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Osteoarthritis – DR DEACPIMP
Definition
Damage to articular cartilage and bone, causing pain and stiffness. Is generally associated with ageing and overuse.
Risk factors
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Age >55
Obesity
Physical occupation
Previous joint damage, eg fracture
Family history
Differential diagnosis
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Bursitis
Gout
Psoriatic arthritis
Rheumatoid arthritis
Osteoporosis
Musculoskeletal injury
Fracture
Cancer
Epidemiology
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Strongly associated with age: 33% 45-65, 49% over 75, even higher proportion have radiological changes
without symptoms
Affects women more than men, 3:2
More common in Caucasian and Native American than Black
WHO: one of the top 10 leading causes of disability
Aetiology
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Previously thought to be simply ‘wear and tear’, but this is now thought to be overly simple
A result of imbalance between stress and capacity/strength – load exceeds critical stress force
Some genetic predisposing factors
Clinical features
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Generally only one joint at a time – asymmetrical
Affects larger joints eg:
o Hip
o Knee
o Spine
o DIP
Cool joints, minimal swelling
Tender and achey joints
Morning stiffness <30 mins
Exacerbated by use/exercise, relieved by rest
Crepitus
Pathophysiology
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Degradation of cartilage: increased water, decreased proteoglycans  decreased elasticity
Chondrocyte death, remaining chondrocytes multiply: ‘cloning’, which results in islands of aggregated
chondrocytes
Proteases break down cartilage and matrix
Increased catabolic cytokines, eg IL-1, decreased anabolic cytokines eg IGF-1
Fibrillation: cracks appear in cartilage, allow synovial fluid in to bone – cause secondary synovitis, and
vascularisation
Osteoblast activation causes osteophytes and subchondral ossification
Eburnation (bone becomes smooth from bone-on-bone grinding)
Bone cysts are a result of synovial fluid entering the bone
Investigations
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X-ray
o Joint space narrowing
o Subchondral sclerosis
o Bone cysts
o Osteophytes
CRP and ESR to rule out inflammatory cause
Management
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Local analgesics are first line:
o Topical NSAIDS
o Capsaicin (chili cream)
Paracetamol added if necessary
Interarticular corticosteroid injections – often give pain relief last weeks to months
Oral NSAIDS and opioids if necessary
Surgical:
o Joint replacement
Physical therapy
Lifestyle advice:
o Healthy diet
o Exercise
o No smoking
Prognosis
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Doesn’t significantly affect life expectancy, although osteoarthritis tends to be progressive, and progressively
disabling. More joints may become affected