Surgical Treatment of Septic Arthritis Periprocedural Care

Updated: Oct 24, 2017
  • Author: Gabriel Munoz, MD; Chief Editor: Harris Gellman, MD  more...
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Periprocedural Care

Preprocedural Planning

Laboratory studies

Laboratory studies should include the following:

  • Complete blood count (CBC) with differential – This often reveals leukocytosis with a left shift
  • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level – These are helpful in monitoring the course of treatment
  • Blood cultures – These may be positive in as many as 50% of  S aureus infections, though they are very poor at detecting  Neisseria gonorrhoeae (approximately 10% of cases prove positive)
  • Urethral, cervical, pharyngeal, and rectal cultures – These have a much higher yield for  N gonorrhoeae than blood cultures do
  • Synovial fluid analysis (see Table 1 below) – This should include Gram stain, culture, cell counts, and crystal analysis

Table 1. Synovial Fluid Classification* (Open Table in a new window)

Quality Reference Range Noninflammatory Inflammatory Septic
Volume <3.5 mL >3.5 mL >3.5 mL >3.5 mL
Viscosity High High Low Variable
Color Clear Straw-yellow Yellow Variable
Clarity Transparent Transparent Translucent Opaque
WBCs <200/µL 200-2000/µL 2000-75,000/µL Often >100,000/µL
PMNs <25% <25% >50% >75%
Culture result Negative Negative Negative Often positive†
Mucin clot Firm Firm Friable Friable
Glucose ~Blood ~Blood Decreased Very decreased
PMN = polymorphonuclear leukocyte; WBC = white blood cell.

*Modified from Schumacher HR. Pathologic Findings in Rheumatoid Arthritis.

†Synovial fluid culture results are positive in 85-95% of nongonococcal arthritis cases and in ~25% of gonococcal arthritis cases.

Imaging studies

Plain radiography may be performed with anteroposterior and lateral views. Findings are often normal. Radiography may be particularly helpful when considering hip involvement in young children.

Look for soft-tissue swelling around the joint, widening of the joint space, and displacement of tissue planes. In later stages of progression, look for bony erosions (see the first image below) and joint-space narrowing (see the second image below).

Anteroposterior view of shoulder demonstrates subc Anteroposterior view of shoulder demonstrates subchondral erosions and sclerosis in humeral head.
Anteroposterior view of knee demonstrates patchy d Anteroposterior view of knee demonstrates patchy demineralization of tibia and femur and joint-space narrowing caused by tuberculoid infection of joint.

Ultrasonography is very sensitive in detecting joint effusions generated by septic arthritis. [34]  It can be used to define the extent of septic arthritis and help guide treatment. In addition, it helps differentiate septic arthritis from other conditions (eg, soft-tissue abscesses, tenosynovitis) for which treatment may differ.

Several authors recommend including magnetic resonance imaging (MRI) in the diagnostic evaluation to rule out the presence of periarticular abscess (see the first image below), osteomyelitis (see the second image below), and septic bursitis, all of which may complicate conservative treatment and require operative debridement.

Septic arthritis with associated soft tissue absce Septic arthritis with associated soft tissue abscess. Coronal T2-weighted fat-saturated magnetic resonance imaging of shoulder demonstrates joint effusion, bone marrow edema, and marked adjacent soft tissue inflammation with fluid collection in infraspinatus.
Hyperintense joint effusion and increased signal i Hyperintense joint effusion and increased signal intensity in bone marrow of pubic rami shown in septic arthritis with associated osteomyelitis and inflammatory changes in soft tissues.

Nuclear scanning may be helpful to differentiate transient synovitis from septic arthritis.

Needle aspiration

In the vast majority of cases, needle aspiration may be the best initial diagnostic and therapeutic procedure. It may allow thorough decompression of the joint, and it can be repeated serially to achieve relief of symptoms, decrease joint effusion, and clear bacteria and synovial WBCs. However, needle aspiration is a poor choice in joints with loculations.