Osteoarthritis

Overview

•Most common joint condition in the UK - predominantly affects adults >45 years
•Women more commonly affected, especially post-menopause; knee, hip, and hand (thumb CMC) most frequently involved

Presentation

•Joint pain - aching, worse with activity/weight-bearing, improved with rest (early); may become continuous at rest in advanced disease
•Morning stiffness - present but brief, resolves within 30 minutes (contrast with RA: >1 hour)
•Bony swelling - hard enlargement from osteophytes; soft tissue swelling during flares
•Crepitus - coarse grating on movement due to irregular articular surfaces
•Reduced range of movement - secondary to osteophytes, effusion, capsular thickening
•Heberden's nodes - bony swellings at DIP joints (hand OA)
•Bouchard's nodes - bony swellings at PIP joints (hand OA)
•Referred pain - hip OA commonly refers to groin, anterior thigh, or knee; always examine the hip in unexplained knee pain
💡
A patient with knee pain or lower back pain without obvious local pathology may have hip OA as the underlying cause. Always examine the hip in unexplained knee pain.

Investigations

🎯
NICE 2022: OA can be diagnosed clinically - NO investigations needed if ALL THREE criteria are met: (1) age >45, (2) typical activity-related joint pain, (3) morning stiffness absent OR <30 minutes.
•Plain X-ray (first-line if imaging required) - classic features: Loss of joint space, subchondral sclerOsis, oSteophytes, Subchondral cysts (mnemonic: LOSS)
•Blood tests (FBC, CRP, ESR, rheumatoid factor, anti-CCP) - only if inflammatory arthritis needs excluding; should be normal in uncomplicated OA
•Joint aspiration - if significant effusion during acute flare, to exclude septic arthritis or crystal arthropathy

Management

•Non-pharmacological (all patients - foundation of treatment):
•Therapeutic exercise - most important non-pharmacological intervention; aerobic and strengthening exercise improve pain, function, and quality of life
•Weight loss - essential in overweight/obese patients; reduces load on lower limb joints
•Patient education, physiotherapy, occupational therapy (splints, walking aids, home adaptations)
First-line · Pharmacological
  1. 1Topical NSAIDs (e.g. diclofenac gel) - first-line for knee OA; effective with lower systemic adverse effects than oral NSAIDs
Second-line · If topical insufficient
  1. 1Oral NSAIDs (e.g. ibuprofen, naproxen, celecoxib) - always co-prescribe a proton pump inhibitor (e.g. omeprazole) for gastroprotection; lowest effective dose, shortest duration; caution in elderly, cardiovascular/renal/hepatic disease
  2. 2Paracetamol or weak opioids (e.g. codeine) - short-term, infrequent use only when NSAIDs contraindicated; NICE 2022 does not recommend regular paracetamol or opioids for chronic OA
  3. 3Intra-articular corticosteroid injection - useful for acute flares; short-term relief (~10 weeks); especially if significant effusion or inflammatory component
Third-line · Refractory disease
  1. 1Joint replacement surgery - for severe OA not responding to conservative measures; hip and knee replacements have excellent outcomes; prostheses last ~15-20 years (important consideration in younger patients)
⚠️
NICE 2022 recommends AGAINST strong opioids (e.g. morphine, oxycodone) for chronic OA pain - no good evidence of benefit, with significant risks of dependence, tolerance, and adverse effects.

Complications

•Progressive functional decline, falls and fractures (muscle weakness, altered proprioception)
•Depression and anxiety - up to 40% of OA patients have clinically significant depressive symptoms
•Opioid dependence - risk if weak opioids prescribed repeatedly rather than short-term
•NSAID-related adverse effects - GI bleeding, acute kidney injury, cardiovascular events (long-term use)