Note: The condylar mass in the younger child will be largely occupied by the distal Schanz screw. The lag screw normally used across the condylar mass may have to be omitted. In this case the Schanz screw will function instead as a positioning screw.
A partially or fully threaded screw can be used. If a fully threaded screw is used, it is necessary to overdrill the near fragment.
To achieve an optimal mechanical outcome, the physis can in be ignored in children who are approaching skeletal maturity.
If cannulated lag screws are available, the two reduced fragments are temporarily fixed with a K-wire.
The guide wire for the cannulated screw is inserted through the center of the capitellum, parallel to the joint surface.
An appropriate screw, depending on the fragment size (3.0, 3.5, or 4.0 mm), is inserted and both wires are removed, unless the first K-wire is required for additional stability.
Note: Once the condylar mass has been reconstructed, the injury has been converted to a simple supracondylar fracture type.
5. Condylar reattachment with external fixator
Distal Schanz screw insertion
A 4.0/3.0 or 4.0 mm Schanz screw is inserted into the condylar mass parallel to the joint (proximal or distal to the lag screw, depending on the fragment size).
The Schanz screw is inserted, from lateral to medial, approximately 2/3 of the condylar width. Excessive depth is to be avoided because of the vulnerability of the ulnar nerve.
Proximal Schanz screw insertion
A second 3.0/4.0 or 4.0 mm Schanz screw is inserted approximately 3 cm above the supracondylar fracture plane and perpendicular to the long axis of the humeral shaft.
Note: Care should be taken not to damage the radial nerve.
Once both Schanz screws are well fixed, the clamps and the bar are applied to connect them.
Using the Schanz screws as joysticks, the fracture can be reduced anatomically under direct vision.
When anatomical reduction is achieved, the clamps are tightened.
To prevent rotation at the fracture site, a K-wire is inserted from the distal lateral aspect, posterior to the distal Schanz screw, towards the proximal medial cortex of the humerus, ending anterior to the proximal screw.
This K-wire also functions as an antirotation device in the distal fragment, preventing its twisting around the axis of the distal Schanz screw.
6. Postoperative care
If the child remains for some hours/days in bed, the elbow should be elevated on pillows to reduce swelling and pain.