One of major joint disease in Indonesia is knee osteoarthritis, but unfortunately, this condition is not well supported for the patients to do their treatment due to lack in accessibility of physical exercise therapy which required an expensive and big-sized equipment. In order to solve those problems, this research aims to make a concept of therapeutic aid that has an affordable price and portable size but still has its functionality to help patients with doubtful to moderate severity knee osteoarthritis do physical exercise to reduce their knee’s pain. This research use the stages of product design described by Ulrich and Eppinger (2012) and assisted by the House of Quality to determine the quality improvement of existing products. The results showed that the type of load used is the important factor that needs more attention. The final chosen concept in this research is a design of ankle weights with additional ties with a bag clip and have adjustable weight. This concept is also received good responses based on the result from WTP and WTU which majority of respondents would like to use and buy this therapeutic aid.