Case 31

Does this prior help?

So yes, this is just straight forward early osteomyelitis. Note the focal osteopenia that has developed of the tuft and even the small area of cortical destruction on the ulnar aspect. There hasn’t been enough time for the bone to react and form periosteal response/sclerosis.

Plain film findings (from http://radiopaedia.org/articles/osteomyelitis )

Plain film

The earliest changes are seen in adjacent soft tissues +/- muscle outlines with swelling and loss/blurring of normal fat planes. An effusion may be seen in an adjacent joint.

In general, osteomyelitis must extend at least 1 cm and compromise 30 to 50% of bone mineral content to produce noticeable changes in plain radiographs. Early findings may be subtle, and changes may not be obvious until 5 to 7 days in children and 10 to 14 days in adults. After this time a number of changes may be noted :

• regional osteopaenia
• periosteal reaction / periosteal thickening - variable, and may appear aggressive including formation of a Codman’s triangle 6
• focal bony lysis
• endosteal scalloping 8
• loss of bony trabecular architecture
• new bone apposition
• eventual peripheral sclerosis