Segond Fractures

For Medical Students

What It Shows

A Segond fracture is an avulsion fragment from the lateral margin of the tibial plateau. 2.11.4 covers the Segond lesion.

It arises from the anterolateral structures of the knee being pulled off under rotational load. 2.11.3 covers the anterolateral ligament.

It matters because the fragment is small and its association with a cruciate tear is strong, so a tiny radiographic finding predicts a major soft tissue injury. 5.7.3 covers complete cruciate tears.

How It Is Acquired

Look at the lateral tibial margin on the anteroposterior view, just below the joint line. 5.3.1 covers the anteroposterior view.

Recognise it as a thin vertically oriented fleck parallel to the tibial cortex. 5.3.14 covers avulsion injuries.

Assess the cruciate deliberately once it is seen, because the association is the point. 5.7.4 covers the acute cruciate injury.

Assess the posterolateral and anterolateral structures, which is where the fragment came from. 5.10.3 covers posterolateral corner injuries.

Proceed to a magnetic resonance study, since the radiograph has done its job by raising the question. 5.1.3 covers choosing the correct investigation.

What Abnormal Looks Like

A thin ossific fleck lateral to the tibial plateau margin, parallel to the cortex.

A corresponding cortical irregularity at the donor site. 5.3.14 covers avulsion injuries.

Associated findings of a cruciate injury: marrow signal, translation and an effusion on the cross sectional study. 5.11.7 covers bone marrow lesions.

Anterolateral soft tissue swelling on the same film. 2.11.3 covers the anterolateral ligament.

MRCS Level

How It Is Acquired

In a viva this is the fracture to name when asked what a small lateral tibial fleck means.

The expected points are the location, the appearance, the cruciate association, the anterolateral and posterolateral structures, and the magnetic resonance study.

Say that the fragment implies a significant rotational injury. 5.7.4 covers the acute cruciate injury.

Say that its size is irrelevant to the injury's severity. 5.3.14 covers avulsion injuries.

Say that it contributes to the argument for an anterolateral procedure alongside a reconstruction. 2.11.3 covers the anterolateral ligament.

What Abnormal Looks Like

The reasoning expected is that the anterolateral structures restrain internal rotation, so the same pivoting mechanism that tears the cruciate loads them, and the fragment records that load. 3.7.7 covers rotational stability.

That is why the fragment is a marker of mechanism rather than a lesion needing treatment in itself. 3.7.14 covers the injury mechanisms.

Its presence supports the argument that the anterolateral complex contributes to rotational control, which is the question an extra-articular augmentation addresses. 2.11.5 covers the anterolateral complex.

The fragment is cortical and thin, so it is the kind of finding a reader not looking for it will pass over. 5.3.1 covers the anteroposterior view.

How Good It Is

The Segond fracture is a small finding with a high implication, and the radiograph is where it is best seen.

Its best contribution is that a plain film raises a specific soft tissue question nobody would otherwise have asked. 5.7.4 covers the acute cruciate injury.

It is limited by being absent in most cruciate injuries, so its absence excludes nothing. 5.7.3 covers complete cruciate tears.

No figures appear for accuracy on this page, under decision 028, and the comparison is the claim: the fragment is more informative than its size suggests, which is a comparison rather than a number.

FRCS Level

How Good It Is

At decision level this fragment contributes to the anterolateral augmentation decision.

A cruciate tear with a Segond fracture is a rotational injury with documented anterolateral involvement, which is part of the case for an extra-articular procedure. 2.11.3 covers the anterolateral ligament.

It is a marker rather than an indication, so it contributes to a decision made on several factors. 5.7.11 covers graft failure.

Its presence on the injury films is worth recording, because it may not be visible later. 5.7.5 covers chronic cruciate injury.

The associated posterolateral corner must be assessed separately, since the two are not the same injury. 5.10.3 covers posterolateral corner injuries.

Where It Misleads

The commonest error is not seeing it, because it is small and at the edge of the film. 5.3.1 covers the anteroposterior view.

It is reported as a non-specific cortical irregularity. 5.20.8 covers common reporting errors.

Its absence is taken to exclude anterolateral injury. 2.11.3 covers the anterolateral ligament.

It is treated as a fracture needing fixation. 5.3.14 covers avulsion injuries.

The cruciate is not assessed after it is found. 5.7.4 covers the acute cruciate injury.

Fellowship Level

Where It Misleads

At fellowship level this fragment sits at the centre of an unsettled question about the anterolateral complex.

The structure it avulses has been described in several ways and its existence as a discrete ligament has been debated, so the fragment's anatomical origin is better established than the structure's identity. 2.11.5 covers the anterolateral complex.

Whether an extra-articular augmentation should be added to a cruciate reconstruction is an active question, and this fragment is one of the inputs rather than an answer. 5.7.11 covers graft failure.

The fragment is visible on the injury radiograph and frequently not on later films, so a patient presenting late has lost the finding, which argues for keeping the original films. 5.7.5 covers chronic cruciate injury.

Magnetic resonance imaging shows the anterolateral structures directly and inconsistently, which is why a bony marker retains value in a cross sectional era. 5.1.3 covers choosing the correct investigation.

The position worth holding is that this is a well established radiographic sign of a contested anatomical structure, and both halves of that should be said. 2.11.3 covers the anterolateral ligament.