investigation of a painful joint prosthesis

Last reviewed 01/2018

Pain in a previously painless artificial joint may be symptomatic of infection or loosening.

It is said that:

• the pain of infection is bad at night
• the pain of loosening is worst first thing in the morning

The following investigations should be performed:

• radiographs:
• infected or loose prostheses are surrounded by a radiolucent rim
• scalloping of the surrounding cortex may indicate infection or the foreign body response to a loose joint

• blood tests:
• blood tests cannot distinguish infection and loosening
• white cell count is usually normal
• the ESR may be raised to 30-50 mm/h

• isotope scans:
• technetium-99m highlights infection and loosening
• indium scans may specifically show infection

• aspiration:
• sterile aspiration does not exclude infection
• aspiration should be performed with full aseptic technique in an operating theatre