Knee arthroplasty is one of most frequent orthopedic surgery perfomed in Indonesia. Unfortunately, most of implant products for knee arthroplasty are imported and designed not specifically for Indonesian. This might negatively affects patients due to improper fitting and non-ideal stress distribution between the implant and the surrounding bone tissue. Here, we design and numerically test knee joint implants based on Indonesian anthropometry. The anthropometry of Indonesian male and female adults are obtained from literatures. In addition, we optimize the design by examining the stress distribution of current commercial knee implant products and looking for geometrical modification to obtain the most ideal stress distribution. The results are designs of knee joint implant which have been designed based on adult Indonesian's anthropometry. Stress distribution can be optimized by providing geometrical features which differ from current commercial product. In addition, our knee implant designs consume less material than current commercial product while providing better fitting and stress distribution. We also consider the design to be able to be fabricated using CNC machining to obtain rapid and customizable fabrication process.