Total Knee Replacement

Total knee replacements are performed in the classic standard procedure but also with modern techniques using computer assisted and minimal invasive techniques. At the Orthopaedic Clinic Gersthof approximately 450 total knee replacements are performed yearly.

The operative technique using navigation, computer assisted surgery and force controlled ligament balancing are illustrated in the following figures. When using the computer technology a navigation unit, a minirobot (computer assisted saw guide) and a force controlled ligament tensioner are required.

  Navigation unit - With this unit a three dimensional reconstruction of the axes of the leg and the appropriate size of the prosthesis are determined.

  Minirobot Computer Assisted Saw Guide)
This device brings the cutting jig in the position for the required femur cuts. It is driven by the computer based calculation for finding the accurate position.

  Force Controlled Ligament Tensioner
With this ligament spreader force controlled tensioning of the ligaments in flexion and extension is possible.

  Computer unit - The computer is the central regulation unit. The display informs the surgeon about the different three dimensional axes, the position of the prosthesis, the achieved alignment and the stability of the ligaments in flexion and extension.

  Balancing in Extension
After cutting the tibia the ligament tensioner is placed between tibia and femur. The tension for the medial and lateral collateral ligament and the overall alignment of the leg is determined. In case of a varus or valgus alignment ligament releases are necessary.

  Balancing in Flexion
After this step ligament balancing is performed in flexion.

  Planning of the femur prosthesis in terms of position and size
To optimize the flexion gap the prosthesis is determined in size and anterior/posterior position.

  Performing the dorsal femur cut
After achieving a stable flexion gap and an ideal size and position of the prosthesis the dorsal femur cut is executed.

  Transfer of the width of the flexion gap to the extension gap
After determination of a distinct width of the flexion gap it is necessary to find the same gap size for the extension gap. The synchronisation of the flexion and extension gap is the last important step when performing a new artificial knee joint. After this step the implantation of the prosthesis is accomplished.