Total Hip Replacement/Arthroplasty

Airway: GA LMA, ETT appropriate if lateral. Can be performed under spinal. Consider CSE if bilateral. Access: 14-16G IVC Pain: ++. Epidura, lumbar plexus block, or PCA may be beneficial but are not required Position: Supine (anterior/anterolateral approach), lateral (lateral/posterior approach) Time: 1-3 hours Blood loss: 1-2 units may be lost. G+H required. Special: Cementing

Involves replacement of the hip joint with prosthesis. May be:

• Unipolar
  Femoral head replaced.
• Bipolar
  Femoral head and acetabular cup replaced.
• Revision
  ↑ operating time and blood loss.
  • May be difficult to extract cemented prostheses
• Girdlestone
  Removal of femoral head or prostheses without replacement. Typically for infection or palliation.
• Bilateral
  Sequential replacement of each hip joint. ↑ operative duration limits utility of single-shot spinal.

Considerations

• Indication
  
  • OA
    Most common indication, often associated with limited exercise tolerance which may mask underlying CVS/respiratory disease.
  • Rheumatoid arthritis
    Associated pulmonary disease, anaemia, potential difficult airway.
• A
  • ETT reasonable if GA in lateral position
• C
  • Relative hypotension ↓ blood loss
  • Cementing may precipitate profound hypotension/cardiac arrest
    Particularly in right heart failure.
• D
  • Neuraxial anaesthesia:
    • ↓ PONV
    • ↓ DVT/PE risk
    • ↓ blood loss and bleeding into operative field
    • May ↓ POCD risk
  • Nerve damage
• E
  • Neuromuscular blockade for placement of prosthesis and testing of passive ROM
• H
  • DVT is common post-operatively
    80% in femoral vein.
  • Major blood loss

Preparation

• Premedication
  • 1g Paracetamol PO
  • 600mg Gabapentin PO
  • 200mg Celecoxib PO

Induction

Techniques include:

• Spinal:
  • Block to T10
  • Consider:
    • 2.5-5ml 0.5% heavy bupivacaine
    • 10-25ug fentanyl or 100-200 mcg spinal morphine
• Epidural
  Smoother haemodynamic induction and postoperative analgesia.
  • Remove D2 post-operatively if used
• GA

Intraoperative

Key intraoperative stage is cementing:

• Methylmethacrylate is pressurised into medullary bone to assist in sealing of prosthesis
• This may lead to:
  • Pulmonary embolus Fat and cement.
    • Pretreat
  • Hypotension
    Direct vasodilation or pulmonary hypertension secondary to embolus.
    • Pre-treat with fluid and vasopressor to optimise right heart function
  • Hypoxia
    Secondary to embolus-related shunt.

Surgical Stages

• Incision
• Dislocation of the femoral head
• Removal of native femoral head
• Reaming of acetabulum for cup replacement
• Placing of femoral head
  Cemented or cementless.
• Hip relocation
• Closure

Postoperative

High perioperative morbidity, typically due to comorbidities/frailty in the elderly:

• 50% respiratory failure
• 50% arrhythmia risk
• 50% MI risk
• 50% UTI
• 50% DVT/PE
• Up to 20% infection risk

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References