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KneeSchool/Clinical Examination Academy/Complex Multi-ligament Injuries

Complex Multi-ligament Injuries

Page 4.23.6 · Special Situations · examination page

The knee with several ligaments torn at once, where the examination's job is the pattern rather than any single test.

Pipeline status. Editorial draft. Evidence verification did not run. Not consultant reviewed. Not for clinical use.

The same topic at 4 depths

Each tier deepens the one below it and never repeats it. Choose the level you want.

Complex Multi-ligament Injuries

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For Medical Students

What It Tests

A multiligament injury involves more than one of the cruciates and the collaterals, so the examination is establishing which combination is present. 4.11.7 covers the combined ligament assessment.

The examination is also a vascular and neurological assessment, because this injury pattern threatens both. 4.6.10 covers the popliteal fossa examination.

It matters because the combination determines the operation and the urgency, and a single positive test does not describe it. 4.14.5 covers the combined instability patterns.

How It Is Performed

Assess the limb's perfusion first, because a dislocated or reduced knee can have an arterial injury with palpable pulses. 4.6.10 covers the popliteal fossa examination.

Assess the common peroneal nerve, since it is injured in a substantial share of these patterns. 4.13.4 covers the posterolateral corner assessment.

Establish the mechanism and whether the knee dislocated and was reduced. 4.2.21 covers the dashboard injury.

Inspect for skin compromise, since the envelope determines the timing of any surgery. 4.3.6 covers skin changes.

Perform the anterior and posterior tests, accepting that a grossly unstable knee makes each harder to isolate. 4.11.2 covers the posterior drawer test.

Perform the collateral tests in extension and in flexion, since opening in extension indicates a more extensive injury. 4.12.1 covers valgus stress testing.

Assess rotational instability, because the posterolateral and posteromedial corners decide much of the plan. 4.13.5 covers the dial test.

Record the whole pattern rather than the most obvious finding. 4.1.8 covers examination documentation.

What a Positive Means

The pattern is the result, and the pattern names the injury rather than any one test.

Opening on collateral stress in full extension indicates injury beyond the collateral alone. 4.12.2 covers the assessment at zero degrees.

Combined anterior and posterior laxity with collateral opening is a dislocation pattern whether or not a dislocation was documented. 4.2.21 covers the dashboard injury.

An absent or asymmetrical pulse is a vascular emergency regardless of the ligament findings. 4.6.10 covers the popliteal fossa examination.

A foot drop with a varus injury pattern is a peroneal injury and part of the diagnosis. 4.13.4 covers the posterolateral corner assessment.

Key Learning Points

  • The pattern, not a single test, is the result.
  • Perfusion is assessed first, because pulses can be present with an arterial injury.
  • Opening in full extension indicates injury beyond the collateral.
  • Combined laxity with collateral opening is a dislocation pattern.
  • A foot drop is part of the diagnosis.

MRCS Level

How It Is Performed

In a viva this is an emergency station and the expected answer puts the vascular assessment before the ligaments.

The expected points are the perfusion, the nerve, the mechanism and any reduction, the skin, the anterior and posterior tests, the collaterals in two positions, the rotational assessment and the whole pattern recorded.

Say that you would assess perfusion first and explain why pulses do not exclude an arterial injury. 4.6.10 covers the popliteal fossa examination.

Say that you would examine the peroneal nerve. 4.13.4 covers the posterolateral corner assessment.

Say that you would record the pattern rather than a grade. 4.1.8 covers examination documentation.

What a Positive Means

The reasoning expected is that the knee's restraints act together, so losing several produces instability in combinations rather than in directions. 4.14.5 covers the combined instability patterns.

Opening in full extension requires the posterior capsule and often a cruciate as well as the collateral, which is why the position matters. 3.9.1 covers valgus stability.

The popliteal artery is tethered above and below the knee, which is why a displacement injures it and why a reduced knee can still have an occluded vessel. 4.6.10 covers the popliteal fossa examination.

The peroneal nerve is tethered at the fibular neck, which is why a varus or posterolateral injury takes it. 4.6.8 covers fibular head tenderness.

How Good It Is

The examination establishes the pattern well in a cooperative patient and poorly in an acutely injured one.

Its best contribution is the vascular and neurological assessment, which is time critical and entirely clinical. 4.6.10 covers the popliteal fossa examination.

It is defeated by pain and guarding in exactly the acute setting where the pattern matters most. 4.23.1 covers the examination under anaesthesia.

Imaging and an examination under anaesthesia complete the pattern, so the acute clinical examination triages. 4.1.6 covers that relationship.

No figures appear for any accuracy comparison on this page, under decision 023, and the comparison is the claim being made.

Key Learning Points

  • Losing several restraints produces combinations rather than directions.
  • Opening in full extension requires more than the collateral.
  • A reduced knee can still have an occluded artery.
  • The peroneal nerve is tethered at the fibular neck.
  • Pain and guarding defeat the examination where the pattern matters most.

FRCS Level

How Good It Is

At decision level the pattern decides the operation, the staging and the urgency, and the examination starts all three.

A vascular injury is the finding that overrides everything else, and it is clinical. 4.6.10 covers the popliteal fossa examination.

A pattern involving a corner changes the procedure, and the rotational examination is where it is raised. 4.13.8 covers the combined posterolateral injuries.

A compromised skin envelope changes the timing rather than the plan, and the examination supplies it. 4.3.6 covers skin changes.

An incomplete acute examination is a specific indication for an examination under anaesthesia before the definitive operation. 4.23.1 covers the examination under anaesthesia.

Where It Misleads

The commonest error is accepting palpable pulses as excluding an arterial injury. 4.6.10 covers the popliteal fossa examination.

The most obvious instability is recorded and the pattern is not. 4.14.5 covers the combined instability patterns.

The collaterals are tested in flexion only, so an extension finding is missed. 4.12.2 covers the assessment at zero degrees.

The peroneal nerve is not examined, so a deficit is found after the operation. 4.13.4 covers the posterolateral corner assessment.

A spontaneously reduced dislocation is treated as a simple ligament injury. 4.2.21 covers the dashboard injury.

Key Learning Points

  • Palpable pulses do not exclude an arterial injury.
  • Recording the obvious instability loses the pattern.
  • Testing the collaterals in flexion only misses an extension finding.
  • An unexamined peroneal nerve becomes a post operative discovery.
  • A spontaneously reduced dislocation is not a simple ligament injury.

Fellowship Level

Where It Misleads

At fellowship level the acute examination of this injury is the one with the highest stakes and the least reliability.

Pain, swelling and guarding defeat the tests at the moment the pattern is most needed, which is why the definitive assessment is deferred and the acute one triages. 4.23.1 covers the examination under anaesthesia.

Gross instability in several directions makes each individual test hard to isolate, so the pattern is inferred from a set of unreliable findings. 4.14.5 covers the combined instability patterns.

Vascular status changes over hours, so a single normal assessment is a measurement rather than a conclusion, and serial examination is the standard. 4.6.10 covers the popliteal fossa examination.

Nerve recovery is unpredictable and the initial examination sets the baseline every later assessment is read against, which makes recording it more important than interpreting it. 4.1.8 covers examination documentation.

The pattern is operatively defined and clinically approximated, so the plan is built on imaging and an examination under anaesthesia with the clinical examination as the trigger. 4.1.6 covers that relationship.

Key Learning Points

  • The acute examination triages and the definitive one is deferred.
  • The pattern is inferred from a set of individually unreliable findings.
  • Vascular status changes over hours, so serial examination is the standard.
  • The initial nerve examination sets the baseline for every later one.
  • The pattern is operatively defined and clinically approximated.

Explore Further

Where this topic came from and where it goes next in the spiral.

References

No reference list is attached to this draft. Evidence verification has not run, because source retrieval was unavailable at generation time. Under the Operations Handbook a missing reference is acceptable and an invented one is a critical failure, so nothing has been cited and no citation marker appears in the text. This page carries no diagnostic accuracy figure, which is decision 023 rather than an omission. The comparative standing of these tests is standard teaching and a specific sensitivity written from memory is the same class of claim as an invented citation, so ACC-001 refuses the number and the page states the comparison. A reviewer with the literature can add the figures into How Good It Is without restructuring the page, and chapter 3.17 lists the studies the figures would come from. Any measurement here, including a flexion angle, is written from standard teaching, has not been checked, and is registered under decision 006 in pipeline/config/figures with a verification state of UNVERIFIED_FROM_MEMORY.

Safety. KneeSchool is educational and does not give individual medical advice. Seek urgent assessment for a knee that cannot bear weight after an injury, a hot swollen knee with a fever, or new numbness, weakness or coldness in the leg or foot.