Your Guide to Shoulder Replacement Success

Outpatient smart implants, navigation software and robots could all play a role in growing this outpatient procedure.

In the outpatient joint replacement world, hips and knees are still king. But shoulder replacements have followed their path and are coming on strong. In fact, even though same-day shoulder replacements are less common than hips or knees, the service line is growing at a faster rate than its more popular predecessors.

How we got here

Patient selection and education, the advent of nerve blocks, ERAS protocols and improved pain control regimens have helped us get this far. And again, as we’ve started to see with total hips and knees, future growth will include things such as smart implants, real-time navigation systems and robotic assistance. Let’s take a glimpse into that future.

• Evolution of implants. The first implants — designed by Charles Neer, the father of modern shoulder arthroplasty — were based on an anatomic model. He used a metal head to replace the humeral head and then a plastic socket to replace the glenoid. That was how it was done for years, and, for the longest time, there wasn’t a good option to treat patients who had rotator cuff tears in addition to degenerative conditions of the joint.

Then came the reverse shoulder replacement, which puts a glenosphere on the socket side of the shoulder and turns the normal ball side of the arm bone into the socket, and basically reverses the configuration that changes the geometry of the shoulder just enough so that the deltoid muscle is able to elevate the arm. This revolutionized how we do shoulder arthroplasty because so many of the patients we see have rotator cuff injuries in addition to arthritis in their shoulder.

Within both of those ways to approach shoulder surgery, the forefront of product design lately has been trying to figure out ways to shorten the stem on the humeral side. For years, we had to insert a stem down the humeral canal that would serve as a platform for the humeral component. Gradually, we’ve shortened those stems to the point now that we have what we call stemless implants. Instead of putting a stem down the canal of the humerus, you make your cut at the humeral head and then put a landing pad called a nucleus into the bone. Then the humeral head components go onto that. This has resulted in shorter procedures that preserve more bone and create less blood loss and less pain for the patient. From an OR logistics standpoint, manufacturers can get their components for these procedures into one or two trays instead of four, which is a huge plus for outpatient facilities where shelf space is always at a premium.

Another major development has been the concept of modularity. Years ago, we would use monoblock implants that were inserted into the humerus and very difficult to remove if a revision were required. Now we have modular stems. The head portion goes onto the stem and can easily be removed and converted into a reverse shoulder component if appropriate. You don’t need to remove the stem, which is great for the patient because it makes for a much less morbid revision surgery.

Smart implants are promising because they allow us to track patients’ progress in real time. We can see how much elevation of the joint they’re getting and receive indicators if the implant might be loosening, or if the area around the joint is infected. The data collection will also allow us to better estimate how long an implant will last in future patients.

ART MEETS SCIENCE The large amount of soft tissue near the joint can make a shoulder replacement trickier than a similar procedure on the knee or hip. | Penn Medicine

• Navigation systems. A small number of companies have been at the forefront of this kind of software, which, again, was first implemented in knee and hip replacements. Now, real-time navigation feedback is beginning to become available for shoulder procedures.

These systems come with a sterile iPad that is set up in the OR, and there are small motion sensors that you must place on anatomic landmarks in the shoulder. The patient’s preoperative CT scan is loaded into the iPad, and you use a probe in concert with the sensors to confirm how everything is aligning before you start making your cuts. There are also sensors in the drills and the implants that allow you to position your drill and screws at the correct trajectory.

Nerve blocks have revolutionized how we can control pain over the past decade.

As you do this, you’re seeing it projected onto the iPad in real time. It’s very much like a video game. These systems will tell you via a color-coded light system whether your drill is at the proper angle or whether you’re about to place a screw too deep or off-center. They also come with their own brand of implants, so surgeons need to like the implants in order to move forward with these navigation brands.

More common currently is preoperative planning software, with which you take a patient’s CT scan, upload it and virtually perform the surgery on your computer to give yourself an idea of the sizes of the implants that you’re going to use. There is also a movement toward augmented reality systems that have the surgeon wear hi-tech glasses or headsets. The patient’s CT scan appears in the headset to essentially allow it to interface with the patient as the surgeon is looking down at the surgical field where his hands are working. One concern worth addressing as this technology advances is to make sure that young surgeons who are learning on it don’t skip the step of mastering the standard orthopedic skillset. Residents shouldn’t become so reliant on any technology that they’ll be unsure what to do if something in the navigation system appears to be wrong. This caution applies to surgical robots as well.

• Robotic assistance. Robots help surgeons make precise cuts that can place an implant within one degree of what the patient’s normal anatomy was. Their use is growing, in part because patients, as consumers, like the idea of going to a facility that has state-of-the-art technology.

Manufacturers say shoulder-specific robots will be on the market in a year or two. This prospect is trickier with shoulders than it is with hips and knees because shoulder replacements are a mix of art and science, and are very much soft-tissue-balancing procedures. A robot can tell you where to make a bony cut, but might not be able to, for example, appreciate how much tension is on the rotator cuff. Robots are expensive and can also take up a lot of space in an ASC, but less pricey and smaller models are expected in the future. In the meantime, some manufacturers will place a robot at a facility for free and make their money on the implants and disposable attachments that must be replaced after several uses.

Once shoulder robots arrive on the scene, their sustainability will rely on studies that show that they improve clinical outcomes. If the systems continue to improve, their price comes down and they prove to be able to make a procedure better, then patients and payers will demand it.

A bright future

PERFECT PAIRING When you combine technological innovations and smart implants with surgeon skill, it’s easy to understand why ASCs are now able to send shoulder replacement patients home on the same day as their surgery.

Less than two percent of my shoulder replacements are inpatient procedures, which is the norm in this specialty. Unless a patient has multiple comorbidities, they can go home the same day or 23 hours or so after extended observation.

In addition to everything discussed here, the pandemic also played a role to speed up this migration. That time proved that the patients who had their replacements done just before the lockdowns were instituted did OK. They weren’t able to attend follow-up appointments or physical therapy as they normally would have, yet their outcomes were very similar to pre-COVID cases. This helped cement the idea that it’s so much better for patients to be able to go home.

Better pain control regimens, wound closing techniques and deep venous prophylaxis preventions helped us get to this point. Moving forward, new implants, navigation systems and robots will only add to this growth. OSM