Periprosthetic malignancy as a mode of failure in total hip arthroplasty.

The presence of periprosthetic malignancy in proximity to arthroplasty implants has been infrequently reported. We present the clinical, radiographic, and pathological features of three patients in whom loosening and failure of total hip arthroplasties occurred secondary to malignant infiltration. They consisted of a 66-year-old man with the first presentation of metastatic gastric carcinoma as a periacetabular lytic lesion, a 64-year-old man presenting with femoral metastases from a previously undiagnosed lung carcinoma, and a 75-year-old woman presenting with a painless discharging thigh sinus around a total hip arthroplasty subsequently diagnosed as immunoblastic lymphoma. Malignant infiltration should be considered part of the differential diagnosis in aseptic and septic loosening of prosthetic implants. Joint aspiration and isotope bone scanning provide useful additional information before surgical intervention.