Glossary

In brief

• The same word may describe different implementations across manufacturers.
• “Robotic” does not mean autonomous: clinical decisions remain with the surgeon.
• A technical term is not, by itself, a claim of better clinical outcome.

Terms

Robotic arm

A mechanical actuator that positions a guide or instrument, constrains its movement, or performs a programmed action under surgeon direction and control. Functions differ: MAKO applies haptic constraints, ROSA Knee positions a cutting guide, VELYS constrains a saw plane, and CUVIS performs automated resection under surgeon control. CORI uses a handheld burr rather than a robotic arm.

Haptic boundary

A software-defined spatial boundary that helps keep an instrument within the planned region. Feedback may be felt as resistance or implemented by restricting cutting. It reduces unintended movement beyond a defined region but does not remove the need for surgeon control.

Registration

Matching the patient’s anatomy in the operating room to a digital model or coordinate system by identifying landmarks and/or mapping a bone surface. Registration error can affect subsequent navigation measurements, so prescribed system and surgeon checks matter.

Navigation

Tracking anatomy and instruments relative to a coordinate system and displaying those data to the surgeon. Navigation may be integrated into a robotic platform or operate independently; it does not necessarily control an instrument.

CT-based

A workflow that uses preoperative computed tomography to construct a three-dimensional model and plan. CT-based identifies the data source; it does not guarantee accuracy or clinical outcome.

Imageless

A workflow without a preoperative CT model in which landmarks and surfaces are registered intraoperatively. It does not mean that no images, cameras, or digital models are involved. CT-free should be interpreted for the specific platform.

Balancing

Assessment of joint-space relationships and soft-tissue tension across positions of the limb. The measurements may inform plan adjustments, but a system does not select one universally “correct” balance for every patient.

Alignment

The spatial relationship of bones and components to selected axes and landmarks. The target depends on the alignment strategy; “alignment” without a named strategy and measured angle is incomplete.

Mechanical alignment

A TKA strategy oriented to the mechanical axes of the femur and tibia, traditionally aiming for a neutral overall mechanical axis. Any acceptable range should be stated by the study or plan.

Kinematic alignment

A TKA strategy intended to reproduce an individual’s pre-arthritic joint lines and axes of motion. Implementation and boundaries vary, and the term does not automatically imply a better functional result.

Functional alignment

Component planning that considers individual anatomy and intraoperative soft-tissue balance within defined constraints. Definitions may differ among publications and software products.

PROM / PROMs

A patient-reported outcome measure is a standardized questionnaire through which a patient reports pain, function, quality of life, or another health domain. A PROM is not radiographic accuracy; interpretation depends on instrument, baseline, follow-up, and the minimal clinically important difference.

Implant survivorship

The proportion of implants that have not reached a predefined event—usually revision—by a stated time. It requires an endpoint definition, revision cause, time horizon, and analytic method. Survivorship does not mean absence of pain or complications.

Using the glossary

The technology, system, and evidence pages explain each term in a platform- or study-specific context. If a manufacturer uses a common term differently, the official documentation for the named version takes precedence.

This material is for information and education only and is not a substitute for medical consultation. Diagnostic and treatment decisions must be made individually with a qualified healthcare professional.