Since the introduction of condylar knee designs, total knee arthroplasty has become a remarkably successful and durable procedure. Improvements in instrumentation systems, fixation, and patellar resurfacing have been widely applied and have made total knee arthroplasty a reproducible procedure. The appropriate role for the posterior cruciate ligament in total knee arthroplasty, however, continues to be debated. Proponents of both cruciate substitution and cruciate retention can point to excellent clinical and radiographic results in the literature with knee designs of both types. Recent research findings in the areas of biomechanics, histology, and gait analysis, combined with refinements in intraoperative technique, have further sharpened the focus of the posterior cruciate ligament debate.