Bennett and Namnyak used clinical criteria to diagnose acute septic arthritis of the hip in pediatric patients. The authors are from Dammam Central Hospital in Saudi Arabia.
Acute septic arthritis was diagnosed if 3 or 4 of the following were present:
(1) one or more of the following:
(1a) fever > 38°C
(1b) pain localized to the hip joint, made worse by gentle motion
(1c) hip muscle spasm
(1d) reduced hip range of motion
(2) gross pus aspirated from the hip joint
(3) examination of joint aspiration fluid shows one or more of the following:
(3a) > 50,000 leukocytes per µL with >= 90% neutrophils
(3b) positive Gram stain
(3c) culture positive for a pathogenic organism
(4) imaging studies show one of the following:
(4a) osteomyelitis of the proximal femur
(4b) subluxation of the hip joint
(4c) widening of the joint space
where:
• I would think 2 of the 3 items in the third criterion might be very suspicious for the diagnosis.
• Imaging studies are useful for excluding other causes of hip pain like fracture.
• The first criteria could be modified to require 2 or 3 of the 4 items.
• Aspiration of the joint fluid is usually done now under ultrasound guidance.
• A child with neutropenia might not meet criterion 3a.
