Simini Surgery Review: Small Animal Edition
Welcome to the Simini Surgery Review: Small Animal Edition—your shortcut to staying sharp in small animal surgery. We break down the latest peer-reviewed studies into clear, time-saving episodes you can listen to on your commute, between cases, or while walking the dog. Focused, fast, and clinically relevant—this is how busy surgeons stay current without spending hours digging through journals. Produced by Simini, creators of Simini Protect Lavage—the non-antibiotic lavage designed to target surgical site risks like biofilms and resistant bacteria.
Simini Surgery Review: Small Animal Edition
VCOT July 2025 – Ortho Part 1: TPLO Remnants, MPL Locking Plates & Implant Stress Risers
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In this Simini Small Animal Surgery Podcast episode, we continue our orthopedic coverage from the July 2025 issue of Veterinary and Comparative Orthopaedics and Traumatology (VCOT) by exploring how seemingly small surgical decisions can have major biomechanical consequences.
From preserving partial cruciate ligament remnants during TPLO to modern fixation strategies for tibial tuberosity transposition and the persistent challenge of stress concentration in locking plates, these studies provide practical insights for improving surgical outcomes and reducing complications.
In this episode:
✅ Almeida et al. — Investigated whether transecting the remaining fibers of a partially ruptured cranial cruciate ligament during TPLO influences postoperative patellar ligament thickening or shortening. Evaluating 56 stifles, the authors found no difference in postoperative patellar ligament changes between dogs whose remnants were transected and those whose remnants were preserved. Importantly, preserving the residual ligament may provide ongoing biomechanical support by limiting cranial tibial translation during gait and potentially reducing future meniscal injury and osteoarthritis progression.
✅ Eskelinen et al. — Evaluated a locking plate and pin fixation technique for tibial tuberosity transposition (TTT) in 65 medial patellar luxation surgeries. The technique achieved resolution of lameness in all patients and successful correction in 64 of 65 stifles. In cases where the surgical protocol was followed precisely, there were zero tibial tuberosity fractures, avulsions, or luxation recurrences, highlighting the importance of rigid fixation and meticulous implant placement.
✅ Hawker et al. — Examined whether locking head inserts (LHIs) improve the mechanical performance of locking compression plate constructs. Despite testing constructs with up to nine inserts torqued to 4 Nm, the authors found no measurable improvement in plate strain, construct stiffness, or compressive displacement. The findings challenge the assumption that filling empty combi holes strengthens plate constructs and reinforce the importance of thoughtful plate selection and working-length management instead.
Together, these studies emphasize a central orthopedic lesson: sometimes the best surgical decision is not adding more hardware—but understanding which details actually matter.
🎓 Journal Articles Discussed
- Almeida et al. — Effect of Cranial Cruciate Ligament Transection during TPLO on Patellar Desmitis in Dogs with Partial Cranial Cruciate Ligament Rupture
- Eskelinen et al. — Outcome and Complications Following Medial Patellar Luxation Corrective Surgery with Tibial Tuberosity Transposition Using a Locking Plate and a Pin Fixation: 45 Unilateral and 20 Single-Session Bilateral Procedures
- Hawker et al. — The Effect of Locking Head Inserts on the Biomechanical Properties of a 3.5-mm Broad Locking Compression Plate When Used in an Open Fracture-Gap Model
📚 From the July 2025 issue of VCOT
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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 continues our orthopedic coverage from issue 4, 2025, of veterinary and comparative orthopedics and traumatology, and we're focusing on a theme every orthopedic surgeon faces: optimizing outcomes through better surgical decision making. First, we'll look at a study by Almeida et al. Examining a question that many TPLO surgeons have debated for years. When managing a partial cranial cruciate ligament rupture, should the remaining ligament fibers be transected? The authors investigate whether removing the remnant ligament influences postoperative patellar ligament thickening and shortening, offering new evidence on the relationship between TPLO biomechanics, patellar desmitus, and cruciate preservation. Next we turn to Eskelen et al. who evaluate a novel locking plate and pin fixation technique for tibial tuberosity transposition during medial patellar luxation surgery. With complications related to traditional pin and tension band constructs remaining a concern, this study explores whether a more rigid fixation strategy can improve outcomes and reduce recurrence. Finally, we'll review Hawker et al. who tackle another important orthopedic question examining factors that influence surgical success and postoperative outcomes in canine orthopedic patients. Their findings add further perspective on how technical choices made in the operating room can affect long-term function and complication rates. Three studies. One common message small surgical decisions can have big consequences. From cruciate preservation during TPLO to fixation strategies for patellar luxation repair to the factors that shape postoperative success, this episode is all about refining technique through evidence. Let's dive in.
SPEAKER_03I've imagine you're uh fixing a freight bridge cable. Do you cut away the snapped hanging strands so the new structural supports can settle? Or do you leave them intact for whatever strength they have left? I mean, in veterinary surgery, that's kind of the exact dilemma you face with a partial cranial cruciate ligament tear or CCL.
SPEAKER_00Right. Yeah, it's a classic debate.
SPEAKER_03Exactly. When you're doing a TPLO procedure to stabilize a dog's stifle joint, do you transect the remaining ligament or not? So today we're doing a deep dive into some brand new data from Almeida et al. 2025 to definitively answer this. And um later we'll look at a massive blind spot inside closure that might actually be undoing all that hard work.
SPEAKER_00Yeah, this Almeida study is honestly exactly what we needed to settle the debate. They reviewed 56 stifles undergoing TPLO for partial CCL ruptures.
SPEAKER_01Okay, 56.
SPEAKER_00Right. And for 29 of those joints, the surgeons went ahead and cut the remnant CCL. For the other 27, they just, you know, left it right where it was. Got it. The whole goal was to see if cutting the remnant actually prevented postoperative patellar ligament thickening.
SPEAKER_03Aaron Powell I mean, I have to admit, my instinct is always to just clean the joint. Like snipping the remnant just feels right, you know.
SPEAKER_00Aaron Ross Powell Right, because you're looking at damaged tissue.
SPEAKER_03Aaron Powell Yeah, exactly. You've got this frayed damaged tissue in there. If you want to prevent inflammation, isn't it better to just get that dead tissue out of the way?
SPEAKER_00Aaron Powell Well, you'd think so, but the data says otherwise. Snipping it offers like zero protective effect against inflammation.
SPEAKER_03Aaron Powell Wait, really? None at all?
SPEAKER_00None. Across the board, patellar ligament thickness increased significantly anyway, jumping from a median of uh 2.4 millimeters before surgery to 5.8 millimeters six weeks post-op.
SPEAKER_02Oh wow.
SPEAKER_00Yeah, there was absolutely no statistical difference in thickness or length whether the remnant was cut or left alone.
SPEAKER_03Aaron Powell So the inflammation just happens regardless.
SPEAKER_00Aaron Powell Exactly. The inflammation is likely driven by the biomechanical changes, right? And you know, the s surgical trauma of the procedure itself, not the mere presence of the remnant ligament.
SPEAKER_03Aaron Powell Okay, so cutting it doesn't help with the inflammation. But um if it's already torn, what's the actual harm in just snipping it to tidy up the joint?
SPEAKER_00Aaron Powell The harm is that you're throwing away vital biomechanical support. Oh, I see. Yeah. Going back to your analogy, that frayed bridge cable still plays a crucial role. An intact partial CCL actually limits cranial translation of the tibia during the swing phase of the dog's gait.
SPEAKER_03Oh, so it's actively doing something.
SPEAKER_00Yes. Leaving it intact helps maintain stifle stability, which can decrease the chance of future meniscal injury and you know osteoarthritis down the road.
SPEAKER_03That makes total sense.
SPEAKER_00So the immediate takeaway for your practice is super clear, do not transect the remnant as a preventative measure.
SPEAKER_03So we're talking about consciously leaving something behind in the joint, that CCL remnant, because it actively helps the patient. Right. But let's flip that. What are we leaving behind in the joint that is actively harming the patient? Because according to independent head-to-head studies, our standard closure practices might be doing just that.
SPEAKER_00Yeah, this is a big one. At closure, most surgeons just default to a standard saline rinse.
SPEAKER_03Right. Just flesh it out.
SPEAKER_00Exactly. We assume it's physically fleshing out all the contaminants, but those independent studies reveal a major blind spot. Saline actually leaves 42% of bacteria behind in the joint.
SPEAKER_03Almost half. I mean, that is a massive risk to leave behind after you just spend all that time carefully preserving joint stability.
SPEAKER_01There really is.
SPEAKER_03Which brings us to Semini Protect Livage. It's a it's a 60-second non-antibiotic lavage that you use right before suturing. Unlike saline, which just loosely washes over the area, this upgrade actively removes 100% of the bacteria.
SPEAKER_00And the really great part is it doesn't disrupt your existing protocol, it simply reinforces it.
SPEAKER_03Yeah, you don't have to change your whole workflow.
SPEAKER_00Right. It targets exactly what saline mechanically misses, including resistant bacteria. You're no longer just like diluting the surgical site, you're actively clearing it. It basically replaces the microscopic doubt of a saline wash with actual clinical confidence.
SPEAKER_03It makes you wonder, you know, if standard saline is leaving behind almost half the bacteria during closure, what other gold standard protocols in our clinics are giving us a false sense of security?
SPEAKER_00That is a very good question.
SPEAKER_03Definitely something for you to ponder before your next procedure. Thanks for joining us on this deep dive, and we'll catch you next time.
SPEAKER_00You know, you just finished the tibial tuberosity transposition. The pins and the tension band wire look okay, but in the back of your mind, you are just waiting for something to migrate.
SPEAKER_03Oh, yeah. It is the classic OR headache. I mean, traditional TTT using pins and tension band wires carries an overall complication rate that sits uh anywhere from 11 to 43 percent.
SPEAKER_00Aaron Ross Powell Right. Which is exactly why we're doing this deep dive today. We are looking at a new surgical approach to see if it should, you know, change how you operate tomorrow. Our focus is a recent paper by Eskalin et al. 2025.
SPEAKER_03Aaron Powell Yeah. So the data we are looking at comes from a multi-center study by Eskelinen's team. They looked at 65 of these surgeries in small dogs with a median weight of about 6.2 kilograms.
SPEAKER_00Okay, so fairly small patients.
SPEAKER_03Exactly. And instead of the traditional pin and wire, they used a five-hole locking plate and a single pin to fixate the transposed tibial tuberosity.
SPEAKER_00Aaron Powell Well, let's jump straight to the clinical punchline here. After treating any like initial complications, lameness resolved in 100% of the cases. And the MPL resolved in 64 out of 65 stifles?
SPEAKER_03Aaron Powell Which are undeniably strong outcomes.
SPEAKER_00Aaron Powell Yeah, they really are. But I have to ask, I mean, is this just unnecessarily upgrading standard hardware? Like, is swapping a tension band for a locking plate actually changing the mechanical stability of the joint? Or is it just the difference between, say, taping two blocks of wood together versus bolting them to a steel bracket?
SPEAKER_03Aaron Powell It is absolutely the steel bracket scenario. And it really comes down to the biomechanical reality of what a plate allows you to do.
SPEAKER_00Aaron Powell Because of the compression.
SPEAKER_03Aaron Powell Well, tension band wires rely on compressing the bone fragment against the tibia, which makes that fragment incredibly prone to shifting under, you know, the cyclic load of a dog running and jumping.
SPEAKER_00Well, those shear forces are massive.
SPEAKER_03Exactly. A locking plate, however, acts like an internal fixator. The screws lock directly into the plate, which neutralizes those shear forces entirely.
SPEAKER_00Aaron Powell Ah, I see. Which is especially critical for your grade three and four MPLs, right? Because you need a marked transposition of the tibial tuberosity to properly align the quadriceps mechanism.
SPEAKER_03You do, and moving the tuberosity that far creates a massive mechanical vulnerability. Historically, with the pin and wire techniques, we see a luxation recurrence rate of uh five to twelve point four percent.
SPEAKER_00Yeah, you move it and the quad just wants to rip that fragment right back off.
SPEAKER_03Which brings us to the standout statistic from this study. In the 56 cases where the specific surgical protocol for the plate and pin was followed strictly, there were zero tibial tuberosity evolsions, zero fractures, and zero laxation recurrences.
SPEAKER_00Wait, zero?
SPEAKER_03Zero.
SPEAKER_00Okay, that is a number that makes you stop and pay attention. But uh the operative phrase there is when the protocol was followed strictly, right?
SPEAKER_03Oh yes. The data comes with a massive statistical warning. Deviating from their specific surgical protocol, increase the odds ratio of complications by 11.3.
SPEAKER_00Wow. 11.3 times more likely to have a complication. That is huge. I mean, if we are talking about cyclic fatigue and metal failure, my guess is surgeons are trying to get away with minimal hardware and basically paying the price.
SPEAKER_03You hit the nail on the head.
SPEAKER_00So is the intra-op adjustment here just about redundancy, like just adding more screws?
SPEAKER_03Well, a crucial interop adjustment is to always use at least three screws for your secure fixation. The data showed that when surgeons use 1.5 millimeter screws, they occasionally broke during the follow-up period.
SPEAKER_00Because the sheer forces of a running dog on a transpose tuberosity are just immense.
SPEAKER_03Precisely. If you drop down to two screws, the cyclic load concentrates on too small a cross section of titanium and it just snaps. You need that minimum of three intact screws to handle the fatigue and keep the tuberosity stable.
SPEAKER_00Got it. So the take-home message for you in the OR tomorrow is that plate pin fixation is a highly stable alternative that significantly lowers luxation recurrence. I mean, it provides the mechanical superiority of an internal fixator as long as you strictly follow the plate sizing and positioning protocols.
SPEAKER_03Yeah, knowledge is most valuable when applied correctly. But uh this raises an important question for the future of this procedure.
SPEAKER_00Oh, what's that?
SPEAKER_03Out of the 20 recorded complications across the entire study, eight of them were actually caused by the pin itself, migrating, bending, or breaking.
SPEAKER_00Wait, really? So the pin was actually the weak link?
SPEAKER_03It seems that way, yeah.
SPEAKER_00That's wild. If the locking plate is doing all the heavy lifting for stability and, you know, neutralizing those shear forces, could future iterations of this surgery just ditch the pin entirely and rely purely on the locking plate?
SPEAKER_03That is the big unknown right now.
SPEAKER_00Man, it is a fascinating question to chew on before your next MPL repair. I mean, could you eliminate that post stop rad dread just by leaving the pin on the tray?
SPEAKER_03Well, if you want to dive into the exact plate positioning protocols from Eskalin et al. 2025, be sure to check the show notes for the full article link.
SPEAKER_01Next study.
SPEAKER_00We know your OR schedule is packed, so we are jumping right in.
SPEAKER_03Exactly. And our mission today is extracting actionable OR intelligence from a single critical article. We're looking at Hawker et al. 2025. So picture this. You are in the OR.
SPEAKER_00Right, a familiar scene.
SPEAKER_03Right. And you're applying a minimally invasive locking compression plate, an LCP. Naturally, you leave some screw holes empty over the fracture gap to uh preserve the biology.
SPEAKER_00Which is standard, good practice, yeah.
SPEAKER_03Aaron Ross Powell But you know those empty cobby holes act as stress risers. Like weak points where fatigue and catastrophic failure are most likely to occur.
SPEAKER_00They are basically ticking time bombs in a high stress construct. Yes.
SPEAKER_03So think of those empty holes like the perforated line on a notepad.
SPEAKER_00Oh, that's a good way to put it. Trevor Burrus, Jr.
SPEAKER_03Right. That perforation is exactly where the material naturally wants to bend or snap. So logically, dropping an insert into that hole, like a locking head insert or LHI, that should act like reinforcing the perforation and stiffen the whole construct.
SPEAKER_00Aaron Powell Well, it is a very tempting anatomical logic. I mean, we instinctively want to fill a weak spot to make it stronger.
SPEAKER_03Aaron Powell I mean, yeah, it totally makes sense.
SPEAKER_00Trevor Burrus, Jr.: Right. But Hawker et al. 2025 actually just put this exact idea to the test. They ran an ex vivo study using 13-hole, 3.5 millimeter broad LCPs.
SPEAKER_03Aaron Powell Okay, and they mounted those on bone models, I assume?
SPEAKER_00Aaron Powell Yes, surrogate bone models with a 10 millimeter central fracture gap. And they cyclically loaded them with either zero, three, or nine LHIs placed in those empty holes.
SPEAKER_03Wow. Up to nine inserts.
SPEAKER_00Yeah. They really uh wanted to see if quantity mattered at all. And to give the inserts the absolute best chance to stiffen the construct, they torque them down to a solid four newton meter.
SPEAKER_03Wait, four newton meters? That is a serious amount of torque for just a plug.
SPEAKER_00It really is.
SPEAKER_03So with that massive amount of friction, especially cramming nine of them in there, surely nine inserts perform better under load than zero.
SPEAKER_00You would totally think so. But biomechanics, um, it doesn't really care how tight the screw is if the underlying geometry is flawed.
SPEAKER_03Yeah, wow. Okay, so what is the clinical punchline here?
SPEAKER_00It's quick and clear. There was absolutely no difference.
SPEAKER_03Wait, no difference at all?
SPEAKER_00None. Adding LHIs did not change plate strain, it didn't change peak-to-peak compressive displacement, and it did not alter the axial construct stiffness whatsoever.
SPEAKER_03So even with nine inserts torqued down, the strain over the central fracture defect remained identical.
SPEAKER_00Exactly identical. Well, it really comes down to the unique architecture of the combi hole itself. Think of the combi hole like a figure eight cutout.
SPEAKER_03Right, the two distinct halves.
SPEAKER_00Yeah. So when you drop an LHI in, you are only plugging the threaded locking half of that figure eight.
SPEAKER_03Oh, I see. You are completely ignoring the unthreaded compression side of the hole.
SPEAKER_00Precisely.
SPEAKER_03Ah, so it's like putting a solid steel peg into a sliding track. Sure, the peg itself is incredibly strong, but because the rest of the track is just, you know, empty air, the metal around it can still flex and bend under an axial load.
SPEAKER_00That is the exact mechanism. An asymmetrical hull under axial load simply cannot be stabilized by a symmetrical plug.
SPEAKER_03That is fascinating.
SPEAKER_00Yeah, even with nine of these inserts clamped down at four newton meters, they failed to provide any biomechanical advantage to the 3.5 millimeter broad plate.
SPEAKER_03So the maximum strain predictably hit right over that fractured defect anyway.
SPEAKER_00Exactly as it did when the holes were left completely empty.
SPEAKER_03You know, usually we're digging through these papers looking for a new technique or like an extra step that fixes a complication. But honestly, I think this is the best kind of data because it gives you permission to do less.
SPEAKER_00Yes, absolutely.
SPEAKER_03Don't waste valuable ORR time or client money meticulously plugging empty combi holes, hoping for a magic biomechanical boost.
SPEAKER_00That is the immediate practical takeaway here. But the real aha moment is realizing that a combi hole isn't just an empty space you can fill, it is a structural compromise built directly into the plate's DNA.
SPEAKER_03You can't patch it from the inside out.
SPEAKER_00Exactly. If you are facing a high implant load scenario with a 3.5 millimeter broad LCP, LHIs will not save the construct. You just must rely on alternate methods of strain reduction.
SPEAKER_03So what does this all mean for your surgical strategy moving forward?
SPEAKER_00It means thinking outside the hole, literally.
SPEAKER_03Yeah. Since plugging the holes doesn't work, how else might you creatively manipulate your working length, your plate selection, or um the biological envelope to protect that vulnerable center point?
SPEAKER_00That is the real question surgeons need to ask themselves.
SPEAKER_03Absolutely. You have to design a better way to hold the bone together from the start, rather than just trying to plug the gaps later. Well, that's something to mull over before your next procedure. You can find the full link to Hawker et al. 2025 in the show notes.
SPEAKER_01That's it for this episode of the Simony Small Animal Surgery Podcast. This show is brought to you by Simony 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.