Yoga is particularly well suited to help prevent or minimize the erosion of cartilage that causes the joint pain of osteoarthritis, and to create greater ease of movement and decrease pain within joints that have already sustained such damage.
In therapeutic yoga you learn to actively engage the muscles that can help realign the bony parts of the joints.
Yoga is, one of the most effective ways to improve posture ever invented. If, for example you normally stand with your shoulders slumped and your head held several inches high in front of your spine---a postural habit common to most people who sit at desk all day---you are putting excessive pressure on the joints in the lower body. Postural changes and chest opening poses like backbends can slowly correct the problem.