Vascular surgery: arterial injury after knee dislocation: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Vascular surgery: arterial injury after knee dislocation

Sample item

A motorcyclist has a posterior knee dislocation that is reduced in the emergency department. The foot is warm with palpable pulses, but the ankle-brachial index in that leg is 0.8. What is the most appropriate next step?

ASerial examination alone because the pulses are palpableBDischarge in a knee immobiliser with outpatient reviewCImmediate four-compartment fasciotomyDCT angiography of the leg

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. CT angiography of the leg

Knee dislocation is associated with popliteal artery injury, including intimal tears that can thrombose later. Palpable pulses do not exclude injury. An ankle-brachial index below 0.9 should lead to arterial imaging, whereas a normal index allows careful observation.

Option by option

A. Serial examination alone because the pulses are palpable
Observation alone is reserved for patients with normal pulses and a normal ankle-brachial index.
B. Discharge in a knee immobiliser with outpatient review
Discharge risks missing an intimal injury that may thrombose and threaten the limb.
C. Immediate four-compartment fasciotomy
Fasciotomy is needed for established compartment syndrome and not for a possible arterial injury in a warm limb.
D. CT angiography of the leg (correct)
Correct. An index below 0.9 after knee dislocation mandates imaging of the popliteal artery.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is D, CT angiography of the leg. Knee dislocation is associated with popliteal artery injury, including intimal tears that can thrombose later.

Why is "Serial examination alone because the pulses are palpable" not the answer?

Observation alone is reserved for patients with normal pulses and a normal ankle-brachial index.

Why is "Discharge in a knee immobiliser with outpatient review" not the answer?

Discharge risks missing an intimal injury that may thrombose and threaten the limb.

Why is "Immediate four-compartment fasciotomy" not the answer?

Fasciotomy is needed for established compartment syndrome and not for a possible arterial injury in a warm limb.

What concept does this question test?

It tests Vascular surgery: arterial injury after knee dislocation in General Surgery. Palpable pulses do not exclude injury. An ankle-brachial index below 0.9 should lead to arterial imaging, whereas a normal index allows careful observation.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Vascular surgery: arterial injury after knee dislocation?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.