Founder Stories with exo360 : From one PowerPoint to reinventing a 200 year old cast
Founder Stories with exo360 : From one PowerPoint to reinventing a 200 year old cast
In South Africa in 2017, a young trauma surgeon kept seeing the same thing every morning: 25 patients on the ward with shattered limbs, waiting days for surgery, their bones held in place only by a technique invented 200 years ago. Nearly five years later, Mads Terndrup, Michael Rosenfeldt and their team behind exo360 are about to put a device on the first patient that aims to change that.
With Mads Terndrup (Co-founder & CEO, MD & PhD) and Michael Rosenfeldt (co-founder, COO)
Can you start by introducing yourselves and telling us a bit about your background, and how that led you to co-founding exo360?
Mads: I am originally a doctor. I trained as a trauma surgeon, worked at trauma centres in South Africa and Australia, and did a PhD on ankle fractures. Along the way I grew frustrated that surgery has advanced enormously over the last hundred years, yet we still stabilise injuries with a 200-year-old non-surgical method. In 2021 I quit my job, tried it alone for six months, and then asked my friend Michael to join me.
I was actually shopping around for co-founders. I spoke to serial entrepreneurs, people within medtech, but I kept coming back to Michael. Everyone told me you spend more time with your co-founder than with your wife, so it had to be someone I loved being around. But there was something more specific than that. I knew that in the early days, when neither of us was technical, everything was going to come down to making people understand the problem and bringing them onto our side. Michael had done brand work for fashion labels and restaurants, and before that he was flying to music festivals, filming sets and cutting edits for Instagram. He could make things look cool, and he could tell a story. I had no idea how well that partnership would actually play out, but it has been a lot of the fuel behind our success. I do the talking; he makes the message land.
Michael: I am from South Africa, which is just a weird coincidence. Mads has a few ties there and I am one of them. We met walking our dogs in Copenhagen. My work on exo360 started with helping Mads build slides and videos to get into accelerators, and after one day at the Danish Tech Challenge he asked me to join for real. He sold it as two years and an exit. Five years on, I know I was in for a lot more than I bargained for!
What was the moment you realised there was a real problem with how fractures and injuries are treated, and that the solution had not been built yet?
Mads: It started in South Africa in 2017, during my PhD. In Denmark you get your cast and any surgery within 24 hours, but the public hospitals in South Africa were overwhelmed with trauma. Every morning, 25 patients lay on the ward with shattered limbs in plaster, and we re-plastered them again and again while they waited for surgery. That is when I understood that casting is a craft, and the result depends entirely on the person applying it.
“There was a nurse called Gitte. When she was in the ER you would get a perfect cast and you might not need surgery. If Gitte was sick, you might get a bad cast and you might need surgery. That’s the problem I’m still in love with five years down the line.”
You have a PhD in orthopaedics. At what point did you go from being a researcher and clinician to thinking “I need to build a company around this”? What does that transition feel like?
Mads: It was hard, because it meant giving up an identity. Med school trains you, in a good way, to let go of commercial ambitions: the only thing that matters is the patient. Letting go of that took time, and I kept taking on-call shifts at the hospital until two years ago. The hardest part was personal. My daughter used to say her dad is a doctor who helps injured children. Now she tells her little brother that dad is an inventor, and I have come to be proud of what she sees instead.
Can you walk us through the exo360-rf and what actually makes it different for someone who has never heard of metamaterials?
Mads: Most people know what a cast is. The therapeutic effect comes from the pressure of the wrap: not too tight, not too loose, just right. That is the art, and the problem is that nobody actually knows what the pressure under a cast is, so you cannot measure it, improve it or research it. Patients often go through two or three attempts in the ER before it sits right. The exo360-rf takes the art out of casting. Using lattice technology, or metamaterials, you engineer the mechanical properties into the structure, so it delivers the same pressure whether it is compressed by 1mm or 12mm. In practice it closes like a shell from the outside, as foolproof as closing a Kinder egg, and the metamaterial inside creates the exact pressure needed to hold the bones in place. We first heard about lattices in 2021, and today we are the company working most with elastic lattices in medical devices in Europe.
Building in medtech means navigating regulation, clinical validation and investor scepticism all at once. What has not gone to plan, and what have you learned?
Mads: The clinical side and the branding were our background, so we had those under control, and regulation is what it is. The hard part was investor scepticism. At our third meeting we were out of money, and the investor said he understood the value proposition and the market, but a wrist healing slightly out of position just was not a big enough problem for him. That made us turn the pitch deck upside down. Within three days Michael rebuilt it entirely around diabetic foot ulcers, where casting is also the standard of care. We pitched it, closed the round, and got wind in our sails. Sometimes it is about telling people what they need to hear to take a bet on you.
What made that period particularly brutal was the timing. In 2022 it was just me and Michael and a PowerPoint, and we pitched three investors who all came in at a 25 million pre-money valuation. We had nothing: no IP, no team. Then eighteen months later we had all of that, but the macro environment had shifted and startup investment had dried up. Q1 2024 was the hardest stretch. There were just crickets.
Michael: For a long time we were raising month to month. This year is one of the first times we have had more than three months of runway. You get used to presenting budgets full of grand plans while knowing you still need to raise to make next month’s salaries. It taught us to treat funding as a discipline rather than a panic, and the runway we have now feels like real freedom to build.
“It’s only a house of cards until you pour concrete on it.”
Mads: The grants were a blessing and a burden at the same time. You need to front the spend and then wait for the reimbursement: spend 100% to get 35% back. That means escalating your R&D expenses just to realise the grant, and it compounds quickly. Our theory was always that “it’s only a house of cards until you pour concrete on it” and that held.
You have built your funding on a mix of grants and investments. How do you think about those two sources differently, and what would you tell a founder figuring out the right mix?
Mads: It depends heavily on your industry and the macro climate. Take the money on the table, but not at any cost. We use a coffee test: if you cannot see yourself having a coffee or a beer with the person across the table, it is probably not worth it. With grants, be clear about what they actually commit you to, and underpromise and overdeliver. Our first large Innobooster grant had an activity plan that was far too ambitious for the budget, and we spent years running behind it. Being backed by investors who believe in your strategy beats any grant. And we were very deliberate about not giving up control too early. We raised 13 million on convertible notes with extremely founder-friendly terms. It was only at the end of last year that we took on other shareholders at all. Until then it was just me and Michael, with the freedom to make our own mistakes and choose our own path. The two of us still hold majority today.
At what point did you realise you needed external sparring on the financial and funding side, and what difference has that made?
Mads: Michael was the one who said we needed help. None of us has a financial background, so our books were a mess, and an investor who was scrutinising our amateur budgets recommended Scaleup. We honestly thought it would just be some help in Excel. We had no idea what a part-time CFO actually meant, or that the tech stack would set the bar for all our internal systems, from regulatory documentation to how we book holiday. Everything had to live up to that standard.
There is also something deeper in how we think about building. From day one our instinct has been to overreach, to behave like the company we intend to become before we are actually there. When we had nothing, we presented as if we were expensive. Now, having just raised 12 million Danish kroner, we are looking for an HQ as if we have already made millions. Scaleup understood that ethos immediately, and I think that is part of why the relationship works.
Michael: When you are starting out you cannot afford to hire for these things. It felt like getting a whole team to handle everything you have no idea how to manage. The mental and financial cost of adding even one person is enormous. We had not fully understood that until we were in it, and Scaleup made that transition manageable and made it much easier to scale.
You are heading into your first test cases this year. What did early validation actually look like before you had a product in someone’s hand?
Mads: With these customers you only get one shot. In Denmark, ten hospitals make up about 90% of the market, and in each one a single person decides. Choosing when to go on the first patient is hard, but at some point you have to press play.
For us, validation is also marketing. It is about giving our clinical champions across Europe the confidence to back us, so we deliberately overshoot what regulation requires. From the very start, with nothing but a prototype and a PowerPoint, Michael and I knocked on doors at the biggest hospitals across Europe and brought clinicians onto the journey early. We have since done cadaver and healthy-volunteer testing, 77 applications of our device over ten days, to prove the mechanics work, and our regulatory package is now complete. Everything is culminating around October or November this year.
We are also less scared than we once were, because we have built a platform rather than a single product. We think of ourselves a bit like a biotech: we have four applications in development, broken wrists, diabetic foot ulcers, military evacuation stabilisation, and one we are not talking about yet. One of them will be a home run. We do not know which one, and that is fine.
As COO you are the one keeping the engine running. What does the operational and financial side of building a medtech company actually look like in practice?
Michael: There is a lot for a small management team to handle in a startup, and even more as you scale. The way I have found to cope is to build systems and use tools that make our own involvement unnecessary, so the things we set up now keep running without us. That frees us up for the parts still ahead, like sales, where there is a lot we have yet to learn.
Mads: And a lot is still ahead of us. Right now it is relatively simple because we are only spending money, not making it, so we do not yet track inventory or orders. We take it step by step, and it is genuinely exciting to have those problems waiting for us, because it means we are about to start selling.
You and Michael have now worked together for five years. What have you learned about what makes a co-founder relationship actually work?
Mads: We have never had an argument. Disputes, yes, but never an argument. Part of that is genuine respect for each other’s skill sets. But we also built a practice early on that I think has been more important than people might expect. We have something we call the exobox: a monthly one-on-one where anything that has been mildly frustrating, anything that could have been handled differently, just gets put on the table. My wife is a psychologist and she told us we were crazy for doing it. But the number of times something comes up that was completely off your radar, even with someone you talk to every day, is remarkable. It catches things before they become anything.
Michael: If one of us is down, the other is usually up. That balance has kept us moving through the hardest stretches more than anything else.
Where does exo360 go from here, and what does the landscape look like if this works the way you hope?
Mads: We used to plan on building the technology and selling to one of the big players, the usual route for orthopaedic startups. With our board and backers, we now have a different goal: to build a Danish medical company in the tradition of William Demant or Coloplast, one that pays its taxes and manufactures in the Nordics and stands for quality. We make plastic devices, and even with IP we will get copied, so the real differentiator is trust. We are inspired by the 3Shape story: building a growth company takes longer, but we love running a company and helping brilliant people reach their potential. The team is everything to us, and that is what is most inspiring.
Looking back, what do you know now that you wish someone had told you on day zero?
Michael: Honestly, I am glad I did not know what I know now, because I might not have started, and then I would have missed the best thing I have built. Be kind to yourself and go for plenty of runs along the way.
Mads: Know yourself going in, because you will be tested. Agree the ground rules with your co-founder early: decide what you will and will not do, and if anything feels like a grey area, treat it as a no. The journey is harder than you expect, but it is also far more rewarding. We are about to put our first product on patients, we are leading the field in Europe, and we get to build something lasting with a team we love. I would do it all again.
In South Africa in 2017, a young trauma surgeon kept seeing the same thing every morning: 25 patients on the ward with shattered limbs, waiting days for surgery, their bones held in place only by a technique invented 200 years ago. Nearly five years later, Mads Terndrup, Michael Rosenfeldt and their team behind exo360 are about to put a device on the first patient that aims to change that.
With Mads Terndrup (Co-founder & CEO, MD & PhD) and Michael Rosenfeldt (co-founder, COO)
Can you start by introducing yourselves and telling us a bit about your background, and how that led you to co-founding exo360?
Mads: I am originally a doctor. I trained as a trauma surgeon, worked at trauma centres in South Africa and Australia, and did a PhD on ankle fractures. Along the way I grew frustrated that surgery has advanced enormously over the last hundred years, yet we still stabilise injuries with a 200-year-old non-surgical method. In 2021 I quit my job, tried it alone for six months, and then asked my friend Michael to join me.
I was actually shopping around for co-founders. I spoke to serial entrepreneurs, people within medtech, but I kept coming back to Michael. Everyone told me you spend more time with your co-founder than with your wife, so it had to be someone I loved being around. But there was something more specific than that. I knew that in the early days, when neither of us was technical, everything was going to come down to making people understand the problem and bringing them onto our side. Michael had done brand work for fashion labels and restaurants, and before that he was flying to music festivals, filming sets and cutting edits for Instagram. He could make things look cool, and he could tell a story. I had no idea how well that partnership would actually play out, but it has been a lot of the fuel behind our success. I do the talking; he makes the message land.
Michael: I am from South Africa, which is just a weird coincidence. Mads has a few ties there and I am one of them. We met walking our dogs in Copenhagen. My work on exo360 started with helping Mads build slides and videos to get into accelerators, and after one day at the Danish Tech Challenge he asked me to join for real. He sold it as two years and an exit. Five years on, I know I was in for a lot more than I bargained for!
What was the moment you realised there was a real problem with how fractures and injuries are treated, and that the solution had not been built yet?
Mads: It started in South Africa in 2017, during my PhD. In Denmark you get your cast and any surgery within 24 hours, but the public hospitals in South Africa were overwhelmed with trauma. Every morning, 25 patients lay on the ward with shattered limbs in plaster, and we re-plastered them again and again while they waited for surgery. That is when I understood that casting is a craft, and the result depends entirely on the person applying it.
“There was a nurse called Gitte. When she was in the ER you would get a perfect cast and you might not need surgery. If Gitte was sick, you might get a bad cast and you might need surgery. That’s the problem I’m still in love with five years down the line.”
You have a PhD in orthopaedics. At what point did you go from being a researcher and clinician to thinking “I need to build a company around this”? What does that transition feel like?
Mads: It was hard, because it meant giving up an identity. Med school trains you, in a good way, to let go of commercial ambitions: the only thing that matters is the patient. Letting go of that took time, and I kept taking on-call shifts at the hospital until two years ago. The hardest part was personal. My daughter used to say her dad is a doctor who helps injured children. Now she tells her little brother that dad is an inventor, and I have come to be proud of what she sees instead.
Can you walk us through the exo360-rf and what actually makes it different for someone who has never heard of metamaterials?
Mads: Most people know what a cast is. The therapeutic effect comes from the pressure of the wrap: not too tight, not too loose, just right. That is the art, and the problem is that nobody actually knows what the pressure under a cast is, so you cannot measure it, improve it or research it. Patients often go through two or three attempts in the ER before it sits right. The exo360-rf takes the art out of casting. Using lattice technology, or metamaterials, you engineer the mechanical properties into the structure, so it delivers the same pressure whether it is compressed by 1mm or 12mm. In practice it closes like a shell from the outside, as foolproof as closing a Kinder egg, and the metamaterial inside creates the exact pressure needed to hold the bones in place. We first heard about lattices in 2021, and today we are the company working most with elastic lattices in medical devices in Europe.
Building in medtech means navigating regulation, clinical validation and investor scepticism all at once. What has not gone to plan, and what have you learned?
Mads: The clinical side and the branding were our background, so we had those under control, and regulation is what it is. The hard part was investor scepticism. At our third meeting we were out of money, and the investor said he understood the value proposition and the market, but a wrist healing slightly out of position just was not a big enough problem for him. That made us turn the pitch deck upside down. Within three days Michael rebuilt it entirely around diabetic foot ulcers, where casting is also the standard of care. We pitched it, closed the round, and got wind in our sails. Sometimes it is about telling people what they need to hear to take a bet on you.
What made that period particularly brutal was the timing. In 2022 it was just me and Michael and a PowerPoint, and we pitched three investors who all came in at a 25 million pre-money valuation. We had nothing: no IP, no team. Then eighteen months later we had all of that, but the macro environment had shifted and startup investment had dried up. Q1 2024 was the hardest stretch. There were just crickets.
Michael: For a long time we were raising month to month. This year is one of the first times we have had more than three months of runway. You get used to presenting budgets full of grand plans while knowing you still need to raise to make next month’s salaries. It taught us to treat funding as a discipline rather than a panic, and the runway we have now feels like real freedom to build.
“It’s only a house of cards until you pour concrete on it.”
Mads: The grants were a blessing and a burden at the same time. You need to front the spend and then wait for the reimbursement: spend 100% to get 35% back. That means escalating your R&D expenses just to realise the grant, and it compounds quickly. Our theory was always that “it’s only a house of cards until you pour concrete on it” and that held.
You have built your funding on a mix of grants and investments. How do you think about those two sources differently, and what would you tell a founder figuring out the right mix?
Mads: It depends heavily on your industry and the macro climate. Take the money on the table, but not at any cost. We use a coffee test: if you cannot see yourself having a coffee or a beer with the person across the table, it is probably not worth it. With grants, be clear about what they actually commit you to, and underpromise and overdeliver. Our first large Innobooster grant had an activity plan that was far too ambitious for the budget, and we spent years running behind it. Being backed by investors who believe in your strategy beats any grant. And we were very deliberate about not giving up control too early. We raised 13 million on convertible notes with extremely founder-friendly terms. It was only at the end of last year that we took on other shareholders at all. Until then it was just me and Michael, with the freedom to make our own mistakes and choose our own path. The two of us still hold majority today.
At what point did you realise you needed external sparring on the financial and funding side, and what difference has that made?
Mads: Michael was the one who said we needed help. None of us has a financial background, so our books were a mess, and an investor who was scrutinising our amateur budgets recommended Scaleup. We honestly thought it would just be some help in Excel. We had no idea what a part-time CFO actually meant, or that the tech stack would set the bar for all our internal systems, from regulatory documentation to how we book holiday. Everything had to live up to that standard.
There is also something deeper in how we think about building. From day one our instinct has been to overreach, to behave like the company we intend to become before we are actually there. When we had nothing, we presented as if we were expensive. Now, having just raised 12 million Danish kroner, we are looking for an HQ as if we have already made millions. Scaleup understood that ethos immediately, and I think that is part of why the relationship works.
Michael: When you are starting out you cannot afford to hire for these things. It felt like getting a whole team to handle everything you have no idea how to manage. The mental and financial cost of adding even one person is enormous. We had not fully understood that until we were in it, and Scaleup made that transition manageable and made it much easier to scale.
You are heading into your first test cases this year. What did early validation actually look like before you had a product in someone’s hand?
Mads: With these customers you only get one shot. In Denmark, ten hospitals make up about 90% of the market, and in each one a single person decides. Choosing when to go on the first patient is hard, but at some point you have to press play.
For us, validation is also marketing. It is about giving our clinical champions across Europe the confidence to back us, so we deliberately overshoot what regulation requires. From the very start, with nothing but a prototype and a PowerPoint, Michael and I knocked on doors at the biggest hospitals across Europe and brought clinicians onto the journey early. We have since done cadaver and healthy-volunteer testing, 77 applications of our device over ten days, to prove the mechanics work, and our regulatory package is now complete. Everything is culminating around October or November this year.
We are also less scared than we once were, because we have built a platform rather than a single product. We think of ourselves a bit like a biotech: we have four applications in development, broken wrists, diabetic foot ulcers, military evacuation stabilisation, and one we are not talking about yet. One of them will be a home run. We do not know which one, and that is fine.
As COO you are the one keeping the engine running. What does the operational and financial side of building a medtech company actually look like in practice?
Michael: There is a lot for a small management team to handle in a startup, and even more as you scale. The way I have found to cope is to build systems and use tools that make our own involvement unnecessary, so the things we set up now keep running without us. That frees us up for the parts still ahead, like sales, where there is a lot we have yet to learn.
Mads: And a lot is still ahead of us. Right now it is relatively simple because we are only spending money, not making it, so we do not yet track inventory or orders. We take it step by step, and it is genuinely exciting to have those problems waiting for us, because it means we are about to start selling.
You and Michael have now worked together for five years. What have you learned about what makes a co-founder relationship actually work?
Mads: We have never had an argument. Disputes, yes, but never an argument. Part of that is genuine respect for each other’s skill sets. But we also built a practice early on that I think has been more important than people might expect. We have something we call the exobox: a monthly one-on-one where anything that has been mildly frustrating, anything that could have been handled differently, just gets put on the table. My wife is a psychologist and she told us we were crazy for doing it. But the number of times something comes up that was completely off your radar, even with someone you talk to every day, is remarkable. It catches things before they become anything.
Michael: If one of us is down, the other is usually up. That balance has kept us moving through the hardest stretches more than anything else.
Where does exo360 go from here, and what does the landscape look like if this works the way you hope?
Mads: We used to plan on building the technology and selling to one of the big players, the usual route for orthopaedic startups. With our board and backers, we now have a different goal: to build a Danish medical company in the tradition of William Demant or Coloplast, one that pays its taxes and manufactures in the Nordics and stands for quality. We make plastic devices, and even with IP we will get copied, so the real differentiator is trust. We are inspired by the 3Shape story: building a growth company takes longer, but we love running a company and helping brilliant people reach their potential. The team is everything to us, and that is what is most inspiring.
Looking back, what do you know now that you wish someone had told you on day zero?
Michael: Honestly, I am glad I did not know what I know now, because I might not have started, and then I would have missed the best thing I have built. Be kind to yourself and go for plenty of runs along the way.
Mads: Know yourself going in, because you will be tested. Agree the ground rules with your co-founder early: decide what you will and will not do, and if anything feels like a grey area, treat it as a no. The journey is harder than you expect, but it is also far more rewarding. We are about to put our first product on patients, we are leading the field in Europe, and we get to build something lasting with a team we love. I would do it all again.
FAQs
All the answers you need for all the questions you’ve got.
(But also TL;DR)
How should a startup business prepare its budget?
To prepare a budget for your startup, begin by listing all potential expenses you anticipate in starting and operating your business. Next, organise these expenses into categories. After that, estimate your monthly revenue and calculate the total costs required to start and run your business.
What are the key steps to creating an effective budget?
Step 1: Determine and track your income sources.
Step 2: Make a list of your cost. Include both fixed and variable costs.
Step 3: Set achievable financial goals.
Step 4: Develop a plan to meet those goals.
Step 5: Put everything together to build your budget.
Step 6: Regularly review and revise your forecast to ensure it remains effective.
What does capital budgeting entail for a startup?
Capital budgeting for a startup involves allocating a set amount of funds for specific purposes, such as purchasing new equipment or expanding business operations. This process is crucial as it supports making strategic investments that are expected to yield long-term benefits for the startup.
FAQs
All the answers you need for all the questions you’ve got.
(But also TL;DR)
How can a startup forecast its cash flow?
To forecast cash flow for a startup, follow these steps:
Step 1: Create a sales forecast by estimating the revenue your products or services will generate over the forecast period.
Step 2: Develop a profit and loss forecast to understand your expected expenses and income.
Step 3: Prepare your cash flow forecast, which involves calculating expected cash inflows and outflows. This can often be done for longer-term by using assumptions around payment terms to forecast a Balance Sheet, and using the movements in Balance Sheet and Net Profit/Loss to calculate the cashflow.
Step 4: Consider ways of improving cash flow by improving your invoicing methods, considering short-term borrowing, and negotiate better payment terms to manage cash flow effectively.
What is the most accurate method to forecast cash flow?
The most accurate method for forecasting cash flow in the short-term is the direct method, which utilises actual cash flow data. In contrast, the indirect method is better suited for longer term forecasting using projected balance sheet movements and income statements to estimate future cash flows.
How is cash flow calculated?
Cash flow is calculated by deducting cash outflows from cash inflows over a specific period. This calculation alongside forecasts of future cash flow helps determine if there is sufficient money available to sustain business.
How do you project cash flow over three years?
To project cash flow over a three-year period, undertake the following steps:
Step 1: Collect historical financial data.
Step 2: Identify all expected cash inflows, which could include revenue, investment, grant income, etc.
Step 3: Estimate all anticipated cash outflows including expenses, suppliers that need to be paid, investments into assets, debt repayments, etc.
Step 4: Calculate the net cash flow by subtracting outflows from inflows.
Step 5: Consider your cash reserves and explore financing options if needed.
Step 6: Regularly review and adjust your projections to ensure accuracy and relevance.
FAQs
All the answers you need for all the questions you’ve got.
(But also TL;DR)
When should a startup consider hiring a CFO?
A startup should think about hiring a Chief Financial Officer (CFO) when it begins to experience rapid growth, finds it challenging to manage finances, or needs to navigate complex investment scenarios. A seasoned financial professional can provide the necessary expertise to handle these challenges effectively.
What are the indicators that my business might need CFO support?
You might need to hire a CFO or consider outsourcing this role if you notice any of the following signs: a decrease in gross profit margins despite increasing revenue, uncontrolled business growth, lack of cash reserves despite having a financially successful year, or a halt in business growth.
Does my startup really need a full-time CFO?
Recruiting a full-time CFO is an expensive hire. Given budget constraints and the need to prove the viability of your business idea, founders will often need to prioritise investing into building and commercialising their product. That's where CFO services for startups are a cost-effective solution for founders looking to take their financial management to the next level.
