Imaging of Musculoskeletal Disorders
Crystal arthropathy

Key features

  • Erosions
  • Soft tissue swelling
  • Monosodium urate crystal deposition in gout
  • Calcium pyrophosphate deposition in pseudogout

Gout is the most common of the crystal arthropathies. Unlike rheumatoid, gout does not usually have a symmetric distribution. It most commonly affects the first metatarsophalangeal joint.

In patients with acute gout the X-ray may appear normal.

Juxta-articular erosions become visible in chronic gout.

Gout – First metatarsophalangeal joint

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Gout – First metatarsophalangeal joint

  • A juxta-articular erosion has formed in the head of the first metatarsal
  • Soft tissue swelling due to inflammation is a common finding in active gout

Gouty tophus

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Gouty tophi

  • Speckled increased density of peri-articular soft tissue is due to deposition of monosodium urate crystals within a gouty tophus

CPPD/Pseudogout

Calcium pyrophosphate dihydrate deposition disease (CPPD) is frequently asymptomatic but may cause an acute arthritis which manifests clinically as pseudogout.

CPPD does not cause erosions as seen in rheumatoid or gout.

CPPD is a common cause of chondrocalcinosis (calcified cartilage) which is most frequently seen in the knee. It has many X-ray features similar to osteoarthritis such as joint space narrowing and sub-cortical cyst formation. Osteoarthritis can also cause chondrocalcinosis, so the two diseases cannot be differentiated on the basis of the presence of these X-ray features. CPPD tends to be more symmetrical and does not have a predilection for weight-bearing joints, as does osteoarthritis.

CPPD – Chondrocalcinosis

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

CPPD – Chondrocalcinosis

  • Chondrocalcinosis is visible in the knee menisci of this patient with CPPD

CPPD – Sub-cortical cyst

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

CPPD – Sub-cortical cyst

  • This detail image of the lateral compartment of the knee shows chondrocalcinosis and formation of a large sub-cortical cyst

Page author: Salisbury NHS Foundation Trust UK (Read bio)

Page edited by: Dr Richard Smith BSc MSc MBBS FRCP PGDip - Consultant Rheumatologist (Read bio)

Last reviewed: January 2020