Fractures: induced membrane technique: 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 · Fractures: induced membrane technique

Sample item

A patient has a 6 cm segmental tibial defect after debridement of an infected open fracture. In the Masquelet technique, what is the role of the cement spacer placed in the first stage?

AIt provides permanent structural supportBIt releases bone morphogenetic protein aloneCIt acts as a sequestrum for the infectionDIt induces a vascular membrane that later contains the bone graft

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

The answer and the reasoning

D. It induces a vascular membrane that later contains the bone graft

In the first stage the defect is debrided, stabilised and filled with a cement spacer, which provokes a vascularised, growth-factor-rich membrane around it over about four to eight weeks. In the second stage the spacer is removed and the pocket is filled with cancellous autograft. The membrane keeps the graft in place and aids union.

Option by option

A. It provides permanent structural support
The cement is temporary and is removed at the second stage.
B. It releases bone morphogenetic protein alone
The membrane produces growth factors and the cement does not release BMP.
C. It acts as a sequestrum for the infection
The spacer is not left as a sequestrum and is removed.
D. It induces a vascular membrane that later contains the bone graft (correct)
Correct. The spacer induces a membrane that holds the later graft.

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 Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is D, It induces a vascular membrane that later contains the bone graft. In the first stage the defect is debrided, stabilised and filled with a cement spacer, which provokes a vascularised, growth-factor-rich membrane around it over about four to eight weeks.

Why is "It provides permanent structural support" not the answer?

The cement is temporary and is removed at the second stage.

Why is "It releases bone morphogenetic protein alone" not the answer?

The membrane produces growth factors and the cement does not release BMP.

Why is "It acts as a sequestrum for the infection" not the answer?

The spacer is not left as a sequestrum and is removed.

What concept does this question test?

It tests Fractures: induced membrane technique in Orthopaedics. In the second stage the spacer is removed and the pocket is filled with cancellous autograft. The membrane keeps the graft in place and aids union.

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 Fractures: induced membrane technique?

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.