UCSD Musculoskeletal Radiology bonepit.com Case of the week 005

Dec 18th 2002                                                                        Prior cases of the week

History.

69F several years post TKA

Pictures.

Questions.

Describe the appearance and try to explain its cause.

Answers.

Subluxed / dislocated TKR.  Large dense effusion with large popliteal recess collection.  Metal debris dependant in popliteal recess.  Appearance suggests a metal induced synovitis, which accounts for the large dense effusion.

Discussion.

The arthrographic appearance and the metal line sign are caused by deposition of metal debris in the synovium.  Various metals can cause synovitis including lead, mercury, iron and gold

Prior cases of the week