Cane use may reduce risk of knee osteoarthritis progression

A common, incurable joint disease, osteoarthritis (OA) is the leading cause of disability in elderly people. While nearly any joint can be affected, OA most often strikes the knee, particularly the inner aspect of the tibiofemoral joint. One source of stress on this vulnerable joint compartment is the knee adduction moment, an indication of weight placement while walking. A 20 percent increase in the peak knee adduction moment is associated with a 6-fold or greater increase in the risk of knee OA progression over 6 years. To reduce knee load, pain and damage in knee OA patients, physicians often prescribe two inexpensive interventions: footwear and cane use. While these simple strategies have the potential to alter the knee adduction moment, there is little research attesting to their specific benefits for knee OA sufferers.

To assess the immediate effects of walking shoes and a walking cane on the peak knee adduction moment in people with knee OA, researchers at the University of Melbourne turned to 3-dimensional (3-D) gait analysis. Their findings, featured in the May 2008 issue of Arthritis Care & Research (www.interscience.wiley.com/journal/arthritis), strongly support using a cane on a regular basis to reduce the load borne across the knee, while underscoring the urgent need for studies into which aspects of shoe design best support the treatment of knee OA patients.

Led by Dr. Rana S. Hinman, the team recruited 40 volunteers—16 men and 24 women—from the Victoria, Australia, community who met the clinical and radiographic criteria for knee OA. All had medial tibiofemoral osteophytes, as well as knee OA symptoms such as persistent knee pain and loss of physical function. None had a history of joint replacement. The group’s mean body mass index was 29.6 and mean age was 65 years.

Each subject underwent 3-D gait analysis, focusing on the knee most affected by OA, using a state-of-the-art Vicon 6-camera motion analysis system. Embedded in the test area walkway, and unknown to participants, two force plates captured ground impact. Reflective markers, strategically placed on the pelvis, thigh, knee joint, and foot, captured limb movement.