AICKH symposium examines new uses for computer-assisted navigation

Using computer-assisted (CA) navigation in total knee arthroplasty (TKA) has become a hotly debated issue in the United States—effectively dividing the orthopaedic community into two “camps,” according to S. David Stulberg, MD, in his presentation of “Navigation TKA: State of the art and rationale” at the Advanced Imaging and Computer Assisted Surgery of the Knee and Hip (AICKH) symposium, held in March 2008.

“The first, larger ‘camp’ is composed of those who don’t believe orthopaedic surgeons need a computer to do a TKA,” he said. “The second group strongly supports its use because it has been shown to produce more accurate results.”

Good news, bad news
“Initially, surgeons hoped that CA navigation in TKA surgery would improve both their accuracy and their consistency. The limb would be more accurately aligned in the frontal and sagittal planes and, as a result, the implants would be more precisely positioned relative to these planes,” he explained.

Other anticipated benefits of CA navigation included reducing the number of “outliers” and the facilitating minimally invasive TKA surgical techniques.

Although several studies have shown a “slight improvement in limb and implant alignment accuracy and reproducibility, evidence that this improvement is associated with better clinical outcomes or prolonged implant durability is lacking,” Dr. Stulberg said.

At the same time, CA navigation has also been reported to increase surgical times, to be very expensive, and to have a long learning curve. The time it takes to learn this technology has decreased, however, according to Dr. Stulberg.

Reframing the discussion
As this debate continues, Dr. Stulberg proposed “reframing the discussion” to include new uses for this technology. “CA navigation has been largely used by experienced surgeons who, by their own acknowledgement, have become much better surgeons as a result of using this technology.”

Because using CA navigation improves skills, Dr. Stulberg would like to see it applied in the classroom.

“This technology could be an extremely powerful educational tool at all levels. We should be developing this as an efficient, cost-effective teaching tool—putting a computer education module at current teaching sites or integrating one into our training programs,” he said.

“The way we currently assess a student’s performance can be quite subjective,” he continued. “If a student makes a tibial cut, for example, one faculty member may judge the cut to be good while another may see it as sub-par.

“Though this technology would require reconfiguration for teaching purposes, it would measure the cut according to an objective standard. The feedback the student gets via the computer would allow him or her to make an immediate correction,” said Dr. Stulberg.

Dr. Stulberg also believes that CA navigation could be used as a tool for developing techniques or even instruments that are not computer-based but can help surgeons do a better job. It can also be used to validate those approaches.

“The value of navigation as an intra-operative measurement tool has refocused attention on this critical aspect of TKA surgery,” he said. “The valuable feedback that navigation provides is now being appreciated.

“Current investigations are focusing on the value of intra-operative measurements in predicting subsequent clinical outcomes,” he concluded.

Dr. Stulberg reports no conflicts of interest with the contents of this presentation.

Annie Hayashi is the senior science writer for AAOS Now. She can be reached at hayashi@aaos.org