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Keeping the "Boing" in Arthritic Knees

Knee pain from osteoarthritis (OA) is becoming more common every day. It is now the leading cause of disability in older adults. OA makes walking and stair climbing the most difficult tasks. Many studies have been done on the forces placed on the arthritic knee during walking. Researchers are now turning their attention to stair climbing.

Going up and down stairs is more demanding than level walking. Greater muscle strength and control are needed. OA is often linked with weak muscles. Pain causes the affected person to move less often. This sets up a cycle of pain, loss of motion, weakness, and more pain--and ultimately less activity. Weak muscles get tired easily. Weak and tired muscles don't contract quickly or on time. All of these factors make stair climbing difficult.

The knee joint takes a greater force going down stairs. Patients with OA bend the knee less when going down stairs. This loads the joint because the muscles are slow to contract to protect the joint. If the thigh muscle doesn't contract in time during stair descent, the knee doesn't absorb shock as well. The puts a much bigger load on the joint and can make arthritis worse.

Having good control of the muscles is important in knee OA. It gives full motion to the joint and reduces the load. Finding out when the muscles aren't contracting properly may help prevent arthritic changes. This is the focus of research by physical therapists, so they can better prescribe exercises to keep knee arthritis from getting worse.

References: Rana S. Hinman, BPhysio, et al. Delayed Onset of Quadriceps Activity and Altered Knee Joint Kinematics During Stair Stepping in Individuals With Knee Osteoarthritis. In Archives of Physical Medicine and Rehabilitation. August 2002. Vol. 83. No. 8. Pp. 1080-1086.

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