Musculoskeletal Imaging

Pyrophosphate arthropathy

structural joint damage occurring in calcium pyrophosphate dihydrate crystal deposition disease, which simulates osteoarthritis in many ways but has a peculiar pattern. Pyrophosphate arthropathy is usually bilateral and is most common in the knee, wrist and metacarpophalangeal joints. Joint space narrowing, bone sclerosis and cyst formation are typical, but the apperance of pyrophosphate arthropathy differs from that of osteoarthritis in five respects:

  • unusual joint distribution;

  • unusual intra-articular distribution;

  • prominent subchondral cyst formation;

  • severe and progressive destructive bone changes; and

  • variable osteophyte formation.

    DR