Deep Digital Flexor Tenotomy: Pain Relief and Comfort for Horses with Chronic Laminitis

Chronic laminitis forces every equine clinician into the same hard question: when comfort keeps slipping and radiographs keep worsening, what can truly change the mechanics of the foot and the horse’s day-to-day life? We sit down with Dr. Jim Orsini to talk about deep digital flexor (DDF) tenotomy, a procedure many people still treat as “last resort,” and why the data argue it may deserve earlier consideration in the right chronic rotational laminitis cases.

We dig into what the surgery is actually trying to accomplish: reducing the pull of the deep digital flexor tendon on the coffin bone (third phalanx) so the foot can realign to the ground surface. Jim walks us through the patient selection details that matter, including the rotation versus sinking distinction, and why great farriery is not optional. We also discuss the practical, clinic-friendly ways to judge success, from owner-observed comfort and stable pain-medication needs to radiographic progression like lysis, sole penetration, and hoof wall separation.

Then we get into the findings that made us pause, including the striking improvement signal at three to six months and the nuance around age, underlying causes like equine metabolic syndrome, and why chronic cases can be recognized late. We close with the real-world conversation every veterinarian has to have: cost, expectations, and the truth that chronic laminitis care is a long-term commitment, not a one-and-done fix.

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Transcript

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Meet The Hosts And Guest

Lisa Fortier 0:35

Welcome to Epic Award-winning Veterinary Vertex, the Avium May Journal's podcast where we delve in behind-the-scenes looks with manuscript authors. I'm editor-in-chief Lisa Fortier, joined by Associate Editor Sarah Wright. Today we're discussing how deep digital flexor tenotomy or DDF tenotomy provides pain relief and clinical comfort in horses with chronic laminitis with my longtime colleague who I admire dearly, Jim Orsini. Thank you for joining us, Jim.

SPEAKER_03 1:03

Oh, it's a pleasure to be here. It's great to see a great colleague. So thank you both for the invitation and the opportunity.

Why Chronic Cases Needed Surgery

Lisa Fortier 1:10

Yeah, thanks, Jim. Many of us really struggle with as the when, the how, the why. What led your team to really take this a step further and examine how DDF tenotomy as a treatment option for horses with chronic laminitis?

SPEAKER_03 1:24

Yeah, this is something that, you know, when you see a lot of laminitis cases, and our certainly our hospital population sees many of these cases, and a lot of them are performance horses. Uh, but we're also seeing a lot, we were seeing a lot more of the geriatric horse, the horses that were in their teens and twenties that were developing laminitis. And likely due to equine metabolic uh syndrome or disease. And so, you know, owners obviously were so committed to the care of their horse. Um, and you'd do the routine stuff as far as looking at what may be the underlying cause, obviously, and then trying the the normal uh analgesics and farrier. Um and then many of these would continue to progress relative to one, their lack of comfort or improvement in comfort, and more importantly, what we're seeing radiographically. And so in many of these cases, we were seeing that the third phalanx, uh coffin bone, was actually starting to deteriorate. And certainly the area where we were seeing it most is at the toe, where when the rotation, you know, they were again, as I always try to explain to owners, is that that the horse, instead of weight bearing on on the entire foot, is weight bearing on a small portion of it. And so we were seeing lysis of the third phalanx, and with that, certainly decrease in comfort. And this was based on certainly the owner's um uh findings, and that is they spend more time down, uh, they had to increase the amount of of analgesics, and then, as I said, radiographic evidence where the third phalanx continued to rotate. So it became a point where we tried what was considered to be all the routine options relative to management. Uh, and then when you always bring the term surgery in, it always always creates some resistance because it's invasive in their minds and potentially has complications. And so sadly, many of these cases were cases that were done sort of as a last resort. And these were cases that have progressed over months uh and were unresponsive to treatment. And so what we saw is that in working with um uh our farrier, uh very talented uh you know, individual that actually we decided that if we could realign the third phalanx, and currently the literature is out there about that, um, uh, but also uh do it in a way that was uh continuous. It was just it wasn't a one-time treatment, but was done over months, uh, that we actually saw the comfort improve, that the soul depth, actually the the point from the bottom of the third phalanx to the soul actually increased, uh improved relative to growth. We knew that the blood supply was improved as well, too. So it it became more of a kind of a backdoor entrance into this, more as a last resort. But we think that, you know, in case selection, that this could be done even sooner, and you still have a much better outcome relative to quality of life. And I think that's really the goal.

Sarah Wright 4:27

Jim,

What DDF Tenotomy Aims To Do

Sarah Wright 4:28

for clinicians who may be unfamiliar with the procedure, when is deep digital flexor tonotomy typically considered? And what are its intended goals?

SPEAKER_03 4:36

Okay, so the the goals of the procedure is to um reduce the tension or the pull of the deep digital flexor on the third phalanx. And people say, well, if you do that, that's so important relative to the flexion of the uh of the of the distal phalanx and in particular the third phalanx. Um but what we found is that what you do is you allow the foot to realign. You take the tension off the pull of the deep digital flexor tendon. It allows us to take that third phalanx and put it in a position that mechanically is going to be much better at actually supporting the weight of the uh of the individual horse. And so I think that the important thing is to think about it from a mechanical standpoint, i.e., realigning the coffin bone relative to the ground surface. Uh, and also that the tenotomy, although it does create a separation, over time fills them with fibrous tissue. But by that time, we hope we hope we have them in a mechanical position so that we've actually lengthened the deep deflexor tendon without actually uh inhibiting the ability to actually flex the the uh the the third phalanx or the distal phalanx uh in particular. So it's it's really uh twofold, as I said, reduce the pole of the deep deflexor tendon and realign that coffin bowl relative to the ground surface.

Farrier Mechanics And Rotation Criteria

Lisa Fortier 5:57

So you're very privileged, as I am at Cornell, to have a great farrier to work with because it takes a big team to take care of these horses and the clients.

SPEAKER_03 6:05

Right. Yeah, for sure. I mean, I think that that's probably one of the most important things is to uh for clinicians to align themselves with a talented farrier, someone who actually is willing to look at at uh what needs to be done to improve the mechanics of the foot. Uh and it takes some, you know, real uh expertise because what you want to do, I think, as we all know, is you want to try to realign from dorsal to palmer or plantar, but also medial to lateral. And I think sometimes we forget about the medial to lateral realignment, which is also very important in uh and in comfort and in reducing the progression of the disease relative to uh the third phalanx uh separation or or sinking or rotation. And again, I want to emphasize that the tonotomy is for those horses that are rotating and not sinking. I think in sinking, it really has no purpose, uh purpose clinically that's going to improve

Measuring Comfort And Radiographic Change

SPEAKER_03 7:06

it.

Lisa Fortier 7:06

Yeah, it's a good distinction. You've talked about this heterogeneous patient population. So some are metabolic, some might not be. Uh, chronic laminitis is, of course, that we're talking about here, or acute on chronic, maybe even, but uh, and then depth of the soul, all sorts of things. Uh, can you describe that patient population, how those things are evaluated, especially pain and comfort following DDF tonotomy?

SPEAKER_03 7:31

Sure. Um, and we tried to keep it relatively simple. Uh, and we use kind of what I consider a binary system, and we use uh a statistical analysis called incident rate ratio, and it really compares two groups. And so we divide them up into three groups. One, did they improve or not improve? And this was certainly based on the uh primary care veterin's assessment. Certainly the owner's input relative what they were seeing uh relative to that. Uh also, as part of that improvement, is is that they need to be maintained on the same level of pain medication as they were prior to the procedure. So those are so the so that's the one improved versus unimproved. The other is whether there are progressive changes in the third phalanx and whether was there continuous lysis or loss of bone? Was there penetration of the soul? Uh, was a separation of the hoof wall. So that was the second group was relative to third phalanx. And then the other one was very simple. Were they discharged if they were hospitalized or not? And and those many times would be those that went on uh to um for for euthanasia. Um and so those are sort of how we approached it uh to keep it simple, but yet statistically important relative to trying to differentiate those three categories.

Sarah Wright 8:51

That

Results And The Age Question

Sarah Wright 8:52

is a great segue into our next question. Jim, what were the most significant findings regarding outcomes in horses that underwent deep to shelf flexor tonotomy?

SPEAKER_03 9:00

The thing that surprised us was that the improvement um at a three to six months, and we use a relatively short term because, as I said, many of these have been so chronic for so many years. We thought that if we at least tried to get some uh handle or arms around a timeline, um, and we figured figured that three to six months certainly should be a time whether we either see an increase in improvement or we see a decline to help us. And we found that those that actually had the tenotomy uh were twenty-fold more improved by a fold by a factor of twenty. So that told us that um if you compare the improved versus non-improved, that those in the improved group were 24 20fold more likely to be improved than those that did not have the tonotomy.

Lisa Fortier 9:49

Yeah, really amazing. Like, you know, before this, most of us are just like it's chronic, do all the other things that wouldn't be considered a DDF. So this is really important to share. Um I was surprised, Jim, that age was a factor associated with complications of the third failings. At least I they seem these chronic cases seemed, as you said, they've been going on a long time. The age group sort of clusters. Uh, what's the take-home from that finding?

SPEAKER_03 10:14

Yeah, I think that's still unclear. You know, although there certainly the trend was looking at the uh incident rate ratio, that uh clearly age did have a factor where each increase in age was an increase of about a 16% chance of of uh of problems. And we think it's probably, and again, without having the the data to actually support that, that probably in the younger age is that the underlying cause for the disease was different from those in the older group. And in the older group, I think what we found is that um uh most of the time the incidence of or occurrence of uh laminitis was more insidious. All right. And so, you know, in the younger group, there usually some sort of traumatic event or some sort of uh colitis or some other medical problem that are acute or more acute in nature, versus in the older group, it's more insidious and many times not recognized until it's uh much further along in the in the disease where the owner recognizes that there is a real problem. So we think that might be the the uh explanation, uh although, you know, without having uh looked at that and taken a deeper dive, I think that's just uh more thought thought-provoking rather than actually uh confirmatory.

Lisa Fortier 11:35

Yeah. And so wouldn't age wouldn't make you think, oh no, you're 15. I'm not going to consider this for your patient demographic.

SPEAKER_03 11:44

Absolutely not. I I think that in fact, um, you know, as as they enter that period of of uh being older, certainly uh what they do as well certainly uh reduces. So, you know, the real athletes of thermodynamics, which was the actually the breed that was represented as the as their largest number in our study, are those that are their racing career or their athletic performance are usually in the much younger age. And so I think that as they age, you know, um, that they have less expectations relative to the owner, they're sort of retired. You know, they may be doing some um low-level stuff, but in fact, uh the demands on them are much less. And so I think those those cases in particular probably still have uh a very good uh outcome uh relative to age. So age, uh although may play a role in the incidence of it, it doesn't necessarily uh predict the outcome. All right so I think that those uh older horses still can do very, very well. Uh again, assuming that we try to address the underlying cause, right? And that's I think we all know that with laminitis, uh identifying what is the the cause or suspected cause uh for the for the uh uh occurrence of the disease is really critical. And managing that. So the overweight horse needs to be on a different diet. Uh they need to be getting some exercise. You know, all the things that we talk about uh in on the human side of metabolic disease, where they're they're uh eating poorly and they're not getting exercise. Same thing holds true for our older horses.

Medical Management Plus Long-Term Farriery

Sarah Wright 13:27

Jim, what role should deep digital flexor tonotomy play alongside medical management in chronic laminitis cases?

SPEAKER_03 13:34

I think probably the thing that I came away with is that um, you know, you can't separate the medical management and the farrier uh treatment uh versus the surgery itself. I think they're all related. In other words, so I think um that that the medical management for whatever the underlying cause needs to be managed so that we can actually control if they're insulin dysregulation, that that needs to be addressed by diet, et cetera, um, or other medication. And there are new meds meds that are coming out now that actually can do a much better job of managing these horses with insulin dysregulation. And certainly the farrier part, I think, is really critical. Um, you know, one of the things that uh Pat Riley and I did, we worked is that really trying to maintain a program where these horses came back on a regular basis to be sure that they were getting uh the correct uh mechanical support to the foot. You know, what happens is that I think we become complacent. The horse improves, and so we think great, we don't need to do uh make that trip to uh the hospital to have a farrier do it or have a farrier come out more often. But in fact, doing that is an is an imperative that in fact you need to maintain the good medical care, uh the good farrier management along with the deep digital flexor tenotomy as for long-term success.

Sarah Wright 14:59

What additional evidence is needed to better define patient selection and timing for the procedure?

SPEAKER_03 15:05

Yeah, I think, you know, as I'm as we talked about earlier, one of the things that we um we mentioned in our paper is that it was more considered as a salvage procedure rather than actually something that might actually have some real benefit earlier on. And so one of the things I think we need to think about, and it would be great to actually develop a prospective study uh looking at those horses that have the treatment done uh much sooner. And I think one of the things that sort of drove us down the path of the thanotomies was was when we were seeing progressive lysis of the third phalanx, the complications that occur with with chronic glaminitis. And so I think maybe looking at a group that in fact have the rotation uh and are not responsive to uh treatment both medically and for standard farrier treatment, that those actually have the tonotomy much earlier. Because I think they have a better chance of having a better long-term outcome relative to quality of life and even your function. I think those horses then can do some light work, you know, with pleasure riding, that many of these older horses that we waited until it was a salvage procedure, you know, they basically were um comfortable in their stall, out walking a little bit, but not doing anything athletic at all. So I think we can we can move that that uh uh caliber earlier and probably have a much better effect long term.

Three Takeaways And Earlier Timing

Lisa Fortier 16:35

Yeah, I think this final takeaway will certainly show my bias as an equine veterinarian. We typically ask our guests what is one key takeaway? Uh, I can think of handfuls, because again, what we're talking about today with Jim is chronic laminitis, not acute. Uh so, Jim, what are the top three takeaways that you hope equine veterinarians will take away from your study in this podcast?

SPEAKER_03 16:59

Yeah, I think number one is that there um are newer and better options that are either currently available or coming available to treat these horses much earlier in the disease. Um, that too, farrier is an essential component of any successful outcome, uh, whether it's before they have a tonotomy or after tonotomy, that without a talented farrier working with the the uh veterinarians and clinicians treating these cases, that the chance for long-term success is certainly lessened. And number three is that um educating the owner earlier on in the in the disease, I think is really important. I think one of the real primary importance is that it's a team of uh team approach. It involves the owner, it involves the the um uh the veterinarian, and it involves the farrier, and of course the patient, and assessing the patient really is important too, as to whether they really are a candidate for the procedure based on a criteria that we develop for that. So those are the three points I think that really are important. Um uh recognizing that this is not a hopeless disease, two, getting the owner involved early on, and three, making sure that the team is well well organized to actually continue to manage these horses.

Counseling Owners On Cost And Commitment

Lisa Fortier 18:21

Yeah, what one more question, Jim. This is something I sort of struggle with with trying not trying to be realistic, but not discourage owners. How do you counsel them to say, look, your horse is nine and you're going to put in this amount of money, your horse could live to be 30. Like, do the math. Like you could buy a very nice house for the amount of money that you might spend on this horse. Yeah. How do you counsel them?

SPEAKER_03 18:45

Well, I think a lot of it is um providing the facts um and being very open about um about things such as you said, because it is a financial commitment, really, to treating these horses. Because, as I said, you know, you you you get an improvement, um, but it requires the consistent farrier management in order to maintain the mechanics of it. And so I think that it's really just I think a matter of uh being openly, openly honest about it. Uh, and I think a lot of it is really the owner's um really connection with that particular course, really. And it's such a personal decision. And, you know, people will say to me, Well, what would you do? And I said, I, you know, I think it's it's fairly easy for me to to to uh tell you what I think I should do, but it this is really an a decision that is not just for today, but it's long-term. And I think that they have to understand that it's a long-term commitment in managing these horses. Uh and it's not a one and done type deal, and then uh you can move on and everything will be the same. It's it is a chronic disease, and I think that's what people need to

Wrap-Up And Listener Requests

SPEAKER_03 19:53

understand.

Sarah Wright 19:53

Perfect. Yes, very well said. Jim, thank you so much for joining us today.

SPEAKER_03 19:59

My pleasure. Thank you for the invitation.

Sarah Wright 20:01

For our listeners and viewers, you can read Jim's article in Japan. I'm Sarah Wright with Lisa Cortier. Be sure to tune in next week for another episode of Veterinary Vertex. And don't forget to leave us a rating and review on Apple Podcasts or a re-listen.