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

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.