Executive Editor: Chris Colton

Authors: Peter V Giannoudis, Hans Christoph Pape, Michael Sch├╝tz

Femur shaft 32-A3 ORIF subtrochanteric

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Glossary

1 Principles top

Principles enlarge

Compression plate

Compression plating provides fixation with absolute stability for two-part fracture patterns, where the bone fragments can be compressed. Compression plating alone is typically used for simple fracture patterns with low obliquity, where there is insufficient room for a lag screw. Where the obliquity will permit, the addition of a lag screw, across the fracture and through the plate, enhances stability.

Compression plating can only be applied in an open procedure.

The objective of compression plating is to produce absolute stability, abolishing all interfragmentary motion.


Principles enlarge

Dynamic compression principle

Compression of the fracture is usually produced by eccentric screw placement at one or more of the dynamic compression plate holes.


Principles enlarge

The screw head slides down the inclined plate hole as it is tightened, the head forcing the plate to move along the bone, thereby compressing the fracture.


Principles enlarge

Plate position on the femur / tension band principle

As a general rule the plate should be positioned on the lateral aspect of the femur.

A plate acts as a dynamic tension band when applied to the tension side of the bone and when a cortical contact is present on the opposite side to the plate.

With vertical load, the curved femur creates a tensile force laterally and a compressive force medially.

A plate positioned on the side of the tensile force resists it at the fracture site, provided there is stable cortical contact opposite to the plate.


Reduction

It is important to restore axial alignment, length, and rotation. That means that, in a simple A-type fracture, a direct reduction of the main fragments is required.

Reduction can be performed with direct reduction tools.

2 Reduction top

Reduction enlarge

General considerations

Subtrochanteric fractures present a particular problem in terms of fracture reduction and alignment. Due to the strong iliopsoas muscle pull, the proximal fragment is flexed and externally rotated and therefore difficult to control.

In an open plating technique a preliminary reduction can be undertaken to facilitate the final reduction.


Reduction enlarge

The proximal fragment is flexed and externally rotated by the iliopsoas muscle.

3 Plate fixation to proximal fragment top

Plate fixation to proximal fragment enlarge

Guide wire insertion

As a first step a guide wire for the condylar screw is inserted proximally.

Therefore, the aiming device is lined up parallel to the femoral neck in both the axial and the AP views, the guide wire should be aimed at the lower portion to the femoral head.

The wire is advanced to just short of the subchondral bone of the femoral head. Its position is checked fluoroscopically in two planes, and adjusted, if necessary.


Plate fixation to proximal fragment enlarge

Reaming

After indirectly determining the screw length by using the measuring device over the protruding guide wire, reaming is performed over the guide wire with a triple reamer that has been set to the measured screw length.


Plate fixation to proximal fragment enlarge

Condylar screw insertion

The condylar screw is inserted to its final position over the guide wire. The T-handle is lined up parallel to the femoral shaft in order to ensure correct plate alignment.


Plate fixation to proximal fragment enlarge

Plate and screw combination

Next, the plate barrel is slid over the condylar screw shank.

In transverse fractures, where a supplementary lag screw can not be used, the plate should be prebent slightly, so that, when the load screw in the distal fragment is tightened, the medial (trans) cortex is compressed first. This avoids gapping of the medial cortex, which would otherwise occur and result in cyclical motion, leading to excessive strain in the healing tissues, delayed union and fatigue failure of the plate.

In order to determine the exact point of prebending, fit the plate barrel partially over the screw shank, note the appropriate level, then remove the plate to prebend it.


Plate fixation to proximal fragment enlarge

Plate fixation with cortical screw

After checking the correct plate position, a cortical screw is inserted into the proximal plate hole, in order to secure the plate in the proximal fragment.

4 Plate fixation to distal fragment top

Plate fixation to distal fragment enlarge

Insertion of first screw into distal fragment

If the overall reduction is found to be satisfactory, the first cortical screw is placed in the distal fragment near the fracture. The screw is placed eccentrically.


Plate fixation to distal fragment enlarge

Alternative: articulated tension device

In cases of nonunion, the articulated tension device is helpful in producing compression.


Plate fixation to distal fragment enlarge

To improve the compression further, the first screw in the distal fragment can be placed eccentrically.

The tension device is dismantled after two additional neutral screws are placed in the distal fragment.


Plate fixation to distal fragment enlarge

Insertion of additional screws into the distal fragment

According to the preoperative planning, additional screws are placed in the proximal and distal fragments.

v1.0 2007-12-02