Calcium pyrophosphate dihydrate (CPPD) deposition disease ('pseudogout') characteristically affects which radiographic finding distinguishing it from osteoarthritis?
- A Chondrocalcinosis — calcification within fibrocartilage (knee menisci, triangular fibrocartilage of the wrist, pubic symphysis) and hyaline cartilage ✓
- B Marginal erosions with overhanging cortex and surrounding sclerosis
- C Periarticular osteoporosis with uniform joint space loss
- D Subchondral cysts with periosteal new bone formation
Correct answer: A. Chondrocalcinosis — calcification within fibrocartilage (knee menisci, triangular fibrocartilage of the wrist, pubic symphysis) and hyaline cartilage
Explanation
CPPD deposition causes chondrocalcinosis — punctate or linear calcification within fibrocartilage (knee menisci, triangular fibrocartilage complex of the wrist, symphysis pubis, acetabular labrum) and hyaline cartilage (visible as calcification along joint cartilage margins). This distinguishes it from osteoarthritis (no calcification) and gout (soft-tissue tophi, periarticular erosions with overhanging edges). Polarised light microscopy shows positively birefringent rhomboid-shaped crystals in synovial fluid.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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