London Devices is one of the newer additions to the Cambridge Angels portfolio and a great example of the science-led medtech companies the group backs. The orthopaedic device company came out of stealth in September 2026 with ARRO, a system that measures bone depth in real time as the surgeon drills, combining two steps of the operation into one.
We recently sat down with co-founders Omar Musbahi and Ruben Doyle to discuss their journey so far.
Can you tell us about the problem you're solving and how you came together?
Screws are the most common implant placed in the human body, Musbahi tells us, with well over $1 billion worth inserted worldwide every year. Each one must be measured and sized and, remarkably, this is still done with a manual depth gauge. According to the company, sizing screws can take up to 20% of operative time, and 44% of screws are incorrectly sized.
Rather than just build a better gauge, the founders set out to remove the step altogether by measuring depth while the surgeon drills. ARRO's one-step digital measurement makes operations faster and more accurate, and it gives every surgeon the same reading regardless of experience.
Musbahi, an orthopaedic surgeon, caught the entrepreneurial bug during a fellowship in Boston. Shortly after he returned to London, his father suffered a bad wrist fracture, which brought the problem very close to home. He took the idea to an engineering friend at Imperial, who was too busy to take it on but fortunately introduced him to Doyle.
Doyle, an engineer, had recently sold Additive Instruments, the company he founded out of his own PhD work on hip and knee replacements, to Smith & Nephew. "Once you've sold a company, you lack a problem to solve, and you're not allowed to go near the first one," he explains. The pair met in the second half of 2023 and spent considerable time validating the market before building their first prototypes.
Why did you stay in stealth, and what are your goals for the next two years?
The company spent around two years in stealth. Musbahi admits that may have been a little too long, but it gave the team a significant head start: when London Devices launched in September, not one competitor had heard of it. The main cost was slower hiring, although the founders are proud of the team they have built.
The focus now is getting products into the market and scaling, with first use in theatre expected next year. The ambition is clear: "In two years, we want this to become the standard of care in one of the most common procedures performed worldwide." Having been on the road with their VP of Sales, Musbahi believes few people yet realise how big the opportunity is.
What is a challenge you've had to navigate as founders?
For Doyle, the defining challenge has been founder dynamics. Two founders who always agree add little, but genuine differences of view make some decisions harder and more draining. He frames the tension as speed versus quality: move too fast and the result is poor, move too slowly and the opportunity passes. Finding the balance is the hard part, and it matters even more in medical devices, where a product must be right before it reaches a patient.
What advice would you give to a founder going into a funding round, particularly in medtech?
Doyle's view is that fundraising is always about the story, but in medtech the story has to be more deliberate. Unlike a SaaS business, a medtech company cannot simply promise exponential growth if it gets the product right. Founders need to be clear about where they fit in the market, how big that market is and what growth is realistic, including where they sit in the intellectual property landscape relative to large corporates. "You need to find the right kind of investor, one who likes the risk-reward profile of what you're offering, which may not be the same as a unicorn."
How has having Cambridge Angels in your investor group assisted you?
Both founders say the value has gone well beyond the capital. Doyle contrasts it with a large VC or family office that isn't involved day to day: with experienced angels, the team can have honest conversations with people who understand the journey, including when things take longer than planned.
Musbahi says the team was deliberate about building its investor list, looking for reputable investors with a track record in technology who would not simply invest and disappear. "People will find money, but the advice is really golden," he says. "That's where Cambridge Angels excels, because you have people who have invested in tech, seen investments both fail and succeed, and bring all of those learnings with them." Two Cambridge Angels members, Rajat Malhotra and Simon Blakey, now sit on the London Devices board.