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OR3.2 | Joint Aspiration Practice — SDL Guide (Part 3)

Self-Assessment: Procedural Competence Checklist

Before being signed off for supervised participation in joint aspiration, you should be able to answer each of the following questions correctly and demonstrate each practical step on a model or in simulation. Work through this checklist independently, then review with your supervising clinician. The questions below are grouped into four domains — clinical reasoning, anatomy, procedure, and interpretation — mirroring the four competency domains of the DOPS assessment tool used in orthopaedic training. Where you identify a gap, revisit the relevant section of this module or practise on a simulation model under supervision. Honest self-assessment at this stage is far more valuable than waiting for an examiner to identify your gaps. Use the answer key at the end to verify your responses and note any areas requiring targeted review before your next clinical session.

Clinical reasoning:
- What are the two contraindications to joint aspiration at the planned entry site?
- A patient is on warfarin with INR 2.1. Is aspiration contraindicated? Justify your answer.
- Name the four Kocher criteria. At what score threshold do you proceed to aspiration?

Anatomy:
- Describe the surface landmarks for knee aspiration via the superolateral approach.
- Why is blind hip aspiration contraindicated? Which imaging modality is used?
- Which neurovascular structures must be avoided during ankle aspiration?

Procedure:
- Why must antiseptic dry completely before needle insertion?
- What does 'loss of resistance' feel like during needle insertion, and what does it indicate?
- If aspiration flow stops mid-procedure, what manoeuvre can restore it?

Interpretation:
- A synovial fluid WBC of 35,000 with 88% neutrophils in a febrile patient — how do you manage this?
- Gram stain is negative. Does this exclude septic arthritis?
- Why must culture bottles be plain (not EDTA) and be sent before antibiotics?

Answers to self-check items:
Contraindications: overlying skin infection (cellulitis) at entry site; severe uncorrected coagulopathy. Warfarin at INR 2.1 is a relative contraindication — the urgency of diagnosis outweighs the risk in suspected septic arthritis. Kocher: all four criteria; threshold ≥2 criteria (~40% probability). Knee superolateral: 1 cm superior and 1 cm posterior to superolateral patella border. Hip: femoral vessels anteriorly — use ultrasound. Ankle: avoid dorsalis pedis artery. Antiseptic must dry: wet solution is less bactericidal. Loss of resistance = needle has entered joint capsule. If flow stops: rotate 90° or reposition slightly. WBC 35,000 + 88% neutrophils in a febrile patient is presumptive septic arthritis — treat as such. Negative Gram stain does not exclude septic arthritis (sensitivity only 50-70%). Culture is the definitive test and must precede antibiotics.