Unicompartmental knee arthroplasty (UKA) is an alternative procedure to high tibial osteotomy. This study assessed the procedure using computer navigation to improve implantation accuracy and presents early radiological results of a group of patients implanted with the univation UKA (B. Braun Aesculap, Tuttlingen, Germany) with navigation instrumentation and a minimally invasive approach. The authors concluded that navigated implantation of a UKA using a nonimage-based system improved radiologic accuracy implantation without significant inconvenience and minimal change in the conventional operating technique.