Advances in robotics are among the biggest changes to joint replacement surgery in the last decade. Robotic-assisted hip and knee replacement make implant positioning more accurate, protect soft tissues, speed recovery, and can improve patient outcomes and satisfaction. There are many robots available in the joint replacement marketplace, and we will highlight three of the most commonly used, MAKO, ROSA and Velys.
What are the big advantages of using robotics for hip & knee replacement?
- Improved implant positioning and alignment.
Multiple systematic reviews and clinical studies show robotic-assisted total knee and hip arthroplasty can reduce alignment outliers and improve the precision of bone cuts and component placement compared with conventional instruments. This improved accuracy translates into more predictable joint mechanics and fewer revisions. PMC 1 - More consistent soft-tissue balancing and less need for releases.
Robotic systems allow anatomic placement planning and soft tissue assessments that can reduce the soft-tissue releases needed to achieve stability. This can translate into less pain and faster functional recovery in the early postoperative period. PMC 2 - Personalized planning.
Robotics lets the surgeon plan implant size/positioning using pre-op imaging or intra-op mapping and then execute that plan with sub-millimeter guidance allowing close matching to a patient’s anatomy. MAKO 1 - Potential for faster early recovery and shorter length of stay.
Several studies report earlier functional recovery and shorter hospital stays after robotic-assisted procedures. Long-term superiority for function research is ongoing. MAKO 2 - Press fit implants can often be more reliably used due to the increased precision that comes with robotic cuts which removes the cement interface from knee replacements which may reduce future revisions related to loosening.
MAKO
Overview: MAKO is a CT-based, robotic-arm–assisted system widely used for partial and total knee arthroplasty and for total hip and knee arthroplasty. It combines a preoperative CT-based 3D plan with an instrumented robotic arm that enforces boundaries during bone preparation.
Key advantages:
- High accuracy and reproducibility of component positioning. Reduced alignment outliers and increased reproducibility across surgeons. PMC+1
- Haptic control during bone resection limits the boundaries of surgery protecting soft tissues. Stryker
- Strong evidence base and broad adoption. MAKO has been widely studied and is commonly referenced in literature comparing robotic systems. This gives clinicians and patients a large body of performance and safety data to review.
Considerations: CT-based planning adds pre-op imaging steps. As with all image based robotics there can be increased costs.
VELYS
Overview: VELYS is an imageless robotic-assisted solution that helps surgeons with intraoperative soft tissue balancing and alignment.
Key advantages:
- Imageless workflow uses intraoperative anatomy mapping, which can save on the cost and logistics of CT imaging and simplify scheduling. This is attractive for ambulatory surgery centers aiming to lower pre-op and cost burden.
- Early real-world data showing favorable 90-day utilization outcomes. A recent database study found lower early postoperative revisit rates and knee-related readmissions in the first 90 days compared to traditional instrumentation. It was not compared to other robotic systems. Velys 1
Considerations: As a newer imageless approach, long-term comparative outcome data are still accumulating. Because it does not use pre-op CT, some surgeons favor other CT-based planning systems for complex anatomy.
ROSA
Overview: ROSA is a robotic platform used for knee arthroplasty. It supports both image-based and imageless workflows.
Key advantages:
- Versatile workflow options support different surgical philosophies giving surgeons flexibility based on patient anatomy and surgeon preference.
- Excellent component placement accuracy in several comparative studies. Recent work has shown achieves very close to planned target angles for femoral and tibial components.
- Reported efficiency gains in some datasets. In a manufacturer summary ROSA procedures may have slightly shorter operative times compared with MAKO in select series. Zimmer 1
Considerations: As with other systems, long-term superiority in clinical outcomes vs. conventional methods is still being studied.
Head-to-head highlights — MAKO vs VELYS vs ROSA
- Accuracy: All three systems are associated with improved implant positioning and reduced alignment outliers vs conventional techniques in multiple studies. Direct head-to-head accuracy differences are modest and depend on study design and endpoints.
- Workflow & pre-op imaging: MAKO typically uses CT-based planning (higher pre-op imaging burden), ROSA supports either image-based or imageless options, and VELYS emphasizes an imageless intra-op mapping workflow.
- Operative time & OR efficiency: All robotic platforms increase OR time compared to traditional techniques however this time difference it not clinically relevant.
- Clinical outcomes & recovery: Robotic systems generally show improved early recovery metrics (pain, function, reduced LOS) in numerous cohorts. That said, medium- and long-term functional outcomes are still being investigated. All robotic systems allow for more functional or kinematic alignment and less soft tissue release which may result in improved long term outcomes.
- Cost & value: Upfront robot purchase and disposables vary by system and hospital contracts.
An exciting time for patients!
Patients should expect that robotic-assisted joint replacement will continue to improve implant placement, early function and hospital stays. If you’re choosing a surgeon or hospital, ask which system they use and how experienced the team is with that robot. Evidence suggests surgeon and institutional experience matters a lot for efficiency and outcomes. PMC 3
Bottom line
Robotic assistance in hip and knee arthroplasty reliably improves the precision of implant positioning and provides tools for better intraoperative decision-making and soft-tissue management. Among the three systems:
- MAKO stands out for CT-based planning and well-documented precision and adoption.
- VELYS emphasizes imageless workflows, compact integration, and early evidence for favorable short-term utilization.
- ROSA offers workflow flexibility (image-based or imageless).
No single robot is universally “best”. The right choice depends on surgeon preference, patient anatomy and goals, institutional resources, and the type of replacement. The common denominator: robotic assistance is a powerful tool that can increase the precision and predictability of joint replacement. Visit catherinecahillmd.com for more specific information regarding my approach to robotic hip and knee replacement using MAKO robotics from Stryker.