Being pet parent to an amputee dog or cat sometimes feels like flying blind. It's hard to know what to expect as their bodies grow older. That's why we want to see a Tripawd Lifetime Study happen!

Can we make a Tripawd Lifetime Study happen? 

Tripawds can have great lives, there's no doubt about it. But the fact is, the longer they live as amputees, the more they are prone to osteoarthritis and injury. The severity and types of problems are difficult to predict though, because not enough Tripawd-specific studies exist. 

A few years age the Morris Animal Foundation kicked off multi-million dollar Golden Retriever Lifetime Study. It's largest study of its kind to support canine health and will examine risk factors for cancer and other important diseases in dogs. The findings will be used as a launching point for many other health studies in dogs. 

When we heard about this study, our first thought was: Cool! Our next was, "Why can't we do a smaller version of this for Tripawd dogs and cats?"

Watching many dogs in the Tripawds community grow old has demonstrated to us that even amputee dogs like Spree who get the best rehab, pain management and vet care will still be affected by musculoskeletal problems.

Wouldn't it be great if we could research those changes in Tripawds over time, to help Tripawd pet parents of the future avoid them? We think a "Tripawd Lifetime Study" can do it!

Today on Tripawd Talk Radio we explore that idea in a chat about the what, why and how to conduct a major Tripawd Lifetime Study. Our vet expert is Dr. Felix Duerr from Small Animal Orthopedics and Sports Medicine at Colorado State University. For time considerations, we limit the discussion to dogs but hope to have a future chat about the possibility of a Tripawd cat lifetime study. 

Don't want to listen to the podcast? Check out the full transcript below!

Transcript:
The What, Why and How of a “Tripawd Lifetime Study”

TRIPAWDS: This is Tripawd Talk Radio recorded on October 7th, 2019. Welcome to the show, Dr. Duerr!

DR. DUERR Thank you very much. Thank you for having me and thank you for bringing this topic – giving this topic some attention.

TRIPAWDS: Dr. Duerr, it’s so good to have you back and this is a really fun topic that we’re going to discuss today because it’s kind of – it’s a wild dream really and something that you and I talked about when Wyatt was at CSU for his last evaluation. I’ve been thinking about a lifetime study for a while now because I’ve been watching our dog get older and I have seen the effects that being three-legged has had on him.

I know there are other dogs out there who are going through the same thing, if not much worse because they’re not receiving the kind of awesome care that Wyatt gets when we’re at CSU.

So you and I had kind of bounced around this idea during our appointment and I thought, well, let’s do a little discussion about it so that maybe we could get some input from other people and see if we can make this dream a reality. So thank you so much for sharing your expertise with us.

DR. DUERR: I’m happy to do so.

What are the long-term issues of being a Tripawd?

TRIPAWDS: So when it comes to three-legged dogs, you see a lot of them in your work. Can you describe to us the kinds of challenges that you’re seeing with dogs who have been on three legs, even for a short period of time, but definitely over the course of two, three or more years?

DR. DUERR: Yeah, I would love to. So I think maybe to give everybody a little bit of a summary of kind of what we see here, I think there’s a wide range of reasons for dogs to become tripods. So one of them could be that there is let’s say bone cancer. It’s a common problem in the lower leg and then amputation is still one of the most common choices to treat that and that’s probably where most of the research was done in the cancer world and there are – as all of you probably have heard this before, there is a saying that dogs come with three legs and a spare, meaning that they do quite well with a limb amputation.

I think that’s very true. When there is a cancer or if there is something that can be fixed or that we don’t have a good treatment option for, it is a great option and it’s good for us to have that as a solution that they get around very well on three legs and particularly during the early phase, we can help them to adjust to that.

But they can do amazing things on three legs as most people that listen to this probably know. So that’s great but then there’s this other part and that is when dogs become older like you mentioned and they have been walking on three legs for a long time.

There are a lot of changes that occur and that then has an impact on many of the joints and that’s what we see a lot in our orthopedic medicine and mobility service and that is that dogs, at some point, they have a more difficult time to compensate for that.

That becomes harder then to address because now you have all these joints that are arthritic or collateral ligaments that are – have been – taken over too much work and it’s harder than to address that once they – those changes are chronic.

What is known about the bio mechanical changes of being a Tripawd?

TRIPAWDS: We’ve definitely seen that in Wyatt over time. Arthritis has kind of taken over his world a little bit and we try to manage it as best we can. These are things that we never saw in our first tripawd who lost a front leg, which I know has different consequences. He was only a tripawd for two years, so we didn’t get to experience this whole range of effects. Can you tell me what – what do we know and not know about the bio mechanical challenges of being a tripawd?

DR. DUERR: Yeah, that’s a great question. There actually is some work that came out of the oncology department here at CSU where basically what they did is they did gait analysis and kinematics. So that is putting markers on the dogs and looking at the motion in the joints and the spine.

They basically compared normal dogs to tripods. They had one group that was full limb amputees and one group that was pelvic limb amputees. We do know a lot about that. There’s quite a few changes as one might expect that happened with that. Obviously when you remove one of the legs, there are more forces that are acting on the other three legs because the dog is still weighing the same amount.

They also were – identified specific joints that then have to have greater range of motion because of that. So it’s a compensation mechanism. There’s much more motion in the spinal column and one of the other things is – that happens with that and that’s I think what we see clinically a lot is that because that second leg is missing in the front or in the back, the remaining leg has to shift the location. So shift the center of gravity, and it’s not really designed that way.

That’s I think why we see a lot of these secondary arthritic changes and changes to the collateral ligaments or the ligaments that are stabilizing the joints over time because it’s not something that’s a problem for – like you say, maybe a year or two or something like that.

But when you see dogs that had for example an amputation as a puppy, when they become older, yeah, that’s where that becomes an issue.

Are there any studies specific to Tripawds?

TRIPAWDS: Just off the top of your head, how many studies exist right now that look at this specific subject about the effects of amputation on a dog? Can you guess?

DR. DUERR: Oh, sure, yeah. I think that there are different types of studies, right? So there’s quite a few. I mean when I say quite a few overall, I think the effects that we’re talking about, a couple of handful of studies.*

But there are a number of studies that have done – basically have surveyed owners of dogs with three legs and the question has been, “What’s their quality of life and what kind of changes do they see?” and not surprisingly, this is a bit of a – it’s not the greatest way to research that question, asking owners that potentially have elected to amputate their dog’s leg, to be like, “What do you think about it?” because obviously you want to do the best for your dog and you don’t want to feel like oh, that was the wrong decision.

So I think there’s a little bit of bias with that. But despite that, I think people identify that there are some changes in the dog’s attitude, what they do and all that. But it is really – it goes back to your point of none of these studies have really looked at this more in the long term, right?

That’s really the information that’s missing and that’s where I think we have some work to do is identifying, “Well, what is the timeline for a dog to really have significant problems that are not easily fixable from amputation?”

*See CSU study: "Risk of Orthopedic Disorders in Canine Amputees"

What is a "Longitudinal Study" and why should we design one this way?

TRIPAWDS: That’s where I think a lifetime study of a group of dogs would be amazing because I have known so many tripawds who are – who had amputations as puppies and now they’re older. They’re like my dog. They’re nine, ten, eleven years old. I know one that’s 13 and she’s a German shepherd, a large dog. It would have been great if back when they were puppies, we had been able to track the changes that are happening to them.

When the Golden Retriever Lifetime Study came out, I thought, “Well, what if we could do that for tripawds? What if we could follow these dogs around all their life and see what happens so that clinicians like you have the data that you need to help improve their quality of life and educate us owners?”

First can you explain a little bit just briefly what is a longitudinal study? I heard the Golden Retriever one is a longitudinal.

DR. DUERR: Basically what that means is that you follow the same study participant over time. So I guess in this scenario, what we basically – what we want to know is what are the impacts of amputation in – down the road?

You know, let’s make it ten years, right? So there are two ways to study that. There is one way where you say we’re just going to – what’s called a cross-sectional study where we’re going to look at ten-year-old dogs with four legs and then compare them to ten-year-old dogs with three legs and then see what is the difference in degree – amount of arthritis and all that.

The problem with that is that we cannot necessarily say that that degree of arthritis is because of being a three-legged dog. Let’s say we find more arthritis in the three-legged dogs than the four-legged dogs. It could be that that was because there was another disease. There was – maybe they had elbow dysplasia to start out with.

We don’t know what they started with and so that’s the reason to do a longitudinal study that you basically get the information that you need to know as you – as these dogs age. So the Golden Retriever Study enrolls the dogs and then follows them on an annual basis to know, well, what has changed in their environment and what other problems that they have. Did they have any accidents? That type of thing.

What can we learn from a Tripawd lifetime study?

TRIPAWDS: And what kind of solutions can we extract from what we would learn from a lifetime study of three-legged dogs?

DR. DUERR: Yeah. I think that there’s a lot of things that we can learn from this. That’s where the Golden Retriever Study – I think that’s a – I mean the amount of work and effort and the team involved in that. That it’s incredible how when you actually start looking more into these questions, the amount of information that’s collected is just incredibly large.

So that’s the problem. You start out with the questions with the – for this study for example, well, what – how much arthritis is it? But then you want to know, well, what did they start out with? So then you got to decide, well, what is the test that we want to do at the time of enrollment?

So would this have to be for example a whole body CT where you can look at every joint and decide what is the amount of arthritis they started out with? Do you need to know “is this dog genetically predisposed for example for bad hip dysplasia, that type of thing,” right?

Then it goes to the next part. Well, how active is the dog? What are they doing? Are they overweight? All of these things play a role in joint disease. When were they neutered? So all that information has to be collected so that we then later on have data that actually answers the question and that we know what would be the what we call confounding factors. So factors that may then make that group appear like it has more arthritis because they’re three-legged. But truly it might have been because of something else.

How much money is needed for a long-term Tripawd study?

TRIPAWDS: So in other words, there’s a lot of important information about all aspects of their life that we could take from a study like this. I mean everything from how being overweight affects them to how the right and wrong kinds of activity impacts them.

It would be wonderful if we could do this. But here’s the million dollar question. Like how much money would we need for something like this and how many dogs would it take to come up with a good sampling of data for you guys?

DR. DUERR: Yeah. I think that’s funny that you said it’s a million dollar question. So this is really – yeah, that’s a great question and I think that really depends on how we would design that study.

So the more information we get, the better is – in the end, what we can make out of that data in ten years or so and you can’t turn back time. So what I mean by that is most of the problems that we have is – and as well-funded as the Golden Retriever Study is.

There are for example some questions we won’t be able to answer with that because for example, they didn’t have some of the screening for orthopedic disease that we would want to incorporate into a study like this where we’re really focused on orthopedic problems, right? Because you can’t cover everything and it’s just impossible.

I guess the cost of a study like this really depends on how many dogs do we enroll. How often do we evaluate them? And then what are the type of evaluations that we want to do? And then what – what is the owner’s – what is their expectation? Does everything have to be free or does it just have to be discounted?

It will give you an idea on if we’re going to just talk through the enrollment. So I think if we would do that, we would like to know – and I mentioned a whole body CT. What is the status of the joints when they are receiving their amputation or potentially some might be born with that?

So, a CT scan and obviously this wouldn’t be just a single institution study. This would need multiple institutions so that we can get enough cases in a meaningful timeline, meaning that we will still know the results while we’re alive.

I think a CT scan, depending on where you live, costs anything between somewhere – maybe the lowest cost somewhere, maybe $1,000 to maybe $2,500. So then the rechecks, they could be a CT scan but they could also just be radiographs.

It really becomes costly quite quickly. Then the other part that’s really important with this is that we want to have good data. So we want to make sure that we actually ask owners and that’s a big part of what the Golden Retriever Study is doing, making sure that people actually fill out the surveys and then follow up with them because if you just look 10 years later, you will find out, oh, we only have complete surveys on 10 percent of the dogs. And that’s not really what we want, right?

You need people that their job is to literally track down the data and then you got to pay those as well. So yeah, no, I think it’s definitely – it’s a pricey endeavor.

What can we do with $3 million dollars?

TRIPAWDS: Do you think it’s realistic? I mean if we had some very generous donors who donated – let’s dream and say $3 million. I mean could that cover the cost you think, if we designed it in a way that you could get some meaningful information with that amount of money or would it take even more than that?

DR. DUERR: No, I think – honestly I haven’t really done a true budget on this, I think, but those are the numbers that we’re talking about. Yeah. I think with those figures, we would hire somebody that that’s their responsibility and then we would design the study according to what the funds available are and will have to decide. What is it that we really want to focus on and what do we spend the money on?

Maybe it would be – maybe we will just do radiographs of the most commonly affected joints. That might be easier and more feasible. So I think there are ways to make it work. But I think that is kind of the numbers that I’ve been thinking of that it is in the multiple million dollar range unfortunately.

How long would we need for an effective study?

TRIPAWDS: OK. And would that amount be for like a ten-year study or could we do a three or five-year study? What would be the best amount of time within a reasonable budget to come up with some useful data?

DR. DUERR: Yeah. I think that my answer to that would be that once we have these dogs enrolled, I would love to continue following them lifelong. The reason for that is because there’s a lot of work that goes into the enrollment and you already have that baseline data. So I think you probably then – once you actually have a dog and an owner that are committed to this, supplying all the data, then I think the extra cost to say just make it three or five years rather than lifelong, I think that is – I would probably rather enroll less dogs than stop early.

I do think however that this is not a study that would just be published in 15 years. But rather I think you publish data along – you know, while you collect some information. So one of the questions that came up during this conversation is, “Well, what is the timeline? When do dogs actually develop arthritis after this?”

That’s great information to have. Just even being able to say a one-year follow-up of a subset of dogs enrolled would already be super valuable information. I’m kind of thinking if we show that yeah, there actually are already changes that one year that maybe this would be information for the veterinary community to consider and consider some of these newer options.

We’ve talked a lot about prosthetics and we’re doing a lot of work in that. There are some new options that are becoming more popular and I think if we have that data, that will probably make it more common knowledge amongst veterinarians and dog owners too.

How many Tripawd dogs are needed for a good study?

TRIPAWDS: With the dogs that you would sample, what would be an ideal number would you say for a lifetime study?

DR. DUERR: That really depends on the question that we want to ask. So that is something that we would decide based on what is our – you know, what’s the number one question that we want to answer?

But the truth about this is that there isn’t going to be like a lot of data that we have to do a real what we call power calculation, a sample size calculation where we know exactly how many dogs we need. But based on understanding arthritis and the secondary effects, there’s a lot of variables that play a role.

Like we talked about genetic predisposition, their weight and their activity level and all that. So I guess I would say there really isn’t a real limit to the number of dogs.

I think we do want to include as many as possible. I think if we can get into the three digits, that would be something that we would love to do and the answer to that is really it’s dependent on the funding. The more, the better.

How can we recruit Tripawd parents?

TRIPAWDS: OK, that totally makes sense and getting back to your previous statement, I really like the idea of being able to track them through their lives and then release findings as we go because I see that being done with the Golden Retriever setting and that’s pretty cool and it keeps it in the public eye for sure.

As far as the incentives for people to participate, you handle a lot of studies in your position. What do you find is the biggest incentive for pet parents to participate in something like this? What makes them do it?

DR. DUERR: I think for our studies, we do have very – there are different groups of dog owners. For some owners, they want to support the research and honestly the finances or the time they spent doesn’t really matter. They would do it even if they pay full cost.

For some other people, it’s just – you know, that it helps doing the best for their dogs. So helping with the treatments that they would like to do for their dog.

I think one of the concerns is that it just – it always takes a lot of time, right? Filling out these questionnaires and going to the vet and having those X-rays done. If there isn’t a real direct benefit for their dog, it’s going to be a little bit harder to get people to do these follow-up visits.

What I mean by that is the more things we can offer that are actually having a potential impact for the direct health of that individual enrolled patient, the better. Things like routine blood work and recheck radiographs on – if there’s a problem, the study covers it. That encourages people to actually go see their veterinarian so that we know, oh, there’s a problem and we have the data and it is of direct benefit for that individual dog.

I think that would be a really important part to include in the study and then obviously that’s hard to plan for, right? Because somebody – obviously we can’t say recover the cost of any orthopedic injury and that a dog needs bilateral total hip replacement. Then in certain areas, that will cost $20,000 together, right? So then that shrinks the budget pretty quickly.

But some sort of incentive of like – kind of like a pet insurance where per visit if you have completed all your questionnaires and if you’ve done all your exams and all that, the study pays a part of those diagnostics and treatments up to a certain amount.

I think something like that would be a really great incentive to make sure that we get good data.

TRIPAWDS: Oh, I do too. I could see how it would really encourage people to keep up with the regular wellness visits and heck, I know I would love for Wyatt to have radiographs paid for once or twice a year. That would be awesome.

Dr. Duerr, we have taken way too much of your time. I can’t thank you enough for being here and bouncing these ideas around with us. I can’t wait to hear what our community has to say about maybe embarking on a study like this and finding the funding to do it because it would be so helpful for us. Thank you for kicking this off and hopefully you and I will get to see it happen.

DR. DUERR: That sounds great. I look forward to it. Thank you very much for your time.

[End of transcript]