Computer-Assisted Knee Replacement Surgery: Myths vs. Facts


For years, the thought of robotics in surgery has provided hope for the future of countless medical procedures.  Robotics can be used to guide instruments, provide more precision in cutting, require less space with which to operate, and, as a result, result in less blood loss during surgery.  The hope was that robotic surgery would help decrease recovery time because less tissue would need to be affected by the surgery.  However, according to a new study published in Journal of Bone and Joint Surgery, computer-navigated total knee replacement surgery appears to provide few of the benefits once anticipated.

There are, of course, several factors that should be noted.  First, this study took place in South Korea; it is not known is similar results would be found in the American health system.  Second, in order for a patient's knee replacement to be evaluated 10 to 12 years after the procedure, the computer-assisted surgery would have been done at a time when the technology is not as advanced as it is today.

Myth #1: Computer-assisted surgery improves positioning, sizing and alignment of knee replacement joints.

One of the major selling points for using computers in surgery is the belief that computers can do a better job of fitting the replacement joint into place.  Unfortunately, the study found no difference in knee function or alignment when surgery was completed with computer navigation over conventional methods.

Myth #2: Computer-assisted surgery results in greater durability of joints.

In theory, this would seem to be true.  However, 10.8 years after the operation--the mean duration at which the joint was assessed--98.8 percent of the computer-navigated surgeries had survived as compared to 99.2 percent of the conventional procedures.

Myth #3: Computer-assisted surgery results in better knee function, motion and activity.

In this study, patients were evaluated for function, motion and activity before the surgery, then at three months after surgery, one year after surgery, then annually thereafter.  Evaluated using the Knee Society rating system and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), no statistically significant differences were found between the computer-assisted surgeries and the conventional surgeries.

Myth #4: Computer-assisted surgery results in a patient feeling less pain post-surgery.

One of the hopes of computer-assisted surgery is to help lessen the amount of pain a person may experience after surgery.  There was no significant difference on the Knee Society rating nor the WOMAC rating for computer-assisted procedures and done through the conventional procedure.

Myth #5: Computer-assisted surgery requires a much smaller incision.

One of the primary selling points of computer-assisted surgery is the belief that it would reduce the size of the incision needed to perform the surgery.  However, the study found no evidence that there was a significant difference in incision size between the two processes. _[QUIZ: Hip Replacement Surgery] Myth #6: Computer-assisted surgery results in less blood loss during surgery.

According to a report from International Orthopaedics, patients lost an average of 663 ml of blood in a total knee replacement surgery.  Doctors hoped that by making a smaller incision and shortening the length of the operation, less blood could be lost during surgery.  But the volume of blood lost was not significantly different between the computer-assisted surgeries and the conventional procedures.

Myth #7: Computer-assisted surgery results in a shorter duration of surgery.

According to International Orthopaedics, the average surgical time for a conventional knee replacement is roughly 117.9 minutes.  Instead of lowering that time, the Journal of Bone and Joint Surgery study found that the mean operative time was, in fact, significantly longer in computer-assisted total knee replacements than with conventional surgery.

This is also not to say that computer-assisted surgeries (or the use of robotics) should be avoided.  Many doctors are using computers to assist with precision as a means to augment more traditional surgical methods.  This study should, though, serve as a reminder that technology may not always improve medical procedures as much as we may expect.