Post-operative PLC Imaging

For Medical Students

What It Shows

Post-operative imaging of a posterolateral corner reconstruction shows the grafts, their tunnels and fixation, and the structures that were not reconstructed. 3.10.8 covers the PLC reconstruction biomechanics.

Radiographs show the tunnels and the fixation, and magnetic resonance imaging shows the grafts. 5.3.2 covers the lateral view.

It matters because the techniques differ in which structures they reconstruct, so without the technique the appearance cannot be classified. 5.20.7 covers reporting the post-operative knee.

How It Is Acquired

Establish which operation was performed before reporting. 5.20.7 covers reporting the post-operative knee.

State the interval, since grafts remodel. 5.5.3 covers the post-operative protocol.

Assess each graft from fixation to fixation. 5.5.9 covers the ligaments.

Assess the tunnels in the fibula and the femur, and whether any converges with a cruciate tunnel. 5.7.12 covers the tunnel assessment.

Assess the common peroneal nerve, which the approach passes. 5.10.5 covers the common peroneal nerve.

What Normal Looks Like

Grafts continuous between their fixation points. 5.5.9 covers the ligaments.

Tunnels in the fibula and the femur with no convergence. 5.7.12 covers the tunnel assessment.

Fixation in position with no migration. 5.5.6 covers the bones.

A nerve unchanged from before the operation. 5.10.5 covers the common peroneal nerve.

Signal around the tunnels appropriate to the interval. 5.5.3 covers the post-operative protocol.

What Abnormal Looks Like

A graft that is discontinuous or pulled off its fixation. 5.5.9 covers the ligaments.

Tunnel convergence with a cruciate tunnel, which is a technical finding. 5.7.12 covers the tunnel assessment.

A fibular fracture through a tunnel. 2.3.2 covers the attachments.

Fixation migration or breakage. 5.5.6 covers the bones.

A new nerve lesion. 5.10.5 covers the common peroneal nerve.

MRCS Level

How It Is Acquired

In a viva the expected answer asks which structures were reconstructed.

The expected points are the operation, the interval, each graft, the tunnels and convergence, and the nerve.

Say that the reconstruction restores function rather than anatomy. 3.10.8 covers the PLC reconstruction biomechanics.

Say that tunnel convergence is worth reporting whether or not it is symptomatic. 5.7.12 covers the tunnel assessment.

Say that the examination reports the rotational result. 4.13.5 covers the dial test.

What Abnormal Looks Like

The reasoning expected is that no reconstruction reproduces the corner's several small structures, so each technique substitutes a graft for a function, and the imaging describes a construct with no native equivalent. 3.10.6 covers the posterolateral corner function.

That makes the expected appearance a property of the technique rather than of the anatomy, so the operative detail is part of the imaging task. 5.20.7 covers reporting the post-operative knee.

Fibular tunnels weaken a small bone, so a fracture through one is a recognised complication rather than a surprise. 2.3.3 covers the clinical importance.

Tunnel convergence with a cruciate tunnel is created at the index operation and limits what a revision can do. 5.7.14 covers the revision ACL imaging.

How Good It Is

Imaging is a good test of this construct's integrity and no test of the rotational result.

Its best contribution is graft continuity, the tunnel positions and their convergence, and the nerve. 5.7.12 covers the tunnel assessment.

It is limited because the expected appearance is technique specific and usually unpublished, and because rotational stability is clinical. 4.13.5 covers the dial test.

No figures appear for accuracy on this page, under decision 028, and no tunnel positions, graft dimensions or convergence thresholds appear either: those are published quantities tied to particular techniques and this environment cannot check them.

FRCS Level

How Good It Is

At decision level the imaging separates a technical failure from an unaddressed problem. 5.10.3 covers PLC injuries.

A discontinuous graft or migrated fixation is technical. 5.5.6 covers the bones.

An intact construct with persisting rotational laxity points at the cruciate, the alignment or the structures not reconstructed. 3.10.9 covers the combined PCL and PLC injury.

Varus alignment loads the reconstruction and belongs in a failure assessment. 5.17.4 covers the osteotomy.

A revision is planned around the existing tunnels. 5.7.12 covers the tunnel assessment.

Where It Misleads

The commonest error is reporting against an anatomy the operation did not restore. 3.10.8 covers the PLC reconstruction biomechanics.

Expected peritunnel signal is read as loosening. 5.5.3 covers the post-operative protocol.

A graft running an unfamiliar course is reported as displaced. 5.5.9 covers the ligaments.

Tunnel convergence is omitted because it was not looked for. 5.7.12 covers the tunnel assessment.

A pre-existing nerve deficit is attributed to the operation. 5.10.5 covers the common peroneal nerve.

Fellowship Level

Where It Misleads

At fellowship level the corner was reconstructed elsewhere and the technique is unknown. 5.20.7 covers reporting the post-operative knee.

Without it the report can describe the construct and cannot say whether it is as intended, which is this chapter's closing position. 5.20.1 covers structured reporting.

The pre-operative study is the only record of which structures were injured, and it is often the only way to work out what was reconstructed. 5.10.3 covers PLC injuries.

Varus alignment left uncorrected at the index operation is the commonest reason these reconstructions stretch out. 5.3.6 covers the long leg alignment films.

An examination under anaesthesia and the dial test report the result that no imaging finding reports. 4.13.5 covers the dial test.

The useful report gives the operation if known, the interval, each graft, every tunnel with its convergence, the nerve and the alignment. 5.20.1 covers structured reporting.