What are the key clinical features that differentiate rheumatoid arthritis from osteoarthritis in a primary care setting?

Key clinical features differentiating rheumatoid arthritis (RA) from osteoarthritis (OA) in primary care:

• Joint involvement: RA typically affects the small joints of the hands and feet and usually involves more than one joint, whereas OA commonly affects larger weight-bearing joints such as the hips, knees, and shoulders, as well as the hands but with a different pattern ¹,³.
• Onset and symptoms: RA presents with persistent synovitis, joint swelling, tenderness, and prolonged morning stiffness lasting more than 30 minutes, while OA is characterized by activity-related joint pain with either no morning stiffness or stiffness lasting no longer than 30 minutes ¹,³.
• Inflammatory signs: RA is an inflammatory arthritis with signs of active inflammation such as joint swelling, warmth, and systemic symptoms like fatigue, whereas OA is a degenerative joint disease with less prominent inflammation and no systemic features ¹,³.
• Symptom duration before presentation: RA patients often have a delay of 3 months or longer before seeking medical advice, and early referral is recommended if persistent synovitis is present, regardless of blood test results ¹,². OA diagnosis is clinical and usually does not require imaging unless atypical features are present ³.
• Morning stiffness duration: RA morning stiffness typically lasts longer than 30 minutes, whereas OA morning stiffness is brief, usually less than 30 minutes ³.
• Joint deformity and progression: RA can cause progressive joint deformity and loss of function due to erosive synovitis, while OA leads to joint space narrowing and osteophyte formation without systemic inflammation ¹,³.