Executive Editor: Chris Colton

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

Femur shaft 32-A2 ORIF subtrochanteric

back to skeleton

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, 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.


Reduction enlarge

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


Reduction enlarge

Reduction clamps

In an open plating technique, a preliminary reduction can be undertaken to facilitate the final reduction. Usually, large reduction clamps are used under direct vision.


Reduction enlarge

A collinear clamp can also be very helpful.

3 Plate fixation to proximal fragment top

Plate fixation to proximal fragment enlarge

Guide wire insertion and verification of trajectories

The proximal femoral plate is anatomically shaped to match the profile of the upper femur. First, the plate is adjusted optimally to fit the proximal fragment. Through the two attached wire guides, the proximal 2.5 mm guide wires are inserted into the proximal fragment.


Plate fixation to proximal fragment enlarge

The positions of the guide wires are verified under image intensification in both planes (AP and lateral).


Plate fixation to proximal fragment enlarge

Screw length measurement

The correct screw lengths are determined by measuring the remaining guide wire length, using the dedicated measuring device.


Plate fixation to proximal fragment enlarge

Proximal 7.3 mm screw insertion

Cannulated 7.3 mm screws (locking or nonlocking) are inserted over the guide wires into 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.

Before compressing the fracture plane by tightening the eccentrically inserted screw, in fractures with the illustrated obliquity (laterally and distally) a firm clamp should grip the medial tip of the distal fragment to the plate to prevent shearing at the fracture. This clamp can be removed prior to insertion of the supplementary lag screw.


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

Placement of additional screws in the distal fragment

In accordance with the preoperative planning, additional screws are placed in the proximal and distal fragments.


Pearl: osteoporotic bone

In osteoporotic bone the use of locking screws is advantageous.


Plate fixation to distal fragment enlarge

Pearl: lag screw

The use of lag screws, inserted after fracture compression, is recommended in simple A1- and A2-type fractures.

The lag screw may be independent of the plate, or through the plate, depending on the exact fracture configuration.


Plate fixation to distal fragment enlarge

Illustration showing the lag screw inserted through the plate.

v1.0 2007-12-02