Executive Editor: Chris Colton

Authors: Florian Gebhard, Phil Kregor, Chris Oliver

Distal femur

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Glossary

Safe zones
Overall neurovascular status of the limb enlarge

General Considerations - Upper leg

Anatomy
The diaphysis of the femur is surrounded by a thick muscular envelope. The major neurovascular structures are located medially and posteriorly, and, therefore, the femur can safely be approached over the anterolateral region.

Overall neurovascular status of the limb
For pin insertion, the condition of the soft-tissue envelope of the femoral shaft has to be considered (areas of crush injuries, or areas of extensive soft-tissue damage should be avoided, in order to minimize the risk of subsequent pin-track infection).

Safe zones
The safest anatomical zones for pin insertion are the anterolateral and direct lateral regions of the femur. See anatomical location of muscle groups and neurovascular bundles in each respective region.


Common peroneal nerve - Saphenous nerve enlarge

General Considerations - Lower leg

Common peroneal nerve
The common peroneal nerve runs from the center of the popliteal fossa laterally and curves distally around the fibula head in an anterolateral direction. It separates into a superficial and a deep branch. Injury of this nerve will result in severe functional deficits.

Saphenous nerve
The saphenous nerve runs distally along the anteromedial aspect of the thigh and as it passes the knee joint it branches off the infrapatellar nerve. Injury of this nerve will not result in functional deficit, but can give rise to cutaneous sensory.


Popliteal artery enlarge

Popliteal artery
The popliteal artery runs through the center of the popliteal fossa. It separates into the anterior tibial artery, the fibular artery and the posterior tibial artery at the level of the proximal tibia shaft (the trifurcation).

Safe zones
The anteromedial aspect of the tibia provides an easily accessible and safe area for the insertion of external fixator pins.


General Considerations - Conversion of a temporary external fixator to nailing, or plating

Care should be taken over pin insertion in cases where the external fixator is used as a temporary device and where it is to be converted, either to an intramedullary nail, or to a plate fixation, at a later stage. A common mistake is to insert the pins too close to the future surgical zone. Therefore, in the distal femoral fractures, the pin should be inserted into the proximal one third of the femur and into the midshaft area of the tibia.


Anterolateral approach enlarge

Safe zone in the midshaft of the femur

The anatomy in the area between the two solid green lines (on the enlarged view) is represented by one cross section and does not vary significantly between different levels of cross section within this zone.

Anterolateral approach
Palpate the vastus lateralis and the rectus femoris muscle bellies, with the patient in the supine position. The pin should be inserted through in the plane between these two muscles.


Palpate the vastus lateralis muscle belly and insert the pins as shown in the diagram, aiming to gain purchase in both cortices. enlarge

Direct lateral approach
Palpate the vastus lateralis muscle belly and insert the pins as shown in the diagram, aiming to gain purchase in both cortices.


The pins in the tibia should start approximately 1 cm medial to the tibial crest, on the anteromedial aspect of the tibia. enlarge

Safe zone in the midshaft of the tibia

The neurovascular bundle with the anterior tibial artery and vein, together with the deep peroneal nerve, runs close to the posterolateral border of the tibia.

These structures are at risk if the pin is inserted in the direction indicated by the red dotted line.

The pins in the tibia should start approximately 1 cm medial to the tibial crest, on the anteromedial aspect of the tibia, and are angled approximately 20° from the sagittal plane.

v1.0 2008-12-03