Screw insertion in compression mode

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Introduction

The principle of applying dynamic compression depends on relative movement between the bone and the plate as the screw is tightened.

Principle of dynamic compresion

Insertion of screw in compression mode for transverse fracture (application of compression plate)

Insertion of screw in compression mode for oblique fracture (application of compression plate)

Technique

For one-third tubular plates the universal spring-loaded DCP drill guide is used without pressing it against the bone. The guide is placed against the edge of the plate hole, distal to the fracture.

universal spring-loaded DCP drill guide

For LC-DCP plates, the DCP drill guide with a gold collar is used. The arrow should point in the direction of the fracture. 

DCP drill guide with gold colar

In LCP combi holes, the universal spring-loaded DCP drill guide without pressure against the bone can be used in the non-threaded portion of the hole.

universal spring-loaded DCP drill guide

The hole is drilled through both cortices.

Drilling

A depth gauge is used to determine the screw length.

If self-tapping screws are used add 2 mm to the screw length so that the portion of the screw in the far cortex is fully threaded.

Determination of screw lenght

The hole is tapped.

If self-tapping screws are used, this step can be omitted.

Tapping of screw holes

As the screw is tightened, the head displaces in relation to the plate, moving the bone sideways with it in relation to the plate.

Compression of fracture

After the screw has been tightened, the fracture gap should have closed and now be compressed.

Screw insertion in compression mode