Paget's Disease of Bone and Osteoarthritis: Different Yet Related

Paget's disease and osteoarthritis are completely different disorders that share some of the same symptoms; namely, joint and bone pain. This fact sheet describes the differences between Paget's disease of bone and osteoarthritis, the similarities in their symptoms, how Paget's disease can cause osteoarthritis, and issues related to diagnosis and treatment.

What is Paget's disease?

Paget's disease is a chronic disorder that can result in enlarged and misshapen bones. The excessive breakdown and formation of bone tissue causes affected bone to weaken, resulting in pain, misshapen bones, fractures, and other bone and joint problems, including osteoarthritis. Paget's disease typically is localized, affecting just one or a few bones, as opposed to osteoporosis, for example, which affects all the bones in the body. Scientists do not know for sure what causes Paget's disease.

What is osteoarthritis?

Osteoarthritis is a condition that causes changes in cartilage, the elastic tissue that cushions the joints. Healthy cartilage allows bones to glide over one another, while absorbing energy from the shock of physical movement. In osteoarthritis, the surface layer of cartilage breaks down and wears away. This allows bones under the cartilage to rub together, causing pain, swelling, and loss of motion of the joint.