fractures and fixation with image intensifier or x-ray.

If elbow instability or dislocation are identified, it is essential to maintain elbow alignment. This can be done with temporary hinged external fixation. If a hinged external fixator is not available, the significantly unstable elbow should be bridged with a non-hinged external fixator.

v1.0 2016-10-24