Histiocytic reaction to hip arthroplasty.

Pain secondary to loosening of a total hip prosthesis is a common complaint and a major complication after surgery. Periprosthetic lucency is a well-recognized result of loosening of the prosthesis and of infection. We describe histiocytic proliferation as an additional cause of periprosthetic lucency and lytic change in two patients. To our knowledge, this has not been previously reported in the radiological literature.