Executive Editor: Chris Colton

Authors: Mariusz Bonczar, Daniel Rikli, David Ring

Distal humerus 13-B1 Open reduction; screw fixation

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Glossary

1 Introduction top

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Fracture assessment

Take care when approaching an apparently non-articular lateral condylar fracture, as these are unusual. Preoperative imaging, including computed tomography, can be used to identify associated articular fractures.


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Indication

Only when bone quality is excellent will screw fixation alone provide adequate stability for early active exercises, and when the fracture is simple and non-fragmented.

In practice, screw fixation alone is used primarily in skeletally immature patients, who can be immobilized for 3-4 weeks in a cast without getting too stiff.

Most lateral condylar fractures in adults are fixed with a plate and screws, in order to allow more confident early active motion.


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

Elevate the triceps and anconeus off of the posterior aspect of the lateral column.

Open the fracture site by gently retracting the fragment anteriorly.


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Clean the fracture site

Clear the fracture of any blood clots, loose pieces of bone, or interposed tissue. Inspect the joint to ensure that no additional intraarticular fracture component was missed when examining the imaging.


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Reduction

Realign the fracture.

Monitor fracture reduction by realigning the metaphyseal fracture lines.

Depending on the extent of exposure, you can also 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 condylar mass, and one screw in the lateral column.


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Insertion of the guide wires

The wires will be placed exactly where the screws will go.

Be sure to use the wires intended for the chosen screws.

Insert a first wire going up the lateral column perpendicular to the fracture plane at that level. Then insert a second wire across to the condylar mass.

Drill the wires most of the way across the bone. Be careful of the ulnar nerve. Use an oscillating drill if available in order to avoid wrapping the nerve should you over penetrate.

Check 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 the wire beyond the intended screw length, so that it will not come out when you drill the pilot hole.

Using a threaded-tipped guide wire also helps to anchor it. Place the cannulated drill over the guide 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 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 wire. 


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Insert two or more screws. Once the guide wires are satisfactorily inserted, complete the entire sequence for each screw before inserting the next screw. The screws are tightened to produce interfragmentary compression.


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Alternative: Drill a gliding hole (for a lag screw)

Use a 3.5 mm drill to create a gliding hole, in the near fragment.

Using an appropriate drill sleeve, drill through the near (cis) cortex, following the track of the pilot hole through the near fragment. This will permit the use of a fully threaded screw, where the fracture configuration is such that a standard, partially threaded cannulated screw may leave some thread purchase also in the near fragment.

6 Additional plate fixation top

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Adult patients should have additional buttress/protection-plate fixation, in order to allow immediate exercise of the elbow.

Skeletally immature patients can be fixed with screws alone and protected in a cast for 3 or 4 weeks prior to starting exercises.

v1.0 2016-10-21