Background/Purpose: The iASSIST system is a novel navigation system for total knee replacement. It is based on accelerometers built within electronic pods attached to the instruments within the operative field. The objective of this study was to compare the accuracy of iASSIST navigation with that of the conventional alignment technique. Methods: A total of 91 patients (92 knees) retrospectively matched for age, gender, preoperative range of motion, and lower limb deformity underwent total knee replacement using iASSIST navigation (45 patients, 46 knees) or conventional instrumentation (46 patients, 46 knees). Operative time and radiological alignments were compared. Results: The use of iASSIST navigation resulted in fewer outliners (as defined by >3 deviation from the neutral mechanical axis) in lower limb alignment. Operative time with iASSIST navigation was not longer than that using conventional instruments. Conclusion: iASSIST navigation reduces the incidence of lower limb malalignment without adding extra time to the procedure. 中 文 摘 要 簡介: iASSIST是一個全新的全膝關節置換術電腦導航系統。本研究的目的是比較iASSIST 導航系統及傳統全 膝關節置換術的準確性。 方法: 回顧性分析91位病人(92膝) 的全膝關節置換術，病人、年齡、性別、術前活動範圍和下肢畸形的狀態 匹配。45位病人(46膝) 接受了iASSIST電腦導航全膝關節置換術。46位病人接受了傳統全膝關節置換術。我 們對两組病人的手術時間及術前術後的影像對線進行了比較。 結果: 使用iASSIST電腦導航全膝關節置換術之整體下肢對線較傳統全膝關節置換術較少 對線異常值 (>3 偏 離中立機械軸)。而使用iASSIST電腦導航全膝關節置換術之手術時間並不比傳統全膝關節置換術長。 結論: iASSIST電腦導航降低整體下肢對線出現偏差的機會，同時無需增加額外手術時間。