Extra-articular Deformity

Causes of Deformity

 

Metabolic Bone Disease

Paget's

Fracture Malunion

Previous Osteotomy

 

Options

 

1.  Intra-articular correction

2.  Simultaneous osteotomy and TKR

3.  Staged correction and TKR

 

1.  Intra-articular correction 

 

Indications

 

Femur

- draw line of mechanical axis of femur

- line perpendicular to this / proposed distal cut

- this line must pass below insertion of collaterals

- sagittal and coronal planes

 

Max 20˚ coronal plane

Max 25˚ sagittal plane

 

Previous Unicondylar Fracture 1Previous Unicondylar Fracture 2Previous Unicondylar Fracture 3

 

Tibia 

- line drawn medullary canal of distal segment

- must pass between condyles

- maximum 30˚ varus

 

TKR Preop Tibial Deformity

 

2.  Osteotomy and TKR

 

Advantage

- bone preserving

- less bone resection to achieve correction

- augments not required

 

Disadvantage

- bigger procedure

- risk of nonunion

- must use stems to bypass

 

3.  Stage osteotomy then TKR

 

A.  Femoral Osteotomy

 

TKR Stage Osteotomy Preop 1TKR Staged Osteotomy Preop 2TKR Staged Osteotomy Post op correction

 

B.  HTO

 

Indications

- severe varus deformity

- would need > 1 cm of medial augments

 

Technique

- medial opening wedge osteotomy

- preserves bone