Osteoarthritis
About
- Very common seen with increasing age
- Affects the synovial joints with loss of cartilage
- Commoner in whites and familial tendency
- Strong heritability - polygenic
Joints affected
- Hand, Knee
- Hips, Spinal apophyseal joints
Aetiology
- Not just "wear and tear"
- Destruction and loss of articular hyaline cartilage
- There is sclerosis and cyst formation due to adjacent bone remodeling
- Attempts at repair lead to osteophyte formation
Secondary OA may result from other causes
- Trauma with previous fractures through the joint
- Metabolic diseases, Haemochromatosis - check ferritin and Iron and transferrin saturation
- Chondrocalcinosis, Acromegaly - Measure GH following OGTT
- Ochronosis - see below
- Systemic diseases : Haemophiliacs, Sickle cell disease, Joint damage, Rheumatoid arthritis, Gout, Seronegative arthropathies
- Septic arthritis, Paget's disease, Avascular necrosis, Thiemann's disease
- Osteochondrosis affecting the hands, Obesity, Previous fractures and trauma
- Perthes disease, Congenital dislocation of the hip
Clinical
- Activities which worsen with activity and decrease on rest
- Morning stiffness < 30 minutes
- Age > 50
- Crepitus on joint movement
- Bony tenderness on examination
- Bony enlargement on examination
- No palpable warmth on examination
- Hands : DIP and 1st MCP
- Foot 1st MTP
- Spine, hips and knees
- Heberden's nodes at DIP
- Bouchard's nodes at the IPJ
- Knee - varus and valgus deformities +/- knee effusion
- Baker's cyst behind knee
Investigations
- ESR < 40 mm/hr
- RF titre < 1:40
- Radiology : Joint narrowing, sclerosis, osteophytes, localised osteoporosis, cyst formation
- Arthroscopy may show cartilage destruction
Differentials
- Age < 45 consider inflammatory arthritis, severe trauma, metabolic disease
- Marked early morning stiffness > 1 hour - inflammatory arthritis
- Unusual joints eg MCPs - Metabolic disease eg haemochromatosis
- Multiple regional pains 'tender spots' - fibromyalgia
- Joint locking or giving way - meniscal or ligamentous injury
- Fever or systemic upset - consider joint sepsis
- Warm and erythema - sepsis or crystals
- Pain mainly at night - malignancy, osteonecrosis
Management
- Rest and analgesia but careful exercise to maintain muscle bulk
- Cardiovascular exercise, quadriceps strengthening
- Weight loss to reduce body mass index
- Heat therapy is useful, physiotherapy and OT
- Correct use of walking stick can reduce hip loading by 1/5th
- Paracetamol is first line agent but NSAIDs and weak Opiates may be needed
- Glucosamine sulphate may be added
- Topical NSAIDs or Capsaicin can help knee and had OA
- Intra articular steroids can give approximately 4 to 6 weeks of pain relief. Sepsis is a very rare complication.
- Surgery - joint replacement effective for Hip and Knee
page revision: 1, last edited: 09 Jan 2010 00:14