ORLANDO, Fla. — Use of handheld navigation should be adopted by surgeons performing total knee replacement because it is easy to use and contributes little additional time to surgery, according to a presenter at the Current Concepts In Joint Replacement Winter Meeting, here.
The handheld navigation unit is applied
to the distal femur.
Images: Su EP
“I believe handheld navigation for total knee replacement is easy and fast. It is accurate, it is relatively cheap and it is like your smart phone. It is hard to imagine life now without it, and in my opinion, there is no reason not to use it,” Edwin P. Su, MD, of Hospital for Special Surgery in New York City, said during his presentation.
Su noted that although there is no evidence of the clinical benefit in using computer navigation for total knee replacement (TKR), some studies have shown that greater than 3° of varus alignment of the tibial component could pose a risk for early loosening. Critics of computer navigation also cite high cost as a reason to stay away from routine use of the technology. However, Su noted that the KneeAlign 2 System (OrthAlign; Aliso Viejo, Calif.) is an affordable handheld device that uses accelerometers and gyroscopes similar to the technology seen in smartphones.
“You can use it for both the tibial and femoral cuts,” Su said. “It does not disrupt your flow at all. You attach the first guide to your distal femur, it is going to help you make your distal femoral varus/valgus cut. You do not need an [intramedullary] IM rod, you just put it at the center of the knee, affix it to the bone, attach your sensors and you go through a quick registration process.”
The cutting guide is applied to make the tibial cut.
This side view shows the navigation unit and tibial cutting guide.
The accuracy of the device is comparable to larger computer navigation units and assists in making cuts within 2° of the desired alignment, according to the abstract. Su cited a 2013 study by Denis Nam, MD, and colleagues in which 96% of the handheld navigation unit tibial cuts were within 2° of the coronal plane alignment compared to 68% in the conventional cutting guide group; another study by Nam’s group found no difference in radiographic results between handheld navigation units and conventional imageless computer navigation units. – by Jeff Craven
Nam D. J Arthroplasty
. 2013;doi: 10.1016/j.arth.2012.04.023.
Nam D. J Arthroplasty
. 2014; doi: 10.1016/j.arth.2013.06.006.
Ritter MA. J Bone Joint Surg Am
. 2011;doi: 10.2106/JBJS.J.00772.
Su EP. Paper #114. Presented at: Current Concepts in Joint Replacement Winter Meeting; December 12-14, 2013; Orlando, Fla.
For more information:
Edwin P. Su, MD, can be reached at Hospital for Special Surgery, 535 E. 70th St., New York, NY 10021; email: firstname.lastname@example.org
Su is a consultant for Smith & Nephew.