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septic arthritis


  • septic arthritis is one of those diagnoses you do not want to miss
  • delay in diagnosis may cause joint damage as well as life threatening sepsis / septicaemia
  • unfortunately, many other conditions cause a hot, swollen joint, and some with associated fevers
    • are you sure it is not a bursitis or overlying cellulitis with no joint involvement?
    • full range of movement of the joint with minimal pain in a normal patient makes it unlikely to be infected
  • joint infections are generally from penetrating injuries, haematogenous spread, post-operative, or spread from local osteomyelitis
  • investigation and management is different for native vs prosthetic joint infections (PJI)

Adult patients with possible native joint infection

ED Mx of the adult patient with possible native joint infection

  • IV access
  • take bloods for FBE, U&E, CRP, ESR, urate, blood cultures x 2
  • Xray joint to exclude fracture
    • later changes include:
      • narrow joint space if > 1 week
      • subchondral osteoporosis
      • end-stage bone destruction
  • if hip joint, consider USS
  • discuss with orthopaedic team early
    • ?role of joint aspiration
      • essential for knee, elbow or gleno-humeral joint
      • joint aspirate suggesting septic:
        • WCC > 50 000/mm^3 (usually > 100 000/mm^3)
        • Neutrophil usually > 75%
        • Glucose < BSL
        • Protein levels increased - usually 6-8g/dL
        • ± Crystals as acid pH decreases solubility
        • bacteria seen in 30%
        • 60% are culture positive
    • ?delay antibiotics if no severe sepsis until after surgery
    • consider Te99 Scan
      • helps differentiate osteomyelitis

Patients with a prosthetic joint and possible joint infection

Types of infection

  • surgical infection “early PJI”
    • these present within 3 months of implantation
  • delayed or late PJI
    • these present after 3 months of implantation (3-24 months = delayed; > 24 months = late)
  • haematogenous spread PJI:
    • usually occur after 24 months of implantation

Dx of prosthetic joint infections

  • at least one of the following:
    • ≥2 cultures of synovial aspirate or tissue cultures of intraoperative specimens yields the same microorganism
    • Purulence surrounding the prosthesis is observed during reoperation
    • Presence of sinus tract
    • Histopathological findings consistent with acute infection

ED Mx of the patient with possible PJI

  • IV access
  • take bloods for FBE, U&E, CRP, ESR, blood cultures x 2
  • Xray joint to exclude fracture and to look for loosening
  • If the patient is not systemically unwell (signs of severe sepsis / septicaemia), HOLD OFF giving antibiotics until after 1st surgical debridement
  • If severe sepsis, then consult with orthopaedic team and consider starting (also consider ID consult if starting antibiotics):
  • contact ortho team for admission
    • patients with haematogenous or early PJI may be candidates debridement and retention of the prosthesis IF there is no loosening AND symptom duration < 3 weeks
    • other patients are likely to be managed with resection +/- reimplantation
    • multiple intraoperative tissue samples (>3 and ≤5) should be obtained for microbiological examination.
    • post-operatively patients are usually discharged on 6-12 months oral antibiotics followed by longer term review at 18-24 months
arthritis_septic.txt · Last modified: 2018/03/26 17:06 (external edit)