Fractures and dislocations: total hip replacement dislocation: 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 and dislocations: total hip replacement dislocation

Sample item

A patient with a total hip replacement done by the posterior approach stands from a low chair, feels a pop and now has a shortened leg held flexed, adducted and internally rotated. What has happened?

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

The answer and the reasoning

A. Posterior dislocation of the prosthesis

Dislocation after posterior approach THR is most often posterior and is provoked by flexion, adduction and internal rotation, for example rising from a low seat. Precautions are to avoid these positions for a period. Recurrent dislocation prompts a search for component malposition.

Option by option

  • A. Posterior dislocation of the prosthesis (correct)

    Correct. Shortening with flexion, adduction and internal rotation after rising from a low chair is posterior dislocation.

  • B. Periprosthetic fracture of the femoral shaft

    A periprosthetic fracture presents with pain and deformity of the thigh after a fall.

  • C. Anterior dislocation of the prosthesis

    Anterior dislocation causes external rotation and extension and is provoked by extension and external rotation.

  • D. Aseptic loosening of the stem

    Loosening causes gradual start-up thigh pain, without a sudden pop and fixed deformity.

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 A, Posterior dislocation of the prosthesis. Dislocation after posterior approach THR is most often posterior and is provoked by flexion, adduction and internal rotation, for example rising from a low seat.

Why is "Periprosthetic fracture of the femoral shaft" not the answer?

A periprosthetic fracture presents with pain and deformity of the thigh after a fall.

Why is "Anterior dislocation of the prosthesis" not the answer?

Anterior dislocation causes external rotation and extension and is provoked by extension and external rotation.

Why is "Aseptic loosening of the stem" not the answer?

Loosening causes gradual start-up thigh pain, without a sudden pop and fixed deformity.

What concept does this question test?

It tests Fractures and dislocations: total hip replacement dislocation in Orthopaedics. Precautions are to avoid these positions for a period. Recurrent dislocation prompts a search for component malposition.

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 and dislocations: total hip replacement dislocation?

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.