Primary Knee Symposium: Biomechanical Considerations in the Knee

Navigation – Kenneth Greene, MD

Dr. Green's presentation was not intended to show the audience how to use the navigation system, rather it was to discuss what navigation can offer. He uses the system in select cases as a feedback tool in the OR. With it, he asserts that the mechanical axis is pretty constant and he believes it reduces the sources of malalignment errors, which is the goal.

We are not far enough out enough with navigation to have a lot of survivorship data. Dr. Greene believes that input = output (i.e. garbage in = garbage out). If you do not know how to do registration, you are going to be inaccurate. He outlined some of the advantages of navigation, suggesting that one advantage is in assessing varus-valgus. However, if you are not in neutral (after making your cuts at 0 degrees), you may still have a ligamentous imbalance. PSlide A

Dr. Greene's case for using navigation included the challenge achieving femoral alignment, PSlide B the potential downside of intramedullary instrumentation, PSlide C and the potential risks introduced as a result of mini-incision TKA. PSlide D

His presentation included a series of slides showing the screens throughout each step of the procedure on the Stryker Navigation System.

In conclusion, Dr. Greene believes that navigation, although it takes more time, makes him a better surgeon. PSlide E