Makindo Medical Notes

🧸 Always consider if there is any Non-accidental injury and safeguarding issues — a painful or reluctant child must always be assessed in context. ⚠️

🦴 About

• A relatively common but anxiety-provoking presentation in children, often seen in ED and general practice. The challenge lies in distinguishing benign transient synovitis from serious pathology such as septic arthritis or SUFE.

🧬 Aetiology (Age-related Patterns)

🔍 Causes Explained

• 🦠 Septic arthritis: True orthopaedic emergency — untreated infection can destroy the joint. Differentiation from transient synovitis is vital.
• ⚫ Perthes disease: Idiopathic avascular necrosis of the femoral head; typically 4–10 yrs (peak 5–7), 4× more common in boys, bilateral in 10%.
• ⚖️ Slipped Upper Femoral Epiphysis (SUFE): Posteroinferior displacement of femoral head, usually 11–14 yrs; common in obese boys, bilateral in 20–40%.
• 🌿 Transient synovitis vs septic arthritis: Both cause limp, hip/groin pain, and low-grade fever — Kocher criteria help risk-stratify.
• 🦴 Osteomyelitis: May involve proximal femur/pelvis; pain ± fever; passive motion often preserved if not intra-articular.
• 🔥 Juvenile idiopathic arthritis (JIA): Chronic inflammatory disease; hip involvement bilateral in 30–50%.

🩺 Clinical Features

• Groin, thigh, or knee pain (referred from hip pathology).
• Limp or refusal to bear weight.
• Swelling, warmth, or reduced movement of the hip.
• Systemic features — fever, malaise, irritability.

🧍‍♂️ Hip Movement Ranges

• Active: Flexion 120–135°, Extension ≈ 30°, Abduction 45–50°, Adduction 20–30°.
• Passive rotation: Internal + external ≈ 90°. Internal rotation ↑ with femoral anteversion (common in younger children), which decreases with age (~30° → 15° by adolescence).

🚨 Red Flags

• Infant < 3 yrs with painful joint.
• Fever, night sweats, weight loss, anorexia.
• Nocturnal pain, stiffness, or swelling.
• Systemic illness or toxic appearance.

🔬 Investigations

• 🧫 Bloods: FBC, ESR, CRP, U&E, Ca, Mg, LFTs, blood cultures.
• 📈 Raised CRP/ESR → suggests infection or inflammation.
• 🩻 Imaging:
  • X-ray (AP + frog-leg) — assess for SUFE or Perthes.
  • Ultrasound — detect effusion (septic arthritis vs transient synovitis).
  • MRI — osteomyelitis or early avascular necrosis.
  • Bone scan — localises infection or stress fracture.

⚕️ Management Overview

• 🚑 Urgent orthopaedic referral for any child < 3 yrs or > 9 yrs with acute hip pain or inability to weight-bear.
• 🦠 Suspected septic arthritis → immediate aspiration and IV antibiotics.
• 💤 Transient synovitis → rest + NSAIDs + reassess after 48 h.
• 🏥 SUFE → non-weight-bearing + urgent fixation.
• 🔁 Ongoing follow-up for Perthes or JIA under paediatric orthopaedics/rheumatology.

📚 References

• Review for the Generalist: Evaluation of Paediatric Hip Pain
• Royal College of Paediatrics and Child Health (RCPCH) Safeguarding Guidance.
• NICE NG87: Suspected Bone and Joint Infection (Children & Young People).

💡 Teaching tip: In a limping child, always ask: “Is it infection, is it SUFE, or is it transient synovitis?” Remember the mnemonic “STOP JOG” — Septic arthritis, Transient synovitis, Osteomyelitis, Perthes, JIA, Overuse injury, Growth plate slip. 🏃‍♂️