Metastatic Carcinoma as an Unusual Cause of Knee Pain After Total Knee Arthroplasty

Abstract

Common causes of pain after total knee arthroplasty include component loosening, infection, instability, extensor mechanism dysfunction, stress fracture, or periprosthetic osteolysis1. Extra-articular causes of pain include radiculopathy, hip disease, vascular disease, or tendonitis. Metastatic disease as the cause of knee pain after total knee arthroplasty has rarely been reported. A thorough history and physical examination can often identify the nature and cause of the pain. The traditional diagnostic workup for knee pain after total knee arthroplasty includes radiographs (both stress and plain radiographs), serology (C-reactive protein level and erythrocyte sedimentation rate), and knee aspiration. Nuclear medicine scans are occasionally helpful when other tests are negative1. We report the case of a patient who presented to our office with knee pain following total knee arthroplasty. This patient was later discovered to have metastatic cholangiocarcinoma to the distal aspect of the femur as the cause of the knee pain. The family of the patient was informed that data concerning his case would be submitted for publication. A sixty-nine-year-old man underwent a right total knee arthroplasty with cement and with a posterior stabilized mobile-bearing prosthesis (PFC Sigma Rotating Platform; DePuy, Johnson and Johnson, Warsaw, Indiana) for end-stage osteoarthritis in October 2006. A routine pathology report of a random sampling of the bone cut from the knee during surgery showed cartilage-capped bone with degenerative change, osteoarthritis, and no signs of a malignant lesion; however, it is not known specifically which bone fragment was examined. The postoperative course was complicated by hypoxia, pulmonary embolus, atrial fibrillation, and myocardial infarction. The patient was also diagnosed as having Guillain-Barre syndrome in the month after surgery. All of these problems slowed his …