Needling the Knee OSCE by Katrina Romualdez

You have 3 minutes reading time. This OSCE will run for a maximum of 7 minutes.


A 55 year old male presents to your ED with a painful left knee. He has had 2 days of pain and swelling. On examination the knee is hot, red and swollen with a limited range of motion. He has severe difficulty weight-bearing. Vital signs, including a temperature, are normal.

Instructions for the candidate

Take a focused, relevant history then explain to your patient re: what investigations will be required.

Domains being examined

  • Medical Expertise
  • Prioritisation And Decision Making
  • Communication
  • Health Advocacy
The candidate has 3 minutes reading time. This OSCE is expected to run for a maximum of 7 minutes.

For the actor

You are in pain and if analgesia is not offered fairly quickly, become less forthcoming with information and slightly more difficult re: obtaining consent. You are anxious re: needle aspiration and have questions about making the infection worse, etc. If the procedure is explained well, you give consent.

Re: history --Slightly overweight male, divorced, in construction. Severe L knee pain, worse overnight, pain score 8/10, localised to knee, taking about 8-10 paracetamol + codeine a day. No recent trauma/knee surgery. Travelled to Bali with friends 6 months ago --went to a few girly bars, went home with a few local girls. No other symptoms of systemic infection. No previous history of gout, family history of gout (brother, father). No illicit drug use. Drinks 1-2 beers daily, more on weekends.

For the examiner

If needle aspiration is mentioned, and the candidate is doing well with time to spare: Show him/her the results of the aspirate


– volume 60 ml

– Description: turbid yellow


– Leucocytes 20000/uL

– Polymorphs 80%

– Mononuclear 20%

– RBC 1000/uL

Ask for an interpretation of the results. (Septic knee is likely)
Additional questions:
1.) what other tests are required
-- Synovial fluid: crystals, culture
-- Imaging
-- Septic screen
-- STI screen
2.) what are the important aspects of treatment for this patient?
-- extended course of IV antibiotics if septic knee: staph and STI cover
-- Analgesia
-- Orthopaedic admission

Domains Assessment Objectives

Medical Expertise
- Focused history taking with knowledge of risk factors for septic arthritis
- Interpretation of knee aspirate

Prioritisation And Decision Making
- Appropriate investigations (knee aspiration over blood tests)
- Offering analgesia

- discussion of indications and CIN for knee aspiration
- obtain consent
- sensitive, nonjudgemental discussion re: STI risk

Health Advocacy
- safe sex practices
- appropriate paracetamol use
- alcohol consumption

Other Assessment Notes

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