Veterinary Surgery Deep Dive: Equine Ortho — April 2026 Edition

In this episode of the Simini Equine Surgery Podcast, we explore the orthopedic research from the April 2026 issue (Issue 3) of Veterinary Surgery, where two studies examine how precision—both in pain management and implant design—can improve orthopedic outcomes in horses. 

One study investigates a novel method for targeted forelimb analgesia using cervical epidural catheterization, while the second evaluates whether polyaxial locking plate technology can provide greater flexibility and stability during fetlock arthrodesis.

In this episode:

✅ Edwards et al. evaluated an ultrasound-guided cervical epidural catheter placed at the C1–C2 intervertebral space to deliver detomidine and morphine for horses with experimentally induced forelimb pain. In a crossover study involving five horses with carpal synovitis, four of five horses demonstrated greater than 50% improvement in lameness within two hours of treatment. The catheter remained functional for more than 10 days, supporting its feasibility for prolonged analgesia. However, despite localized drug delivery, horses still developed systemic effects including sedation, ataxia, and tachycardia, likely due to cranial migration of medication within the epidural space. The study demonstrates that cervical epidural catheterization is both technically safe and clinically effective, while highlighting the need for refined dosing strategies to minimize neurologic side effects. 

✅ Kadik et al. compared a traditional 5.5-mm locking compression plate (LCP) with a polyaxial non-contact bridging (NCB) locking plate system for equine fetlock arthrodesis using an ex vivo biomechanical model. During cyclic fatigue testing, the NCB construct demonstrated less than half the displacement of the standard LCP (0.22 mm versus 0.56 mm), indicating significantly greater construct stiffness during simulated postoperative loading. Although both systems exhibited similar ultimate failure strength, the polyaxial plate allowed 30 degrees of variable screw angulation, enabling surgeons to optimize screw placement in comminuted fractures or irregular bone while preserving construct stability. The findings suggest that polyaxial technology may offer meaningful advantages in complex arthrodesis cases by combining mechanical strength with greater intraoperative flexibility. 

Together, these studies demonstrate that modern orthopedic innovation extends beyond stronger implants—it also includes delivering therapy more precisely and adapting surgical technology to the unique challenges of equine anatomy.

🎓 Journal Articles Discussed

• Edwards et al. — Cervical epidural catheter for administration of detomidine and morphine in a model of carpal synovitis in the horse
• Kadik et al. — An ex vivo comparison of mono-versus polyaxial locking compression plates for metacarpophalangeal joint arthrodesis in the horse

📚 From the April 2026 Issue (Issue 3) of Veterinary Surgery

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Transcript

SPEAKER_01 0:04

Hey, I'm Carl Damiani, and this is the Simene Equine Surgery Podcast, your fast, focused update on what matters most from the latest equine surgical literature. In each episode, we break down key articles from the veterinary journals and translate them into practical surgical insight you can use today, not someday. This episode covers the orthopedic section from the April 2026 issue of veterinary surgery, and we're exploring two studies that push the boundaries of both pain management and implant technology in equine orthopedic surgery. First, we'll look at a study by Edwards et al. evaluating the use of a cervical epidural catheter to deliver detamidine and morphine for horses with experimentally induced forelimb pain. The authors examine whether this novel analgesic approach can improve lameness while minimizing complications, offering a potential new tool for managing challenging orthopedic pain. Then we'll review Caddock et al. who compare traditional monoaxial locking compression plates with a polyaxial locking plate system for FETLOC Arthurdesis. Using an ex vivo biomechanical model, they investigate whether newer implant technology can provide greater construct stability and more flexibility for surgeons without sacrificing strength. Two studies. One important theme: improving orthopedic outcomes through smarter innovation, whether that's delivering more effective pain control or advancing the implants we rely on to stabilize complex injuries. Let's dive

Edwards et al. Study: Evaluating an Ultrasound-Guided Cervical Epidural Catheter for Detomidine and Morphine Delivery in Horses with Forelimb Pain.

SPEAKER_01 1:43

in.

SPEAKER_02 1:44

Welcome to today's deep dive, everyone. Our goal, as always, is to deliver fast, actionable surgical intelligence you can actually use in the OR tomorrow.

SPEAKER_00 1:53

Absolutely.

SPEAKER_02 1:54

So, okay, let's unpack this. Today we are focusing on a really interesting paper, Edwards et al. 2026.

SPEAKER_00 2:02

Yeah, it is a great one. So the clinical challenge they're tackling is severe thoracic or you know, forelimb pain in horses. Normally we have to treat that with pretty heavy systemic drugs, right?

SPEAKER_02 2:13

Right, which, I mean, carry some massive side effects. Trevor Burrus, Jr.

SPEAKER_00 2:17

Exactly. You end up with gastrointestinal stasis or even severe ataxia. The horses get so uncoordinated they can't even stand up safely. So the team looked at an alternative. They used an ultrasound guided cervical epidural catheter.

SPEAKER_02 2:29

Trevor Burrus, And that gets placed right at the C1C2 space, right? To deliver detomatine and morphine locally. It's kind of like, well, I always think of traditional systemic pain management as trying to put out a small kitchen fire by like flooding the entire house.

SPEAKER_00 2:43

Aaron Powell That is a perfect way to look at it. And the clinical punchline from the study is actually pretty huge.

Pain Relief Efficacy: Reviewing a five-horse carpal synovitis model showing over a 50% decrease in lameness within two hours of targeted local delivery.

SPEAKER_00 2:47

They did a crossover study on five horses with induced carpal cinnavitis. Okay. And with this targeted catheter delivery, four out of five of those horses showed over a 50% decrease in lameness.

SPEAKER_02 3:00

Aaron Powell Wait, really? Over 50%.

SPEAKER_00 3:02

Yeah, and that was within just two hours of treatment.

SPEAKER_02 3:04

Aaron Ross Powell That is incredibly fast for that level of relief. But I mean I have to ask, did this localized delivery actually solve the side effect problem? Because the anatomy up there is incredibly tricky. Are they genuinely bypassing the brain's broader neurochemistry?

SPEAKER_00 3:19

Aaron Powell Right. Well, what's fascinating here is that um they aren't fully bypassing it. I mean the catheters safely stayed patent for over 10 days, which is amazing.

SPEAKER_02 3:28

Yeah, a huge technical win.

SPEAKER_00 3:30

Definitely. But the horses still develop systemic effects. We were talking sedation, ataxia,

Cranial Spread and Systemic Effects: Tracking the technical success of a 10-day catheter patency alongside a pressure-driven cranial fluid drift that triggers sedation, ataxia, and tachycardia.

SPEAKER_00 3:35

tachycardia. The drugs just didn't sit perfectly at the injection site.

SPEAKER_02 3:39

Aaron Powell So why the cranial spread? Is it like a pressure dynamic issue, or is it just the sheer volume of the fluid pushing the drugs up toward the brainstem?

SPEAKER_00 3:47

Aaron Powell It's a combination of both, actually. The cervical epidural space is relatively narrow, you know. When you introduce a set volume of liquid, the pressure dynamics naturally push that fluid along the path of least resistance.

SPEAKER_02 4:02

Which just sends it right up to the brain.

SPEAKER_00 4:03

Precisely. It migrates toward the cerebrospinal fluid pathway. It's sort of like trying to dye just one tributary of a river. The uh fluid mechanics will eventually carry some of that dye downstream to the main water supply.

SPEAKER_02 4:15

Right. The current just takes it. So clinically, we are still fighting those fluid mechanics. The drugs migrate and you still get ataxia.

SPEAKER_00 4:23

We are. The real take-home message for surgeons here is that the C1C2 catheter is a safe and viable route for prolonged forelimb analgesia. It does work, but until we refine the protocols, maybe through microdosing or using higher viscosity drug carriers to stop that, cranial drift surgeons must still monitor really closely for those neurologic side effects.

SPEAKER_02 4:44

You know, upgrading

Simini Protect Lavage Study: Contrasting standard saline's 42% bacterial remainder with a 60-second surfactant alternative that achieves total biofilm disruption and complete pathogen clearance at closure.

SPEAKER_02 4:45

existing surgical protocols for better risk management without overcomplicating the workflow. That's a massive theme right now. And this fluid migration problem is the exact same physical challenge we face during wound closure. Fluids don't always do what we want them to do in a surgical space.

SPEAKER_00 5:02

Oh, 100%. Just look at routine surgical lavage.

SPEAKER_02 5:05

Right. We flush a site with saline and just assume the sheer volume washes out the debris.

SPEAKER_00 5:10

But it doesn't. Standard saline just kind of glides right over the surface of biofilms. I mean, independent head-to-head studies show traditional saline lavage leaves 42% of bacteria behind at the surgical site.

SPEAKER_02 5:21

Which is a terrifying stat when you're closing an orthopedic case.

SPEAKER_00 5:25

Right. The fluid dynamics of saline just cannot break the surface tension of a mature biofilm. You need a targeted upgrade, which is where the mechanics of a product like Semony Protect Lavage come in.

SPEAKER_02 5:35

Because it's not just dumping more antibiotics into the site.

SPEAKER_00 5:38

Exactly. Implementing just a 60-second non-antibiotic Seminy Protect Livage step right before suturing physically breaks down that biofilm matrix. Saline leaves 42% behind, but simony removes 100% of bacteria and biofilms.

SPEAKER_02 5:55

It really comes down to controlling the mechanics of the fluids we use. You know, whether we're trying to keep an epidural strictly localized or physically breaking down a biofilm in a single minute, these smart localized enhancements can drastically shift patient outcomes.

SPEAKER_00 6:10

Absolutely. We are moving past the era of systemic scattergun approaches and relying on true precision.

SPEAKER_02 6:15

Yeah, exactly. So I want to leave you with a final thought to ponder before your next case. If targeted cervical epidurals can dramatically reduce forelimb pain, but still trigger systemic neurologic responses like ataxia, how far away are we from developing localized molecular therapies?

SPEAKER_00 6:30

That's a great question.

SPEAKER_02 6:32

Right. Imagine a localized pain relief that physically binds only to the targeted nerve roots, making it impossible for the brain's broader neurochemistry to be affected, regardless of pressure or volume. Something to think about. We'll catch you next time.

SPEAKER_01 6:49

Here's the next article.

Kadik et al. (Catac et al.) Study: An Ex Vivo Biomechanical Comparison of Traditional Monoaxial LCPs vs. a Human Polyaxial Locking Plate System (NCB) for Fetlock Arthrodesis.

SPEAKER_02 7:03

Oh, absolutely. It's uh it's a nightmare for post-office stability.

SPEAKER_00 7:06

Right. And, you know, for years we've relied on these rigid locking compression plates, the standard LCPs, with their fixed 90-degree screws to hold a shattered FET lock together.

SPEAKER_02 7:16

Aaron Powell Yeah. Which works, but it definitely has its limits.

SPEAKER_00 7:19

Aaron Powell Exactly. So the mission today is asking: what if the solution to a highly comminuted MCP joint isn't making the construct more rigid, but you know, making the screws more adaptable?

SPEAKER_02 7:29

Aaron Ross Powell Right. And that is exactly the core question driving this recent ex vivo biomechanical study, uh Tac et al. 2026. They actually took the traditional 5.5 millimeter stainless steel FCP and pitted it against an implant originally designed for human

Non-Contact Bridging Physics: Preserving the crucial periosteal blood supply in highly comminuted fractures by utilizing a titanium plate that hovers slightly off the bone surface.

SPEAKER_02 7:46

femurs.

SPEAKER_00 7:46

Aaron Powell Human Femurs. Okay, well that's a bit of a jump.

SPEAKER_02 7:48

Trevor Burrus, it is, yeah. It's a titanium non-contact bridging or NCD polyaxial locking plate. And that non-contact aspect is really crucial.

SPEAKER_00 7:55

Aaron Powell Because it hovers just slightly off the bone surface, right?

SPEAKER_02 7:58

Trevor Burrus Exactly. Yeah. It preserves the period steel blood supply, which, as you know, you desperately need for healing in those highly comminuted fractures.

SPEAKER_00 8:05

Aaron Powell Well, sure. Preserving blood supply is great, but I mean just knowing an implant is made of titanium doesn't exactly tell us if it can survive like a horse actually waking up from anesthesia.

SPEAKER_02 8:16

Aaron Powell Right. The dreaded recovery stall.

SPEAKER_00 8:17

Yeah.

SPEAKER_02 8:18

Yeah.

SPEAKER_00 8:18

How did this human plate actually handle a stall rest simulation?

SPEAKER_02 8:22

Aaron Powell So they ran cyclic fatigue testing to mimic those early critical days of recovery. And by applying uh 3,600 cycles of force to both constructs, the data showed something really interesting. Aaron Powell Okay.

SPEAKER_01 8:35

What did they find?

SPEAKER_02 8:36

The NCB plate actually provided a significantly stiffer construct under these conditions. We're looking at a mean displacement of just 0.22 millimeters for the NCB. Wow, 0.22. Yeah, compared to a much looser um 0.56 millimeters for the standard LCP.

SPEAKER_00 8:52

Aaron Powell Wait, so that's less than half the displacement?

SPEAKER_02 8:55

Exactly.

SPEAKER_00 8:55

Why is there such a massive difference in stiffness if you know they're both locking plates?

SPEAKER_02 8:59

Aaron Powell Well, it really comes down to uh the material physics. I mean, titanium is naturally more elastic than stainless steel.

SPEAKER_00 9:07

Right. It flexes a bit more.

SPEAKER_02 9:09

Yeah. So instead of concentrating all that mechanical stress right at the rigid screw heads, which is what happens with the LCT, the titanium MTB actually absorbs and disperses that continuous shock.

SPEAKER_00 9:21

Ah, so it spreads those micro movements across the entire plate.

SPEAKER_02 9:24

Exactly. It handles the shock absorption much better.

SPEAKER_00 9:27

Aaron Powell So it's kind of like the difference between driving nails straight into a flatboard versus using a tripod design, you know, where you can angle the legs outwards to grab the most solid, healthy wood available.

SPEAKER_02 9:38

Aaron Powell That's a great analogy, yeah. Because you can lock the NCB screws in place at variable angles using these specific caps, it creates a remarkably tighter, more stable hold against that

Single Cycle Failure Testing: Demonstrating identical maximum failure loads between constructs, while noting a distal screw bone-interface pull-out pattern on the third metacarpal bone (MC3) under supraphysiological stress.

SPEAKER_02 9:49

constant shifting.

SPEAKER_00 9:49

Aaron Powell Okay, but what about maximum load? Because, well, shifting is one thing, but sudden acute stress is another.

SPEAKER_02 9:55

Aaron Powell Right. And they tested that too. They did single cycle to failure testing. Okay. Basically applying massive acute force until the construct just broke.

SPEAKER_00 10:01

Aaron Powell And how did they compare there?

SPEAKER_02 10:03

The maximum failure loads were virtually identical. So the overall ultimate strength is totally comparable. But the NCB did show a really unique failure pattern under that extreme stress.

SPEAKER_00 10:15

Oh. What kind of pattern?

SPEAKER_02 10:17

The most distal screw in the third metacarpal bone, the MC3, it actually pulled out directly at the bone interface.

SPEAKER_00 10:24

Wait, really? If the most distal screw is ripping out of the bone, isn't that a massive red flag for you as a surgeon in the OR?

SPEAKER_02 10:31

It sounds bad, I know.

SPEAKER_00 10:32

I mean, why would I want to use a plate that risks bone interface failure right at the joint?

SPEAKER_02 10:37

Well, it sounds alarming, but context is key here. That pullout only occurred at ultimate failure loads that far exceed any normal post-op weight bearing.

SPEAKER_00 10:45

Okay, so we're talking absolute worst-case scenario loads.

SPEAKER_02 10:48

Exactly. It's a byproduct of the titanium's elasticity at the absolute breaking point. At normal loads, that flexibility actually protects the bone.

SPEAKER_00 10:57

Got it. So it's not failing under everyday stallwalking.

SPEAKER_02 11:00

Right. And more importantly, the polyaxial technology is what gives you

Variable Angle Trajectory: Harnessing a 30-degree cone of flexibility to capture irregular bone fragments and adjust for severe angular deformities without plate bending.

SPEAKER_02 11:04

the power to avoid placing screws and compromised bone to begin with.

SPEAKER_00 11:08

Ah, because you aren't forced into that standard 90 degree trajectory like you are with the LCP.

SPEAKER_02 11:12

Precisely. You're not stuck. Unlike the LCP, the NCB allows you to insert screws anywhere within the 30-degree cone.

SPEAKER_00 11:20

Oh wow. 30 degrees gives you a lot of room to work with.

SPEAKER_02 11:23

It really does. You just lock them into the plate after you've found the optimal angle.

SPEAKER_00 11:27

I mean, for a surgeon staring down a highly committed fracture or a severe angular deformity, being locked into 90 degree screw angles is a total nightmare.

SPEAKER_02 11:37

It is, and this means you can adapt your trajectory on the fly. You can capture those really difficult irregular bone fragments.

SPEAKER_00 11:45

Right, and you can adjust for severe valivus or valgus deformities.

SPEAKER_02 11:49

Exactly. And you can do it without having to awkwardly bend the plate or compromise its proximal alignment on the MC3 just to get a single screw to bite.

SPEAKER_00 11:57

So it aligns the hardware to the anatomy rather than forcing the anatomy to fit the hardware.

SPEAKER_02 12:02

That is exactly it. It's a huge clinical advantage.

SPEAKER_00 12:05

So just to wrap this up, for complex FETlock arthrodesis, borrowing this human femur technology offers you comparable ultimate strength to the standard LCP, but with much better immediate post-op stability against continuous micro movements.

SPEAKER_02 12:19

Yeah, and you get that vital interoperative flexibility to angle your screws exactly where they need to go in shattered bone.

SPEAKER_00 12:26

Which is huge. It fundamentally changes how you approach challenging joint anatomy.

SPEAKER_02 12:30

It really does. And it leaves you with this final thought. I mean, if a human femur plate translates this effectively to an equine fetlock, what other cross-species implant adaptations are sitting on the shelf right now, just waiting to solve your most frustrating veterinary orthopedic challenges?

SPEAKER_01 12:49

That's it for this episode of the Simony Surgery Podcast. This show is brought to you by Simony Protect Lavage, 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.