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• somelimcs difficult (o identify both epicondyles, especially the medial (Hie (92).

  When ihe femoral component has not migrated, preoperative ("f will 'mernsurc-lhc aivgle-b-e4ween ihe transverse axis of the component and the epicondylar line. This procedure helps to rotate the new femoral component appropriately (92).

  c-Distal femur position:

  The key to this step is restoring the distance from the joint line, distally and posteriorly. The epicondyles are a useful landmark to determine the joint line (93).

  The joint line on average is 25 mm from the lateral epicondyle and 30 mm from the medial epicondyle. Because the tibial cut. is established at 90 degrees to the tibial shaft, the joint line of the prosthetic knee, of average size, is 30 mm from both epicondyles (93).

  The distance from the epicondyles to the posterior joint line is similar to that of the distal joint line and is helpful in confirming the correct femoral component size (93).

  II-Rebuild the flexion space:

  a-Create a flat tibial surface:

  «.

  The key in selecting the correct size tibial component is to choose a size that will cover the entire proximal tibia without overhanging. The tibial surface should be perpendicular to the tibial shaft. This should be accomplished with minima! bone resection; when necessary, appropriate wedge or block augmentation should be added (93).

  b-Balance the flexion space:

  This step requires choosing the correct tibial polyethylene articulation. The provisional femoral component needs to be in place. The size of the polyethylene chosen should fill the flexion space (93).
  
  
  
  

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