Executive Editor: Peter Trafton, Michael Baumgaertner

Authors: Peter Kloen, David Ring

Proximal forearm Ulna, extraarticular, simple

Compression plate and lag screw

1. Compression plate principles

In simple oblique fractures, compression can be achieved by combining axial compression with interfragmentary compression using a plate and a lag screw.

2. Plate selection

Use a seven-hole plate. The plate may be a small fragment (3.5 mm) dynamic compression plate (DCP), or limited contact dynamic compression plate (LC-DCP), or (contoured) locking plate (LCP).

Note: In osteoporotic bone there is an indication for the use of a LCP in combination with locking head screws and/or using a longer plate that cradles the olecranon tip.

3. Positioning and approach

Positioning

This procedure is normally performed with the patient either in a lateral position or in a supine position for posterior access .

Approach

For this procedure a posterolateral approach is normally used.

4. Reduction and preliminary fixation

Cleaning the fracture site

Expose the fracture ends with minimal soft tissue dissection off the bone. Remove hematoma and irrigate. Reduction can be achieved by direct or indirect reduction techniques.

Direct reduction

Reduce the fracture with the help of small pointed reduction forceps and provisionally fix it with pointed reduction forceps or small K-wires. It is helpful to anticipate plate position when placing reduction forceps and/or K-wires so that they do not interfere with positioning the plate and drilling.

Reduction with a plate

Fix the contoured plate with one screw to the appropriate fragment. Then reduce the distal fragment against plate and proximal fragment by manipulation of the distal ulna, possibly aided by a clamp outside the fracture site. Final adjustment of the screw may affect reduction, and may be delayed until a screw is placed in the opposite fragment.

5. Creating compression with the plate

Apply a 3.5 mm cortical screw in neutral position next to the fracture into the proximal fragment.

Note: To avoid the risk of shortening the plate has to be attached to the correct fragment first. The first screw should attach the plate to the fragment which forms an angle >90 degrees beneath the plate. The next screw is inserted into the opposite fragment.

Insert a second 3.5 mm cortical screw in eccentric position next to the fracture into the opposite fragment.

Tightening of the second screw creates compression across the fracture.

6. Insertion of a lag screw

Further compression can then be achieved by inserting a lag screw through the plate as perpendicularly as possible to the fracture plane, or through the center of the fracture line.

7. Finish plate fixation and final assessment

Insert the rest of the screws in neutral position.

After fixation of the ulna, assess the range of motion in pronation, supination, flexion and extension. Fixation should be stable and crepitus or restricted motion should be absent. Radiocapitellar and ulnohumeral joints should remain located through a full range of motion.

Check results with image intensifier or x-ray

Appendix

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v2.0 2018-04-30