Diagnosing Osteoarthritis

Clinical Diagnosis

The European League Against Rheumatism recommends that osteoarthritis (OA) can be diagnosed primarily through clinical assessment in patients with typical presentation, which includes usage-related pain, short duration morning stiffness, age >40, and symptoms affecting one or a few joints 1, 2
Clinical hallmarks of OA include usage-related joint pain that worsens with activity, short duration morning stiffness, age over 40 years, and symptoms affecting one or a few joints 1
For hand OA specifically, the American College of Rheumatology suggests diagnosis based on Heberden and Bouchard nodes and/or bony enlargement with or without deformity affecting characteristic target joints (DIPJs, PIPJs, thumb base, index and middle MCPJs) 3

The American College of Radiology recommends plain radiographs as the gold standard for morphological assessment when imaging is needed, with classical radiographic features including joint space narrowing, osteophytes, subchondral bone sclerosis, subchondral cysts, and in erosive OA, subchondral erosion 4, 5, 6
Imaging is indicated in atypical presentations to confirm OA or make alternative diagnoses, when there is unexpected rapid progression of symptoms, or when there is a change in clinical characteristics suggesting another diagnosis 1, 2
For knee OA specifically, weight-bearing and patellofemoral views are recommended for optimal detection 1, 2

Erosive OA is a specific subgroup with worse clinical and structural outcomes, characterized by abrupt onset, marked pain and functional impairment, inflammatory symptoms and signs, mildly elevated CRP levels, and radiographic subchondral erosion 4
The European League Against Rheumatism suggests considering differential diagnosis, including psoriatic arthritis, rheumatoid arthritis, gout, and hemochromatosis for hand OA, and meniscal pathology, anterior cruciate ligament injury, and other crystal arthropathies for knee OA 3, 4

The American College of Radiology recommends that physical examination and plain radiographs be used for diagnosis of osteoarthritis in adults over 40, as they are superior to MRI, with MRI showing only moderate sensitivity (61%) but high specificity (82%) when compared to various reference standards 7
The European League Against Rheumatism suggests that radiographs should be obtained first in essentially all cases of suspected osteoarthritis, not MRI, and that clinical diagnosis alone is sufficient for typical presentations: usage-related pain, morning stiffness <30 minutes, age >40 years, affecting one or few joints 8
The American College of Radiology states that physical examination combined with radiography has better sensitivity and specificity than MRI for osteoarthritis 7

The European League Against Rheumatism recommends that MRI be reserved for specific scenarios, such as atypical presentations requiring differentiation from inflammatory arthritis or alternative diagnoses, and unexpected rapid progression or change in clinical characteristics 8

The European League Against Rheumatism suggests starting with clinical assessment: age >40, usage-related pain, short morning stiffness, one or few joints affected, and obtaining weight-bearing radiographs if imaging is needed 8
The European League Against Rheumatism recommends that routine follow-up imaging with MRI is not recommended unless there is rapid unexpected progression or change suggesting an alternative diagnosis 8