paediatric
Pediatric Septic Arthritis of the Hip
advanced
6 min
28 marks
6 questions
Clinical Scenario
A 2-year-old boy presents with a 2-day history of fever, irritability, and refusal to bear weight on his left leg. He has been crying when his hip is moved. On examination, his temperature is 39.2°C. He holds the left hip in flexion, abduction, and external rotation. There is exquisite pain with any hip movement, particularly internal rotation. He appears toxic. Blood tests show WCC 18 × 10⁹/L, CRP 95 mg/L, and ESR 65 mm/hr.
AP pelvis radiograph of a 2-year-old child demonstrating left hip septic arthritis. The left hip joint space is widened compared to the right. There is lateral subluxation of the femoral head with disruption of Shenton's line. Soft tissue swelling is visible around the hip. No bony changes yet (early presentation). The constellation of findings suggests septic arthritis with effusion requiring urgent intervention.
Image source: Open Access medical literature (NIH/PubMed Central) • CC-BY License
Questions
Question 1 (4 marks)
Describe the clinical presentation and differential diagnosis.
Question 2 (5 marks)
Explain the Kocher criteria and how they guide management.
Question 3 (6 marks)
What investigations are required and how do you interpret them?
Question 4 (5 marks)
Describe the surgical technique for hip joint washout.
Question 5 (4 marks)
What is the antibiotic management?
Question 6 (4 marks)
What are the complications and prognostic factors?
Exam Day Cheat Sheet
Must Mention
- •Kocher criteria (4/4 = 99.6%)
- •Non-weight bearing, fever >38.5°C, WCC >12, ESR >40
- •Joint WCC >50,000 = septic
- •S. aureus most common, Kingella <4yr
- •Urgent washout (<24 hours)
- •IV flucloxacillin empiric
Common Pitfalls
- •Missing Kocher probability
- •Delay in washout
- •Wrong antibiotics
- •Missing Kingella
- •Wrong aspiration cutoffs
- •Incomplete antibiotic course