jointpathology

Joint pathology refers to the structural and functional abnormalities that affect synovial joints due to disease or injury. It encompasses changes in articular cartilage, the synovium, subchondral bone, ligaments, and other periarticular tissues. The field integrates clinical signs, histology, and imaging to characterize disease processes and guide management.

Major categories include inflammatory arthritis (for example rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, reactive arthritis), degenerative and traumatic conditions (such as osteoarthritis and post-traumatic arthritis), crystal arthropathies (gout, calcium pyrophosphate deposition disease), septic arthritis, metabolic or endocrine joint diseases, and developmental or autoimmune conditions. The same joint can display overlapping features.

Pathologic changes vary by disease but common themes include synovitis with inflammatory cell infiltration, pannus formation and cartilage erosion in inflammatory arthritis; cartilage loss with subchondral sclerosis and osteophyte formation in osteoarthritis; crystal deposition; bone erosions or periarticular osteopenia; and joint effusions. Identification of crystals may be achieved in synovial fluid or tissue.

Diagnosis combines clinical evaluation, serologic tests, imaging (radiographs, MRI, ultrasound), and analysis of synovial fluid for cell counts, crystals, Gram stain, and culture. Histopathology of synovium or cartilage may be required to distinguish infection, neoplasia, or atypical disease, often with immunohistochemical studies.

In research and clinical practice, joint pathology enhances understanding of disease mechanisms, supports classification, and informs treatment decisions and monitoring in rheumatology and orthopedics.