CHAPTER SYNOPSIS:

Angular deformities of the leg, whether due to previous trauma (most often) or congenital, pose a major additional challenge when planning and performing a total ankle arthroplasty. Failure to take these deformities in account, and to correct them as needed, will negatively affect the longevity of the replacement.

IMPORTANT POINTS:

• 1
  

  Both the level and the actual degree of angulation are important.

  
  
• 2
  

  The more proximal the location of the angulation, the greater is the displacement of the ankle and foot from their functional position directly under the weight-bearing line of the leg.

  
  
• 3
  

  Varus angulation or medial displacement from the weight-bearing line is more disabling and dysfunctional than valgus angulation.

  
  
• 4
  

  An extension deformity creates more difficulties than a flexion deformity in that it places the foot anterior to the weight-bearing line and disturbs gait by making it difficult to “get over” the forefoot without lifting the leg.

  
  
• 5
  

  An extension deformity opens the front of the ankle; the talus becomes prone to gradual anterior extrusion and this, in turn, causes progressive painful arthrosis.