Continuity Clinic

Hip Pain and Septic Arthritis

Continuity Clinic

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

Continuity Clinic

Definition

• Septic Arthritis - disorder of joint where joint capsule is infiltrated by bacteria

• Transient synovitis - nonspecific inflammation and hypertrophy of the synovial membrane

Continuity Clinic

IncidenceTransient 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

Septic Arthritis

• Unknown number

• Non-gonococcal before age 5– male: female 2:1)

• Gonococcal adolescent females

Continuity Clinic

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??

Continuity Clinic

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

Continuity Clinic

Anatomy of Region

Continuity Clinic

Sequence of Events1. Bacteria deposited in subsynovial

capillary network2. Immune response – may abort at this

point if bacterial growth halted3. Inflammatory cascade initiated with

release of proteolytic enzymes and toxins

4. Articular cartilage degradation5. Increased fluid and pus leading to

pressure and ischemia from compression

Continuity Clinic

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

Continuity Clinic

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)

Continuity Clinic

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)

Continuity Clinic

How can one be sure a painful hip with effusion is not a septic joint???

Continuity Clinic

Evidence Based MedicineStudy 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.

Continuity Clinic

Clinical Criteria – Study 1

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

Pain Tenderness Temp > 38 ESR > 20

Transient Synovitis

Septic Arthritis

Continuity Clinic

EBM – Study 21. 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

Continuity Clinic

Clinical Criteria – Study 2

Continuity Clinic

Predicted Probability – Study 2

0.2 3

40

93.199.6

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4

Continuity Clinic

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

Continuity Clinic

Complications of Septic Arthritis• Osteonecrosis

• Cartilage destruction

• Postinfectious degenerative arthritis

• Joint instability

• Deformity

Continuity Clinic

Bibliography1. Do Twee T. Transient synovitis as a cause of painful

limps in children. Current Opinion in Pediatrics. 12 (1): 48-51.

2. 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.

3. 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.

4. Chen C, Ko J, Li C, Wang C. Acute septic arthritis of the hip in children. Archives of Orthopedic Trauma Surgery. 121: 521-526.