We reported the functional outcomes, component alignment and optimal thickness of the tibial inserts and joint line changes of 21 arthritic valgus knee deformities using preoperative templating and computer-assisted total knee arthroplasty(TKA). The osseous cut was modified using a novel preoperative templating technique. Soft tissue balance and component implantation were implemented with the aid of a computed tomography-free navigation system. The arthritic valgus knees had clinical, and functional improvement of the knee Society scores and Lysholm scores postoperatively, at an average of 37.8±7.2 months. The mean anatomic axis (15.2°±4.5° vs. 6.1°±1.4°) and mechanical axis (8.3°±5.2° vs. 0.28°±1.6°) were also significantly improved postoperatively. The mean thickness of tibial inserts and joint line changes was 10.7±1.46 mm and 0.1±1.4 mm. This computer-assisted technique with preoperative radiographic templating is an alternative strategy to improve TKA results in arthritic valgus knees.