Osteomyelitis and septic arthritis

  • See also: 

    The Acutely Swollen Joint 
    The Limping or non-weight bearing Child
    Upper limb non-use

    Osteomyelitis and septic arthritis can affect any joint or bone, but most commonly involve the lower limbs. Both are most commonly caused by Staphylococcus aureus but can be caused by group A b -haemolytic streptococci and Haemophilus influenzae. Children with sickle cell anaemia are prone to infection by salmonellae.


    There is considerable overlap in the presentation of osteomyelitis and septic arthritis

    Osteomyelitis Septic arthritis
    • Subacute onset of limp / non-weight bearing / refusal to use limb
    • Localised pain and pain on movement
    • Tenderness
    • Soft tissue redness / swelling may not be present & may appear late
    • +/- Fever
    • Acute onset of limp / non-weight bearing / refusal to use limb
    • Pain on movement and at rest
    • Limited range / loss of movement
    • Soft tissue redness / swelling often present
    • Fever


    • FBE, ESR (may be useful for monitoring progress), blood culture, xray (often normal, but may exclude trauma, etc), Bone Scan.

    NB Consultation and treatment should not be delayed while waiting for a bone scan


    • Refer to Orthopaedics if osteomyelitis/septic arthritis suspected or confirmed
    • Septic arthritis requires urgent aspiration +/- arthrotomy and washout* Flucloxacillin 50mg/kg (max 2g) 6 hourly IV
    • Elevate and immobilise limb