Knee: J sign: 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 · Knee: J sign

Sample item

As a patient with recurrent patellar instability actively extends the knee from a flexed position, the patella shifts laterally in a J-shaped path at terminal extension. What does this J sign indicate?

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

The answer and the reasoning

C. Patellar maltracking, as in trochlear dysplasia or patella alta

A J sign is lateral displacement of the patella in terminal extension as it leaves the trochlear groove, and it indicates maltracking. It is associated with trochlear dysplasia, patella alta and a lateralised tibial tuberosity. It guides surgical planning such as tibial tubercle transfer.

Option by option

  • A. Anterior cruciate ligament deficiency

    ACL deficiency causes instability on pivoting and not patellar tracking.

  • B. Normal patellar tracking

    Normal patellar tracking is smooth and central.

  • C. Patellar maltracking, as in trochlear dysplasia or patella alta (correct)

    Correct. A J-shaped path signals patellar maltracking.

  • D. Meniscal bucket-handle tear

    A bucket-handle tear causes locking and not patellar shift.

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, Patellar maltracking, as in trochlear dysplasia or patella alta. A J sign is lateral displacement of the patella in terminal extension as it leaves the trochlear groove, and it indicates maltracking.

Why is "Anterior cruciate ligament deficiency" not the answer?

ACL deficiency causes instability on pivoting and not patellar tracking.

Why is "Normal patellar tracking" not the answer?

Normal patellar tracking is smooth and central.

Why is "Meniscal bucket-handle tear" not the answer?

A bucket-handle tear causes locking and not patellar shift.

What concept does this question test?

It tests Knee: J sign in Orthopaedics. It is associated with trochlear dysplasia, patella alta and a lateralised tibial tuberosity. It guides surgical planning such as tibial tubercle transfer.

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 Knee: J sign?

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.