Executive Editor: Chris Colton

Authors: Mariusz Bonczar, Daniel Rikli, David Ring

Distal humerus 13-A2.1/2 Open reduction; screw fixation

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Glossary

1 Principles top

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This fracture may occur in a young patient with strong bone. Shear forces lead to an oblique separation of the metaphyseal / articular block from the shaft. Due to strong rotational forces at the level of the elbow, stabilization with plates on the ulnar and radial columns is preferred. The plates should be applied in a compression mode.

The obliquity of the fracture plane can be in two directions: A2.1 passes obliquely downwards and inwards (medial) (as shown in the image above), and A2.2 obliquely downwards and outwards (lateral, radial, as shown below).


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The A2.2 fracture is oblique downwards and outwards (lateral).

2 Reduction top

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In a simple fracture with strong bone stock, the main fragments can be reduced anatomically. Preliminary fixation with axial K-wires may be helpful.


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3 Plate preparation top

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Plate selection and contouring

Precontoured anatomic plates have been produced. If these are not available, a one-third tubular plate may be used on the crest of the medial supracondylar ridge, and a reconstruction plate on the posterior aspect of the lateral column. If a stronger plate is required, a small fragment dynamic condylar plate may be used, but this is more difficult to contour.


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The plate length should allow for at least 2 screws in each fragment. On the ulnar side, the plate is bent around the epicondyle, in the A2.1 type.

To facilitate contouring, malleable templates are used.


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In the A2.2 type, on the radial side, the plate can be placed distally onto the back of the lateral condyle.

 

4 Plate application (13-A2.1) top

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Ulnar: One-third tubular plate

The ulnar plate is applied first. It serves as an antiglide plate. The plate is contoured around the medial epicondyle and fixed distally. The proximal fragment is then pulled underneath the plate with a first eccentrically drilled screw in the proximal fragment.


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Insert second proximal screw

A second bicortical screw in the proximal fragment completes fixation on the ulnar side.


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Radial plate

The radial plate is applied dorsally on the radial column. Drilling of an eccentric hole for a load screw in the proximal fixation creates compression of the fracture plane.


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Option: additional lag screw

If the fracture configuration, bone quality and medial plate position permit, a lag screw through the plate, as illustrated, will enhance the rigidity of the fixation.

5 Plate application (13-A2.2) top

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See step 4. For A2.2 fractures, a posterior placement of the lateral plate is necessary. You may start with either the radial or the ulnar plate. Compression is exerted by eccentric drilling.


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Option: additional lag screw

If the fracture configuration, bone quality and medial plate position permit, a lag screw through the plate, as illustrated, will enhance the rigidity of the fixation.

v1.0 2007-06-21