The purpose of this is to test lateral foot orthoses with different amount of wedging to find a model that predicts the optimal lateral inclination of foot orthosis based on biomechanical or feelings measures. This study was a cross-sectional study with patients serving as their own control. The investigators recruited 24 knee osteoarthritis. Knee radiography and clinical angles measures was carried out before making orthoses, then motion analysis with an optoelectronic system was performed with each pair of foot orthoses. During motion analysis, five gait trials were carried out in each condition.

Inclusion Criteria:

• Symptomatic medial knee osteoarthritis (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)