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How can inflammation cause permanent joint deformity?

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Inflammation in arthritis leads to permanent joint deformity through a progressive process of tissue destruction and structural instability.

Initially, inflammation targets the synovial membranes, causing them to become red, swollen, and thickened. This active inflammation produces a layer of roughened granulation tissue known as pannus, which protrudes over the surface of the cartilage. As the pannus expands, it erodes and destroys the underlying cartilage and bone.12

When this injury is severe, the loss of protective cartilage allows the articular surfaces to form adhesions. These adhesions can transform into fibrous or bony connective tissue, resulting in ankylosis—a state where the joint becomes fused, rigid, and immobile. Furthermore, the destruction of cartilage and bone, combined with the weakening of supporting ligaments and tendons, leads to joint instability and partial dislocation. Over time, these cumulative changes cause the joints to become fixed in place and visibly deformed.231