In calcium pyrophosphate deposition disease (CPPD/pseudogout), the radiological finding on plain film that confirms the diagnosis is chondrocalcinosis. The most common sites where chondrocalcinosis is visible radiographically are:

• A Lumbar spine and sacroiliac joints
• B Knee (medial and lateral menisci), triangular fibrocartilage complex (TFCC) of the wrist, and symphysis pubis ✓
• C First MTP joint
• D Cervical spine intervertebral discs only

Explanation

Chondrocalcinosis (calcification of fibrocartilage and hyaline cartilage by CPPD crystals) is most consistently seen radiographically at three sites: (1) knee — linear calcification along the medial and lateral fibrocartilaginous menisci (and sometimes hyaline articular cartilage); (2) wrist — calcification of the triangular fibrocartilage complex (TFCC) visible on posteroanterior wrist X-ray; and (3) symphysis pubis fibrocartilage. The knee and wrist are the first sites checked when CPPD is suspected. Gout affects the first MTP characteristically. Chondrocalcinosis should trigger investigation for metabolic conditions predisposing to CPPD: hyperparathyroidism, haemochromatosis, hypomagnesaemia, hypophosphataemia, and hypothyroidism.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.