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Executive Editor: Peter Trafton

Authors: Kodi Kojima, Steve Velkes

Proximal forearm 21-B3.1 ORIF

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Glossary

1 Principles top

Preliminary remark

Anatomical reduction and stable fixation of both fractures are desirable for 21-B3.1 fractures. Begin by exposing both fractures. Usually, the ulnar fracture will be fixed first. Difficulty in reducing either fracture may be caused by malreduction of the fracture in the other bone.

Rare type IV Monteggia variant fractures (complete dislocation of the radial head relative to capitellum) must be recognized, since open reduction will be necessary for both dislocation and fracture.

The fixation of each fracture is presented separately. The specific fracture fixation is determined by the character of each fracture.


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Lag screw principles

In an oblique fracture, compression across the fracture is achieved with a lag screw.

The screw slides through the overdrilled near cortex. Its thread pulls the opposite bone fragment towards the head of the screw, creating compression across the fracture.

Insert the lag screw as perpendicularly to the fracture plane as possible.


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Protection plate

As a lag screw osteosynthesis alone is not able to resist shearing and torsion forces, a protection plate has to be added to allow early mobilization.

Note
Whenever possible (considering soft-tissue condition, fracture configuration, associated radial head fracture etc.), insert the lag screw through the plate to achieve better stability.

2 Reduction top

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Cleaning the fracture site

Expose the fracture ends with minimal soft tissue dissection off the bone.

Remove hematoma and irrigate.

Check elbow stability.


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Direct reduction

Reduce the fracture with the help of small pointed reduction forceps and provisionally fix with forceps or K-wires.

3 Plate preparation top

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Choosing the right plate

Plate length should be sufficient to place, usually, three screws in each fragment.

The plate may be a small fragment dynamic compression plate (3.5 DCP), or limited contact dynamic compression plate (LC-DCP), or locking plate (LCP) with conventional screws.

Note
In osteoporotic bone, a LCP with locking head screws should be used, after insertion of a conventional lag screw through the plate.


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Contouring

Contour the plate according to the posterior surface anatomy of the proximal ulna.

Contouring of the plate is achieved with bending irons or bending press.

4 Lag screw insertion top

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Application of the protection plate

Apply the contoured plate and hold it against the bone with a bone clamp or one or two fingers.


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Drilling

Through the hole just proximal to the fracture drill a 3.5 mm gliding hole for the lag screw into the posterior cortical bone of the proximal fragment. This screw must avoid the proximal radius.

Insert the 2.5 mm drill sleeve into the gliding hole until it reaches the far cortical bone.

Now drill the far cortex with the 2.5 mm drill bit.


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Measuring

Measure the depth of the hole with the hook of the depth gauge pointing distally.

Tap the far cortex with the 3.5 mm cortical tap and protection sleeve.

Note
Always measure before tapping so as not to disturb the tapped thread.


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Insertion of the lag screw

Closely observe the compression effect on the fracture line while tightening the lag screw.

The reduction forceps should be removed just before the final tightening of the screw.

5 Finish plate fixation top

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Fix the plate to the bone with three screws proximal and three screws distal to the fracture in neutral position to protect the lag screw.

Assess the range of motion in pronation, supination, flexion and extension. Screw tips should not touch the radius. Range of motion and stability must be assessed again after fixation of the radius fracture.

Check results with image intensifier or x-ray.

v1.0 2007-10-14