Osteoarthritis of Shoulder

OA Shoulder: Intro & Epi - Creaky Joint Culprits

• Definition: Cartilage degeneration in Glenohumeral (GH) or Acromioclavicular (AC) joints.
• Types:
  • Primary: Idiopathic, age-related wear.
  • Secondary: Due to trauma, Rotator Cuff (RC) tear, instability, overuse, genetics, obesity.
• Prevalence: Common, incidence ↑ with age. Affects women more than men, especially post-menopause.
• Key Risk Factors: Age >50 yrs, female, obesity, prior trauma, repetitive overuse, RC tears, chronic instability, genetics.

⭐ Glenohumeral OA is less common than knee/hip OA but significantly disabling.

OA Shoulder: Patho & Types - Joint's Slow Grind

• Pathophysiology: Joint's slow grind.
  • Cartilage: Initial loss of proteoglycans & water, then collagen network disruption, and chondrocyte dysfunction/death.
  • Subchondral Bone: Sclerosis (thickening), marginal osteophytes (bone spurs), and subchondral cyst formation.
  • Synovitis: Mild, chronic inflammation of the synovial lining.
• Classification (GH OA): Samilson-Prieto (humeral/glenoid osteophytes).
  • Grade 1: Osteophytes <3 mm.
  • Grade 2: Osteophytes 3-7 mm.
  • Grade 3: Osteophytes >7 mm; may show joint space narrowing, sclerosis.

⭐ > Posterior glenoid wear is a common finding in advanced glenohumeral OA.

OA Shoulder: Clinical & Dx - Spotting the Stiffness

• Symptoms:
  • Pain: Insidious onset, activity-related, night pain, progressive.
  • Stiffness: Morning or after inactivity, progressive.
  • Crepitus: Grinding/popping sensation with movement.
  • ↓Range of Motion (ROM): Global, particularly external rotation & abduction.
  • Functional limitation: Difficulty with ADLs (dressing, combing hair), overhead activities.
• Signs:
  • Tenderness: Over glenohumeral joint line (anterior/posterior).
  • Muscle atrophy: Supraspinatus, infraspinatus, deltoid in advanced stages.
  • Deformity: Flattening of shoulder contour (late).
• Diagnosis:
  • History & Physical Exam:
    • Apley's scratch test: Assesses functional internal/external rotation.
    • Hawkins-Kennedy, Neer's: For associated rotator cuff pathology.
  • Imaging:
    • X-ray (Standard views: AP, axillary lateral, Grashey):
      • 📌 LOSS: Loss of joint space (JSN - often superior/posterior), Osteophytes (humeral head/glenoid), Subchondral sclerosis, Subchondral cysts.
      • Glenoid erosion patterns (e.g., Walch B2: biconcave glenoid, posterior wear).
    • MRI/CT indications: Evaluate rotator cuff, bone stock for arthroplasty, diagnostic uncertainty.

⭐ Axillary view is crucial for assessing glenohumeral joint space narrowing, posterior glenoid erosion, and osteophytes.

OA Shoulder: Management - Easing the Ache

Conservative:

• Patient education, activity modification (e.g. avoiding overhead work).
• Physiotherapy: ROM, strengthening - esp. rotator cuff & deltoid.
• NSAIDs for pain/inflammation.
• Intra-articular injections:
  • Corticosteroids: Short-term relief (limit <3-4/year).
  • Hyaluronic acid: Variable evidence for benefit.
  • PRP: Emerging evidence, research ongoing.

Surgical Intervention: (For failed conservative Rx, persistent pain, functional limitation)

Surgical Options:

• Arthroscopic debridement: Limited role, mainly for mechanical symptoms, temporary relief.
• Hemiarthroplasty: For intact glenoid, functional cuff, younger patients.
• Total Shoulder Arthroplasty (TSA): Gold standard for intact rotator cuff, good glenoid stock.
• Reverse TSA (rTSA): For cuff tear arthropathy, severe glenoid bone loss, or failed TSA. 📌 Deltoid driven.

⭐ rTSA is preferred in OA with irreparable rotator cuff tears or severe glenoid bone loss, as it biomechanically compensates for cuff deficiency, relying on the deltoid.

High‑Yield Points - ⚡ Biggest Takeaways

• Glenohumeral joint is the most common site for shoulder OA.
• Symptoms: activity-related pain, night pain, progressive stiffness.
• X-ray: joint space narrowing, osteophytes (inferior humeral head - "Goat's beard"), subchondral sclerosis.
• Primary OA is less common than secondary OA (e.g., post-traumatic, cuff tear arthropathy).
• Management: conservative (NSAIDs, physiotherapy) then surgical (arthroplasty).
• Total Shoulder Arthroplasty (TSA) for severe OA with intact rotator cuff.
• Reverse TSA if rotator cuff deficient.