Executive Editor: Chris Colton

Authors: Mariusz Bonczar, Daniel Rikli, David Ring

Distal humerus 13-B2.1 Open reduction; screw fixation

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Glossary

1 Introduction top

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Medial epicondylar fractures are more common in skeletally immature patients. 

It is not uncommon for an elbow dislocation in a skeletally immature patient to be associated with a medial epicondylar fracture. 

One or two screws will provide sufficient fixation.

It can be useful to incorporate the soft tissue attachments to the medial epicondyle in the fixation by using a washer.


Screw types

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


Non-cannulated screw technique

If the bone fragments are large enough to accommodate a screw and a K-wire, the provisional reduction should be held with K-wires placed in a position which will not interfere with definitive screw fixation. If the fragments are too small the reduction and provisional fixation should be held with K-wires which are then exchanged carefully, one at a time, for the definitive screws.

2 Open reduction top

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Mobilize the fragment and clean the fracture site

Identify and protect the ulnar nerve. 

Open the fracture site by gently retracting the fragment anteriorly.

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


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Reduction

Realign the fracture by traction with a small hook or dental pick.

Monitor fracture reduction by realigning the metaphyseal fracture lines.

Depending on the extent of exposure, you can check the anterior and posterior fracture lines, including the articular surface.

3 Insertion of guide wires top

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Planning for screws

The screws must not enter the olecranon fossa or pierce the articular surface. Generally there is room for one screw across the articular candylar mass, and one screw in the medial column.


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Insertion of guide wires

The wires are placed exactly where the screws will go.

Be sure that the diameter of the wires corresponds with the screw to be inserted.

If the patient is skeletally immature, a single screw should be placed up the medial column.

Use an oscillating drill, if available, in order to avoid wrapping the ulnar or radial nerve, should you over penetrate.

Check the wire position and fracture alignment using an image intensifier.

4 Drilling top

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Measuring screw size

After confirming correct placement of guide wires, measure the screw length off of the wire, using the appropriate depth measuring device.


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Drilling the pilot hole for the screw

Prior to drilling, and only when safe, carefully advance each wire beyond the intended screw length, so that it will not come out when you drill the pilot hole for the screw.

Alternatively, use of a threaded-tipped guide wire is helpful.

Place the cannulated drill over the wire and drill the pilot hole for the screw to, or just short of, the planned screw length.

Depending on bone quality, the surgeon may choose to drill only the near cortex, in order to avoid inadvertent guide wire pullout.

In patients with hard bone, if self-tapping screws are not available, the hole should be tapped.

5 Definitive fixation top

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Insertion of first screw

Use a partially threaded screw with all its threads placed in the far fragment.

Advance the screw over the wire.

For poor bone quality, it may be helpful to use a washer with the screw.

For unstable fractures a temporary K-wire can be used to stabilize the fracture as the screw is placed.

Once the screw is inserted, remove the guide wire.


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Insertion of a second screw

If a second screw is inserted, repeat the steps as described for the first screw.

v1.0 2016-10-21