Calcium pyrophosphate crystal deposition disease (pseudogout) most commonly affects which joint?
- A First metatarsophalangeal joint
- B Elbow joint
- C Knee joint ✓
- D Wrist (triangular fibrocartilage complex)
Correct answer: C. Knee joint
Explanation
Pseudogout most commonly affects the knee joint, where chondrocalcinosis (calcification of hyaline and fibrocartilage) is visible on X-ray as a dense linear shadow within the menisci. Crystals are positively birefringent (blue when parallel to polariser) rhomboid-shaped calcium pyrophosphate dihydrate. Wrist is the second most common site. First MTP joint is the hallmark of monosodium urate (true gout). Treatment is joint aspiration, NSAIDs, or intra-articular corticosteroids.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.