Rheumatology and Exercise: Osteoarthritis and Rheumatoid Arthritis

Rheumatology and Exercise: Osteoarthritis and Rheumatoid Arthritis

Learning Outcomes

  • Understand prevalence of OA (Osteoarthritis) and RA (Rheumatoid Arthritis) in New Zealand.
  • Learn about the causes and risk factors for OA and RA.
  • Understand the clinical course of each condition.
  • Explore medical and surgical management options.
  • Discuss implications for physiotherapy.

Prevalence of Arthritis in New Zealand

  • General Statistics:
    • Approx. 7000 new cases of arthritis annually.
    • 1 in 10 New Zealanders affected by arthritis.
    • Higher incidence of OA in European populations compared to Māori.

Osteoarthritis (OA)

  • Overview:

    • Most common musculoskeletal disorder affecting ~500 million people worldwide.
    • Affects all synovial joints, with the knee being the most prevalent.
    • In NZ, approximately 10% of adults have OA, expected to rise to 13% by 2040.
    • Roughly 8% of Māori adults are affected.
    • Māori males have a higher incidence and are more likely to undergo Total Knee Arthroplasty (TKA) at a younger age.

  • Risk Factors:

    • Traumatic joint injury is a significant modifiable risk factor for post-traumatic OA.
    • Knee OA: Primarily affects the medial tibiofemoral compartment and can also include the patellofemoral joint.
    • Post-traumatic OA accounts for at least 12% of cases.

  • Illness vs Disease:

    • OA manifests as both an illness (individual experience) and as a disease (structural changes in joints).
    • The experience of pain drives healthcare seeking behaviours, sick leave, and early retirement.

Causes and Risk Factors for OA

  • Causes:

    • Previous trauma can lead to secondary OA.

  • Common Risk Factors:

    • Obesity, older age, and being female significantly increase the risk.
    • Comorbidities contribute to a reduction in Quality of Life (QoL).

  • Modifiable Risk Factors:

    • Local muscle weakness, traumatic joint injury, overweight/obesity, high-impact sports, and altered joint mechanics.

  • Non-modifiable Risk Factors:

    • Age, sex, race, genetic factors, and structural changes that cannot be modified.

Burden of Disease

  • Knee OA constitutes approximately 85% of the global OA burden.
  • OA and diabetes significantly contribute to increases in years lived with disability.
  • Direct healthcare costs in NZ estimated at ~ $993 million.

OA as an Inflammatory Condition

  • Emerging evidence suggests OA has an inflammatory component, shifting from a purely degenerative condition.
  • Synovial inflammation can exacerbate cartilage degradation and pain.
  • IL-1 and TNF-α are key inflammatory cytokines implicated in OA.

Pathophysiology of OA

  • Degradation of proteins within cartilage, driven by matrix metalloproteinases (MMPs) and aggrecanases (ADAMTS).
  • Inflammation leads to structural changes in articular surfaces.

Diagnosis of Knee OA

  • Criteria include symptoms such as knee pain, age >50 years, morning stiffness,<30 minutes, and radiographic findings.
  • Kellgren-Lawrence grading scale for assessing severity:
    • Grade 1: Normal appearance.
    • Grade 2: Doubtful; minor osteophytes present.
    • Grade 3: Definite osteophyte, moderate joint space.
      - Grade 4: Severe; significantly reduced joint space and subchondral sclerosis.

Treatment Recommendations for OA

  • Non-pharmacologic Interventions:
    • Exercise and education prioritized over medication.
    • Emphasis on weight loss and active lifestyle.
  • Exercise Types:
    • Land-based exercise, mind-body exercises, and diet management have shown effectiveness comparable to analgesics.

Rheumatoid Arthritis (RA)

  • Overview:

    • Chronic autoimmune disease leading to inflammatory polyarthritis.
    • Affects joints in hands, wrists, knees, and can have systemic implications.
    • Symptoms include joint pain, morning stiffness >30 minutes, fatigue and systemic symptoms affecting other organ systems.

  • Prevalence:

    • Affects ~1% globally; more common in women.
    • Typically presents in ages 30-60 years; can manifest slowly or more explosively.

Causes and Pathophysiology of RA

  • Causes: Interaction of genetic susceptibility and environmental triggers, such as smoking and infections.
  • Pathophysiology:
    • Autoimmune processes leading to joint destruction characterized by the presence of anti-citrullinated protein antibodies (ACPAs).
    • Progression can lead to inflammatory cascades, extensive synovial infiltration, and joint erosion.

Extra-articular Manifestations and Complications

  • RA can lead to issues in multiple systems including pulmonary, cardiovascular, and neurological conditions.
  • Can cause joint deformities andcrippling complications if not effectively managed.

Clinical Course and Management of RA

  • Varies widely; some may experience spontaneous remission, while others may have persistent disease with progressive disability.
  • Medical Management: Primarily includes Disease Modifying Anti-Rheumatic Drugs (DMARDs).

Physiotherapy Considerations

  • Assessment:
    • Focus on joint function, strength, pain levels, and overall physical capacity.
  • Exercise Recommendations:
    • Frequency at least 2 days/week for strength, with 5 days for aerobic activity.
    • Employ gradual increase of exercise intensity while monitoring responses to activity.

Juvenile Idiopathic Arthritis

  • Onset before age 16; requires careful management similar to adult forms.
  • Often impacts growth and development; family support is essential.

Comparison: RA vs OA Pain

  • RA typically results in symmetrical pain with significant morning stiffness and joint inflammation.
  • OA can occur unilaterally with less stiffness duration in the morning and tends to affect older patients.