We recently had the opportunity to meet with Mark Schrumpf, M.D., specifically to talk about his background and his experiences using the InSet™ Total Shoulder System from Shoulder Innovations.


Dr. Mark Schrumpf is an Orthopedic Surgeon in San Francisco, CA


David Blue: Dr. Schrumpf, would you please share your background with us, including how you became involved in healthcare and specifically orthopedics?

Dr. Schrumpf: My dad was a radiologist, so I was continually exposed to medicine growing up. I knew from an early age that I wanted to be a physician.

When I was in high school, I became involved with an orthopedics group and was able to observe a surgeon performing a total knee replacement. Watching that surgery made me want to be an orthopedic surgeon when I grew up.

In medical school, I worked with Dr. John Itamura, and was exposed to shoulder and elbow surgery, and that became the part of orthopedics that I was most interested in.

I pursued shoulder and elbow surgery throughout my residency and fellowship. I ended up working in the same group that I had spent time with, in high school, so that was exciting to watch my orthopedic interest come full circle.

David Blue: How did you first learn about the InSet™ Glenoid, and the Shoulder Innovations team?

Dr. Schrumpf: I was introduced to SI InSet™ through Aaron Miller, who is a long-time industry player here in the Bay Area. Also, one of my former partners and my fellowship mentor, Dr. Tom Norris, has been using the InSet™ Glenoid for some time.

I watched from the sidelines for a while to see how those patients responded to the SI InSet™ before using it myself. I was a little slow to jump on the bandwagon but have been very satisfied with the results I’ve seen.

David Blue: What was your first impression of this technology?

The design principles of the InSet™ glenoid do not follow the principles of most options in the marketplace. If you’re going to rethink the way you do something, you need to make sure the outcomes support your decision to change.

I had used the traditional peg glenoid for the first 5 or 6 years of my practice with reasonably good results. But as the follow-ups became longer, I began to see more glenoids that looked loose or suspicious. So, I was looking to make a change.

This technology held the promise of better fixation. They had published some single surgeon long-term follow-up that looked promising.

Then I was able to watch some of Dr. Norris’ patients get their 2- and 3-year follow-up x-rays and I was very satisfied with what I saw. I recognized that this was a better solution than what I had been using so I was interested and motivated to change.

David Blue: What types of indications do you primarily use the InSet™ Glenoid with?

Dr. Schrumpf: I use it when I’m putting in an anatomic total shoulder replacement.

I make my decisions for an anatomic total shoulder based on rotator cuff and glenoid deformity. If there’s substantial glenoid deformity or if the rotator cuff is suspicious or torn, the patient is getting a reverse shoulder replacement. In my practice, I’d say 70% of my patients get a reverse. But for the people who are getting total shoulders, they get the InSet™ glenoid.

David Blue: If you were sitting down with a fellow surgeon to talk to them about this technology for the very first time, what would you tell them?

Dr. Schrumpf: What is most satisfying about the InSet™ glenoid component is its immediate stability. The surgeon is able to secure a well-fixed glenoid with relative ease because of the way the InSet™ glenoid enters into the prepared surface.

My prior concerns were about the fact that it doesn’t resurface the entire glenoid and that it is a circle for something pear shaped but, after researching this along with reviewing Frankel’s paper on where the shoulder articulates, this became not a concern.. But I have also found in using it that the way the instruments work makes the prep faster and more accurate than when using a traditional glenoid. More accurate prep allows for better seating and better fixation of those components.

Traditional glenoid components require many more steps to prep the glenoid and each of those steps introduces the potential for error. But the great thing about the InSet™ glenoid system is that it’s just two basic steps.

I have to use something before I really trust it and I think that other surgeons may be like that too. They may need to start using the InSet™ glenoid before they fully comprehend its advantages.

David Blue: Do you have any tips or pieces of advice that you would give other surgeons if they were using the system for the first time?

Dr. Schrumpf: If you’re trying to correct a glenoid deformity in a younger patient, using the thicker 8mm glenoid allows you to correct a substantial deformity.

It’s really important to make sure that the InSet™ glenoid component is just proud of the native glenoid so that the humeral head is articulating with the polyethylene as opposed to the native glenoid. When slightly raised, the InSet™ component works well even though it doesn’t cover the whole surface of the native glenoid.

There was some initial apprehension about how deep you need to ream, but you quickly realize that you do end up still in the subchondral bone for most all of the cases and not into the cancellous bone, since the glenoid vault is a concave surface. When you remap the concave surface and you make that etch mark, the center of the glenoid is still sitting on a cortical bone, and most of the periphery is still sitting on cortical bone too. There’s only rarely an area where you get into cancellous bone.

When I’ve shown my partners the x-rays, they’ve sometimes commented about how much bone it appeared I was removing. But in reality, you’re reaming something flat into something that’s concave, so you’re actually only removing a little trough around the side of the reamers.

The flat-back design on the InSet™ glenoid and the peripheral ring of support means that the pegs are much smaller than on traditional glenoid components. On a revision, the InSet™ glenoid would not have the same huge cavitary defect that you would find with a loose pegged component or keeled component.

In terms of long-term planning, having most of the glenoid vault still available for your revisions is extremely valuable. There’s nothing worse than doing a revision from one of the traditional pegged glenoids that’s been loose for a couple of years and finding a huge central cavitary defect that goes out the floor of the vault.

The peg on the InSet™ glenoid is around 5 to 7mm whereas the Magic Peg is 17 or 18mm. That’s a third of the length and that makes a huge difference.

David Blue: Thank you Dr. Schrumpf. Do you have any closing thoughts today?

Dr. Schrumpf: While I was initially skeptical, I’ve been very satisfied with the InSet™ glenoids intraoperative performance and with my patient outcomes. I haven’t had any problems with it.

As a surgeon who does a fair amount of revision surgeries, I feel more comfortable putting in the InSet™ than any other glenoid because it sets me up to be successful for future surgeries if revision becomes necessary.

When the metal-backed components or metal annealed-to-a-poly components become loose, they can be destructive and are very difficult to remove. And the InSet™ glenoid doesn’t have any of those issues.

I’m very pleased with it and will continue to use it.