Bone tumours: rotationplasty: 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 tumours: rotationplasty

Sample item

A 6-year-old girl has an osteosarcoma of the distal femur. The surgeon resects the knee with the tumour and reattaches the tibia to the femur with the foot rotated by 180 degrees. What is the aim of this operation?

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

The answer and the reasoning

D. The ankle then functions as a knee joint in a below-knee prosthesis

In the Van Nes rotationplasty, the knee and tumour are resected and the distal limb is rotated 180 degrees so the ankle lies at the level of the knee. The ankle's plantarflexion acts as knee flexion in a prosthesis. It is used in young children with distal femoral tumours where growth would otherwise produce a large limb length discrepancy.

Option by option

  • A. To lengthen the limb by distraction

    The operation does not lengthen the limb by distraction.

  • B. To avoid chemotherapy

    Chemotherapy remains part of osteosarcoma treatment.

  • C. To preserve the knee joint itself

    The knee joint is resected with the tumour.

  • D. The ankle then functions as a knee joint in a below-knee prosthesis (correct)

    Correct. The rotated ankle functions as a knee in a prosthesis.

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.

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Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is D, The ankle then functions as a knee joint in a below-knee prosthesis. In the Van Nes rotationplasty, the knee and tumour are resected and the distal limb is rotated 180 degrees so the ankle lies at the level of the knee.

Why is "To lengthen the limb by distraction" not the answer?

The operation does not lengthen the limb by distraction.

Why is "To avoid chemotherapy" not the answer?

Chemotherapy remains part of osteosarcoma treatment.

Why is "To preserve the knee joint itself" not the answer?

The knee joint is resected with the tumour.

What concept does this question test?

It tests Bone tumours: rotationplasty in Orthopaedics. The ankle's plantarflexion acts as knee flexion in a prosthesis. It is used in young children with distal femoral tumours where growth would otherwise produce a large limb length discrepancy.

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 tumours: rotationplasty?

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.