This study evaluates the effects of specialized footwear on pain and knee loading in knee osteoarthritis. The hypothesis is that this footwear will lead to decreased knee loading and knee pain.

Inclusion Criteria:

• Able and willing to give informed consent and to comply with the study protocol and follow-up instructions.
• Symptomatic OA of the knee, 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 by the subject 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.

Exclusion Criteria:

• Inability or unwillingness to wear study shoes for at least 6 hours/day for 6 days/week
• Knee flexion contracture of > 15 degrees or inability to ambulate without assistance.
• Presence of clinically significant OA of the hip or ankle or pain greater than 20 mm at these sites (WOMAC).
• > 3 degrees valgus or >12 degrees varus deformity of either knee, defined by the mechanical axis (hip-knee angle).
• Predominant lateral compartment OA, defined as narrowing of the lateral joint space in excess of the narrowing of the medial joint space in either the index or the contralateral knee.
• Concurrent systemic inflammatory arthropathy,
• Prior knee or hip arthroplasty, or surgical arthroscopy of either knee within previous 3 months or history of fracture of either lower extremity within 6 months of study entry.
• Intrinsic foot disease including hallux rigidus, hallux abducto-valgus, metatarsalgia, plantar fasciitis, peripheral neuropathy, or any foot condition that may be exacerbated by particular footwear.
• Intra-articular injection in the index knee: steroids within 6 weeks, hyaluronan derivatives within 4 months.
• Pregnant subjects will be excluded because of the X-rays required.
• Any medical condition that, in the opinion of the PI, would render the subject unable to complete the study.