Rheumatoid arthritis is a connective tissue disorder of unknown etiology that can affect any synovial joint in the body. It is a bilaterally symmetric inflammatory degenerative disease that involves the following joints in order of decreasing frequency: :
- Small joints of the hands and feet, with the exception of the distal interphalangeal joints
- Knees
- Hips
- Cervical spine
- Shoulders Elbows
The major radiographic findings include the following: :
- Symmetric periarticular soft-tissue swelling
- Juxta-articular osteoporosis proceeding to diffuse osteoporosis
- Erosions of the intracapsular portions of the articulating bones not covered by cartilage, which can proceed to severe subchondral bone erosion
- Uniform joint space narrowing
- Synovial cysts (e.g., Baker’s cysts behind the knee)
- Subluxations (e.g., boutonniere or swan-neck deformities of the fingers, and palmar and ulnar subluxation of the proximal phalanges on the metacarpal heads) (Fig. 6-40A,B) (54)