Robotic-assisted knee replacement combines digital surgical planning, anatomical mapping, tracking and instrument guidance to help surgeons perform knee arthroplasty. The technology connects a patient’s anatomy with a surgical plan and supports controlled bone preparation during the procedure.
For medical technology companies, innovation extends beyond the robot itself. Improvements in planning software, anatomical measurement, surgical instruments and data integration can influence how these systems operate and differentiate themselves.
Stryker’s Mako, Zimmer Biomet’s ROSA Knee and Smith+Nephew’s CORI illustrate three approaches to robotic-assisted surgery. Understanding their differences helps explain where the technology is evolving and what medtech innovators should consider when developing and protecting new solutions.
How Does Robotic Knee Replacement Work?
Robotic-assisted systems support surgeons through four interconnected stages:
- Anatomical mapping: Medical imaging or measurements collected during surgery help establish a digital representation of the patient’s knee.
- Surgical planning: Software supports decisions about implant positioning, alignment and bone preparation.
- Instrument guidance: Tracking systems connect the digital plan with the patient’s physical anatomy. Depending on the platform, guidance is delivered through a robotic arm or handheld instrument.
- Intraoperative assessment: Measurements of alignment and joint gaps help surgeons assess the knee and make decisions during surgery.
These systems assist the surgeon rather than independently performing the entire operation. Their value depends on how effectively planning, tracking and instrument guidance work together.
Three Approaches to Robotic Knee Replacement
Mako: CT-Based Planning and Robotic Guidance
Stryker’s Mako SmartRobotics uses preoperative computed tomography (CT) to create a three-dimensional model of the patient’s anatomy. Surgeons use this model to plan implant positioning and bone preparation.
During surgery, tracking and a robotic arm connect the plan with instrument guidance. Haptic technology helps constrain instrument movement around the planned surgical region.
In July 2026, Stryker announced the US commercial launch of Mako RPS, expanding its portfolio into handheld robotics for total knee replacement. The system combines intraoperative planning with a robotically enabled saw featuring active adjustment technology designed to respond to the surgeon’s hand movements and help maintain alignment with the surgical plan.
Why it matters: Mako illustrates how a surgical technology platform can expand beyond its original configuration. Innovators can examine opportunities in planning, instrument control and the integration of hardware with software.
ROSA Knee: Personalised Planning and Anatomical Measurement
Zimmer Biomet’s ROSA Knee combines robotic assistance with anatomical landmarking, tracking and surgical planning. Its OptimiZe software suite supports implant positioning according to the surgeon’s planning preferences.
Its features include OptimiZe Landmarking, designed to reduce variability in landmark identification, and OptimiZe Tracking, which allows cutting without pinning the cut guide to the bone. Its kinematic alignment functionality generates a plan based on bony landmarks, with the aim of restoring the knee towards its pre-arthritic position.
Zimmer Biomet’s wider ZBEdge Analytics platform connects intraoperative information with mobility and outcome insights, helping surgeons examine surgical decisions alongside recovery data.
Why it matters: ROSA demonstrates that innovation can extend beyond robotic positioning into measurement, personalised planning and data-supported assessment. These functions may create opportunities for medtech companies developing complementary technologies.
CORI: Image-Agnostic Mapping and Handheld Robotics
Smith+Nephew’s CORI uses image-agnostic smart mapping to create a three-dimensional model of the joint during surgery, without requiring preoperative CT or MRI scans for this mapping workflow.
The system combines anatomical registration, real-time planning and a surgeon-operated handpiece for guided bone preparation. It also supports intraoperative gap assessment, helping surgeons evaluate alignment and balancing.
Smith+Nephew reports that its CORI technology includes improvements in tracking refresh rate, resection speed and cutting volume compared with specified earlier technology and software configurations. These are manufacturer-reported comparisons, not independent head-to-head results against Mako or ROSA.
In June 2026, Smith+Nephew announced the first clinical cases using its next-generation CORI XT platform across knee and shoulder arthroplasty.
Why it matters: CORI illustrates how image-agnostic mapping and handheld instruments offer an alternative to workflows built around preoperative imaging and robotic arms. It also demonstrates how a platform can expand across surgical applications.
Mako vs ROSA vs CORI: Understanding the Differences
| What to compare | Mako | ROSA Knee | CORI |
| How it maps anatomy | Uses preoperative CT to create a 3D anatomical model. | Uses intraoperative anatomical landmarking and measurements. | Builds a 3D model through image-agnostic mapping during surgery. |
| How it guides surgery | Uses robotic-arm guidance and haptic constraints; Mako RPS adds a handheld option. | Combines robotic assistance, tracking and surgical planning. | Uses a surgeon-controlled handheld system with guidance and precision milling. |
| Planning approach | Plans implant positioning and bone resection using the CT-based model. | Supports personalised implant positioning and different alignment strategies. | Supports real-time planning and intraoperative gap assessment. |
| Practical distinction | Connects preoperative imaging with robotic guidance during bone preparation. | Emphasises landmarking, planning preferences and alignment assessment. | Emphasises intraoperative mapping and handheld surgical assistance. |
| Potential innovation areas | Planning workflows, instrument control and integration between hardware and software. | Anatomical measurement, personalised planning and surgical data integration. | Image-agnostic mapping, handheld instruments and workflow design. |
These distinctions describe technological approaches, not clinical superiority. Outcomes depend on the procedure, implant system, surgeon, workflow and measures being evaluated.
What Does Clinical Evidence Tell Us?
A 2025 systematic review and meta-analysis examined 21 randomised controlled trials involving 2,692 patients undergoing total knee arthroplasty.
Compared with conventional surgery, robotic-assisted procedures were associated with:
- A 67% lower relative risk of mechanical-alignment outliers.
- An average reduction of 0.93 degrees in deviation from the neutral mechanical axis.
- Approximately 20 minutes longer operative time.
- No statistically significant differences in WOMAC or Oxford Knee Scores at the assessed follow-up points.
The findings suggest that robotic assistance can improve alignment accuracy, but this does not automatically translate into better short- or medium-term patient-reported outcomes.
The review compared robotic-assisted surgery with conventional surgery; it did not establish a winner among Mako, ROSA and CORI. Longer-term outcomes and cost-effectiveness also remain important considerations.
For innovators, the distinction matters: technical performance is one part of a product’s value. Workflow efficiency, usability and meaningful clinical benefits are also relevant when evaluating new developments.
Where Do Patent Opportunities Emerge?
Robotic knee replacement brings together several technology areas. Companies do not necessarily need to develop an entirely new robotic system to innovate. Improvements to existing components, software or the interaction between different functions may also offer opportunities.
| Technology area | What it does | What innovators should consider |
| Anatomical mapping and tracking | Connects physical anatomy with a digital model during surgery. | Review existing approaches and identify what is genuinely new in a proposed mapping or tracking solution. |
| Surgical planning software | Supports implant positioning, alignment and bone preparation decisions. | Determine whether the contribution lies in a specific planning method, software function or workflow. |
| Robotic guidance and instruments | Helps translate the surgical plan into controlled instrument movement or bone preparation. | Consider whether the innovation lies in the instrument, control mechanism or interaction between the surgeon and the system. |
| Intraoperative measurement | Provides information about alignment, joint gaps and movement. | Examine how a new measurement or assessment approach differs from existing solutions. |
| Alternative robotic configurations | Delivers assistance through different instrument and hardware arrangements. | Assess the potential contribution of the design, instrument interface or surgical workflow. |
| Surgical data integration | Connects procedural information with planning, mobility or outcome data. | Identify the specific technical contribution rather than assuming that collecting or displaying data alone establishes a protectable invention. |
These are potential areas for investigation, not findings from a completed patent landscape or conclusions about the patentability of specific inventions.
What Should Medtech Innovators Know?
Start with the existing landscape. Reviewing relevant technologies and patent publications early can help companies understand established approaches, identify potential areas of differentiation and inform development priorities.
Define the invention clearly. The contribution may be a new instrument, a measurement approach, a planning workflow or an improvement in how existing components interact. A broad product concept is not a substitute for identifying the specific technical contribution.
Consider IP during development. Early IP assessment can help inform decisions about which innovations merit further evaluation for patent protection and how protection may support the product’s commercial direction.
Distinguish patentability from freedom to operate. An invention may warrant investigation for patent protection without establishing that a product can be commercialised without infringing existing rights. These assessments answer different questions.
Plan for product evolution. New instruments, software capabilities and surgical applications can extend an established platform. An IP strategy should account for the technology’s potential development rather than focusing only on its initial configuration.
These are general considerations, not invention-specific patentability or freedom-to-operate advice.
The Opportunity for Medtech Innovation
Mako, ROSA Knee and CORI demonstrate that robotic knee replacement is advancing through different combinations of imaging, anatomical mapping, planning, tracking and instrument guidance.
For medtech companies, the opportunity lies in identifying unmet technical needs, developing meaningful improvements and understanding how those improvements differ from existing solutions.
Patent strategy can support this process by helping innovators assess the existing landscape, identify potentially protectable contributions and consider freedom to operate before major commercial commitments.
The objective is not simply to build another robotic system. It is to understand where a meaningful improvement is possible and develop an IP strategy that supports the technology from development through commercialisation.
Sources
- https://www.stryker.com/us/en/about/news/2026/stryker-expands-mako-robotics-portfolio.html
- https://www.stryker.com/us/en/joint-replacement/systems/Mako_SmartRobotics_Overview.html
- https://www.zimmerbiomet.eu/en/products/rosa-knee-with-optimize
- https://www.smith-nephew.com/en/health-care-professionals/products/orthopaedics/cori
- https://www.smith-nephew.com/en/news/2026/06/08/first-clinical-cases-with-the-next-generation-cori-xt
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11918693/
- https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2025.1523631/full
