1 Preliminary remarks top
Anatomical reduction and stable fixation of both fractures are desirable for 21-B3.1 fractures. Begin by exposing both fractures. Usually, the ulnar fracture will be fixed first. Difficulty in reducing either fracture may be caused by malreduction of the fracture in the other bone.
Rare type IV Monteggia variant fractures (complete dislocation of the radial head relative to capitellum) must be recognized, since open reduction will be necessary for both dislocation and fracture.
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 topenlarge
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.
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 topenlarge
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.
Use the capitellum as a reference guide. A K-wire as a joy-stick in the radial head may aid reduction.
4 Preliminary fixation topenlarge
Provisionally fix the head with two 1.0 K-wires either to the radius or to the proximal ulna.
Position the K-wires in such a way that they do not interfere with the planned plate position.
5 Choice of implant topenlarge
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 topenlarge
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.
Fill the bone defect with cancellous bone graft taken from the lateral humeral condyle.
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 topenlarge
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.