Executive Editor: Chris Colton

Authors: Mariusz Bonczar, Daniel Rikli, David Ring

Distal humerus 13-B3.1 Open reduction; headless screw fixation

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Glossary

1 Introduction top

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Take care when approaching an apparently simple capitellar fracture. These are often complex.

The majority extend into the lateral trochlea and should not be considered for nonoperative treatment.

Many fractures also involve a fracture of the lateral epicondyle and impaction of posterior aspect of the lateral column, or the posterior trochlea.

Computed tomography with 3D reconstructions helps to identify these fracture characteristics, and facilitates planning.


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This module addresses coronal plane fractures of the capitellum and part of the trochlea, without fracture of the lateral epicondyle, or of the posterior aspect of the distal humerus.

These fractures can be repaired with buried headless screws, or alternatively, with screws that are inserted from posterior to anterior.

Screw fixation is straightforward using cannulated screws, but can also be undertaken with non-cannulated screws if cannulated screws are not available.

If non-cannulated screws are being used, provisional fixation should be achieved with K-wires which are then exchanged carefully, one at a time, for the definitive screws.

2 Open reduction top

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Exposure

The origins of the extenser carpi radialis longus and extenser carpi radialis brevis (ECRB) are elevated from of the anterior aspect of the humerus, along with the brachialis.

The interval between the ECRB and the extenser digitorum communis (EDC) is split distally. Care is taken not to go posterior to the midpoint of the radial head, in order to protect the lateral collateral ligament.  

The capsule is incised, if not already ruptured.


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The fracture fragment should be apparent in the anterior aspect of the joint.


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Clean the fracture site

Clean out the fracture by removing blood clots, loose pieces of bone, and any interposed tissue. Inspect the joint to ensure that no additional intraarticular fracture component was missed when examining the imaging.


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Reduction

Reduce the fracture. If the anterior exposure is in any way limited and digital reduction is not possible, a K-wire "joystick" and small pointed reduction forceps can be used.

Monitor fracture reduction by realigning the metaphyseal and articular fracture lines.

3 Fixation top

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Headless screws

Insert the guide wires across the fracture site, where the planned screw tracks will be. Be sure to use the correct diameterguide wires for the chosen screw size.


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Insertion of screws

Measure the screw length of the guide wire, using the appropriate depth measuring device.


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Overdrill the wire

Insert the wire deeper so that it is not dislodged during drilling.


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Drilling

Drill the pilot hole for the screw to the appropriate depth, using the cannulated drill bit placed over the guide wire.


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Screw insertion

Insert the chosen screw over the wire, then remove the guide wire. Complete the insertion of the first screw, before inserting the second screw.


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Closure

The muscle interval is then closed.

v1.0 2007-06-21