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