Efficacy Study of an Unloading Brace for Knee Osteoarthritis

Inclusion Criteria: * Age 30-80. * History of medial unicompartmental knee pain \> 3 months duration (medial compartment only). * Narrowing of medial joint space \< one half of lateral compartment * Varus deformity no greater than 80 * Mild to moderate limitation in Activities of Daily Living (ADL's) and/or recreational activities. * Must read and understand English language and demonstrate the ability and willingness to follow the protocol and complete the questionnaires and diaries. * Manual dexterity sufficient to perform all tasks required of study participants. * Willingness to wear the brace a minimum of 4 hours per day. Exclusion Criteria: * Arthritides other than osteoarthritis. * Previous high tibial osteotomy of the affected knee. * Previous surgery of affected knee other than diagnostic arthroscopy with joint debridement, soft tissue reconstruction, menisectomy. * Fixed flexion deformities / limitations \>10 degrees as compared to the contralateral limb. * Flexion limitation \> 20 degrees. * Significant soft tissue compromise preventing long-term brace use. * Peripheral vascular disease or other neurovascular complaints. * Leg-length discrepancy \> 2cm.