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| Benefits of greater accuracy:
How it works? |
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| Transducers applied to leg |
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Twenty years of research on total knee replacements suggest that
mechanical alignment and soft tissue ligament balance are critical
factors in success and lifespan of the joints. Navigation provides
a powerful tool to improve the precision of mechanical alignment
and verify soft tissue balance during the operation.
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| System in use in OR |
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Prior to navigation, the surgeon would assess pre-operative X-Rays
and formulate a plan to correct deformities and align the knee. During
surgery, the plan would be executed using metal rods and mechanical
guides to determine placement of the knee. The mechanical systems
provide only crude methods to determine if the plan was properly executed
during surgery. Ligament balancing could only be verified by the “touch
of the surgeon. Amazingly, using these crude tools, experienced surgeons
can obtain good results lasting 15 years or better for more than 90%
of patients. |
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| Knee alignment diagram |
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In contrast to the metal rods, with navigation, the surgeon uses
the navigation computer to create a digital model of each individual
patient. The digital model includes alignment of the femur, tibia,
individual arthritic deformities of the joint and a dynamic map of
ligament balance during movement of the knee. Using navigation, the
surgeon plans the surgery using the digital model. Next the plan is
transferred to the patient using special wireless instruments to make
precise bone cuts according to the plan. The system allows the surgeon
to verify the actual bone cuts, and refine them as needed. |
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Computer workstation, display and position monitor
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Distal femoral cut |
Studies using the navigation system show that the expected alignment
is achieved more predictably when using the navigation system. In
our practice, we expect that this technology will help improve the
quality and success of traditional knee replacement, as well as increase
the number of patients that may benefit from smaller incision approaches. |
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