Hip: centre-edge angle: 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 · Hip: centre-edge angle

Sample item

A 25-year-old woman has groin pain. On an AP pelvis radiograph the lateral centre-edge angle of Wiberg is 12 degrees. What does this indicate?

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

The answer and the reasoning

A. Acetabular dysplasia with undercoverage of the femoral head

The lateral centre-edge angle is formed between a vertical line and a line from the head centre to the lateral edge of the acetabulum. Values below about 20 degrees indicate dysplasia with a shallow socket, while values above about 40 degrees suggest overcoverage. Dysplasia leads to early osteoarthritis.

Option by option

  • A. Acetabular dysplasia with undercoverage of the femoral head (correct)

    Correct. A reduced angle indicates a shallow acetabulum.

  • B. Normal acetabular coverage

    Normal values are roughly 25 to 40 degrees.

  • C. Pincer-type overcoverage

    Overcoverage gives a high angle.

  • D. Protrusio acetabuli

    Protrusio shows a medially displaced head with a high angle.

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 A, Acetabular dysplasia with undercoverage of the femoral head. The lateral centre-edge angle is formed between a vertical line and a line from the head centre to the lateral edge of the acetabulum.

Why is "Normal acetabular coverage" not the answer?

Normal values are roughly 25 to 40 degrees.

Why is "Pincer-type overcoverage" not the answer?

Overcoverage gives a high angle.

Why is "Protrusio acetabuli" not the answer?

Protrusio shows a medially displaced head with a high angle.

What concept does this question test?

It tests Hip: centre-edge angle in Orthopaedics. Values below about 20 degrees indicate dysplasia with a shallow socket, while values above about 40 degrees suggest overcoverage. Dysplasia leads to early osteoarthritis.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Hip: centre-edge angle?

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.