Bone infection: practice question

A Orthopaedics 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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Orthopaedics · Bone infection

Sample item

A man has a chronically discharging sinus over the tibia after an old open fracture. A radiograph shows a dense bone fragment lying in a lucent cavity with surrounding thick new bone. Which element must be removed to achieve cure?

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

The answer and the reasoning

B. Sequestrum

In chronic osteomyelitis, a sequestrum is a piece of dead bone separated from living bone, and bacteria hide on its avascular surface protected from antibiotics and host defences. The involucrum is the new bone surrounding it, and the cloaca is the opening through which pus drains.

Option by option

  • A. Involucrum

    The involucrum is living new bone that gives stability and is retained where possible.

  • B. Sequestrum (correct)

    Dead bone harbours bacteria beyond the reach of antibiotics, so sequestrectomy is needed.

  • C. Cloaca

    The cloaca is only the drainage opening and will close once the infected dead bone is removed.

  • D. Periosteal new bone

    Periosteal new bone is living reactive bone and is not the source of persistent infection.

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.

More Orthopaedics questions

Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is B, Sequestrum. In chronic osteomyelitis, a sequestrum is a piece of dead bone separated from living bone, and bacteria hide on its avascular surface protected from antibiotics and host defences.

Why is "Involucrum" not the answer?

The involucrum is living new bone that gives stability and is retained where possible.

Why is "Cloaca" not the answer?

The cloaca is only the drainage opening and will close once the infected dead bone is removed.

Why is "Periosteal new bone" not the answer?

Periosteal new bone is living reactive bone and is not the source of persistent infection.

What concept does this question test?

It tests Bone infection in Orthopaedics. The involucrum is the new bone surrounding it, and the cloaca is the opening through which pus drains.

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 Bone infection?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.