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Michael E. Seem, MD

Understanding the Technology · No. 1

What “robotic surgery” actually means.

The honest version, what the robot does, what it doesn’t, and why your surgeon still makes every decision.

The one-minute version

If you only read one thing, read this.

  • The robot does not operate; it measures, guides, and verifies while your surgeon performs every step.
  • Its real value is objective information: balance and alignment measured instead of estimated.
  • Dr. Seem plans each knee to the patient, functional alignment, rather than one standard target.
  • Hips get computer navigation on every case; select cases add mixed-reality guidance.
  • Choose the surgeon, not the machine.

Dr. Seem’s perspective

I adopted robotics because I wanted better information in the operating room, not because it looks good in an advertisement. The robot has never made a decision in my OR, and it never will. What it does is let me measure what I used to estimate, and personalize what used to be standardized.

The two-sentence version

A surgical robot does not perform your operation, decide where your implant goes, or work on its own. It is a very precise measuring-and-guiding tool that helps your surgeon execute a plan: a plan the surgeon makes, checks, and adjusts throughout your operation.

“The robot gives me better information. It doesn’t give me better judgment; that’s still my job.”

Why the name is misleading

“Robotic surgery” suggests a machine operating while the surgeon supervises. The reality is closer to a GPS with lane-keeping assistance: you still drive the car. The system Dr. Seem uses, ROSA®, holds guides in precisely the planned position and continuously reports measurements, while the surgeon performs every step of the operation.

What ROSA actually does during a knee replacement

  1. Builds a working model of your knee. Using X-rays taken before surgery and landmarks the surgeon maps in the operating room, the system creates a picture of your specific anatomy, your bone shape, your alignment, your ligament behavior.
  2. Measures how your knee balances. As the surgeon moves your knee through its range, the system measures gaps and tension that would otherwise be estimated by feel.
  3. Positions cutting guides to the plan. When the surgeon settles on the plan, the robotic arm holds guides at the planned angles, typically within a degree, so what was planned is what happens.
  4. Verifies the result before the implant goes in. The surgeon checks the real measurements against the plan and can adjust before anything is final.

What it does not do

  • It does not choose your alignment, your implant, or your plan.
  • It does not cut on its own; the surgeon performs the resections.
  • It does not respond to the unexpected; surgical judgment does that.
  • It does not replace experience. A tool is only as good as the plan it executes.

Why Dr. Seem uses it anyway

Because better information supports better decisions. Every knee balances differently, and the difference between a knee that feels “fine” and one that feels natural is often a matter of small choices, a degree here, a millimeter there. Objective measurement helps personalize those choices to your knee instead of applying one standard target to every patient. It also supports a philosophy Dr. Seem practices called functional alignment, adapting the plan to the way your knee is built and moves, rather than forcing every knee to one universal angle, while staying within well-studied safe boundaries.

Hips: navigation and augmented reality

For hip replacement, Dr. Seem uses computer navigation on every case, with ROSA hip software providing real-time measurements of implant position during surgery. In select cases he also uses HipInsight™, a mixed-reality system that projects a three-dimensional view of the plan into the surgeon's field of view. Same principle: more information, surgeon in control.

Fair questions to ask

  • “Do you use the robot on every case, or only some?” (And why?)
  • “What happens if the robot is unavailable: can you do my operation without it?” A surgeon should be fully capable either way; the technology assists, it doesn't carry.
  • “Does the robot change my incision, my recovery, or my risks?”
The bottom line
Choose the surgeon, not the machine. The right question isn't “is it robotic?”; it's “does this surgeon plan around me, measure what matters, and stay in control of every step?”

What happens next

Ready to talk through your options with Dr. Seem?