A 55-year-old woman presents with knee pain, crepitus, and restricted range of motion. Joint fluid shows few cells (non-inflammatory). X-ray reveals asymmetric joint space narrowing, subchondral sclerosis, and osteophytes at joint margins. The primary pathologic process driving this condition is:
- A Degeneration and loss of articular cartilage with reactive bony changes ✓
- B Synovial inflammation driven by autoimmune T-cell activation
- C Deposition of monosodium urate crystals in synovium
- D Fibrinoid necrosis of vessel walls in the synovial membrane
Correct answer: A. Degeneration and loss of articular cartilage with reactive bony changes
Explanation
Osteoarthritis (OA) is a degenerative joint disease primarily involving loss of articular cartilage due to an imbalance between chondrocyte matrix synthesis and degradation by MMPs and aggrecanases. Secondary reactive changes include subchondral sclerosis (eburnation), subchondral cysts, and osteophyte (enthesiophyte) formation at joint margins. The synovial fluid is characteristically non-inflammatory with fewer than 2000 cells/µL. Autoimmune T-cell synovitis is the mechanism of rheumatoid arthritis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.