Better Alignment with Robotic Assistance?

Better Alignment with Robotic Assistance?
Walter Eisner • Fri, Apr 16th, 2010

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Computer-assisted robotic total knee replacements result in "far better leg alignment, much less likelihood of complication infection, and a far lower early failure rate" than surgeries using conventional techniques.
That's the conclusion of a five-year study by Jan Koenig, M.D., Director of Orthopedic Surgery at the Mercy Medical Center in Rockville, Center, New York. Koenig presented the study at the recent AAOS meeting in New Orleans. His presentation, “The Evolution of Computer-Assisted Total Knee Replacement (CAS-TKR) Past, Present and Future,” was a featured part of Medacta Orthopedics Scientific presentations.
The typical failure rate for knee replacements is three to eight percent per year, according to the study. In addition, one half of early knee replacement failures, those occurring less than two years after surgery, are attributed to misalignment, instability and aseptic loosening. These typically require a revision total knee replacement.

No Early Failures, Revisions or Loosening

At Mercy Medical Center, there were no early failures and no revision operations secondary to misalignment, instability or aseptic loosening in the first 1,000 consecutive computer-assisted robotic total knee replacement patients over the first five years of the study.
Precise placement of the artificial joint so that the center of the patient’s hip and knee lines up within three degrees of the patient’s ankle, is the key factor in a successful total knee replacement, according to the Center's press release.
Using conventional techniques, the best surgeons achieve alignment within three degrees 50% to 80% of the time. At Mercy Medical Center, alignment within three degrees was achieved in all of the 1,000 computer-assisted robotic procedures performed between February, 2005 and January, 2010. Final post-surgical alignment averaged just under one degree (0.8).
The Center claims the longest consecutive experience with computer assisted robotic total knee replacement in the country. The procedures at Mercy were performed using the PiGalileo, developed and manufactured in Switzerland by PLUS Orthopedics. But this is also good news for robotic systems made by other manufacturers like MAKO Surgical Corp.

Not All Agree

The Center's findings are different from a 2007 scientific paper, “Alignment and orientation of the total knee components with and without navigation support,” noted on the AAOS Web site. In that study, the researchers found that “postoperative limb alignment was not significantly better in the computer-assisted group than in the conventional group.”
However the group acknowledged that, “utilization of the computer-assisted navigated TKA contributed to improve the surgical technique performing the conventional TKA,” leading to a reduction in the prevalence of outliers in the conventional group.
Fuente: Orthopedics News