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

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

• Age of onset: OA typically affects people aged 45 years and over, whereas RA can occur from age 16 onwards.
• Joint involvement pattern: OA usually involves larger weight-bearing joints such as hips, knees, and shoulders, and is often localized to a few joints. RA commonly affects multiple joints, especially the small joints of the hands and feet, with symmetrical involvement.
• Morning stiffness: OA presents with either no morning stiffness or stiffness lasting less than 30 minutes. RA is characterized by prolonged morning stiffness lasting more than 30 minutes.
• Inflammatory signs: RA shows signs of persistent synovitis, joint swelling, tenderness, and loss of function, often with systemic symptoms like fatigue. OA typically lacks significant inflammatory signs and systemic symptoms.
• Progression and deformity: RA can cause progressive joint deformity and erosions visible on X-ray, while OA leads to joint space narrowing and osteophyte formation without erosions.
• Response to treatment: RA requires early specialist referral and disease-modifying treatments, whereas OA management focuses on symptom relief, exercise, and weight management.

These clinical distinctions guide diagnosis and management in primary care settings.

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