1 General considerations 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. Radial fracture repair usually follows the ulna.
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
Lag screw fixation of three-part radial head fractures
In three-part fractures where the fragment configuration allows reconstruction, the radial head is reconstructed with lag screws and attached to the shaft with a T-plate. Proximal radius fractures with more than three fragments can usually not be repaired satisfactorily.
The lag screws may be inserted through the proximal holes of the plate.
2 Positioning of plate and screws topenlarge
The radial head is completely covered with 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 forprominent fixation) consistently encompasses a 90 degrees angle localized by palpation of the radial styloid andLister's tubercle.
3 Reduction and preliminary fixation topenlarge
Release the annular ligament as necessary to see the radius.
Expose the fracture with minimal soft-tissue dissection off the bone.
Remove hematoma and irrigate.
Directly reduce the joint fragments with the help of small pointed reduction forceps and provisionally fix them with two K-wires.
If joint depression is encountered, the depressed joint fragment is elevated and the underlying defect may be bone grafted with bone from the lateral humeral condyle.
4 Plate preparation 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.
5 Proximal fixation with lag screws and plate topenlarge
Apply the properly contoured plate to the radial head and insert two horizontal lag screws (1.5 or 2.0 mm) into the proximal fragment.
These screws are inserted through the plate to achieve absolute stability of the anatomically reduced joint fragment.
The plate position on the radial head is dictated by the fracture configuration to allow optimal stability and function. If the latter is not possible with the lag screws through the plate, the lag screws may be inserted outside the plate and the plate is fixed in its optimal position.
6 Distal plate fixation topenlarge
Finally attach the plate to the radial shaft with two or three screws, thereby fixing the joint fragment to the diaphysis.
7 Ligament repair and test of stability topenlarge
Repair the annular ligament using non-absorbable sutures.
Test the elbow medial stability by applying valgus stress. If there is an instability, the medial collateral ligament should be repaired.
8 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 hinged external fixation. If a hinged external fixator is not available, the significantly unstable elbow should be bridged with a non-hinged external fixator.