Orthopedics This Week - 2018 | July 17, 2018 | Page 13

ORTHOPEDICS THIS WEEK
VOLUME 14, ISSUE 23 | JULY 17, 2018
13
Trousdale v. Mullaji: Knee Navigation: Lost in Space
BY OTW STAFF
T
his week’s Orthopaedic Crossfire®
debate was part of the 33rd Annual
Current Concepts in Joint Replace-
ment® (CCJR®), Winter meeting,
which took place in Orlando. This
week’s topic is “Trousdale v. Mullaji:
Knee Navigation: Lost in Space.” For is
Robert T. Trousdale, M.D., Mayo Clin-
ic, Rochester, Minnesota. Opposing is
Arun Mullaji, F.R.C.S.(Ed), M.S., The
Arthritis Clinic, Mumbai, India. Mod-
erating is Thomas S. Thornhill, M.D.,
Harvard Medical School, Boston, Mas-
sachusetts.
Dr. Trousdale: I’m going to argue
against the role of routine use of navi-
gation in our simple, primary total knee
replacements. And I would argue that
it remains a somewhat cumbersome,
time-consuming, relatively expensive
tool with some, but very limited proven
clinical benefit.
Certainly, we all share a common goal
that we want our knee replacements to
be reliable, and I think we’ve got that. We
want them to be durable. I think we’ve
achieved that. We want it to be safe. I
think we’ve achieved that as well. We
want to alleviate pain. We’re pretty good
at that for the majority of our patients.
But I think the unknown is improving
function in our patients. And I think
that’s what we are striving for now and
talk about a lot at meetings like this.
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That might be okay if this was a brand
new technology, but we’re now well into
our second decade of computer-assist-
ed surgery and there is limited data that
supports using a computer with your
total knees – that you’re going to have
better range of motion, better function,
better durability, although there is some
new data that supports that, and better
WOMAC SF-36 scores.
In terms of Level 1 studies that have been
published, a meta-analysis (Bauwens, et
al., JBJS-Am 2007) looked at 11 random-
ized controlled trials and the conclusion
was “Navigated knee replacements pro-
vide few advantages over conventional
surgery and its clinical benefits are
unclear and remain to be defined.”
I think that’s still true today.
Arun is going to tell you, and I agree
completely with him, with manual,
routine techniques alone, we are not
very accurate or precise with our com-
ponent position. That’s inarguable. Another series, Level 1 study, random-
ized controlled trial, CAS versus stan-
dard total knee replacement (Harvie, et
al., JOA 2012). At 5 years, CAS had bet-
ter alignment and fewer outliers.
Today, computer-assisted surgery (CAS)
has limited proven clinical benefits. But no difference in Knee Society scores,
patient-reported outcomes, and patient
satisfaction in the CAS group versus
the conventional group. At 5 years the
computer appeared to be no different
than the conventional techniques with
these outcome measures.
What has been demonstrated with the
computer is that it’s a better tool to hit
a specific target than manual instru-
ments. Undeniable. But the problem is
we don’t know what the right target is
for individual patients. I think there are
factors other than alignment that may
be more important for durability than
the sagittal and axial alignment of the
total knee—soft tissue balance, patient
factors, etc.
CAS has increased cost for the surgery.
And there is an increased prevalence of
specific complications such as peripros-
thetic femur fractures from a computer
navigation pin site.
The fundamental premise of the com-
puter is if you use a computer, your
alignment is going to be better, and
that’s going to give better function
and survivorship of the total knee
replacement.
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