VCOT January 2026 – Ortho Part 1: TPLO Plate Design & Patient-Specific Atlantoaxial Implants

In this Simini Small Animal Surgery Podcast episode, we kick off our orthopedic coverage from the January 2026 issue of Veterinary and Comparative Orthopaedics and Traumatology (VCOT) by exploring how implant design can influence surgical success long before the patient leaves the operating room. 

One study demonstrates that subtle differences in TPLO plate geometry can dramatically affect interfragmentary compression and construct stability, while the second introduces a patient-specific 3D-printed implant that could transform the treatment of atlantoaxial instability in toy-breed dogs.

In this episode:

✅ Miraldo et al. — Compared three commonly used 3.5 mm TPLO locking plate systems to determine how plate design affects interfragmentary compression across the osteotomy. Using pressure-sensitive film, the authors found that the Biocurve plate generated the highest and most uniform compression, particularly across the cranial aspect of the osteotomy, owing to its opposing dynamic compression slot orientation. In contrast, the Synthes plate produced the lowest compression, highlighting that implant geometry—not just surgical technique—plays a major role in achieving stable primary bone healing.

✅ Peres Cabrera et al. — Presented a patient-specific 3D-printed titanium implant for dorsal stabilization of atlantoaxial instability (AAI) in dogs. Designed from CT imaging and optimized using finite element analysis, the implant incorporates an integrated drill guide that directs screw placement while allowing up to 12 degrees of variable-angle adjustment. Mechanical testing demonstrated excellent rigidity, with maximum implant stress remaining well below the titanium alloy's yield strength and only 0.13 mm of displacement under supraphysiologic loading. The design eliminates the need for polymethylmethacrylate (PMMA), reducing the risks of thermal injury, infection, and implant-related complications. 

Together, these studies reinforce a simple but powerful lesson: the smartest implant isn't always the strongest—it's the one designed to help surgeons consistently achieve the best biomechanics with the greatest precision.

🎓 Journal Articles Discussed

• Miraldo et al. — Tibial Plateau Leveling Osteotomy Plate Design Influences Interfragmentary Compression: An In Vitro Study
• Peres Cabrera et al. — Development and Finite Element Analysis of a Patient-Specific Implant for Atlantoaxial Joint Stabilization via Dorsal Approach in Dogs

📚 From the January 2026 issue of VCOT

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Transcript

SPEAKER_00 0:04

Hi, I'm Carl Damiani, and this is the Simony Small Animal Surgery Podcast, your fast focused update on what matters most from the latest small animal surgical literature. In each episode, we break down key articles from the veterinary journals and translate them into surgical insight you can use. Today, not someday. This episode kicks off our orthopedic coverage from issue 1, 2026, of Veterinary and Comparative Orthopedics and Traumatology, and we're focusing on two studies that explore how thoughtful implant design can improve surgical precision and construct performance. First, we'll review Miraldo et al. who ask a deceptively simple question Does TPLO plate design influence interfragmentary compression? By comparing three commonly used locking plate systems, the authors show how subtle differences in plate geometry and compression slot orientation can dramatically alter pressure distribution across the osteotomy, raising important questions about construct stability and primary bone healing. Then we turn to Perez Cabrera et al. who present a patient-specific 3D printed implant for dorsal stabilization of Atlantoaxial instability in dogs. Combining CT-based planning, integrated drill guide technology, and finite element analysis, the study explores whether customized implants could make one of the most technically demanding neurosurgical procedures both safer and more reproducible. Two studies. One common theme using smarter implant design to improve surgical accuracy, biomechanics, and ultimately patient outcomes. Let's dive in.

SPEAKER_01 1:54

So you step into the OR for the bread and butter of canine stifle surgery, right? The TPLO. You make the perfect cut, um, execute flawless drill technique, and yet the bone doesn't heal perfectly. What if that outcome was secretly decided before you even picked up the drill?

SPEAKER_02 2:11

Right, like decided by the microscopic geometry of the metal plate sitting right there on your tray.

SPEAKER_01 2:16

Exactly. And well, that is the exact tension explored in Miraldo et al. 2026. Welcome to the deep dive, by the way. So we often assume achieving perfect interfragmentary compression is entirely in the surgeon's hands, right?

SPEAKER_02 2:29

Yeah, which I mean is absolutely non-negotiable for construct stability and primary bone healing. But this research asks if the static machine design of the plate itself is actually doing the driving.

SPEAKER_01 2:40

So if they map the exact footprint of these plates, I'm guessing we finally have like visual proof of which one is clamping down the hardest on the bone.

SPEAKER_02 2:47

We do, yeah. So the researchers used pressure-sensitive film on synthetic keyline tibius to test three different three and a half millimeter locking TPLO plates.

SPEAKER_01 2:56

Okay, pressure film, got it.

SPEAKER_02 2:57

Right. And they divide the surgical site into quadrants. The data was actually really striking. The biocurve plate generated the highest and most uniform compression.

SPEAKER_01 3:08

Oh, wow, really?

SPEAKER_02 3:09

Yeah, hitting around 0.3 megapascals, particularly in the critical cranial quadrants.

SPEAKER_01 3:14

Aaron Powell, let's look at the mechanical house there, because I mean a metal plate is just a piece of metal. It's the whole design doing the actual work, right?

SPEAKER_02 3:21

Aaron Ross Powell Exactly. So the biocurve has these two angled dynamic compression screw holes that face in opposite directions.

SPEAKER_01 3:28

Aaron Powell So it's kind of like tightening a belt by pulling from two opposing angles simultaneously to create a really snug fit.

SPEAKER_02 3:35

Aaron Powell That's a perfect way to picture it. As you load those screws, the opposing angles force the osteotomy closed both cranially and axially at the exact same time.

SPEAKER_01 3:44

Aaron Powell I mean it's almost like turning a corkscrew, right? As you drive the screw downwards, the angled threads physically pull the two pieces of bone laterally together until they lock tight.

SPEAKER_02 3:53

Yeah, exactly. Now on the flip side, you have the synthesis plate, which uses straight dynamic compression holes.

SPEAKER_01 3:58

Aaron Powell And let me guess that one didn't perform as well.

SPEAKER_02 4:01

Aaron Powell Right. It generated the lowest pressure, and then the Arthrex plate landed somewhere in the middle.

SPEAKER_01 4:06

Wait, does this mean the synthes plate is just clinically bad for TPLOs? Because I know a lot of people use it.

SPEAKER_02 4:11

No, not bad at all. It simply demands a different handling strategy. Aaron Powell Okay.

SPEAKER_01 4:15

How so?

SPEAKER_02 4:16

Well, the geometry of the biocurve naturally provides that uniform cranial compression, which significantly reduces risks like rock back, you know, where the tibial plateau unexpectedly shifts post-stop.

SPEAKER_01 4:29

Right, right. Nobody wants rock back.

SPEAKER_02 4:30

Exactly. But if you are using the synthesis or arthrex plates, you just cannot rely entirely on the screws to slide the bone into place.

SPEAKER_01 4:39

So basically you can't just let the drill do the work. Yeah. You have to get in there with pointed bone reduction forceps and like wrestle it closed manually.

SPEAKER_02 4:48

Yeah, almost like a stubborn zipper. You have to force that consistent cranial compression before you actually lock it down.

SPEAKER_01 4:54

Got it. But I mean that brings up a secondary clinical reality, doesn't it? Wrestling that bone with forceps requires extra manipulation around the osteotomy.

SPEAKER_02 5:03

It does. And more manipulation always means increased tissue trauma.

SPEAKER_01 5:07

And where there's extra tissue trauma plus metal hardware, I mean, you are laying out a red carpet for biofilms to thrive.

SPEAKER_02 5:15

Oh, absolutely. We spend all this time getting the compression perfectly gapeless, but then we have to actively protect that hardware during the closure protocol.

SPEAKER_01 5:24

Right, which usually just means a saline rinse for most people.

SPEAKER_02 5:27

Yeah. Standard saline lavage is the familiar choice, sure. But independent head-to-head studies show saline actually leaves 42% of bacteria behind.

SPEAKER_01 5:36

Wait, 42%? That's almost half.

SPEAKER_02 5:38

I know, right?

SPEAKER_01 5:39

Yeah.

SPEAKER_02 5:40

Saline lacks mechanical surfactant properties. It literally just flows right over sticky, adherent biofilms without dislodging them at all.

SPEAKER_01 5:47

Aaron Powell Leaving almost half the bacteria behind over a perfectly compressed osteotomy is a massive blind spot.

SPEAKER_02 5:54

It is. But upgrading the closure protocol with Semini Protect Livage really changes the math there.

SPEAKER_01 6:00

That's a non-antibiotic one, right?

SPEAKER_02 6:01

Exactly. It's used just prior to suturing. Instead of just washing over the site, its specific surfactant properties actively lift and disrupt those resistant biofilms.

SPEAKER_01 6:11

So it actually gets them off the hardware?

SPEAKER_02 6:13

Yes. In those same studies where saline left 42% behind, Simony left 0%, and it did the job in under 60 seconds.

SPEAKER_01 6:22

Oh wow. 0%. So you aren't really changing your workflow, you're just swapping in a smarter mechanical tool for a step you're already doing anyway.

SPEAKER_02 6:29

Precisely. You control the mechanics and you control the surgical environment.

SPEAKER_01 6:32

Okay. So the clinical punchline for your next procedure is basically know your plate's mechanical limits, right? If its geometry doesn't naturally provide uniform compression, adapt your reduction tools to force it.

SPEAKER_02 6:45

And once you have it locked in, obviously protect your closure.

SPEAKER_01 6:48

Absolutely. So here is a thought to leave you with. Think about those subtle delayed post-op complications you might see in your patients. How many of them are actually caused by microscopic gaps in cranial compression, dictated by a plate's hidden geometry, rather than an obvious surgical error?

SPEAKER_02 7:04

Yeah, it definitely makes you look at that metal tray a whole lot differently.

SPEAKER_01 7:08

It really does. Anyway, the link to the full article from Miraldo et al. is in the show notes for you to explore. Thanks for joining this deep dive.

SPEAKER_00 7:20

Turning the page.

SPEAKER_01 7:35

Yeah, that sounds like an absolute nightmare.

SPEAKER_02 7:37

Right. But that is essentially what you face when you're stabilizing atlanoaxial instability or, you know, AAI in toy breed dogs.

SPEAKER_01 7:44

Aaron Powell Welcome to this deep dive, by the way.

SPEAKER_02 7:46

Aaron Powell And the surgical corridors there are just um incredibly unforgiving. Like if you take the ventral approach, you are navigating right around the larynx, the carotid sheath.

SPEAKER_01 7:56

The recurrent laryngeal nerve, yeah. Trevor Burrus, Jr.

SPEAKER_02 7:57

Exactly. So surgeons usually opt for the dorsal approach to avoid all those soft tissue hazards. But historically, I mean that means relying on polymethyl methacrylate or PMMA to basically secure the joint.

SPEAKER_01 8:09

Which brings us back to that hot concrete analogy. And that PMMA carries a massive like 20 to 40% complication rate.

SPEAKER_02 8:16

It really does. It's a huge issue. Trevor Burrus, Jr.

SPEAKER_01 8:18

You're risking thermal injury to the spinal cord as the cement cures, plus pressure necrosis, high infection rates. It is far from ideal. Which is why this paper by Cabrera et al. 2025 really caught our attention.

SPEAKER_02 8:30

Aaron Powell Yeah. Their mission was to see if we can just, you know, ditch the PMMA entirely. Right. They're looking at a 3D printed titanium M alternative.

SPEAKER_01 8:37

Aaron Ross Powell And uh what's really impressive is how they designed it. I mean they relied purely on computed tomography and finite element analysis.

SPEAKER_02 8:45

Aaron Powell So basically building a digital twin.

SPEAKER_01 8:47

Aaron Powell Yeah. A highly accurate digital twin of the dog's spine. And this allowed them to run like thousands of virtual stress tests on the implant design to optimize it, all without ever needing an animal model for the testing phase.

SPEAKER_02 9:00

Aaron Powell Oh, wow. So no animal testing at all for the design optimization.

SPEAKER_01 9:03

Aaron Powell Right. None whatsoever. Aaron Ross Powell Okay.

SPEAKER_02 9:05

So they dial in the perfect shape digitally, and it ends up being this custom patient-specific titanium plate secured dorsally, and it uses um six 1.7 millimeter bicortical locking screws.

SPEAKER_01 9:18

Which importantly includes two transarticular screws, you know, for that maximum rigid hold across the joint.

SPEAKER_02 9:24

Aaron Powell Right, right. But I mean, custom plates aren't entirely new in VetMed. What really caught my attention was how this hardware actually changes the workflow in the OR.

SPEAKER_01 9:33

Oh, the procedural shift is the true breakthrough here. The implant itself serves as your surgical template.

SPEAKER_02 9:38

Wait, the plate is the drill guide.

SPEAKER_01 9:40

Exactly. The housings for the screw heads are specifically engineered to act as direct receivers for a threaded drill guide. You just place the implant, thread the guide directly into the plate, and drill your pilot holes.

SPEAKER_02 9:53

Okay, but wait. I'm trying to picture this in a messy OR. Because if the plate is the guide and the bones aren't perfectly aligned yet.

SPEAKER_01 10:01

Right, because you rarely achieve 100% perfect joint reduction on the table.

SPEAKER_02 10:06

Exactly. So aren't you locking the surgeon into a fixed trajectory? Doesn't a pre-drilled angle mean you risk, I don't know, sending a drill bit straight into the spinal canal if the anatomy is even slightly off.

SPEAKER_01 10:17

Well that's the exact practical hurdle that this design addresses. I mean, it's not a rigid single-angle lock.

SPEAKER_02 10:22

Oh, it's not.

SPEAKER_01 10:23

No. The geometry of those screw housings actually features a variable angle mechanism. It accommodates up to a 12-degree angulation.

SPEAKER_02 10:31

Oh, so the internal mechanics give you kind of a uh cone of flexibility?

SPEAKER_01 10:35

Precisely. So if you know perfect reduction simply isn't possible interoperatively, you have this built-in safety buffer to angle the drill safely away from the vertebral canal, but you're still locking securely into the plate.

SPEAKER_02 10:49

Man, that cone of flexibility is a massive relief. But uh it does make me wonder about the overall structural integrity.

SPEAKER_01 10:56

How so?

SPEAKER_02 10:57

Well, if we aren't encasing this whole joint in a big block of PMMS cement, can a tiny titanium plate with variable angle screws actually withstand, say, a toy breed suddenly jerking on a leash or like jumping off a sofa?

SPEAKER_01 11:11

Mechanical testing answers that beautifully, actually. They uh subjected their digital twin model to supraphysiological loads of 107 newtons.

SPEAKER_02 11:20

107 newtons. To put that in perspective for you listening, normal daily loads in the cervical spine of a toy breed are a fraction of that. I mean, 107 newtons is like applying over 24 pounds of direct force to that tiny joint.

SPEAKER_01 11:32

Yeah, it's a massive impact for a two-pound dog.

SPEAKER_02 11:34

So how did the plate hold up?

SPEAKER_01 11:36

Well, under that extreme stress, the maximum stress point on the implant reached um 425 megapascals. Okay, and the yield strength is the specific titanium alloy they used doesn't even begin to yield until it hits eight hundred and eighty megapascals. Wow. Yeah. So even under forces far beyond what the dog would experience daily, the implant is operating at, well, less than half of its failure threshold. Plus, the maximum displacement of the implant was a completely negligible 0.13 millimeters.

SPEAKER_02 12:04

So it is exceptionally rigid.

SPEAKER_01 12:06

Very. I mean the data speaks for itself.

SPEAKER_02 12:08

Okay. Looking at the big picture for you, the small animal surgeon, this completely changes the risk profile of AAI stabilization.

SPEAKER_01 12:15

It really does. You get a 3D printed patient-specific dorsal plate that functions as his own drill guide.

SPEAKER_02 12:21

Right. It delivers the rigid stability you need, respects the anatomy, and most importantly, completely eliminates the thermal and infectious nightmares of using PMMA.

SPEAKER_01 12:29

Yeah, it replaces guesswork and dangerous materials with pure patient-specific precision.

SPEAKER_02 12:35

No more hot concrete in the fuse box. I love it.

SPEAKER_01 12:37

Exactly.

SPEAKER_02 12:38

But as we wrap up this deep dive, I want to leave you with a final thought to ponder as you prep for your next complex case. If patient-specific implants can safely act as their own drill guides in an area as tight and high stakes as the Atlantara axial joint, how might you utilize this built-in template technology for other high-risk orthopedic subluxations in your practice?

SPEAKER_01 12:59

That is a great question.

SPEAKER_02 13:00

Something to think about. And you can dive into the full methodology of Cabrera et al.

SPEAKER_00 13:11

That's it for this episode of the Simony Small Animal Surgery Podcast. This show is brought to you by Semini Protect Livage, our interoperative lavage developed to target resistant bacteria and biofilms where traditional solutions of saline and post op antibiotics fall short. If you're interested in learning more or trying out your own procedures, you'll find information and links in the show notes. For listening, and we'll see you in the next episode.