The purpose of this study is to evaluate the immediate effects of a knee brace with a new mechanism on the pain and medial knee loading during gait among medial knee osteoarthritis patients. The effects of this new brace is compared to a stabilizing brace and a typical valgus knee brace. The investigators recruited 24 knee osteoarthritis and they have to wear each of the three braces 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 (KOOS, WOMAC and Medical Outcome Score 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 brace and ten with the brace.

Inclusion Criteria:

• Symptomatic medial knee OA (Kellgren-Lawrence grade I, II or III) according to clinical and radiological criteria of the American College of Rheumatology
• Knee pain > 31/100 (Western Ontario and McMaster Universities Arthritis Index - WOMAC)
• Moderately active
• Varus knee alignment equal or superior to 2°

Exclusion Criteria:

• Severe knee OA (K-L grade IV)
• Rheumatoid arthritis or other inflammatory arthritis
• Avascular necrosis
• History of periarticular fracture or septic arthritis
• Bone metabolic disease
• Pigmented villonodular synovitis
• Cartilaginous disease
• Neuropathic arthropathy
• Synovial osteochondromatosis
• Total or partial knee arthroplasty
• Flexion contracture of ipsi- or contra-lateral knee greater than 15°
• Hip or ankle joint damage with mobility limitation
• Obesity (BMI ≥ 40)
• Intra-articular corticosteroids injection in the affected knee during the two previous months
• Reduced mobility (Charnley class C)