Today, the most frequent chronic musculoskeletal disorder and the leading cause of disability in the elderly is osteoarthritis (OA). Approximately 43 million people in the United States and 15% of the world population are affected. Due to demographic changes, the incidence of OA is rapidly increasing, leading to an ascending socioeconomical and personal burden. Despite the exact cause of OA remains unknown, the pathogenic role of biomechanical dysfunction in OA is well established. For weight-bearing joints altered loading mechanisms, increased mechanical forces and changed biomechanics are significant contributing factors for initiation and progression of OA. Thus, OA is a disease of the whole joint, including muscles, tendons, ligaments, synovium and bone. This review focuses on the influence of biomechanics on the pathogenesis and progression of OA. We notably illustrate the pathological bioreactivity of soft tissues, subchondral bone and joint inflammation. Procedures, conservative or surgical, which actively alter the biomechanics of the lower limb, are promising strategies to treat symptoms as well as to influence disease progression in OA.