VCOT January 2026 – Ortho Part 2: Elbow Orthobiologics & Rethinking DPO Plate Selection

In this Simini Small Animal Surgery Podcast episode, we continue our orthopedic coverage from the January 2026 issue of Veterinary and Comparative Orthopaedics and Traumatology (VCOT) by challenging two common assumptions surrounding timing and surgical planning. 

One study investigates whether orthobiologic injections administered immediately after elbow arthroscopy actually remain inside the joint, while the second demonstrates that double pelvic osteotomy (DPO) plates consistently produce less acetabular rotation than their labeled angle, changing how surgeons should approach implant selection.

In this episode:

✅ Rustemeyer et al. — A cadaveric CT study evaluating contrast retention following elbow arthroscopy. Compared with simple arthrocentesis, elbows undergoing arthroscopy demonstrated immediate postoperative extravasation, resulting in an estimated 64.3% dilution of injected fluid. The findings suggest that orthobiologics such as PRP or stem cell therapies administered immediately after arthroscopy may largely escape into the surrounding soft tissues rather than remaining intra-articular. Delaying injections until portal sealing occurs may substantially improve therapeutic delivery. 

✅ Trommelmans et al. — A CT-based retrospective study measuring the true acetabular rotation achieved during double pelvic osteotomy. Across 49 hips, every plate angle consistently underperformed its nominal correction. Thirty-degree plates produced a median correction of only 23.4°, 25° plates achieved 16.7°, and 20° plates achieved approximately 15°. The study demonstrates that surgeons should anticipate 5–8° of lost rotation due to pelvic elasticity and soft tissue tension, recommending that 7–10° be added to preoperative planning measurements when selecting implant angles. 

Together, these studies emphasize that successful orthopedic surgery depends not only on technical execution, but also on understanding what happens immediately after surgery—and how living tissues respond to implanted hardware.

🎓 Journal Articles Discussed

• Rustemeyer et al. — Extravasation of Intraarticular Fluid Injection Following Canine Elbow Arthroscopy: A Cadaveric Study
• Trommelmans et al. — Effect of Double Pelvic Osteotomy on Dorsal Acetabular Rim Angle Using Computed Tomography in 27 Dogs

📚 From the January 2026 issue of VCOT

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Transcript

SPEAKER_01 0:04

Hi, I'm Carl Damiani, and this is the Simene 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 1, 2026 of Veterinary and Comparative Orthopedics and Traumatology, with two studies that challenge assumptions about what happens before and after some of our most common orthopedic procedures. First, we'll examine a cadaveric study by Ruste Meyer et al., investigating what happens to intraarticular injections immediately after elbow arthroscopy. Using CT imaging, the authors demonstrate significant extravasation of injected fluid following arthroscopy, raising important questions about whether orthobiologics and other injectable therapies should be administered at the end of the procedure or delayed until later. Then we turn to Trommelmans et al., who quantify the true amount of acetabular rotation achieved during double pelvic osteotomy. By measuring dorsal acetabular rim angles on CT, the study shows that the correction achieved is consistently less than the nominal plate angle, providing practical guidance for implant selection and surgical planning in dogs with hip dysplasia. Two studies. One common theme: questioning our assumptions and using objective evidence to refine surgical technique from when we inject biologics to how we select implants. Let's dive in.

SPEAKER_00 1:46

Welcome to today's deep dive. We've got a really interesting one tailored for you today. So imagine you just finished a complex canine elbow arthroscopy, right? You pull your scope and you inject a uh a really high-dollar orthobiologic.

SPEAKER_02 2:00

Yeah, like PRP or, you know, stem cells.

SPEAKER_00 2:02

Exactly, stem cells. But according to this new research from Restemeier et al.

SPEAKER_02 2:12

It really isn't.

SPEAKER_00 2:13

I mean, it is less like a targeted therapy and more like uh, well, like porting liquid gold into a bucket with holes drilled in the bottom.

SPEAKER_02 2:20

That is a painful analogy, but it's incredibly accurate. That mechanical mismatch is really the core issue here. I mean, as surgeons, you rely on these intra-articular therapies to promote healing.

SPEAKER_00 2:32

Right.

SPEAKER_02 2:33

But Rustemeyer's team demonstrated just how heavily routine surgical portals compromise the joint's hydrostatic seal.

SPEAKER_00 2:39

Okay, so how did they actually prove that?

SPEAKER_02 2:41

Well, they took 16 canine cadaver elbows. And they tracked contrast fluid using CT scans over uh a 15-minute window. They basically compared a simple arthrosentesis, which is just a basic needle poke, against post-arthroscopy injections.

SPEAKER_00 2:58

But wait, doesn't the joint capsule naturally reseal enough? Like once the instruments are removed, doesn't the surrounding soft tissue envelope provide, I don't know, some immediate mechanical tamponade?

SPEAKER_02 3:08

You'd definitely think so.

SPEAKER_00 3:10

Right. I think it would close up enough to hold a small volume of liquid.

SPEAKER_02 3:13

Yeah, the soft tissue does provide superficial coverage, but it just doesn't restore the capsule's structural integrity against hydrostatic pressure.

SPEAKER_00 3:21

Oh, I see.

SPEAKER_02 3:22

Yeah. The routine widening of your portals with instruments fundamentally stretches and alters the capsular tension. So when you inject fluid immediately co-stop, you're actively increasing intra-articular pressure.

SPEAKER_00 3:33

And it has nowhere to go but out.

SPEAKER_02 3:35

Exactly. That fluid immediately follows the path of least resistance right through those compromised portal tracks. And the CT scans proved it happens at time zero.

SPEAKER_00 3:43

Wait, really? At time zero?

SPEAKER_02 3:45

Yes. It isn't a slow seep, it is an instantaneous dump into the periarticular tissue the exact moment the fluid goes in. The 15-minute tracking showed no progressive leakage because, well, it all happened right away.

SPEAKER_00 3:59

Wow. So the internal pressure forces it out instantly. What are the actual dilution numbers we're looking at here? Because if the therapy is just hitting the periarticular tissue instead of, you know, bathing the cartilage, that severely undercuts the value for the client.

SPEAKER_02 4:12

Aaron Powell It does. The arthroscopy group experienced a massive 64.3% dilution effect directly due to that immediate extravization.

SPEAKER_00 4:20

Over 60%. That's huge.

SPEAKER_02 4:22

Yeah, 64.3%. If you are injecting right after pulling your scope, more than half of your therapeutic concentration is just lost to the surrounding soft tissue.

SPEAKER_00 4:31

Aaron Powell Man. So the actionable surgical takeaway for your OR tomorrow is incredibly clear.

SPEAKER_02 4:36

You have to delay it.

SPEAKER_00 4:37

Right. Delay your liquid orthobiologic injections until a later time point.

SPEAKER_02 4:41

Aaron Powell Exactly.

SPEAKER_00 4:42

Well, that significantly alters the immediate post-op workflow. I mean, if we are delaying those regenerative therapies, our immediate focus before closure has to shift entirely back to joint environment prep.

SPEAKER_02 4:52

Right, decontamination.

SPEAKER_00 4:54

Yeah. We are routinely fleshing the joint, but uh standard saline has its limits there too, right?

SPEAKER_02 5:00

Oh, it definitely does. Independent head-to-head studies show standard saline leaves about 42% of bacteria behind in the joint space.

SPEAKER_00 5:08

Almost half.

SPEAKER_02 5:08

Yep. Saline just lacks the chemical ability to break down bacterial adherence. And this is exactly where integrating Semony Protect Livage into that preclosure window becomes such a powerful tool.

SPEAKER_00 5:20

Because it performs better than saline.

SPEAKER_02 5:22

Way better. In those same studies, Semine left 0% of bacteria behind.

SPEAKER_00 5:28

To achieve total clearance without antibiotics, it must be using something mechanically or chemically different to break those bonds. I mean, how is it clearing the 42% that saline leaves intact?

SPEAKER_02 5:38

It really comes down to targeted surfactants. Simony Protect Livage is specifically formulated to physically disrupt biofilms. It detaches resistant bacteria from the tissue surfaces so they can actually be flushed out.

SPEAKER_00 5:51

Ah, rather than just flowing over them like saline does.

SPEAKER_02 5:54

Exactly. It's just a quick 60-second wash step right before you suture. It effectively gives you a totally clean slate before the capsule seals without disrupting your existing protocol.

SPEAKER_00 6:05

It makes complete sense to optimize the environment if you have to wait to inject the biologics anyway.

SPEAKER_02 6:10

Absolutely.

SPEAKER_00 6:11

So to summarize the protocol shift for you, wait on your orthobiologic injections to avoid that massive time zero extravization, and maximize your closure prep by actively breaking down biofilms rather than just rinsing them.

SPEAKER_02 6:24

That's the perfect summary.

SPEAKER_00 6:25

But uh here's something else to consider before we wrap up.

SPEAKER_02 6:27

Yeah.

SPEAKER_00 6:28

If a standard artoscopic portal compromises the capsule enough to cause a 64% dilution of our injected fluids, how heavily is that same mechanical leakage altering the joint's natural synovial fluid dynamics? Oh wow. Right. And the immediate post-op lubrication before healing even occurs, something for you to chew on. Thanks for joining us for today's deep dive.

SPEAKER_01 6:53

Here's the next article.

SPEAKER_00 6:59

As a surgeon, when you select a 30-degree locking plate from your tray, you know, you expect exactly 30 degrees of rotation. You're dealing with precisely engineered titanium.

SPEAKER_02 7:11

Right, exactly. But you're putting it into a biological environment, right? A young, dysplastic puppy pelvis, which is, well, it's highly elastic and dynamic.

SPEAKER_00 7:20

Aaron Powell Yeah. And that friction between static engineering and dynamic biology is what we're focusing on today. This deep dive is all about translating a retrospective CT study Tramolomens et al. 2026.

SPEAKER_02 7:33

Aaron Ross Powell Right, from Vetcomp orthop traumatol.

SPEAKER_00 7:35

Trevor Burrus Exactly. And we're turning it into a direct, actionable shift for your double pelvic osteotomy planning.

SPEAKER_02 7:40

Trevor Burrus Because the goal in a DPO is pretty straightforward when you want to rotate the acetabulum to improve joint congruency. Trevor Burrus, Jr.

SPEAKER_00 7:46

Right. And you usually just reach for a 20, 25, or 30 degree plate to dictate that shift. But you know, I always think of this like steering a boat.

SPEAKER_02 7:53

Aaron Powell Oh, steering a boat?

SPEAKER_00 7:54

Yeah. Like if I turn the wheel exactly 30 degrees, the current means the boat doesn't actually pivot a full 30 degrees, right? So does the canine pelvis act the same way? Like are surgeons actually getting the ex degree of rotation printed on the box?

SPEAKER_02 8:07

Aaron Powell Well, uh the short answer is no. And Trommelmans et al. 2026 actually proved this. They analyzed 49 hips using pre-op and immediate post-op CT scans.

SPEAKER_00 8:18

Okay. 49 hips.

SPEAKER_02 8:19

Yeah. And by measuring the dorsal acetabular rim angle or diara, they could track exactly how much rotation the surgeon achieved compared to the fixed angle stamped on the plate.

SPEAKER_00 8:29

Aaron Powell And the results. I mean, I'm guessing the implants under deliver.

SPEAKER_02 8:32

Big time. Across the board, there is this phenomenon of lost rotation. Whether they used a 20, 25, or 30 degree plate, there's a really consistent deficit.

SPEAKER_00 8:41

Wait, really? How much of a deficit?

SPEAKER_02 8:42

Uh so 30 degree plates only achieved a median of 23.4 degrees of rotation.

SPEAKER_00 8:47

Wow. So that's a loss of like 6.6 degrees right there.

SPEAKER_02 8:50

Yeah. And 25 degree plates. They achieved about 16.7 degrees, which is roughly an 8.3 degree loss. Right. And even the 20 degree plates only hit 15 degrees, meaning you lose about 5 degrees.

SPEAKER_00 9:01

So you're losing 5 to 8 degrees across the board. Why is that happening?

SPEAKER_02 9:04

Aaron Powell It mostly comes down to the elasticity of the pelvic symphysis and just uh the 3D geometry of the pelvis resisting that rotation.

SPEAKER_00 9:13

Right. Because in young dogs, that symphysis is incredibly pliable.

SPEAKER_02 9:17

Aaron Powell Exactly. Most of the rotation created during a DPO occurs right at the level of the symphysis, not just through iliac torsion.

SPEAKER_00 9:25

Aaron Powell So you're forcing this bone into a new position, but the intact istium and the soft tissues are they're actively pulling it back toward its original state. Ah, so it's acting exactly like a heavy torsion spring. You twist the wrench, but the internal tension pulls some of that rotation right back the second you let go.

SPEAKER_02 9:42

Aaron Powell That's a perfect way to visualize it. That tissue tension is completely fighting your plate.

SPEAKER_00 9:47

So how does a surgeon actually adjust their pre-op planning based on this? Because the standard math clearly isn't working out.

SPEAKER_02 9:53

It's not. Historically, if you wanted an ideal post-op Dera of zero degrees, you'd measure your pre-op Dara, add a standard five degree buffer, and pick your plate size.

SPEAKER_00 10:03

Aaron Powell Okay, so if my pre-op Dara was, say, 19, I'd add five, get 24, and just reach for the 25 degree plate.

SPEAKER_02 10:10

Exactly. But what this data clearly shows is that a five degree buffer is just not enough to overcome that tissue tension.

SPEAKER_00 10:16

You need a bigger margin.

SPEAKER_02 10:17

Right. To actually hit that target Dara of zero, you need to add seven to ten degrees to your pre-op Dara measurement.

SPEAKER_00 10:24

Seven to ten degrees? I mean, that is a massive clinical shift for your next case.

SPEAKER_02 10:29

It really is.

SPEAKER_00 10:30

Yeah.

SPEAKER_02 10:30

If you just select an implant based on a one-to-one rotation assumption, you're leaving the joint under rotated. Bumping your calculation by seven to ten degrees actually respects the biomechanical reality of the patient.

SPEAKER_00 10:42

Don't trust the plate angle to deliver a perfect one-to-one rotation. You always have to calculate for that expected five to eight degree loss.

SPEAKER_02 10:48

Absolutely.

SPEAKER_00 10:49

But you know, this also introduces a really compelling variable into how we view postoperative success overall.

SPEAKER_02 10:55

Oh, for sure.

SPEAKER_00 10:55

Like if there is this much inherent, completely unpredictable tissue resistance dictating the final rotation, could this explain why some structurally perfect DPO surgeries still yield unpredictable long-term kinematic outcomes in these dysplastic dogs?

SPEAKER_02 11:10

That's the million-dollar question. It forces us to ask whether we are truly optimizing the joint mechanics for the long term or simply achieving the maximum rotation the soft tissue tension will allow on that specific day.

SPEAKER_00 11:21

Yeah, that is definitely something to consider next time you're reviewing a post-operative CT scan. Full article links for Trommelman's et al. per 2026 are in the show notes for you to review.

SPEAKER_01 11:50

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.