Shoulder Arthroplasty

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Indications & Contraindications - Who Needs New Shoulder?

  • Indications (PASTA-O):
    • Pain: Severe, unresponsive to conservative Rx
    • Arthritis: Osteoarthritis (OA), Rheumatoid Arthritis (RA), Post-traumatic
    • Stiffness: Significant functional limitation
    • Trauma: Complex fractures (e.g., 4-part proximal humerus #), fracture-dislocations
    • Avascular Necrosis (AVN) of humeral head
    • Osteonecrosis
    • Rotator cuff tear arthropathy (Reverse TSA)
  • Contraindications:
    • Active infection
    • Neuropathic joint (Charcot)
    • Paralysis with inability to stabilize prosthesis
    • Inadequate bone stock
    • Non-compliance

Shoulder Arthroplasty Planning and Result

⭐ Glenohumeral OA is the most common indication for anatomic total shoulder arthroplasty (TSA).

Types of Arthroplasty - Hemi, Total, or Reverse?

  • Hemiarthroplasty (HA): Replaces humeral head only; glenoid cartilage must be intact.
    • Indications: Humeral head AVN (cuff intact), complex proximal humerus fractures (elderly), select cuff tear arthropathy (CTA) in low-demand elderly.
  • Total Shoulder Arthroplasty (TSA): Replaces both humeral head & glenoid; requires functional rotator cuff (esp. subscapularis).
    • Indications: Osteoarthritis (OA), Rheumatoid Arthritis (RA) with intact cuff.
  • Reverse Total Shoulder Arthroplasty (rTSA): Glenoid component is convex (glenosphere), humeral component is concave; deltoid function becomes primary elevator.
    • Indications: CTA, massive irreparable cuff tears with pseudoparalysis, complex fractures (elderly), revision of failed TSA/HA.

⭐ In rTSA, the centre of rotation is medialized & inferiorized, improving deltoid lever arm & function. Shoulder Arthroplasty Implant Categories

Surgical Pearls & Anatomy - Navigating the Joint

  • Key Anatomy:
    • Glenoid: Pear-shaped; version (retroversion <10-15°).
    • Humeral Head: Retroversion 20-30°; inclination 130-140°.
    • Rotator Cuff: Subscapularis (repair crucial).
    • Axillary Nerve: ~5-7 cm distal to acromion. 📌 "Danger zone".
  • Approaches:
    • Deltopectoral: Workhorse; spares deltoid.
    • Anterosuperior.
    • Superior (deltoid-splitting).
  • Pearls:
    • Glenoid exposure: Crucial for placement.
    • Humeral sizing/version: For kinematics.
    • Soft tissue balance: For stability/ROM.
    • Subscapularis repair: Vital.

    ⭐ Axillary nerve is most at risk during deltoid-splitting approaches and inferior capsulectomy. Axillary nerve course in normal vs RCTA shoulder

Implants & Biomechanics - Making It Work

  • Materials: Co-Cr/Titanium alloys; Ultra-High Molecular Weight Polyethylene (UHMWPE) bearings.
  • Anatomic TSA (aTSA):
    • Replicates native anatomy: metal humeral head, polyethylene glenoid.
    • Requires functional rotator cuff for stability and movement.
    • Maintains anatomic Center of Rotation (COR).
  • Reverse TSA (rTSA):
    • Indicated for rotator cuff arthropathy.
    • Design: metal glenosphere (glenoid side), polyethylene cup (humeral side).
    • Biomechanics: Medializes & inferiorizes COR.
    • Enhances deltoid function: ↑ lever arm, ↑ tension. Deltoid becomes primary elevator.

    ⭐ rTSA converts glenohumeral shear forces to compressive forces, improving stability in cuff-deficient shoulders. Reverse Shoulder Arthroplasty Biomechanics

Complications & Management - Uh Oh, Fix It!

  • Infection:
    • Early (<6 wks): DAIR (Debridement, Antibiotics, Implant Retention).
    • Late (>6 wks): Two-stage revision arthroplasty.
  • Instability/Dislocation:
    • Anterior most common.
    • Tx: Closed reduction, sling, physiotherapy. Revision for recurrent instability.
  • Periprosthetic Fracture:
    • Intra-op or post-op.
    • Tx: ORIF; component revision if implant is loose.
  • Glenoid Loosening (Anatomic TSA):
    • Most common long-term issue.
    • Tx: Revision to new glenoid or Reverse Shoulder Arthroplasty (RSA).

    ⭐ Aseptic glenoid loosening is the leading indication for revision surgery in anatomic Total Shoulder Arthroplasty.

  • Rotator Cuff Failure (Post-TSA):
    • Leads to pain, ↓ function.
    • Tx: Physiotherapy; consider revision to RSA.
  • Nerve Injury:
    • Axillary nerve (deltoid weakness) most vulnerable.
    • Tx: Observation, EMG; surgical exploration rare.
  • Stiffness (Arthrofibrosis):
    • Painful restricted motion.
    • Tx: Aggressive physiotherapy, Manipulation Under Anesthesia (MUA).

High‑Yield Points - ⚡ Biggest Takeaways

  • Reverse Shoulder Arthroplasty (RSA) is the choice for cuff tear arthropathy, massive irreparable cuff tears, and complex proximal humerus fractures in the elderly.
  • Total Shoulder Arthroplasty (TSA) is preferred for osteoarthritis with an intact rotator cuff and adequate glenoid bone stock.
  • Hemiarthroplasty is considered for acute proximal humerus fractures in younger patients or when glenoid cartilage is preserved.
  • Key complications include infection, instability, glenoid loosening (especially in TSA), and periprosthetic fracture.
  • Scapular notching is a well-recognized radiographic finding and potential complication specific to RSA.
  • Deltoid dysfunction is a major contraindication for RSA as it relies on a functional deltoid.
  • Glenoid version and bone loss are critical pre-operative considerations influencing implant choice and surgical technique.

Practice Questions: Shoulder Arthroplasty

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Complications of sling procedures (TVT) for USI are all except:

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Flashcards: Shoulder Arthroplasty

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Late management of AVN of femur involves decreasing pressure within the head of femur by drilling holes also known as _____

TAP TO REVEAL ANSWER

Late management of AVN of femur involves decreasing pressure within the head of femur by drilling holes also known as _____

core decompression

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