Femoral Condyle Fractures

For Medical Students

What It Shows

A femoral condyle fracture involves the articular surface of the distal femur, either as a coronal split or as part of a supracondylar injury. 5.2.2 covers the image formation.

The radiograph shows the cortical break and the condylar outline, and shows a coronal plane fracture poorly. 5.3.2 covers the lateral view.

It matters because a coronal fracture of the posterior condyle lies in the plane both standard views project along. 5.16.1 covers the fracture assessment.

How It Is Acquired

Obtain anteroposterior and lateral views and assess the condylar outlines on both. 5.3.1 covers the anteroposterior view.

Look specifically at the posterior condyle on the lateral view, where a coronal split appears as a subtle line. 5.3.2 covers the lateral view.

Look for an intra-articular fluid level, which indicates the fracture reaches the joint. 5.5.12 covers the bursa.

Consider the tunnel view where an osteochondral fragment is suspected. 5.3.4 covers the tunnel view.

Proceed to computed tomography for any suspected articular involvement, because the coronal plane is the plane plain films lose. 5.16.1 covers the fracture assessment.

What Normal Looks Like

Smooth continuous condylar outlines on both views.

An uninterrupted subchondral line along both condyles.

No fluid level in the suprapatellar region. 5.5.12 covers the bursa.

A normal trabecular pattern through the condyles and metaphysis. 5.2.1 covers the generation of X-rays.

What Abnormal Looks Like

A lucent line crossing a condyle in the coronal plane, often subtle on the lateral view. 5.3.2 covers the lateral view.

A displaced condylar fragment with a step in the articular outline. 5.3.1 covers the anteroposterior view.

A supracondylar fracture extending into the joint.

An osteochondral fragment separated from the condyle. 5.11.5 covers osteochondral lesions.

MRCS Level

How It Is Acquired

In a viva this is the fracture to name when asked which knee fracture plain films miss most.

The expected points are the two views, the posterior condyle, the fluid level, the tunnel view, and the computed tomography.

Say that the coronal plane is the plane plain films lose. 5.16.1 covers the fracture assessment.

Say that a high energy mechanism with a normal radiograph still warrants cross sectional imaging. 5.1.3 covers choosing the correct investigation.

Say that associated ligamentous injury is common at this energy. 5.7.4 covers the acute cruciate injury.

What Abnormal Looks Like

The reasoning expected is that a coronal fracture plane is roughly parallel to the lateral beam and roughly perpendicular to the anteroposterior one, so neither view presents it as a line across a cortex. 5.2.2 covers the image formation.

A posterior condylar fragment is also superimposed on the rest of the condyle in both views, which compounds it. 5.16.8 covers three dimensional reconstructions.

The articular surface involved is the one loaded in flexion, so a missed fracture produces symptoms on stairs and squatting rather than in extension. 3.5.4 covers the effects of flexion.

The mechanism is usually axial load through a flexed knee, which also loads the cruciate and the meniscus. 5.7.4 covers the acute cruciate injury.

How Good It Is

Plain films detect displaced femoral condyle fractures and miss coronal undisplaced ones.

Their best contribution is the obvious injury and the fluid level that reveals a subtle one. 5.5.12 covers the bursa.

They are limited precisely where the fracture plane aligns with the beam, which is the commonest subtle pattern. 5.16.1 covers the fracture assessment.

No figures appear for accuracy on this page, under decision 028, and the comparison is the claim: the coronal pattern is detected worse than the sagittal one, which is a comparison rather than a number.

FRCS Level

How Good It Is

At decision level a suspected femoral condyle fracture is a computed tomography decision rather than a radiographic one.

A high energy knee injury with an effusion and normal radiographs justifies cross sectional imaging, because the miss rate for the coronal pattern is the reason. 5.16.1 covers the fracture assessment.

A displaced articular fragment needs anatomical reduction, and the plan comes from the volume rather than the films. 5.16.8 covers three dimensional reconstructions.

The associated ligamentous and meniscal injuries at this energy change the operation and need a magnetic resonance study. 5.7.4 covers the acute cruciate injury.

An osteochondral fragment in a younger patient is a repairable lesion if found early. 5.11.5 covers osteochondral lesions.

Where It Misleads

The commonest error is accepting normal radiographs in a high energy injury. 5.16.1 covers the fracture assessment.

A coronal fracture line is dismissed as an overlapping shadow. 5.2.2 covers the image formation.

A fluid level is not sought on a horizontal beam lateral. 5.5.12 covers the bursa.

The fracture is treated and the ligamentous injury is not looked for. 5.7.4 covers the acute cruciate injury.

An osteochondral fragment is reported as a loose body without its donor site being identified. 5.11.5 covers osteochondral lesions.

Fellowship Level

Where It Misleads

At fellowship level this fracture is the clearest example in the chapter of a lesion whose detection depends on the geometry of the beam rather than on the reader's care.

A fracture plane aligned with the beam produces no edge to see, so reading harder does not help and only a different projection or a volume does. 5.2.2 covers the image formation.

That makes the decision to image further a protocol question rather than a judgement, which argues for a low threshold after a high energy mechanism. 5.1.4 covers imaging pathways.

The coronal posterior condylar fracture is recognised more now than it was, largely because computed tomography became routine for these injuries rather than because anybody reads radiographs better. 5.16.2 covers tibial plateau fractures on computed tomography.

The associated soft tissue injury is still under-recognised, because the fracture occupies the assessment and the magnetic resonance study is often deferred past the point where a repair was possible. 5.6.10 covers ramp lesions.

The honest summary is that plain films in this injury establish that something happened, and everything that changes management comes from elsewhere. 5.1.3 covers choosing the correct investigation.