HIP PAIN IN CHILDREN

Acute hip pain differential is usually primarily between septic arthritis and "transient synovitis"

n.b. Both of the above can present with acute hip pain, fever, limp or unwillingness to bear weight, limited ROM, and joint effusion

I. Septic arthritis

1. Bacterial infection of the joint space
2. Rarer than TS but more dangerous

II. "Transient Synovitis"

1. A syndrome of acute hip pain in children, thought possibly to be viral; self-limited and without serious sequelae

Distinguishing SA from TS:

• In a retrospective study of 168 children with acute hip pain ultimately dx'd as septic arthritis or transient synovitis, the septic arthritis pts had sig. higher ESR and WBC and were more likely to present with inability to bear weight and fever (J. Bone Joint Surg. 81A:1662, 1999--AFP)
• In a prospective study of 154 consecutive children presenting to an ED with acute hip pain (none had inmune deficiency or recent surgery), eventual diagnosis of SA (as defined by positive joint culture or synovial fluid WBC count > 50k/mm3, the following were found to be sig. ass'd with higher likelihood of SA:
  • History of fever
  • Inability to bear weight
  • ESR > 40mm/h
  • Peripheral WBC > 12k/mm3

  With 3 of these, specificity was 89%; with all 4, it was 99% (J. Bone Joint Surg 86-A:1629, 2004--AFP)