In terms of femoral rotation, the goal is to restore a rectangular or symmetric flexion gap. As a guide, I use the transepicondylar axis, the posterior condylar axis or the trans-sulcus axis as landmarks. Ligament balancing in varus and valgus is also similar in both techniques. In my early experience with a rotating platform surgical technique, I often release and sacrifice the ligament. I see little need to substitute for the PCL, but surgeons should use their preferred indications for this technique.
Substituted components are less vulnerable to spin-out.
When substituting for the PCL, the posterior slope should be reduced depending on the design of the system. If the design allows hyperextension before impingement, more posterior slope is permitted than if the design does not allow hyperextension between the components. The amount of posterior slope will most likely vary with the design and the technique of cruciate preservation or sacrifice vs. substitution. With cruciate preservation, a posterior slope will likely enhance the potential flexion of the knee. There are differences in the amount of tibial resection.