This study reviews, over a 5-year period, the records of 70 consecutive patients with prosthetic knee infection and evaluates outcomes as a function of a staging system for prosthetic joint infection. The staging system for prosthetic joint infection was divided into three main categories that include infection type, systemic host grade, and local extremity grade. Outcome indices analyzed included Knee Society Score (KSS), complication rate, amputation rate, and rate of permanent resection. We show that categorizing and stratifying data for patients with infected total knee arthroplasty are useful. A universally accepted staging system would allow for more objective comparisons of treatments and may eventually define particular treatment regimens for particular classes of patients.