Osteoarthritis
A disease of synovial joints characterised by cartilage loss and accompanying periarticular change
Epidemiology of osteoarthritis (OA)
- Very common:
- >80% of over 65 years have radiographic signs of OA
- Women>men, particularly hand and knee OA
- Geographically, OA happens everywhere but is commoner in Caucasians
Pathophysiology of osteoarthritis (OA)
- Inflammation occurs as cytokines and metalloproteinases are released into the joint
- Initially hypertrophic repair of the cartilage, then flaking occurs
- Over time loss of cartilage leads to loss of joint space
Risk factors for osteoarthritis (OA)
- Increasing age
- Female sex
- Abnormal joint e.g. congenital hip dysplasia
- External Joint stress
- Obesity
- Occupational stress on joint (pneumatic drills, athletes, etc.)
- Trauma
- Internal joint stress
- Crystal deposition (gout and pseudogout)
- Previous joint infection
Presentation of osteoarthritis (OA)
- Joint pain exacerbated by exercise and relieved by rest
- Joint stiffness after rest
- Reduced range of movement
- Joint swelling
- Signs of synovitis: warmth, effusion
- Tenderness around joint
- Crepitus
- Malalignment
- Osteophyte formation
- Heberden’s nodes: DIP joints
- Bouchard’s nodes: PIP joints
Diagnosis and investigation of osteoarthritis (OA)
- OA can be diagnosed without investigation in those over 45 with joint pain on exertion and an absence of stiffness
- Body weight and BMI
- Note this as a baseline – obesity is the simplest modifiable risk factor
- If in doubt regarding diagnosis:
- Bloods
- ESR and CRP normal (raised in inflammatory arthropathies)
- Rheumatoid factor
- Joint aspiration and microscopy (excludes septic arthritis and crystal arthropathies)
- Plain X-rays (normal until OA advanced, but will then show):
- Osteophytes
- Bone cysts
- Joint space narrowing
- Sub-articular sclerosis
- MRI
- More sensitive to early cartilage and subchondral bone changes than XR
- Arthroscopy
- Fissuring and early erosion of cartilage
Treatment of osteoarthritis (OA)
- Conservative
- Exercise: aids weight loss and improves muscle mass and strength around the joint, both of which can improve symptoms
- Adjust diet to lose weight
- Physiotherapy
- Heat/cold pads can help with pain
- Pharmaceutical
- Paracetamol (regularly)
- Topical NSAIDs
- Topical capsaicin
- Oral NSAIDs
- If NSAIDs used regularly add gastric protection
- Consider intra-articular steroids e.g. in carpometacarpal joint or knee OA
- Surgical
- Arthroscopy and debridement
- Joint replacement surgery often gives very good results, particularly in the hip and knee
Prognosis of OA
- Most people with OA do not become severely disabled
- Knee OA seems to have the worst prognosis in terms of deterioration over 10 years
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