By Mark W. Pagnano, MD
Background
We previously addressed the issues surrounding computer navigation in total knee arthroplasty, and we came to the conclusion that, in 2008, computer navigation remained a cumbersome, time-consuming, and expensive tool with no proven clinical benefit with regard to function or durability of the total knee prosthesis1. It is not inappropriate to make the same type of statement in relation to computer navigated total hip arthroplasty in 2008.
Methods
In a recent meta-analysis of navigated total hip arthroplasty, the authors concluded that "navigation … improved acetabular cup alignment … It is unclear at present whether this improved surgical precision will translate to improved clinical outcomes. The cost issues surrounding computer navigation in total hip replacement have not been well explored …"2
Clinical Results
While it is clear that use of a navigation system can improve the precision of component placement in both total knee and total hip arthroplasty, there has been no correlation of that marginal improvement with better clinical results. While that might be acceptable if navigation were a brand-new technology, we are now entering the second decade of clinical use with navigation systems and we have still not found evidence of a clinical benefit. As of this writing, a decade later, we have a grand total of three randomized controlled trials that have been published on navigated total hip arthroplasty, and those three studies include a mere 250 patients in total2. The computer is clearly a good tool to capture information for research; that role continues to be important in 2008 and should be promoted3. Also demonstrated with use of the computer, however, are a number of things that are not as favorable, such as increased surgical time, increased cost of surgery, and a higher prevalence of specific complications2. The fundamental premise of computer-assisted surgery is that better component alignment will result in improved survivorship in the long term, but the scientific support for that contention remains surprisingly weak.
Conclusions
Three kinds of evidence can be advanced to prove an argument; in descending order of power, they are: objective data, social consensus, and personal credibility. In 2008, the objective data for computer navigation are lacking. The social consensus is also lacking, as few surgeons actually use navigation for total hip arthroplasty. This leaves personal opinion as the only basis for the use of navigation.
Clinical Relevance
Together, we all seek to improve the reliability, durability, and safety associated with total hip arthroplasty, but the evidence is not yet available to embrace navigation as a means to achieve those objectives.