Table 3

The 2023 EULAR classification criteria set for thumb base OA

Target population (mandatory criteria): persons with pain, aching and/or stiffness in at least one target joint (bilateral thumb base joints) on most days of the previous 6 weeks, and no other disease or acute injury that can explain the symptoms.*
Classification criteria for thumb base OA (score-based algorithm: the scores of the five criteria A–E should be added, and a score of ≥8/15 is needed for classification of thumb base OA):
 Below 45 years0
 45–54 years1
 55–64 years2
 65 years and above3
Duration of morning stiffness in thumb base joints
 Long (more than 30 min)0
 Short (30 min or less)2
Number of CMC1 joints with osteophytes
 1 joint2
 2 joints4
Number of CMC1 joints with JSN
 1 joint2
 2 joints3
Symptom-structure concordance †
  • *Differential diagnoses may include crystal arthropathies, non-inflammatory hand conditions such as haemochromatosis and systemic inflammatory joint diseases such as rheumatoid arthritis and psoriatic arthritis. People with a history of psoriasis should be excluded from the target population.

  • †Radiographic CMC1 OA (osteophytes or JSN) in at least one thumb base joint with pain, aching and/or stiffness on most days of the previous six weeks.

  • CMC1, first carpometacarpal; EULAR, European Alliance of Associations for Rheumatology; JSN, joint space narrowing; OA, osteoarthritis.