Executive Editor: Peter Trafton

Authors: Kodi Kojima, Steve Velkes

Proximal forearm 21-B3.3 ORIF

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Glossary

1 Preliminary remarks 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. In this setting, a coronoid fracture is typically large and can be reduced while seen through the olecranon fracture. Then the olecranon is 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.


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Impacted fractures of the proximal radius suggest the possibility of medial collateral elbow ligament disruption. This must be looked for. Anatomical repair of the proximal radius helps stabilize the elbow by resisting valgus angulation of the joint.

In impacted radial neck fractures with more than 20 degrees of angulation surgery is indicated. The radial head should be elevated to its anatomical position and fixed with a 1.5 or 2.0 T-plate inserted as a bridge plate. The defect created by reduction should be filled with bone graft taken from the lateral humeral condyle.

After fixation of the radial head, medial stability should be tested.

2 Plate positioning top

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The radial head is completely covered by articular cartilage. The implant is applied to the radial head in a location that causes the least compromise of full pronation and supination.

Safe zone for plate and screw insertion

To determine the location of the "safe zone“, reference marks are made along the radial head and neck, to mark the midpoint of the visible bone surface. Three such marks are made with the forearm in neutral rotation, full pronation, and full supination as shown in the illustration.

The posterior limit of the safe zone lies halfway between the reference marks made with the forearm in neutral rotation and full pronation. The anterior limit lies nearly two thirds of the distance between the neutral mark and the mark made in full supination.

Note
The nonarticulating portion of the safe zone for the application of implants to the radial head (or safe zone for prominent fixation) consistently encompasses a 90 degrees angle localized by palpation of the radial styloid and Lister's tubercle.

3 Reduction top

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Expose the fracture site with minimal soft tissue dissection off the bone.

Remove hematoma and irrigate.

Reduce the head to its anatomical position with the help of small pointed reduction forceps or a hook.

 


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Use the capitellum as a reference guide. A K-wire as a joy-stick in the radial head may aid reduction.

4 Preliminary fixation top

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Provisionally fix the head with two 1.0 K-wires either to the radius or to the proximal ulna.


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Position the K-wires in such a way that they do not interfere with the planned plate position.

5 Choice of implant top

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As the radial head is a small fragment, a mini fragment 1.5 or 2.0 T-plate, or a locking proximal radius plate is used to allow purchase of two or three screws in the proximal fragment.

Prebend the plate according to the surface anatomy of the proximal radius.

6 Definitive fixation top

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Plate application

Apply the prebent plate with two or three screws to the radial head.

With the help of reduction forceps, apply the plate to the diaphysis.

Fix the plate with two or three bicortical screws (1.5 or 2.0 mm) to the distal fragment.


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Bone graft
Fill the bone defect with cancellous bone graft taken from the lateral humeral condyle.


Medial stability

Test the elbow medial stability by applying valgus stress. If there is significant instability, the medial collateral ligament should be repaired. Make sure that the coronoid process is intact as well.

7 Final assessment top

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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 bridging or 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 2007-10-14