What is involved in robotic-assisted shoulder arthroplasty? How do we find out if it's worth it?

A recently published article Robotic Assisted Reverse Total Shoulder Arthroplasty: Narrative Review and Surgical Technique of Humeral and Glenoid Preparation summarized the evolution of advanced execution modalities and describes the surgical technique and workflow of the Zimmer Robotic Surgical Assistant (ROSA) Shoulder System for a robotic assisted reverse total shoulder arthroplasty (RSA). 

Two of the authors are early adopters of this technology: Zimmer Biomet Announces Successful Completion of World’s First Robotic-Assisted Shoulder Replacement Surgery with ROSA Shoulder System and UBMD Orthopaedics & Sports Medicine Becomes 3rd Site in the World to Perform a Robotic Shoulder Arthroplasty. As the authors describe:

The Robotic Surgical Assistant system consists of two units: one corresponds to the robotic arm and the other to the optical unit, which includes an infrared camera mounted on a separate arm.

This setup enables communication with the optical markers implanted in the patient’s humerus and coracoid. Operating in a semi-active mode, the robot assists in both humeral and glenoid preparation through three modes: automatic, collaborative, and static. In automatic mode, the robot positions the arm in the surgical area. Once in place, it switches to collaborative mode, allowing the surgeon to move the arm within the limits established in the surgical plan. After the final position is determined, the robot transitions to static mode to perform precise cuts or reaming.

Humeral head resection is performed through robotic positioning of an extramedullary cutting guide, whose final position is adjusted in collaborative mode. The robotic arm controls the cut guide along the plane of the planned resection and the guide is then secured to the humerus with pins. The robot is then placed in static mode and the humeral cut is performed through this guide at the planned version, inclination, and height. The cut surface of the humerus is then validated to confirm appropriate resection of the humeral head. Following validation the remainder of the humeral preparation including reaming and broaching is performed manually.

Glenoid preparation is performed with a conventional reamer attached to the robotic arm that is powered by a standard cordless reamer. This allows glenoid reaming, controlled by the robot with live tracking in collaborative mode, to the desired version, inclination, and depth. Bone preparation for aTSA involves two robotic controlled steps. The first reamer prepares the face of the glenoid to the correct version, inclination and depth. The second prepares the central hole for the hybrid glenoid central post. The remaining glenoid preparation for the implant performed manually. In RSA the glenoid is prepared in a single step ream for the glenoid face and central boss with the robot controlling the version, inclination and depth in collaborative mode.

The steps include 

Humeral clamp placement on the proximal humerus

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

Humeral registration across various landmarks utilizing the probe

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

Robotic insertion of the humeral cut guide

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

The authors provided videos of this technique

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

 Coracoid array tracker secured on the coracoid process using two pins.

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

Glenoid registration across various landmarks using the probe.

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

Robotic assisted glenoid reaming using an implant specific reamer mounted on the robotic arm.

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

 A, Reamed glenoid prepared for baseplate implantation. B, Baseplate inserted onto the prepared glenoid.

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

A trial reduction is performed to assess and optimize soft tissue tension and range of motion. While robotic implantation accurately executes pre-operative planning based on the CT scan anatomy, which can assist in soft tissue balancing, intraoperative adjustments may be necessary to achieve optimal soft tissue balance.

Postoperative radiograph of a RSA with humeral and glenoid based robotic preparation.

Reproduced from Marigi et al., JSES Reviews, Reports & Techniques, 2026, under CC BY-NC-ND 4.0

The ROSA system is reported to cost between $1,000,000 and $1,500,000.  As the authors point out, "The disadvantages associated with the implementation of robotic-assisted SA are not limited solely to the costs involved. This surgery will entail a steep learning curve for surgeons already accustomed to other techniques, and it could also introduce a cognitive bias in trainee surgeons. Furthermore, in centers that do not yet have the robot, it will be necessary to modify operating rooms to provide sufficient space for the installation of the robotic unit."

Robotics is a technology to transfer a preoperative plan to the patient. Thus, this technique guide is not expected to present data on the efficacy of a robotic approach in optimizing component positioning (What Reverse Total Shoulder Geometry Will Give My Patient the Best Function and Lowest Complication Risk?)

This technique guide is not expected to present data on the value of robotics to the patient in terms of comfort, function, and reduced revision rate.

In his recent article, Robot-assisted shoulder arthroplasty  Sanchez-Sotelo opined: "The main theoretical benefits of robot-assisted shoulder arthroplasty include accuracy and precision, data acquisition, and with certain robots, the promise to avoid soft-tissue injury with haptic boundaries, prepare a bone through minimally invasive or cuff-preserving exposures, and the potential for motion assessment and soft-tissue balance. The disadvantages include cost, a certain learning curve, complications related to array insertion, potential for cognitive bias, need for a larger operating room space, and the potential for malfunction. Although adoption is likely to happen in many centers, cost and space constrains may favor alternative technologies, such as mixed reality navigation, especially in ambulatory surgery centers."

When openevidence.com was asked "does robotic-assistance improve patient reported outcomes for anatomic or reverse shoulder arthroplasty?", it concluded "There is currently no clinical evidence that robotic arthroplasty improves patient-reported outcomes for anatomic or reverse shoulder arthroplasty".

Let's think on this a bit.

Great-horned Owl

Seattle

2021

Follow on twitter/X: https://x.com/RickMatsen

Follow on facebook: https://www.facebook.com/shoulder.arthritis

Follow on LinkedIn: https://www.linkedin.com/in/rickmatsenmd

[1-2]

Robotics and reverse shoulder arthroplasty

Currently some shoulder surgeons are considering the value of robotic technology in their arthroplasty practice. Incentives for the use of robotics could include the belief that it will improve patient outcomes, marketing and competitive positioning, industrial financial relationships, higher reimbursement codes, speaking opportunities, and professional advancement.

A general rule in the consideration of advanced technologies, such as robotics, is for the individual surgeon to ask: "does the new technology solve a problem I have in my practice?" Answering this question requires the surgeon to take a critical view of cases that failed to meet expectations, and deciding whether the use of robotics would have significantly reduced the risk of these failures. Different surgeons will reach different conclusions based on their experience and practice.

A recent article, Robot-assisted shoulder arthroplasty is a helpful review of robotic-assisted shoulder replacement. Here are some takeaways from that article along with some additional thoughts for consideration.

Robotics excels in industry - for example in automotive assembly lines- where the desired geometry is accurately defined, the space is plentiful, the exposure is constant, the quality of the materials is standardized, the planning is fixed for all cases, exactly the same step is repeated over and over, the robot is programmed to avoid collateral damage to nearby structures, there is no concern for sterility, different robots perform the procedure identically, the human factor is eliminated, haptic feedback is unnecessary, and quality control is straightforward. None of these conditions exist in shoulder arthroplasty.

As the article notes, available robots differ substantially and "details regarding robotic shoulder arthroplasty are largely safeguarded information at this point and difficult to learn due to intellectual property protection."  Common features include added direct and indirect costs, learning curves, potential complications regarding insertion of the array to align the robot with anatomical landmarks, increased space requirements (e.g. may be a tight fit in a surgicenter), and like all machines, susceptibility to malfunction. Robotics requires additional OR time, personnel, and sterilization protocols. Robotic planning is based on CT scans with up to a 1,000 times increase in radiation exposure compared to plain films of the shoulder.

The literature demonstrates that robotics can increase the precision with which baseplate positioning matches a preoperative plan, especially in laboratory models. The literature does not answer the harder questions: (1) how much placement precision is needed for a good clinical result from RSA, (2) are the patient outcomes clinically significantly better than for reverse shoulder arthroplasty performed without robotics? (3) does the use of robotics reduce the risk of the common complications of RSA, such as infection, component loosening,  instability, acromial/scapular spine fractures, and periprosthetic fracture? and (4) is robotic reverse shoulder arthroplasty of value for the typical shoulder surgeon who performs fewer than ten of these procedures per year.

Answering such questions will require clinical outcomes research comparing robotic and non-robotic RSA, carefully controlling for surgeon experience with both approaches and patient selection (avoiding, for example, a bias toward robotic RSA for younger, healthier patients). Outcome variables will need to include patient reported outcomes, revision rates, and complications. Given the substantial economic implications, transparent disclosure of potential conflicts of interest will be essential in interpreting the emerging literature.

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link)
The total shoulder arthroplasty (see this link)
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link)
Shoulder rehabilitation exercises (see this link).

Arthroplasty - finding our way, what tools are of value?

Navigation and Robotics in Knee Arthroplasty

These authors reviewed the available literature on the use of navigational aids in total knee arthroplasty - a procedure in which the desired anatomic alignment can be precisely defined and accurately measured. 

They note that computer-assisted surgery for total knee arthroplasty can be performed with use of computer-assisted navigation, handheld navigation, partially or fully robot-assisted technology, and patient-specific instrumentation.

The evidence suggests that computer-assisted navigation leads to improved component alignment and a reduction in the likelihood of mechanical axis outliers after total knee arthroplasty, however it is not known whether these differences have any long-term benefit on clinical or functional outcomes.

Robot-assisted surgery

 has not been extensively studied in the context of unicompartmental and total knee arthroplasty, and, although initial reports have been promising in terms of accuracy and precision, this method is associated with substantial cost and a steep learning curve.

Patient-specific instrumentation

was designed to overcome many of the intraoperative challenges associated with navigation or robotic surgery, but early reports have demonstrated only minor improvements in surgical accuracy, and no change in outcomes, compared with conventional total knee arthroplasty.

Comment: These authors offer this commentary on their findings: "At the present time, most of these technologies are too costly to justify their routine use in place of conventional TKA. Nonetheless, much of  the marketing for these technologies tends to emphasize unsubstantiated benefits while disregarding potential drawbacks. As the health-care environment becomes increasingly competitive, hospitals may embrace these technologies to attract patients. It is the role of the surgeon to explain the benefits and drawbacks of these technologies to patients so that they can make informed decisions regarding surgery. Before these technologies are embraced, future studies must demonstrate improved clinical outcomes combined with affordable costs."

We should also ask, even if these technologies are shown to be of clinical benefit, on which cases should they be used and which surgeons and medical centers should use them?

While analogous technologies are advocated for the shoulder, we should pay attending to the data from our knee surgeon colleagues who have a much greater volume of cases/year and clearer measures of the anatomic and clinical outcome.

===

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book

Click here to see the new Rotator Cuff Book

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

See the countries from which our readers come on this post.

Computer-Navigated Versus Conventional Total Knee Arthroplasty: A Prospective Randomized Trial JBJS

Computer-Navigated Versus Conventional Total Knee Arthroplasty: A Prospective Randomized Trial JBJS

This is a remarkable study: a single surgeon, prospective randomized trial of conventional versus computer navigated total knee arthroplasty - all 520 patients had one of each - the average followup of over 10 years. The bottom line is that there were no differences in clinical or radiographic outcome between the two approaches. The computer assisted knees had 16% longer OR times and 40% longer tourniquet times.

8 knees with the computer-navigated technique and four knees with the conventional technique were revised as a result of aseptic loosening of the femoral component. Twenty-six knees  had anterior femoral notching in the navigation group and six in the conventional group. Five knees in the navigation group had excessive resection of the tibia. Both infections were in the navigation group.

The only shortcoming is that, aside from the surgical times, we were not provided with the incremental costs of computer navigation. Even without these data, this study did not establish value of computer navigation in knee arthroplasty.

There has been some interest in computer navigation in shoulder arthroplasty with studies showing its value in vitro, however, we suspect that clinical studies are likely to yield the same result as the current study regarding total knee. In some respects, shoulder arthroplasty may be even more challenging: the errors made in the total knee series reported here were attributed to 'registration errors', that is failure to properly align the navigation system - the deep location of the glenohumeral joint may make this even more difficult in the shoulder.

Unless the value of computer navigation can be robustly demonstrated in clinical practice, we must question if this is a way that we wish to spend our precious health care dollars.

----

If you have suggestions for topics you'd like us to address in this blog, please send an email to
shoulderarthritis@uw.edu

Use the "Topics" box to the right to find other posts of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery.

See the countries from which our readers come on this post.