Test yourself
Hot knee: find the suprapatellar recess
4 questions. Pick an answer to see whether you are right and why. Your score appears at the end.
Question 1Where does a knee effusion collect first on ultrasound?
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Answer a. The suprapatellar recess connects with the knee joint and lies between the quadriceps tendon and the femur. Fluid in front of the patella is prepatellar bursitis, a different problem.
Question 2How do you position the knee to scan for an effusion?
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Answer b. Slight flexion pushes fluid into the suprapatellar recess. Full flexion tightens the quadriceps and squeezes the recess.
Question 3A febrile patient has a hot knee and a small effusion on ultrasound. What is the safest next step?
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Answer a. Ultrasound cannot tell infected from sterile fluid, and a small effusion does not exclude infection. Aspiration and fluid analysis decide.
Question 4A small effusion is hard to see. What helps?
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Answer c. Compressing around the patella moves fluid up into the recess under the probe. Firm probe pressure pushes the fluid away.
Practise it with us
Four or five delegates per instructor, FAMUS-accredited faculty and long, supervised time on the probe.
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