The purpose of this study is to evaluate the immediate and short-term effects of the combination of lateral customized foot orthoses on the pain and medial knee loading during gait among medial knee osteoarthritis patients. The effects of the combination is compared to the single use of these devices. The investigators recruited 22 knee osteoarthritis. They have to wear each of treatments (foot orthoses, knee brace and combination) during three months. A fifteen days wash-out period is given after each three months. Biomechanical evaluation is carried out before and after each three months. This evaluation consisted of three questionnaires (Knee Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC) and Medical Outcome Study Short Form-36( MOS-SF36)), a motion analysis with an optoelectronic system, then a 6-min walk test. During motion analysis, ten gait trials are executed without treatment and ten with the treatment.