Paediatric Septic Arthritis

This is an orthopaedic emergency.  Therefore you need to be able to confidently diagnose and manage a child with a painful joint!

Differential diagnosis of hip pain in child:

Transient synovitis

(Dx of exclusion!!!)

Septic arthritis


Epidemiology 2-5 yrs 50% of cases occur <2yrs old
Cause – Viral (poststreoptococcal)                             – Trauma Risk factors in neonates: Prem’s + CS

Direct inoculation / haematogenous / extension from osteomyelitis

Bacteriology n/a According to age

Neonates: Group B Strep (Com. aquired)

S. Aureus (Nosocomial)

>2yrs: S. Aureus

Adolescents: N. Gonorrheia
NB: H. Influenza less common due to vaccination

Symptoms – Acute hip pain (worse in AM, better during day)

– Refusal to WB

– Recent hx of URTI

– Able to E&D + well (parents not worried)

– Acute hip pain

– Refusal to WB or move hip

– TOXIC looking (parents worried)!!!

Clinical findings – Afebrile/Low grade fever

– Mild-moderate restriction of ABd (most sensitive)

– Fever, effusion, warmth + pain in groin

– Hip rests in Fl/ABd/ER !!!

(Position of comfort due to MAX hip capsular volume)

– Severe restriction in ALL movements    – Must examine adjacent joint involvement!

Bloods ESR <20 – Kocher’s criteria:

  • NWB on affected side                                 – Fever > 38.5 degrees celcius                  – WBC >12.000 – ESR >40
  • 1/4:     3% chance
  • 2/4:     40% chance
  • 3/4:     93% chance
  • 4/4:     99% chance
  • Temp > 38.5 best predictor
  • CRP> 2            2nd best predictor

– USS guided aspiration to confirm Dx

(WBC>50.000,>75%PMN’s, Glucose         < 50mg/dl less than serum)

– Blood cultures

Imaging AP Pelvis: NAD

Hip USS: Fluid in joint

MRI: Differentiates from SA (but needs GA)

AP/Frog lateral: initially NAD, may see joint space widening, subluxation/ dislocation

Hip USS: Identifies effusion + guides aspiration

MRI: Identifies joint effusion + adjacent bone involvement

Treatment Observations + NSAID’s

♯ OPA 1/52 (ensure all is well) then discharge

Conservative: IV abx alone (ONLY for adolescent N. Gonnorrheia)

Surgical arthrotomy:

SURGICAL EMERGENCY (due to chondrolytic effect)

Anterior approach avoid’s femoral blood supply + easy access to inspect +/- drill prox. femoral metaphysis, irrigate joint, leave capsule open and close skin over drain – remove drain after 24-48 hrs

Send synovium + fluid MC&S samples

D/w local Micro team, STOP abx when CRP/ESR normal (usually 3-4 weeks)

Mobilise + ROM of hip joint within few days postop

Complications None
  • Femoral head destruction
  • Angular deformity + LLD (due to physeal damage)
  • Joint contracture
  • Hip dislocation
  • Gait anomalies
  • AVN

Join our question bank for instant access to questions and tips to prepare you for the ST3 Ortho Interview!

 Clinical Questions

Leave a Reply