OSTEOARTHRITIS

Epidemiology

• Most common arthropathy
•  Over 50% of people over the age of 65 years have radiological evidence of disease
• approximately 10% of men and 18% of women have symptomatic OA
• Joint pain and reduced mobility cause considerable impact on quality of life
• with no current cure for this condition, general practitioners are left with a range of management options aimed at
  • optimizing quality of life
  • self-management
  • preventing acute episodes
  • delaying complications
  • preventing progression of the condition

Pathogenesis

• Genetic predisposition
• Abnormal physical forces leading to altered joint function and damage. The primary event is deterioration of articular cartilage due to local biomechanical factors & release of proteolytic & collagenolytic enzymes (develops when cartilage catoblism > synthesis and loss of proteoglycans and water exposes underlying bone)
• Abnormal bone metabolism further damages joint – subchondral sclerosis, osteonecrosis & cyst formation, bone grows beyond joint margin (osteophytes (spurs))
• Synovitis is secondary to cartilage damage

Classification:

• Primary (idiopathic) – most common, aetiology unknown 
• Secondary
  • Post-traumatic/mechanical
  • Post-inflammatory
  • Heritable skeletal disorders (e.g. scoliosis)
  • Endocrine disorders (e.g. acromegaly, hyperparathyroidism, hypothyroidism)
  • Metabolic disorders (e.g. gout, haemochromatosis, Wilson’s disease)
  • Neuropathic (Charcot joints – atypical joint trauma due to loss of proprioceptive senses (diabetes, syphilis))
  • Avascular necrosis (fracture, steroids, alcohol, gout, sickle cell)
  • Other (e.g. congenital malformation)

Assessment

1. Effect on person’s function, quality of life, occupation, mood, relationships and leisure activities
2. History of presenting symptoms and pain assessment
3. Red flags: Signs and symptoms of infection, history of cancer, unexpected weight loss and fractures
4. Medication use, doses, frequency, effectiveness and side effects
5. Quality of sleep and fatigue
6. Psychological factor
7. Health beliefs, concerns, expectations and knowledge
8. Modifiable risk factors (eg obesity, physical activity)
9. Comorbidities

Clinical Features

• Age > 40
• Signs and symptoms localised to affected joints (not a systemic disease)
• Pain is often insidious and gradually progresses over years
• Flare ups and remissions may occur

Symptoms	Signs
Joint pain with motion, relieved with rest Short duration of stiffness after immobility(less than 30 mins morning stiffness) Joint instability/buckling Loss of function Joint locking due to “joint mouse” (loose piece of bone in joint)	Joint line tenderness, stress painBony enlargements at affected joints Malalignment/deformity (angulation) Limited ROM Periarticular muscle atrophy Crepitus on passive ROM

Joint involvement 

• Can be any joint, especially knee, hip, hand, spine (less common are shoulder, elbow, wrist, ankle)
• Hand
  • DIP (Heberden’s nodes = osteophytes → enlargement of joints) 
  • PIP (Bouchard’s nodes)
  • CMC (usually thumb)
  • MCP is often spared
• Hip
  • Dull or sharp pain in trochanter, groin, anterior thigh or knee
  • Internal rotation and abduction are lost first
• Knee
  • Narrowing of one compartment of the knee is the rule (medial > lateral) – standing x-rays must be done
• Foot – most common in 1^st MTP
• Lumbar spine
  • Very common (esp. L4-5, L5-S1)
  • Degeneration of fibrocartilaginous IV discs possibly with disc herniation or listhesis (slippage) and facet joint degeneration
  • Reactive bone growth can complication neurological impingement
  • Sciatic
  • Neurologic claudication (spinal stenosis)
• Cervical spine
  • Common, especially lower areas → neck pain

Laboratory results:

• Lab results are normal – normal FBC, ESR (negative RF, ANA)
• Radiology (4 classic findings)
  • Narrowing of joint space 
  • Geode formation (intraosseous cysts)
  • Subchondral sclerosis (“seagull sign” – whiter than normal area on each side of the bone)
  • Osteophytes

Management:

• No treatment alters the natural history

• Long term Mx
  • Education
  • Land-base exercise
  • Weight loss – aim for loss ≥5% body weight if overweight or obese 
• Optional adjunctive management – Trial for short term and cease if ineffective
  • Aquatic-based exercise
  • Thermal therapy (ie heat pad)
  • Massage, manipulation and mobilisation
  • Assistive walking devices
  • Cognitive behavioural therapy (CBT) for pain coping or psychological symptoms
  • Transcutaneous electrical nerve stimulation (TENS)
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Advanced pharmacological attempts – Trial for short term if symptom still persistent
  • Intra-articular corticosteroid if a flare of symptoms or rapid pain relief is required
  • Duloxetine (off-label use

AIM

1. optimizing quality of life
   • nutritional education
   • low energy diet
   • Exercise
     • land-based exercise
     • Targeted muscle strengthening and general aerobic exercises
     • water-based exercises suggested for those with functional and mobility limitations 
     • exercise provides benefit even if weight loss is not achieved
     • has a role in both symptom management and as a preventive strategy
2. self-management
   • Patients with OA should be provided with information about their condition and advised about appropriate support groups.
   • social, environmental and psychological interventions may be appropriate depending on the patient’s individual needs
   • refer to Arthritis Australia
3. managing and preventing acute episodes
   • pharmacological
     • Regular paracetamol (maximum 4 g/day) (1st line)
     • NSAIDS (2nd line)
     • COX-2 inhibitors (Celecoxib)  (high risk group for GI bleed: >65, GI bleed/PUD, CV disease)
     • Intra-articular corticosteroids
       • (short-term effect)
     • Topical capsaicin can be used as an alternative or as an adjunct to standard drug treatment.
       • Reviews of RCTs found that topical capsaicin is superior to placebo for knee osteoarthritis and reduces pain by 50%
   • Nonpharmacological
     • physiotherapy
     • OT (aids, splints, cane)
4. delaying complications/preventing progression of the condition
   • weight reduction reduces disability in patients with OA
   • Regular follow up of patients with established OA
   • ongoing patient education
   • review of multidisciplinary care
   • medication review
   • behavioural modification

total hip arthroplasty and total knee arthroplasty