Osteoarthritis

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OA Basics & Pathophysiology - Joint Misery Mechanics

  • Osteoarthritis (OA): Most common arthritis; chronic, degenerative disorder characterized by cartilage loss and structural joint changes.
  • Epidemiology: Leading cause of disability worldwide. Prevalence ↑ with age (often >40 yrs), obesity; significant burden in India.
  • Key Pathophysiology:
    • Cartilage: Enzymatic degradation (MMPs) → loss of proteoglycans, Type II collagen damage → fibrillation, erosion.
    • Subchondral bone: Sclerosis (thickening), cyst formation.
    • Osteophytes: Bony outgrowths at joint margins, attempt at repair.
    • Synovium: Mild, secondary inflammation (synovitis) may occur. Healthy vs. Osteoarthritic Joint Anatomy and Stressors

⭐ Osteoarthritis is primarily considered a non-inflammatory arthritis, though secondary inflammatory components can be present.

Risk Factors & Clinical Features - Suspects & Symptoms

  • Risk Factors:
    • Non-Modifiable: ↑Age, Female gender, Genetics.
    • Modifiable: Obesity (BMI > 30), Joint trauma/overuse, Occupation.
  • Clinical Presentation:
    • Insidious onset pain: worse with activity, relieved by rest.
    • Morning stiffness: duration < 30 minutes.
    • Crepitus, restricted range of motion.
    • Bony enlargements (osteophytes).
  • Commonly Affected Joints:
    • Hands: DIP (Heberden's nodes), PIP (Bouchard's nodes), 1st CMC joint. 📌 Mnemonic: 'Bouchard's (PIP) Before Heberden's (DIP)' alphabetically & proximally.
    • Knees, Hips, Spine (cervical, lumbar, facet joints). Heberden's and Bouchard's nodes

⭐ The presence of Heberden's nodes (DIP) and Bouchard's nodes (PIP) is highly characteristic of hand osteoarthritis.

Diagnosis & Imaging - Spotting the Wear

  • Clinical diagnosis (American College of Rheumatology - ACR criteria supportive).
  • X-ray: 📌 LOSS (Loss of joint space, Osteophytes, Subchondral sclerosis, Subchondral cysts). Kellgren-Lawrence (KL) Grade 0-4 (quantifies radiographic severity). Knee Osteoarthritis X-ray with Key Features
  • Labs: Erythrocyte Sedimentation Rate (ESR)/C-reactive Protein (CRP) normal. Synovial fluid: White Blood Cell (WBC) < 2000/μL (non-inflammatory).

⭐ Inflammatory markers (ESR, CRP) are typically normal in Osteoarthritis, distinguishing it from inflammatory arthropathies.

Osteoarthritis (OA) vs. Rheumatoid Arthritis (RA) Highlights

FeatureOARA
Stiffness (AM)< 30 min> 1 hr
JointsAsymmetric; DIP, PIP, 1st CMC, Knee, HipSymmetric; MCP, PIP, Wrist, MTP
SystemicNoYes (fatigue, malaise)
LabsNormal ESR/CRP↑ ESR/CRP, RF/ACPA often +ve
X-rayLOSS findingsErosions, juxta-articular osteopenia

Management Strategies - Easing the Ache

Primary Goals: Pain relief, ↑functional improvement, slowing disease progression.

Non-Pharmacological:

  • Patient education
  • Weight loss (esp. for knee/hip OA)
  • Exercise (aerobic, strengthening, range of motion)
  • Physiotherapy & Occupational therapy
  • Assistive devices (canes, braces)

Pharmacological:

  • First-line: Acetaminophen (up to 3-4 g/day)
  • NSAIDs (oral/topical): Lowest effective dose, shortest duration. Consider GI/CV risk; COX-2 inhibitors an option.
  • Intra-articular corticosteroids: For acute flares.
  • Intra-articular Hyaluronic acid: Viscosupplementation (controversial efficacy).
  • Duloxetine: For chronic pain, esp. with neuropathic component.
  • Avoid long-term opioids.

Surgical (Advanced OA):

  • Arthroscopy (limited role)
  • Osteotomy
  • Arthroplasty (joint replacement for hip/knee)

⭐ Weight loss of even 5-10% of body weight can significantly reduce pain and improve function in overweight individuals with knee OA.

High‑Yield Points - ⚡ Biggest Takeaways

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Practice Questions: Osteoarthritis

Test your understanding with these related questions

Which of the following is difference between Rheumatoid arthritis and osteoarthritis -

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Flashcards: Osteoarthritis

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Rheumatoid arthritis can cause _____ arthritis

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Rheumatoid arthritis can cause _____ arthritis

erosive (erosive/non-erosive)

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