Radiology in osteoarthritis

Characteristic changes of OA are:

• joint space narrowing - focal cartilage loss
• subchondral sclerosis - increased trabecular thickness
• bone cysts
• osteophytes about the joint margins - central, marginal, periosteal
• osteochondral "loose" bodies - islands of chondral metaplasia that have ossified

In the initial stages of OA, the first three features are restricted to the load-bearing part of the osteoarthritic joint. In more advanced disease all five features are present on non-weight-bearing and weight-bearing parts of the joint.

X-rays are not recommended for routine use unless the diagnosis is in doubt.

Reference:

1. Osteoarthritis in over 16s: diagnosis and management. NICE guideline (October 2022)