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How can rheumatoid arthritis cause local muscle and bone atrophy near a joint?
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atrophy
One example of atrophy is the progressive loss of bone that occurs in osteoporosis (normal bone shown on left; osteoporotic bone shown on right).
In the context of rheumatoid arthritis, local muscle and bone atrophy occurs primarily due to disuse and the physical destruction of joint structures.12
The process involves several key factors:
- Disuse: Because rheumatoid arthritis causes painful, inflamed joints, individuals often limit the movement of the affected areas. This inactivity leads to disuse atrophy in the muscles responsible for moving those joints, as well as in the surrounding bone tissue.2
- Joint Destruction: The disease involves the development of pannus, a layer of granulation tissue that erodes and destroys cartilage. As the joint becomes damaged or fixed in place (ankylosed), the resulting loss of function further contributes to the atrophy of adjacent skin, bones, and muscles.1
- Local Osteoporosis: In the bone tissue near the affected joint, the lack of normal mechanical stress and activity can lead to a localized form of osteoporosis, where the bone becomes thinner and loses mineral content.2
Ultimately, this atrophy is a secondary consequence of the chronic inflammation and the subsequent avoidance of movement required to manage joint pain.12