Criteria of Eich et al for Evaluating a Child with a Painful Hip

 

Conditions in patients studied:

(1) septic arthritis

(2) transient synovitis

(3) Perthes disease

 

Parameters:

(1) effusion on ultrasound

(2) rectal temperature

(3) erythrocyte sedimentation rate (ESR)

(4) C-reactive protein (CRP)

 

Parameters	Finding	Points
rectal temperature	< 38°C	0
	>= 38°C	1
erythrocyte sedimentation rate (ESR)	< 20 mm/h	0
	>= 20 mm/h	1
C reactive protein (CRP)	< 20 mg/L	0
	>= 20 mg/L	1

 

where:

• A CRP >= 20 mg/L was seen in 100% of patients with septic arthritis and 14% with transient synovitis.

• An ESR >= 55 mm/h was seen in all patients with septic arthritis.

• Leukocytosis was not found to be significant.

 

number of abnormal findings =

= SUM(points for all 3 parameter)

 

Effusion on US	Abnormal Findings	Diagnosis
present	2 or 3	septic arthritis (100%), transient synovitis (11%, 7 of 64)
absent	0 or 1	transient synovitis or Perthe's disease (0% septic arthritis)
absent	2 or 3	transient synovitis or Perthe's disease (0% septic arthritis)
present	0 or 1	transient synovitis or Perthe's disease (0% septic arthritis)

 

The presence of effusion on ultrasound and 2 or 3 abnormal findings had a sensitivity of 100% for septic arthritis and a specificity of 89%. Considering that 8 patients with septic arthritis and 7 patients with transient synovitis had this pattern (page 927), only 53% of patients with the pattern would have septic arthritis. This underlies the need to know the prevalence of disease in the population.

 

Routine radiographs did not have a significant impact on decision making. However, new imaging techniques have become available since the paper was written that may help. Also radiographs may help identify some causes of painful hip (fracture, slipped capital femoral epiphysis, etc.).

 

The authors did not recommend routine aspiration of an effusion identified on ultrasound since it is expensive and may be associated with complications. However, since many patients with effusion could have transient synovitis I am not sure how this can be avoided. One advantage of aspiration is the ability to identify the organism and do antibiotic susceptibility studies. It can also help exclude septic arthritis if findings are indeterminate.