A knee built for the people who lose them in combat
For a young veteran with a transfemoral amputation, the standard prosthetic knee on the U.S. market is a study in compromise. It walks well on flat ground, hesitates on uneven terrain, and rarely keeps up with the active lifestyle that service members had before injury.
smooth Transition, a pre-seed hardware startup based in Washington, DC, is designing a knee specifically for that patient: the active warfighter and veteran amputee who wants to ruck, hike, and train rather than simply ambulate. Its lead product, the Endura Knee, is built around a mechanical articulation that mimics the natural femoral-tibial joint, an approach founder Sarah Malinowski developed during her Master's thesis at George Washington University [smooth Transition, About].
That patient framing matters because lower-limb prosthetics is one of the few medical device categories where the end user's lifestyle, not just their diagnosis, dictates whether a product succeeds.
Today's standard of care for an above-knee amputee in the U.S. typically runs through a Veterans Affairs prosthetist or a private clinic. Devices range from passive mechanical knees costing a few thousand dollars to microprocessor-controlled knees from incumbents like Ottobock and Ossur that can exceed $50,000 per unit and are reimbursed through Medicare, the VA, or private insurance.
Microprocessor knees are clinically excellent for daily walking, but many veterans report that they are not designed for the loads, terrain, and tempo of an active or athletic life, which is the gap smooth Transition is targeting.
The bet
smooth Transition's wedge is a purely mechanical knee whose articulation is engineered around the geometry of the natural joint rather than around an actuator and battery [smooth Transition, Endura Knee]. If the device performs as described, the implications are practical: no charging, fewer electronic failure modes, lower unit cost, and a profile better suited to environments where service is hard to access.
The company describes the goal as prosthetics that "move naturally with the user, improve comfort and lower overall healthcare costs" [smooth Transition]. That last phrase, healthcare costs, is the one a payer or a VA contracting officer is most likely to underline.
Malinowski has been explicit that the first real-world deployment is unlikely to be in the United States. In an interview with Technical.ly, she described Ukraine as the place to soft-launch the knee, citing clinic work and research conducted during the war and the sheer scale of the amputee population created by the conflict [Technical.ly].
It is an unusual go-to-market for a Washington-area medical device startup, and a defensible one: Ukraine has become, tragically, the largest concentrated population of new combat amputees in a generation, and humanitarian and rehabilitation programs there have been receptive to non-incumbent prosthetic designs.
Why it could be big
The addressable patient population is not small and is, unfortunately, growing. The U.S. Department of Veterans Affairs serves tens of thousands of amputee veterans, and the global pool of trauma-related lower-limb amputees expands with every conflict and every year of diabetes prevalence.
A mechanical knee that approaches microprocessor performance on rugged terrain, at a meaningful fraction of the cost, would have a credible path through both VA procurement and humanitarian channels long before it has to win a pitched battle against Ottobock or Ossur in the private clinic market.
The early validators are modest but real. smooth Transition won the top Tech Venture Track prize and $27,500 at the 2022 GW New Venture Competition, and Malinowski and co-competitor Tanner Reinholtz also took the 4th Place Social Venture Prize of $2,500 at the same event [GW Today, 2026; GW New Venture Competition, 2026].
In 2024 the company received a Catalyst Grant from the Arlington Innovation Fund to pursue patent protection on the Endura Knee design [Arlington Economic Development, 2026]. None of this is a Series A, but for a hardware company at this stage it is the right shape of early support: non-dilutive capital tied to a defensible IP position.
GW New Venture Tech Prize (2022) | 27500 | USD
GW New Venture Social Prize (2022) | 2500 | USD
The team
Malinowski is the CEO of smooth Transition and a co-founder of the LLC [Yahoo News, 2026; GW Today, 2026]. She is a mechanical engineer with a Master's in Biomedical Engineering from George Washington University, where the Endura Knee mechanism originated as her thesis work [smooth Transition, About].
She has stayed connected to the academic pipeline that produced the design, participating in a career panel at GWU's BME Research Day 2023 [GWU BME, 2026], and is based in Arlington, Virginia, within reach of both the VA's clinical research apparatus and the defense procurement community in the National Capital Region [LinkedIn, 2026].
The honest counterfactual
The bear case is straightforward: prosthetics is a regulated medical device category, and any U.S. commercial path will run through FDA clearance (lower-limb prosthetic knees are typically Class I or Class II devices depending on claims), reimbursement coding, and clinical evidence that prosthetists trust.
Microprocessor knee incumbents have spent two decades building that evidence base, and a purely mechanical design, however elegant, will need head-to-head data on stumble recovery, fall rates, and patient-reported outcomes before VA prosthetists prescribe it at scale.
The bull answer is that smooth Transition does not need to win that argument first. A soft launch in Ukraine, where the regulatory and reimbursement bar is structured around humanitarian need rather than CMS coding, gives the company a path to gather real-world performance data on exactly the active, high-load patient it was designed for [Technical.ly].
That data, plus the Arlington-funded patent work, is what would make a U.S. clinical study fundable.
What to watch
The next twelve months are about three things: the patent filing supported by the 2024 Catalyst Grant, the first clinical fittings of the Endura Knee in a Ukrainian rehabilitation setting, and a priced seed round that would let a solo-founder hardware company hire its first full-time engineer and regulatory lead.
Any one of those would be a meaningful signal. All three would put smooth Transition in the small group of veteran-focused medical device startups with a credible shot at moving from thesis project to fielded device.
Disease state: lower-limb (transfemoral) amputation. Patient population: active warfighters, veterans, and combat-injured civilians. Standard of care today: passive mechanical or microprocessor-controlled knees prescribed through VA or private prosthetists, reimbursed through VA, Medicare, or private insurance, and rarely optimized for athletic or rugged use.
Pulse Raman covers health and bio for Startuply.