Using Pressure Detecting Insoles to Reduce Knee Loading

Inclusion Criteria: * Able and willing to give informed consent and comply with the study protocol. * Symptomatic OA of the knee greater than 3 months, as defined by the American College of Rheumatology's Clinical Criteria for Classification and Reporting of OA of the Knee. If symptoms are bilateral, then the knee identified as more symptomatic will serve as the index knee. * Ambulatory knee pain, defined as the presence of greater than 30 mm of pain while walking on a flat surface (corresponding to question 1 of the visual analog format of the WOMAC). * Radiographic OA of the study knee of grade 2 or 3, as defined by the modified Kellgren and Lawrence (K-L) grading scale. * Medial compartment OA, defined as either qualitative joint space narrowing of ≥ 1or the presence of medial bone cyst, sclerosis, or osteophyte. * Able to walk at least 10 minutes without a break. * Age of 40 years or older Exclusion Criteria: * Unwillingness to wear study shoes for at least 6 hours/day for 6 days of the week * Knee flexion contracture of \> 15 degrees or inability to ambulate without assistance. * Presence of clinical OA of the ankle or hip or ankle/hip pain\>10 mm (WOMAC). * Predominant lateral compartment OA, defined as narrowing of the lateral joint space in excess of the narrowing of the medial joint space in either knee. * Concurrent systemic inflammatory arthropathy * Prior knee or hip arthroplasty, or surgical arthroscopy within the previous 3 months. * Intrinsic foot disease: hallux rigidus, hallux abducto-valgus, metatarsalgia, plantar fasciitis, peripheral neuropathy, or any foot condition that may be exacerbated particular footwear. * Intra-articular knee injection: steroids within 6 wks, hyaluronan derivatives within 4 mos. * Body mass index greater than 38.