Fractures: Charnley three-point moulding: 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: Charnley three-point moulding

Sample item

Which condition is necessary for Charnley three-point moulding to keep a reduced fracture stable in a cast?

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

The answer and the reasoning

C. An intact periosteal and soft tissue hinge on the concave side of the deformity

Three-point moulding applies pressure at the fracture and counter-pressure at two points on the opposite side, and it works only if the soft tissue hinge on the concave side is intact. The hinge prevents the fragments from displacing as the cast sets. Without it the reduction cannot be held in the cast.

Option by option

  • A. A very thin cast with no padding

    Excessively thin casts are weak and do not provide the three-point effect.

  • B. A completely divided periosteum around the fracture

    A divided periosteum would remove the hinge that maintains stability.

  • C. An intact periosteal and soft tissue hinge on the concave side of the deformity (correct)

    Correct. An intact soft tissue hinge allows the three points to hold the reduction.

  • D. A cast extending only to the fracture site

    The cast should cross the joints above and below the fracture.

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 C, An intact periosteal and soft tissue hinge on the concave side of the deformity. Three-point moulding applies pressure at the fracture and counter-pressure at two points on the opposite side, and it works only if the soft tissue hinge on the concave side is intact.

Why is "A very thin cast with no padding" not the answer?

Excessively thin casts are weak and do not provide the three-point effect.

Why is "A completely divided periosteum around the fracture" not the answer?

A divided periosteum would remove the hinge that maintains stability.

Why is "A cast extending only to the fracture site" not the answer?

The cast should cross the joints above and below the fracture.

What concept does this question test?

It tests Fractures: Charnley three-point moulding in Orthopaedics. The hinge prevents the fragments from displacing as the cast sets. Without it the reduction cannot be held in the cast.

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 Fractures: Charnley three-point moulding?

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.