OR Manager - November 2019 - 25

Technology
Robotic-arm assisted TKA: A growing and promising technology
otal knee arthroplasty (TKA) is a
highly effective treatment for endstage
degenerative joint disease
and has helped patients regain functional
mobility with reduced pain and
improved quality of life. Every year, almost
700,000 primary TKA procedures
are performed in the US.1 This number
is expected to grow to 3.48 million procedures
by 2030-an increase of more
than 600%.2
T
Robotic technology, which has been
used in orthopedic surgery for more
than two decades, is popular because
of its potential to simplify procedures,
reduce instrumentation, and enhance
accuracy and reproducibility of component
placement. The goals of this
technology include improving patient
outcomes and reducing costs over the
episode of care (EOC).3
Currently available robotic technology
used in TKA can be classified according
to cutting type (direct versus indirect) and
cutting control (boundary control, haptic,
or autonomous). Direct cutting robotic
systems are designed to cut the bone to
the final desired shape. In contrast, indirect
robotic systems machine features
in the bone to allow placement of cutting
jigs or hold cutting jigs in place.4
Robotic
technology can also be
classified in terms of cutting control.
In boundary control, the robotic-arm is
controlled and propelled by the surgeon.
The robotic-arm is free to move within
the set boundary, but it is deactivated
if it travels beyond the predetermined
boundary. In haptic control, human interaction
is required to move the robotic-arm,
but the robotic-arm's movement
is designed to be constrained
within a haptic border. Autonomous systems,
on the other hand, move without
a human hand controlling them.4
Robotic technology in the OR
Learning curve
Fleischman et al defined learning curve
with robotic-assisted TKA (RATKA) as
the number of cases needed to achieve
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time neutral to the surgical team's operative
time when performing manual
TKA. To achieve this, they estimated
the need to perform 10 to 15 RATKA
cases, regardless of experience level
of the surgeon. Although longer surgical
time has frequently been cited as
a disadvantage of robotic technology,
data showed that time neutral could be
achieved after a few cases.5
Kevin Barga,
MS, RN,
CCRP
Kayani et al assessed
surgical team anxiety
levels by having a team
composed of the surgeon,
anesthesiologist,
scrub personnel, and
circulating RN complete
the Spielberger StateTrait
Anxiety Inventory
(STAI) questionnaire.
They reported an increase in stress
level during the initial learning phase,
but STAI scores improved and went
back to baseline levels after seven
cases as the team became more proficient
with the standard RATKA workflow,
which includes setting up trays and instruments,
positioning of the roboticarm
in the OR, and preparing the pins,
checkpoints, and arrays for bone registration.6
Ergonomically
challenging tasks-
such as patient handling, soft tissue
retraction, transferring equipment and
instrument sets, and static motion-
are common in the OR.7 Using motion
sensors to monitor shoulder and lower
back movement and posture in a cadaveric
lab setting, Scholl et al found
that RATKA reduced the risk of neck
injury and increased satisfaction for the
surgeon.8 A surgical assistant was also
found to have reduced ergonomic risk
because RATKA eliminated the need
to participate in instrument placement
and reduced participation in soft tissue
retraction.8,20
In another study, two surgeons wore
biometric-enabled shirts that collected
data on energy expenditure as they performed
35 manual and 29 RATKA procedures.
For both surgeons, RATKA cases
Mako total knee robotic-arm.
Photo courtesy of Stryker.
Used with permission.
took longer and increased the surgeons'
total energy expenditure. Interestingly,
the RATKA cases required one less surgical
assistant, reducing the total staff
required for the procedure.9
Surgical outcomes
Accuracy in component positioning and
limb alignment can influence outcomes
and implant durability. Data from 105
cases performed using haptic-guided
RATKA were prospectively collected at
the Hospital for Special Surgery in New
York. The researchers found high reliability
and accuracy of coronal tibial,
coronal femoral, and tibial sagittal alignment
when comparing the executed
intraoperative plan at 1 year postoperatively
via biplanar hip-to-ankle radiographs.10
CT
imaging is used to create a patient-specific
3D model of the patient's
unique knee anatomy preoperatively.
Marchand et al reported that 97% of
femoral
implants and 99% of
tibial
baseplates were correctly predicted
within one implant size in 335 cases
using CT scans and 3D preplanning
software.11 Researchers concluded that
better implant size prediction has the
potential to improve OR efficiency.
Knowing the implant sizes that will
be used intraoperatively can help hosContinued
on page 26
OR Manager | November 2019
25
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OR Manager - November 2019

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