1 Principles topenlarge
Triangle of stability
Stability of the distal humerus is based on a triangle of stability, comprising the medial and lateral columns, and the transverse condylar mass. In complete articular fractures, all 3 columns have to be restored.
2 Patient preparation top
3 Approaches topenlarge
For this procedure a posterior approach is normally used:
4 Reconstruction of the articular surface topenlarge
Cleaning of the fracture site
Clean out the fracture by removing blood clots, loose pieces of bone, and any interposed tissue.
Reduce the articular fragments. In good bone stock, use pointed reduction forceps.
In compromised bone stock, use temporary fixation with one or preferably 2 K-wires, inserted manually.
Use a lag screw (a partially threaded screw, or a fully threaded screw with
overdrilling the near cortex) to obtain compression.
In osteoporotic bone, use one or more position screws.
Try to use two screws to avoid rotational instability, if possible.
In very distal fractures, generally only one screw can be inserted. An additional K-wire can be used to achieve rotational stability.
5 Condylar reattachment topenlarge
Reduce the reconstituted articular mass to the metaphysis and use K-wires for preliminary fixation.
The plates must be carefully contoured using an appropriate malleable template.
Place the lateral column plate dorsally and the medial column plate medially. In this position their planes form an angle of approximately 90 degrees to each other.
First place a 3.5 mm reconstruction plate posterolaterally. It should curve around the capitellum which has no cartilage cover posteriorly.
The comminution is bridged if it can not be precisely and fixed with absolute stability reduced. A slightly longer plate is used to provide additional stability.
In a more distal fracture, the reconstruction plate can be extended all the way to the edge of the capitellar articular surface. It will not interfere with the radial head during the extension of the joint. The more bone, is covered by the plate, the greater is the stability achieved.
Placement of the lateral plate
Place a K-wire through the distal plate hole. As the plate is pulled gently proximally, stable contact with the bone is obtained.
Now insert the proximal screw without load.
Complete the plate fixation to the bone by inserting the remaining screws.
Place another plate medially on the crest of the medial supracondylar ridge, its plane at a right angle to the lateral plate, in order to increase stability.
It is recommended to insert the distal screws into the trochlea below the medial epicondyle.
In case of great metaphyseal comminution, or missing bone, use a bone graft.