Veterinary Surgery Deep Dive: Equine Ortho — July 2026 Edition

In this episode of the Simini Equine Surgery Podcast, we explore the orthopedic research from the July 2026 issue (Issue 5) of Veterinary Surgery, where three studies challenge common assumptions about infection control, fracture fixation, and athletic prognosis after arthroscopic surgery. 

From questioning whether high-volume arthroscopic lavage can truly eradicate septic arthritis, to comparing fixation strategies for proximal sesamoid fractures, and evaluating the long-term racing performance of Standardbreds following arthroscopic removal of femoropatellar OCD lesions, these papers reinforce the importance of evidence-based surgical decision-making.

In this episode:

✅ Friedlund et al. investigated whether 20 liters of arthroscopic lavage alone could eliminate bacteria from experimentally induced septic arthritis in horses. Despite the large lavage volume, all Staphylococcus aureus joints and half of the Escherichia coli joints remained culture-positive 24 hours later, demonstrating that mechanical lavage alone is insufficient to eradicate infection. The findings reinforce that septic arthritis requires an aggressive multimodal treatment strategy, combining arthroscopic lavage with systemic and local antimicrobial therapy, rather than relying on fluid volume alone. 

✅ O'Brien et al. compared the bone screw fastener (BSF) with traditional 4.5-mm cortical screws in an ex vivo model of mid-body proximal sesamoid bone fracture repair. Although the newer BSF implant offered no biomechanical advantage over conventional cortical screws, the study demonstrated a clear benefit of two-screw fixation, increasing construct yield strength from approximately 1,500 N to over 2,100 N, regardless of implant type. The authors also identified significantly greater fracture gap displacement along the abaxial cortex, highlighting the importance of controlling rotational forces when repairing these challenging fractures. 

✅ Rhodes et al. evaluated the racing performance of 45 Standardbred horses following arthroscopic removal of femoropatellar osteochondrosis dissecans (OCD) lesions and compared them with 196 unaffected paternal half-siblings. Although treated horses recorded slightly fewer starts during their three-year-old season, lesion grade did not significantly affect the likelihood of racing, and there were no meaningful differences in race wins or earnings compared with unaffected controls. Even horses with bilateral or concurrent OCD lesions achieved excellent long-term performance, supporting early arthroscopic intervention before intensive training begins. 

Together, these studies demonstrate that successful orthopedic outcomes depend not on assumptions, but on understanding the biological and biomechanical realities behind every surgical decision.

🎓 Journal Articles Discussed

• Friedlund et al. — The Effect of Arthroscopic Lavage Volume on Bacterial Culture of Egress Fluid in Experimentally Induced Septic Arthritis
• O'Brien et al. — Biomechanical Comparison of the Bone Screw Fastener to Conventional Cortical Buttress Screws for Repair of Mid-Body Proximal Sesamoid Bone Fractures
• Rhodes et al. — Outcome of Standardbred Racehorses Following Femoropatellar Arthroscopy for Osteochondrosis Dissecans

📚 From the July 2026 Issue (Issue 5) of Veterinary Surgery

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Transcript

SPEAKER_00 0:04

Hi, 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 July 2026 issue of veterinary surgery, featuring three studies focused on septic joint management, fracture fixation, and return to athletic performance after arthroscopic surgery. First, we'll look at Friedland et al., who investigated whether high volume arthroscopic lavage is enough to eliminate bacteria from septic equine joints. Even after 20 liters of lavage, bacterial cultures were not consistently negative, and several horses still had positive synovial fluid cultures the following day. The findings reinforce that lavage alone is not sufficient and must remain part of an aggressive multimodal treatment strategy that includes systemic and local antimicrobial therapy. Next we'll review O'Brien et al. who compared the bone screw fastener with conventional cortical screws in an ex vivo model of midbody proximal sesamoid bone fracture repair. The newer implant did not outperform the standard cortical screw, but the study found a clear biomechanical advantage for two screw constructs over single screw repair, regardless of screw type. The authors also identified greater fracture gap displacement on the abaxial side, raising important questions about implant positioning and how surgeons can better counteract the forces acting across these difficult fractures. Finally, we'll discuss Rhodes et al. who evaluated racing performance in standard bred horses after arthroscopic removal of femoropitellar osteochondrosis disicans lesions. Although affected horses had slightly fewer starts at three years of age, lesion grade did not significantly influence the likelihood of racing, and there were no meaningful differences in wins or earnings compared with unaffected siblings. The study provides reassuring evidence that arthroscopy performed before intensive training has minimal impact on early racing potential. Three studies. One common theme using stronger evidence to refine treatment decisions, whether that means recognizing the limits of joint lavage, selecting a more stable fracture construct, or giving owners a clearer prognosis after arthroscopic surgery. Let's dive in.

Friedlund et al. Study: Evaluation of 20-liter high-volume arthroscopic lavage in experimentally induced E. coli and S. aureus septic arthritis in horses.

SPEAKER_03 3:13

Welcome to today's deep dive. So imagine blasting a single infected joint with 20 liters of fluid. You'd think, right, that the sheer mechanical force would just leave the surgical site perfectly sterile.

SPEAKER_02 3:25

You would absolutely think that. I mean, 20 liters is a massive amount of fluid.

SPEAKER_03 3:28

Right. But this new veterinary surgery study we're looking at today proves that assumption completely wrong. And it really rewrites how we need to think about standard closure protocols in your OR tomorrow.

SPEAKER_02 3:41

Yeah, we are diving into Friedland et al. 2026. The researchers experimentally induced septic arthritis in horses using uh E. coli and S. aureus.

SPEAKER_03 3:51

Okay.

SPEAKER_02 3:51

And then they performed orthoscopic lavage using that massive 20-liter volume.

SPEAKER_03 3:55

Aaron Powell, so let's unpack this for a second because 20 liters for one joint is well, it's just an incredible amount of fluid.

SPEAKER_02 4:01

It's basically a flight.

SPEAKER_03 4:02

Exactly. It feels like if you run that much volume through an isolated space, the sheer force should mechanically strip away everything, like power washing a driveway, you know. But clearly that's not what happened.

SPEAKER_02 4:13

Aaron Powell Not at all. The data completely defies that mechanical expectation. So they sampled the synovial fluid 24 hours after the lavage.

SPEAKER_03 4:22

And what did they find?

SPEAKER_02 4:24

Despite 20 liters of flushing, 100% of the Saureus cases and 50% of the E. coli cases still returned positive synovial fluid cultures.

SPEAKER_03 4:34

Wait, 100%. Like all of the S. Aureas joints were still infected?

SPEAKER_02 4:38

Every single one.

SPEAKER_03 4:39

Wow. So they aren't just surviving the fluid, they must be actively resisting it somehow. I mean, this isn't like power washing loose dirt off a driveway anymore. It sounds way more like trying to power wash cured super glue.

SPEAKER_02 4:50

That's a really good analogy, actually.

SPEAKER_03 4:52

Aaron Powell Is this a volume problem, or are we just fundamentally misunderstanding how these pathogens behave under pressure?

SPEAKER_02 4:57

Aaron Ross Powell Well, it is entirely a behavioral and biological problem. The bacteria aren't just sitting loose in the wound bed waiting to be washed away. Trevor Burrus Right.

SPEAKER_03 5:05

They aren't just floating

Biofilm Anchorage and Multimodal Therapy: Failure of mechanical flushing against anchored bacterial biofilms and the necessity of combined systemic and local antimicrobials.

SPEAKER_03 5:06

around in there.

SPEAKER_02 5:06

Exactly. Pathogens like S. aureus rapidly form these microscopic biofilms and physically anchor themselves into the hyperplastic synovium. They literally build a microscopic fortress.

SPEAKER_03 5:18

Aaron Ross Powell A fortress. So the mechanical sheer force of the fluid just washes over the top of them.

SPEAKER_02 5:23

Precisely. It flows right over without breaking their structural hold on the tissue.

SPEAKER_03 5:26

Aaron Ross Powell So for the surgeon standing at the table, the clinical punchline here is that high volume arthroscopic lavage is just biologically insufficient on its own.

SPEAKER_02 5:35

Yeah, that is the core takeaway. The data proves you cannot rely on mechanical flushing alone to clear an infection.

SPEAKER_03 5:41

Right. You have to do more.

SPEAKER_02 5:42

You must back up the mechanical flush with aggressive multimodal therapy. That means integrating systemic and local antimicrobials. The physical volume of standard fluids is essentially useless against anchored biofilms.

SPEAKER_03 5:58

You know, if 20 liters of

Simini Protect Lavage: Application of a 60-second non-antibiotic lavage to eliminate the 42% bacterial remainder left behind by standard saline rinses.

SPEAKER_03 6:00

fluid can't dislodge bacteria in a horse's joint, it completely changes how we should view our standard saline closures in human surgery, too.

SPEAKER_02 6:08

Oh, absolutely. It exposes a massive blind spot in our everyday routines.

SPEAKER_03 6:12

Yeah, we play so much blind faith in standard saline to just do the heavy lifting of clearing bacteria before closing a site.

SPEAKER_02 6:18

And that leap from the veterinary study to your daily OR is exactly where the risk multiplies. Independent head-to-head studies evaluating standard saline rinses before closure actually show that saline leaves a staggering 42% of bacteria behind.

SPEAKER_03 6:35

That is wild.

SPEAKER_02 6:37

It is. But that 42% gap is exactly what SeminiProtect Livage is engineered to eliminate.

SPEAKER_03 6:42

Right. Because in those same head-to-head studies, while saline left 42% behind, Semini Protect Lavage left 0%.

SPEAKER_02 6:50

It's a 60-second non-antibiotic lavage designed specifically to reinforce your existing closure protocol.

SPEAKER_03 6:57

So it just removes what saline misses by breaking down those invisible risks at closure, and it does it without adding antibiotics to the local environment.

SPEAKER_02 7:04

Exactly. It's not disrupting your surgical workflow at all. It's just a strategic swap right at the point of closure to target those anchored pathogens.

SPEAKER_03 7:12

It's just about reinforcing your success. Because as the Friedland study clearly demonstrates, mechanical flushing with standard fluids leaves far too much behind.

SPEAKER_02 7:21

Right. It totally ignores the biological reality of how bacteria secure themselves to tissue.

SPEAKER_03 7:26

So your actionable intelligence for the OR tomorrow is simple. High volume does not equal high clearance. Always back up your lavage with a multimodal approach because those pathogens are actively resisting your standard mechanical flush.

SPEAKER_02 7:40

Absolutely. And we've put full links to the Friedland article in the show notes for you to review.

SPEAKER_03 7:45

Perfect. And this leaves a really important question for you to consider the next time you are closing a site. If bacteria can form impenetrable biofilms so rapidly that 20 liters of fluid can't strip them away, how much invisible pathology are we locking in every time we assume a wound looks clean to the naked eye?

SPEAKER_01 8:06

Turning the page.

SPEAKER_02 8:12

Imagine

O'Brien et al. Study: Ex vivo biomechanical evaluation of proximal sesamoid bone fracture repair comparing bone screw fasteners (BSF) and cortical screws.

SPEAKER_02 8:13

trying to perfectly bolt together two halves of like a highly tensioned spring.

SPEAKER_03 8:19

That's a nightmare scenario.

SPEAKER_02 8:20

Right. Actually, uh it's worse than that. When you're repairing a medial mid-body proximal sesamoid bone fracture, you aren't just fighting straight line tension from the suspensory apparatus.

SPEAKER_03 8:30

You're fighting rotational torque.

SPEAKER_02 8:32

Exactly. So welcome to today's deep dive. We know your time is precious, so our mission today is to extract purely actionable surgical intelligence for the OR. We're applying the strict Semini Style Guide to dissect some new ex vivo data from O'Brien et al. 2026.

SPEAKER_03 8:48

Aaron Powell And this data completely recontextualizes how we secure those repairs. I mean, if you've been reaching for the newest implants, hoping for a biomechanical edge, well, this study might change your entire approach.

SPEAKER_02 8:59

Because the standard assumption in orthopedics is that a more complex implant design, you know, yields superior fixation. Aaron Powell Right.

SPEAKER_03 9:05

Which O'Brien et al. put to the test on equine cadaver forelimbs. They specifically compared the conventional 4.5 millimeter cortical screw against a newer 3.5 millimeter bone screw fastener.

SPEAKER_02 9:17

The BSF, right?

SPEAKER_03 9:18

Yeah. Yeah, the BSF. And this features multi-directional interlocking threads theoretically designed to bite into the bone, locking the fracture fragments together against those massive tensile forces.

SPEAKER_02 9:29

Aaron Powell So the expectation is that those interlocking threads should provide this like iron grip compared to a standard thread profile.

SPEAKER_03 9:37

Aaron Ross Powell That's the theory.

SPEAKER_02 9:38

I mean, if you have an implant engineered specifically to resist pull out, it just stands to reason a single BSF would outperform a single cortical screw.

SPEAKER_03 9:47

You would certainly

Single vs. Double Screw Mechanical Yield: Equivalent yield thresholds between single BSF and cortical screws (~1,500 N) contrasted with a 600 N increase in two-screw constructs (~2,100 N).

SPEAKER_03 9:48

think so. But under single cycle loading to failure, a single 3.5 millimeter BSF yielded at approximately 1,500 buttons.

SPEAKER_02 9:57

Wait, so an implant specifically designed with multi-directional interlocking threads doesn't actually offer a stronger hold than the standard screw we already use.

SPEAKER_03 10:06

Not at all. The standard 4.5 millimeter cortical screw yielded at roughly the exact same threshold.

SPEAKER_02 10:12

Wow.

SPEAKER_03 10:12

Yeah. The multidirectional thread design offered no statistically significant biomechanical advantage when placed as a single implant.

SPEAKER_02 10:20

Well, if the thread profile doesn't change the failure point, the limiting factor isn't the grip of the metal in the bone. The limiting factor must be the mechanics of the bone itself under load. A single implant, no matter how advanced the thread, is still just a single point of fixation.

SPEAKER_03 10:35

Which brings us to the real breakthrough of this study, which is quantity over type. When the researchers moved to a double screw configuration, construct yield jumped to roughly 2100 newtons.

SPEAKER_02 10:46

That is a massive jump.

SPEAKER_03 10:48

It really is. And that 600 newton increase occurred whether they use two BSFs or two standard cortical screws.

SPEAKER_02 10:55

Okay. That jump in holding power really forces us to look at how the stress is distributed across that fracture line. If one screw fails at 1500 and two screws jump to 2100, we aren't just adding metal.

SPEAKER_03 11:08

No, we're fundamentally changing the biomechanical geometry of the repair. Right. And the kinematic data from the failure points explains this perfectly. The study demonstrated that gap displacement at construct failure was significantly higher a baxley than axially.

SPEAKER_02 11:22

Oh, so the outside edge.

SPEAKER_03 11:23

Yes. The baxial edge of the proximal sesamoid is taking the absolute brunt of the tensile forces.

SPEAKER_02 11:28

So if the displacement is entirely a baxial, a single centrally placed screw is essentially acting as a full chrome.

SPEAKER_03 11:36

Exactly.

SPEAKER_02 11:36

It's less like pulling

Abaxial Forces and Rotational Torque: Identification of higher abaxial gap displacement highlighting the need to counteract rotational torque with multi-screw constructs.

SPEAKER_02 11:37

a rope straight back and more like trying to um pry a heavy door off a single hinge. The outside edge takes all the rotational torque, twisting the bone apart regardless of how well the single screw's threads are gripping.

SPEAKER_03 11:49

Aaron Powell That's a great analogy. And placing that second screw fundamentally alters that dynamic. A double screw configuration better distributes those rotational and abaxial forces.

SPEAKER_02 11:58

Because it physically blocks that twisting motion.

SPEAKER_03 12:01

Right. It stabilizes the highly stressabaxial edge, preventing it from pivoting around a single central axis. That stabilization is what provides the 2100 newton yield threshold.

SPEAKER_02 12:11

So for your next medial mid-body PSB case in the OR, the mandate is clear. A two-screw configuration offers a definitive biomechanical advantage over a single screw.

SPEAKER_03 12:21

Absolutely.

SPEAKER_02 12:21

Securing the fracture is about fighting the rotation and stabilizing the abaxial edge, not just fighting the raw pull with a fancy thread. The type of implant you pull from the kit matters far less than simply having two of them.

SPEAKER_03 12:33

Yeah, but since we now know definitively that the abaxial edge suffers the highest displacement, it actually forces us to reconsider how we approach the hardware itself in the future.

SPEAKER_02 12:43

How so?

SPEAKER_03 12:44

Well, if the forces are fundamentally different on the axial versus abaxial sides of the same bone, the future of these procedures might involve deliberately mixing screw types.

SPEAKER_02 12:54

Wait, really? In the exact same bone.

SPEAKER_03 12:56

Yeah, just to neutralize those specific forces. We could potentially see constructs using a standard cortical screw axially paired with a specialized interlocking screw abaxially, engineered specifically for those isolated high displacement forces.

SPEAKER_02 13:11

Custom tailoring the hardware configuration to the specific biomechanical realities of each side of the fracture line. That is definitely something to consider before you scrub in next. Thanks for joining us for this deep dive.

SPEAKER_01 13:26

Continuing with the next published study.

Rhodes et al. Study: Evaluation of racing performance in Standardbred horses following arthroscopic removal of femoropatellar OCD lesions.

SPEAKER_03 13:34

Imagine you are staring at a radiograph of a standardbred yearling stifle. You see this massive subchondral defect on the lateral trochlear ridge.

SPEAKER_02 13:43

Right. And your gut immediately says this horse's racing career is compromised before it even starts.

SPEAKER_03 13:49

Exactly. You're bracing yourself for really difficult conversation with the owner. But uh what if that massive lesion actually doesn't matter?

SPEAKER_02 13:55

Aaron Powell It is such a fantastic question. I mean, we're so conditioned to equate visible tissue damage on a film with a damaged career trajectory.

SPEAKER_03 14:04

Oh, for sure.

SPEAKER_02 14:05

And while arthroscopic removal of femoropatellar osteochondrosis discicins, or OCD, is a super standard procedure, the data we traditionally use to counsel owners is heavily skewed toward thoroughbreds.

SPEAKER_03 14:17

Aaron Powell Which is exactly why today's deep dive is zeroing in on standard breads. We want to extract some actionable surgical decision-making intelligence for your practice.

SPEAKER_02 14:26

Absolutely.

SPEAKER_03 14:27

So we're looking at the clinical punchline from Rhodes et al. 2026 to figure out how this surgery actually impacts their racing career and, you know, give you solid intel for your pre-operative client discussions.

SPEAKER_02 14:37

Aaron Powell Well, to get right into it, Rhodes and the team analyzed a retrospective cohort. They looked at 45 client-owned standard breads that had arthroscopy for femoral patellar OCD.

SPEAKER_03 14:49

Okay, got it.

SPEAKER_02 14:50

But what gives this data real weight is the control group. They compared these surgical cases to uh 196 of their contemporaneous paternal half siblings.

SPEAKER_03 15:00

Wow, that's a big group. Yeah.

SPEAKER_02 15:02

And all those siblings had totally unaffected clean joints.

SPEAKER_03 15:05

Aaron Powell Okay, so it's genetically apples to apples, but um I really have to push back on the size assumption here. Sure. Like, wait, shouldn't a larger, more severe lesion automatically equal a worse prognosis and fewer starts for a race horse?

SPEAKER_02 15:20

You'd totally think so.

SPEAKER_03 15:20

Right. Because more tissue damage usually means more trouble.

SPEAKER_02 15:23

Aaron Powell It seems obvious, but actually the data says otherwise. When they graded these lesions based on the length of the defect, the grade just didn't significantly impact the proportion of horses starting a race.

Prognosis and Lesion Grade: Confirmation that defect size/grade does not significantly affect start rates, total wins, or total earnings compared to unaffected siblings.

SPEAKER_03 15:35

Aaron Powell Wait, really? Not at all?

SPEAKER_02 15:36

Not at all. It was like 77% for horses with grade one lesions that started, and 72% for those with grade two lesions.

SPEAKER_03 15:44

That defies conventional logic. I mean, a grade two lesion is a significantly larger defect. Why wouldn't that hold them back?

SPEAKER_02 15:51

It's wild, isn't it?

SPEAKER_03 15:52

Yeah. How are they compensating for that much missing cartilage?

SPEAKER_02 15:56

Aaron Powell Well, it really comes down to the timing of the intervention in joint biomechanics. By going in arthroscopically around one to two years of age, you are removing the loose flap and flushing the joint out.

SPEAKER_03 16:06

Before intensive training begins.

SPEAKER_02 16:08

Exactly. You're essentially halting the inflammatory cascade early. And because you stop that cascade before repetitive high-speed loading occurs, the joint environment stabilizes.

SPEAKER_03 16:19

Oh, I see.

SPEAKER_02 16:20

Yeah. The size of the initial defect becomes secondary to simply getting the inflammatory debris out of there.

SPEAKER_03 16:24

Aaron Powell So for the owner, this surgery is basically like a reset button, not a career roadblock. Trevor Burrus, Jr.

SPEAKER_02 16:30

That's a great way to put it. You're preserving the machinery.

SPEAKER_03 16:33

Mm-hmm.

SPEAKER_02 16:33

And this shows up in the high yield quantitative data. You know, the numbers that actually matter to a client's wallet.

SPEAKER_03 16:39

Aaron Powell Which is earnings and wins.

SPEAKER_02 16:41

Right. There was absolutely zero difference in total race wins or total earnings between the horses who had the surgery and their unaffected half siblings.

SPEAKER_03 16:51

Zero difference. That's incredible. But uh what if you're in the joint and you find bilateral lesions?

SPEAKER_02 16:57

Yeah, that happens.

SPEAKER_03 16:58

Because usually once they are in the joint and see that or concurrent OCD in other joints,

Bilateral and Concurrent OCD Outcomes: Maintenance of equal earnings and wins despite modest reductions in three-year-old start numbers in bilateral cases.

SPEAKER_03 17:03

my optimism drops. Does this data hold up for bilateral cases?

SPEAKER_02 17:07

It does, and that's a really crucial point for practice. The study found that even with bilateral lesions or concurrent OCD in other joints, it only modestly affected the number of starts during their three-year-old season.

SPEAKER_03 17:19

Just modestly.

SPEAKER_02 17:20

Yeah. And crucially, they still went on to have equal wins and equal overall earnings compared to the controls.

SPEAKER_03 17:25

Wow. So intervening arthroscopically before intensive training really does protect their athletic potential entirely.

SPEAKER_02 17:32

Precisely. The bottom line take-home message here is that you can confidently advise your clients that arthroscopic removal of femoropatillar OCD lesions in standard breads yields an excellent prognosis.

SPEAKER_03 17:43

With minimal impact on overall racing success.

SPEAKER_02 17:46

Exactly. Regardless of the subchondral bone defect size, it shouldn't dictate a panic.

SPEAKER_03 17:51

That is fantastic news for preoperative discussions. But you know, there is one lingering detail from Rhodes et al. 2026 that is worth thinking about.

SPEAKER_02 18:00

Oh, the qualifying times.

SPEAKER_03 18:02

Yeah. The study noted that the affected horses actually had slightly slower qualifying times than the controls, despite having equal earnings later on.

SPEAKER_02 18:09

Right. They caught up but started a bit slower. Exactly.

SPEAKER_03 18:12

It makes you wonder: I mean, could early OCD cause subtle permanent changes in gate mechanics or speed even after a perfectly executed surgery?

SPEAKER_02 18:21

It's a really fascinating question to consider the next time you're reviewing a set of stifles.

SPEAKER_01 18:30

That's it for this episode of the Simony 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 it in your own procedures, you'll find information and links in the show notes. Thanks for listening, and we'll see you in the next episode.