Study of How An Ankle Strap Changes Effects of Insole Treatment for Knee Osteoarthritis

Inclusion Criteria: * Subjects aged 45 or over will be included if they have predominantly medial compartment knee OA by American College of Rheumatology criteria, with medial knee pain rated at least 40/100mm on a visual analogue scale on most days of the month during one of the past 3 months. Exclusion Criteria: * Potential subjects with a body mass index (BMI) of greater than 35 will be excluded to avoid the potential confounding effect of increased weight on the height of the insole. Other exclusion criteria will include: known injury or surgery involving bone or cartilage of the knee or ankle which may alter gait, history of factors which might alter response to use of a laterally wedged insole (e.g. greater or similar reduction in lateral compared with medial femorotibial jont space width on posterior-anterior radiographs, tibial osteotomy, congenital foot problems, fused joints, foot deformity, known limitation of range of motion of the subtalar joint), known neuromuscular disease, co-morbid disease which might confound gait analysis (e.g. hip OA, ankle OA, hallux rigidus, valgus deformity of the midfoot, other symptomatic deformity of the foot, advanced arthroplasty of the hindfoot, previous ankle arthrodesis, unable to walk without a gait aid), current use of an orthotic insole, inability to comply with study protocol.