Foreign Bodies

Question 0

Glass

Answer 0

Reflective echogenic outline

Reverberation artefact posteriorly

Question 1

Wood

Answer 1

Reflective echogenic outline

May or may not shadow

Question 2

Plastic

Answer 2

Slightly less echogenic than wood

Displays shadowing posteriorly

Question 3

Plant thorns

Answer 3

Echogenic outline

No shadowing

Question 4

Metal

Answer 4

Reflective echogenic outline

No shadowing

Question 5

Implanon

Answer 5

Linear echogenic structure with posterior acoustic shadow.

Also has a fibrous sheath around it

Question 6

What are the secondary appearances of foreign bodies?

Answer 6

• surrounding haematoma or granulation tissue
• hypoechoic halo of pus
• air seen as an echogenic foci with shadowing along the entry track site ( acutely)
• synovial inflammation if the foreign body has penetrated a tendon sheath or bursa
• local infection

Question 7

Describe acute complications of orthopaedic prostheses

Answer 7

Post op haematoma

• deep haematoma located immediately over the bone surface - aspiration of fluid if cultures are positive
• superficial haematoma separated from prosthesis by muscle ( May not be treated)
• any fluid around the prosthesis which persists for 2 or more weeks is suspicious for infection
• May not be associated with fever

Question 8

Chronic complications of orthopaedic prosthesis

Answer 8

Infection -more echogenic than simple joint fluid with debris seen

• associated with a fever and pain in the area of the prosthesis
• scan the entire segment of bone in which the prosthesis has been implanted looking for fluid

Soft tissue injury-orthopaedic hardware such as screws may cause inflammation and eventually rupture adjacent tendons and or muscles and nerves