Hip Pain and Septic Arthritis
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Objectives
• Recognize the clinical presentation of a
septic joint and transient synovitis
• Be able to differentiate septic arthritis and
transient synovitis based on evidence
based medicine
• Develop an approach to the assessment
of patients with a swollen or painful joint
• Know the appropriate management of
septic arthritis
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Definition
• Septic Arthritis - disorder of joint where
joint capsule is infiltrated by bacteria
• Transient synovitis - nonspecific
inflammation and hypertrophy of the
synovial membrane
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Incidence
Transient Synovitis
• Age 3 – 8 years old
• Male : Female 2:1
• 0.4-0.9% of pediatric
admissions to ER
• Child’s risk of
developing during
lifetime is 3%
• ?Seasonal
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Septic Arthritis
• Unknown number
• Non-gonococcal 
before age 5
– male: female 2:1)
• Gonococcal 
adolescent females
Etiology of Transient Synovitis
(or so we think)
• Viral agent
– Fourfold increase in viral titers in 45% of patients with
diagnosis (Tolat et al)
– Elevated serum interferon levels in 43% patients
• Trauma
– 17-30% of patients with diagnosis
– Local contusion as self-limiting chemical synovitis
• Allergy – response to antihistamines??
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Etiology of Septic Arthritis
• Metaphysis – tiny blood vessel loops
where low flow and O2 content 
traumatic rupture may provide area of
bacterial growth
• Synovial membrane receptors may have
predilection for bacteria
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Anatomy of Region
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Sequence of Events
1. Bacteria deposited in subsynovial
capillary network
2. Immune response – may abort at this
point if bacterial growth halted
3. Inflammatory cascade initiated with
release of proteolytic enzymes and
toxins
4. Articular cartilage degradation
5. Increased fluid and pus leading to
pressure and ischemia from compression
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Physical Examination
• Unilateral joint (90%)
• No traumatic lesion
• +/- fever and other signs of infection including:
n/v, diarrhea,headache
• Limp or refusal to bear weight
• Decreased range of motion
• Palpation of effusion and tenderness
• Prefer position of hip to be slightly flexed and
externally rotated  maximize joint space to
decrease pressure
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Current Standards of Care
• Labs: CBC, ESR (or CRP)
• Blood Culture – in 1 study only 50% of
patients with documented septic arthritis
had positive blood culture
• Radiography of hip: AP and frog leg
views of hip  some studies question
need for these X-rays
• Gold standard – aspiration of fluid for
cell count, gram stain, culture and
sensitivity (97% sensitivity)
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Other Imaging Modalities
• Standard US – demonstrates an effusion but
cannot differentiate an infectious from
noninfectious etiology
• Doppler Sonography (1998) – look at increase
blood flow; preliminary evidence shows poor
sensitivity but high specificity
• MRI – signal intensity changes seen in bone
marrow of septic arthritis (no difference in
signal of soft tissue or in grade of effusion)
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How can one be sure a
painful hip with effusion
is not a septic joint???
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Evidence Based Medicine
Study 1
• Retrospective study looked at 509 patients
who presented with irritable hip and limp.
• Presence of any two of these clinical
criteria (see next page for graph and
criteria) was 95% sensitive and 91%
specific for septic arthritis.
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Clinical Criteria – Study 1
100.00%
80.00%
60.00%
40.00%
20.00%
0.00%
Pain
Tenderness Temp > 38
ESR > 20
Transient Synovitis
Septic Arthritis
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EBM – Study 2
1. Four Predictors:
•
•
•
•
Fever
Non-weight bearing
ESR > 40
WBC > 12
2. Recommendation:
•
•
3-4 predictors good candidates for aspiration
in OR b/c high likelihood that arthrotomy and
drainage will be needed
2 predictors aspirate with U/S or fluroscopy
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Clinical Criteria – Study 2
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Predicted Probability – Study 2
100
90
80
70
60
50
40
30
20
10
0
93.1
99.6
40
0.2
0
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3
1
2
3
4
Treatment & Prognosis
•
Transient synovitis
–
–
•
Tx  rest and anti-inflammatory agents
Lasts 3-10 days
Septic Arthritis
–
Treatment:
1. Naficillin and 3rd generation cephalosporin
2. Vanco and aminoglycoside
3. Oxacillin and gentamicin
–
Most important prognostic indicators:
1. 4 to 5 days to begin treatment to avoid long-term
consequences
2. Evidence of osteomyelitis  poor prognosis
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Complications of Septic Arthritis
• Osteonecrosis
• Cartilage destruction
• Postinfectious degenerative arthritis
• Joint instability
• Deformity
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Bibliography
1.
2.
3.
4.
Do Twee T. Transient synovitis as a cause of painful
limps in children. Current Opinion in Pediatrics. 12
(1): 48-51.
Klein D, Barbera C, Gray S, Spero C, Perrier G,
Teicher, J. Sensitivity of objective parameters in the
diagnosis of pediatric septic hips. Clinical
Orthopaedics and Related Research. 338: 153-159.
Kocher M, Zurakowski D, Kasser J. Differentiating
between septic arthritis and transient synovitis of the
hip in children: an evidence-based clinical prediction
algorithm. The Journal of Bond and Joint Surgery.
Chen C, Ko J, Li C, Wang C. Acute septic arthritis of
the hip in children. Archives of Orthopedic Trauma
Surgery. 121: 521-526.
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