Evaluation of painful total knee arthroplasty.

Numerous conditions exist that may cause pain following total knee arthroplasty (TKA) that can be categorized into articular versus nonarticular etiologies. To critically evaluate the painful TKA, the treating physician must perform a thorough history and physical examination, as well as both laboratory and radiographic testing. Laboratory analysis is directed to differentiate septic versus aseptic etiologies of knee pain and commonly includes assessment of white blood cell count, erythrocyte sedimentation rate, C-reactive protein, and knee aspiration for cell count and cultures. Available radiographic tools include plain radiographs, stress views, arthrography, nuclear scanning, ultrasonography, and magnetic resonance imaging. In cases of unexplained pain, reoperation is unwise and frequently associated with suboptimal results. Periodic repeat evaluations are recommended until the etiology of pain is clearly determined.