Knee arthrodesis

Question 1

What is the optimial position for knee arthrodesis?

Answer 1

• 5-8^o valgus
• 0-10^o ER
• 0-15^o flexion

Question 2

What are the indications of knee arthrodesis?

Answer 2

• Painful ankylosis after infection/trauma
• neuropathic arthropathy
• tumour resection
• salvage for failed TKR
• loss of extensor mechanism

Question 3

What are the contraindications?

Answer 3

• Absolute
  
  • active infection
• Relative
  
  • bilateral knee arthrodesis
  • contralateral leg amputation
  • significant bone loss
  • ispilateral hip or ankle DJD

Question 4

What is the surgical technique for arthrodesis?

Answer 4

• Intramedullary rod fixation
  
  • long antegrade device or a two part device connected at the knee
  • patella can be left alone or incorporated into arthrodesis
• External fixation
  
  • must allow compression of arthrodesis site
  • done with unilateral external fixation, iliazrov, taylor spatial frame
• Plate fixation
  
  • can be done in combination with IM nailing

Question 5

What are the complications of knee arthrodesis?

Answer 5

• Non union
• infection
• lower back pain
• ipislateral hip degenerative changes
• contralateral knee degenerative change
• fracture
  
  • supracondylar fx or proximal tibial metaphysis fx
  • from increased stress in these regions after arthrodesis