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GENUX 2 Knee Orthosis

GENUX 2 – Knee Orthosis

The lightweight approach to genuine stability around your knee

The new fully updated GENUX 2 Knee Orthosis - lighter, smarter, better -

The GENUX 2 Knee Orthosis (also known as a knee brace or knee splint) is the updated version of the very successful Genux knee orthosis. We’ve managed to improve the unique concept of the Genux into an even lighter, smarter and better brace that offers accurate and individual support, matching the specific needs of its user.

The GENUX 2 is used in cases where genuine support of the knee is needed, for example, in case of valgus– or varus instability, or at the first stages of knee hyperextension. In order to provide functional improvement in those cases, a knee orthosis must be able to generate high-level corrective forces. The GENUX 2 is able to do just that. Due to the structural capabilities of the GENUX 2, the brace is able to provide the required corrective forces needed to relieve pain and improve function.


A worn-out knee… how can GENUX 2 Knee Orthosis help you?

Osteoarthritis (OA), commonly known as degenerative joint disease or ‘wear and tear’ arthritis, is a condition in which the natural cushioning between joints, i.e. the cartilage, wears away. When this happens, the bones of the joints rub more closely against one another with less of the shock-absorbing benefits of cartilage. OA can occur in all joints of the body but occurs most frequently in the hands, hips, and knees. Osteoarthritis of the knee joint is often described as a ‘worn-out knee’.

With OA, when the cartilage within the joint begins to break down and the underlying bone begins to change. These changes usually develop slowly and get worse over time. Bone changes within the knee can cause the knee to become unstable and give way to an x-position (valgus) or an o-position (varus).

OA can cause pain, stiffness, decreased range of motion, and swelling. Usually, the symptoms of OA progress slowly over years. Initially, they may occur only after exercise but can become constant over time. Often it results in reduced function and disability; causing people to no longer be able to do daily tasks or work. A knee orthosis, or knee brace, could offer the solution. Due to the smart mechanical design of the GENUX 2, the brace is able to provide the required corrective forces needed to relieve pain and improve function.


The GENUX 2 can also be used in cases of mild hyperextension (overstretching) of the knee. This occurs for example, in people with hypermobility or the Ehlers Danlos Syndrome (EDS). The GENUX 2 is a slim and lightweight orthosis that can stabilize the knee so that it does not get into the undesired overstretched position.

Specifications of the GENUX 2 Knee Orthosis

Stability with varus

  • Orthosis placed medial (inside leg) (see photo)
  • FS cable lateral

Stability in valgus

  • Orthosis placed lateral (outside leg)
  • FS cable medial

Stability in overstretching

  • Adjustable extension stop built into hinge
  • Smart pre-stressing of knee straps secures direct hyperextension control


      • Soft straps on the backside
      • Carefully placed pelottes for maximum support
      • Lightweight
      • In flexed position straps loosen up to maximize comfort

      Custom made

      Modern design

      • Minimal coverage of the leg
      • Very slim looking

      GENUX 2 for knock-knee or bowleg

      The GENUX 2 is intended for people with knee instability in valgus or varus. At a valgus (x-position) the knee drops relative to the ankle and hip inwards (seen from the front). In a varus (o-position) it is the other way around. The GENUX 2 helps to compensate this, and this usually leads to a quick improvement in the stability and reduction of complaints.

      Instability through osteoarthritis

      This instability can be caused by osteoarthritis (OA), which causes too much joint clearance due to degeneration of cartilage. Usually, on one side of the knee, it is worse than the other. Because at the most affected side the most cartilage is disapperead, the knee just drops that way. At a valgus the lateral (outer) side of the knee is most affected and the knee is lowered more so that an X-position of the knee is created. For varus it’s just the other way around. As a result of this skew, or misalignment, the load on the affected side of the knee is also increased, which only makes the problem worse. Treatment is then necessary to restore the knee functionalities, reduce pressure on the most affected side, eliminate instability and ultimately reduce pain.

      GENUX 2 for instability by ligaments injury

      Sometimes the instability of the knee is not caused by loss of cartilage, but through torn knee ligaments, usually caused by a trauma, for example due to sport, or a car accident. Through torn ligaments, the knee can lose its intrinsic stability. For some, the muscles can catch it a bit, but not more than a little. To prevent the knee (ligaments, joint capsules, tendons) to be further damaged, it is sometimes necessary to wear an orthosis that can take over the frontal stability of the knee. The GENUX 2 is excellent in stabilizing an unstable valgus or varus of the knee.

      GENUX 2 for hypermobility

      Sometimes the knee ligaments are still intact, but they are just weak or stretched too much. This occurs at people with hypermobility complaints (eg Ehlers Danlos Syndrome, EDS). Also in those cases, an orthosis is sometimes needed to increase the functionalities of the knee by taking over the lateral stability with an orthosis.

      GENUX 2 for overstretched knee

      Sometimes the lateral instability of the knee is mild enough to cope with, especially because, as indicated, the muscles can help a little.  However, when frontal instability is combined with  (an initial) hyperextension or overstretching of knee, problems soon become intolerable. This can cause a lot of pain, irritation and uncertainty due to instability. On top of that, an untreated overstretching is a progressive condition, meaning it gets worse, because at each step the ligaments again become a bit more stretched. The GENUX 2 is well-equipped thanks to the built-in (adjustable) extension stop in the knee joint and the long stable structure, which is also able to stabilize the knee in extension. This prevents aggravation of the hyperextension and increases the functional ability of the knee.

      Or all at once

      With the GENUX 2 we can also fortunately stabilize a valgus ánd a hyperextension. The orthosis is strong enough to provide high stability, even in case serious instability. We do advise, however, that you consider a UTX-POST in cases of severe hyperextension. This Ambroise orthosis is even more capable of offering full support and stability in these cases, combined in a lightweight and still comfortable orthosis. Serious hyperextension is often seen as a symptom of more broad clinical problems. With the UTX line we’re able to address other aspects that may be present in such clinical conditions.

      Not suitable in case of:

      • Overweight (> 120 kg)
      • Knee flexion contracture> 10º
      • Non-correctable valgus / varus> 10º
      • Full instability: valgus and varus
      • Hyperextension > 20° (in that case, choose a UTX POST)

      The GENUX 2 can, depending on the use, the adjustment and the degree of instability of the leg, exert significant corrective forces. Therefore, be careful with hypersensitivity to skin pressure.

      For people with poor blood circulation, it is advised to discuss the use of the GENUX 2 with the attending physician. The GENUX 2 calf band is more or less a circular band, that in such clinical situation may not be advised.

      Order codes GENUX 2 for the professional

      450000 | GENUX 2 lateral | left
      450001 | GENUX 2 lateral | right
      450002 | GENUX 2 medial | left
      450003 | GENUX 2 medial | right

      Instructions for the GENUX 2 knee orthosis

      In this video you can see how to open and close the strap clips of the orthosis.

      In this video you can see how the orthosis is put on. For more videos about using the GENUX 2, you can visit our YouTube channel.

      Manual GENUX 2 Knee Orthosis

      Or download the manual here

      How does the GENUX 2 work?

      The GENUX 2 is specially developed for use for people with moderate to severe complaints due to knee osteoarthritis. It is a lightweight orthosis that is custom made for you. The GENUX 2 stabilizes and corrects the affected knee.


      The frame of the GENUX 2 prevents the knee from moving sideways too much in valgus or varus by counteracting this instability. The GENUX 2 frame ‘pushes back’ when the knee starts to get into sideways movement. This reduces the load on the knee at the affected side: less stress is on the knee side where the cartilage is affected most (and slightly more on the other side). As a result, the pain is usually reduced. Because the leg combined with the brace is more stable, it also feels more stable. This sounds very obvious, but is very important.

      A smart cable

      The GENUX 2 frame is able to generate the required forces to push the knee back because of a smart mechanical construction of the frame. A simple, super light weight, soft-feeling but extremely strong cable, placed on the opposite side of the knee joint, leads to a very rigid frame structure, capable of taking on high loads. With the joint placed laterally and the cable running at the inside of the knee (in cases of valgus instability) the GENUX 2 prevents the knee from moving inward. In cases of varus instability the joint is placed medially and the cable runs at the outside of the knee. Just by adding a string of a few grams we’ve changed the stability of the orthosis in a surprisingly simple way.

      Clever mechanics. That’s it! 🙂


      The GENUX 2 is the first Knee Orthosis in the world with Dynamic 4 Point Balancing. This is a truly unique systems that we’ve developed with various positive effects. Dynamic 4 Point Balancing is a system in which the straps of the brace just above and just below the knee are connected to each other by means of a yet another smart cable. This cable runs posteriorly of (behind) the centre of rotation of the knee joint. As a result the cable allows the straps to become loose in flexion, but to tighten in extension.

      Dynamic 4 Point Balancing: Straps tighten when knee extends and loosen when knee flexes.

       The positive effects of this system are subsequently described below:

      Extension Preloading

       When the knee extends, the straps of the interface just above the knee and just below the knee tighten themselves because the cable, that connects these two straps and that runs behind the centre of rotation of the knee joint gets tightened. With this tightening of these two straps the soft tissues of the leg at all 4 interface locations of the brace are compressed/tensioned, gradually ‘gripping’ the brace tightly to the leg. When the leg reaches full extension brace and leg form a rigid combination with a direct transfer of the stabilising forces from the brace to the leg.

       This is (and feels!) much more stable because you prevent that the brace, once you start loading the leg by standing on it is first pressed into the soft tissues, before it actually does anything, allowing the leg to give way a little.

       Extension Triggering

      Patients that need to control a hyperextension feel the built up of the correction forces of the straps just below and just above the knee increasing before their foot is on the floor and the leg gets loaded by body weight. That triggering reduces the active component of pushing the knee in hyperextension that patients often have. They do actively push their knee into (hyper)extension, because the body needs to feel that the knee is stable enough to start loading the leg. There are no sensors in the leg that accurately tell the brain the alignment of the leg, so feeling the ‘end’ of extension (even if that’s in hyperextension) is the only trigger left. With the extension triggering the brace gives that signal a lot earlier, combined with a more rigid grip of the brace to the leg leading to a reduction of the excessive extension forces.

      Force Balancing

      Because of the cable that connects the straps around the knee, the force in these straps need to be equal. If not, the cable is pulling the strap with the lower force until the forces are equal again. This balancing of these two forces ensures that not one is taking most of the load, whereas the other does little to nothing. Furthermore, since the lever arms of the lower leg are made equal to that of the upper leg, the forces on the pelottes (interfaces) at the top and bottom of the brace are equal as well and equal to the balanced strap force. This is a very nice feature, because we now never have the situation in which one interface doing a lot more than another. This prevents excessive interface forces that can be uncomfortable. But it also means that we know a lot more precise what the maximum loading on the system will be and that allows for a huge step in optimization of the weight of the orthosis.

      Sitting Comfort

      A very tight, snug fitting of the brace is nice in having a direct action of the brace to what the leg is doing. However it’s not so nice in sitting, particularly if we realise that the shape of the leg (due to a different alignment of muscles and tendons in a 90° flexed position, compared to a straight leg) is somewhat different. For instance, the upper leg just above the knee is narrower but somewhat higher (in front side to back side of the leg) in sitting than in stance. The coupling of the straps just around the knee loosens these straps in bending the knee. This allows for a great increase in comfort during sitting.

      Anti slipping

      In the earlier model (the Genux) we’ve proven the need for skin migration underneath the brace just above the knee at the front side of the leg in flexing the knee to prevent the skin from pulling the brace downwards. Every time we flex our knee the skin at the front side of our leg stretches around the knee. This effect can lead to relative movements of up to 4 cm. This skin movement is downwards in flexion and back upwards in extension. 

      If a brace sticks to the skin with straps and rubber at the front side of the leg (particularly just above the knee) the skin will try to pull the brace down with every bending movement it makes. Since downwards movement is usually easy because of the shape of the leg, in contrast to upwards movement, this will lead to the brace slipping down.

      In the GENUX 2 we’ve realised the freedom to migrate the skin underneath the brace by loosening the strap of the interface just above the knee (as well as the one just below the knee). As a result of that the contact force of the interface at that location drops to (almost) zero in flexing. This logically results in a drop in the contact-friction forces and thus in the skin trying to pull the brace downwards in flexion. Combined with a very smooth non-stick surface of the interfaces this ensures that the GENUX 2 stays in place on the leg. 

      The orthoses of Ambroise are continuously in development

      The orthoses of Ambroise are continuously in <strong>development</strong>

      GENUX 2 knee orthosis

      • Up to 35% weight reduction The use of modern materials and thin-walled high strength tubing allowed us to further optimize the design, resulting in an astonishing reduction of weight up to 35%  .
      • Dynamic 4 Point Support A very smart system loosens the straps around the knee, when the knee is flexed, but tightens them when the knee extends. This leads to high comfort due to low forces in flexion and a snug fitting and direct force control in extension.
      • Adjustable knee joint The fully redesigned knee joint is adjustable in flexion. You can change the alignment in flexion up to 15° by just turning a simple screw.

      With every knee bending the skin stretches. Together with the patella (kneecap) it slides smoothly over the leg down. This video shows one of the earliest prototypes of the Genux. It is clear that the orthosis allows the skin to move freely thanks to the rolls. The stripes show that this is about 4 cm!

      Why do knee braces slip down?

      That a knee orthosis should not slip down may sound very obvious. Nevertheless, it is less obvious than many people think. Slipping down of knee braces is one of the most commonly reported complaints with these orthoses.

      Ambroise has developed a unique patented anti-slip system for knee orthoses. We got there by repeatedly asking ourselves why knee braces actually slip. Commonly used braces are usually not that heavy and have more than enough rubbery interfaces and Velcro straps to stick well to the skin. Nevertheless, they slip.

      However, ‘sticking to the skin’ turns out to be much more disadvantageous, if you know exactly what our skin actually does while bending the knee. Just look at the video on the right. There you can see that with every bending of the knee the skin migrates (moves) up to 4 cm. By ‘sticking’ your brace to the skin, you create a situation where the skin draws down the orthosis with each bending movement. Eventually that will result in a brace that has slipped.

      The GENUX 2 does not slip down

      The video here next to shows one of the first prototypes of the Genux. The rolls on the upper leg are located around the three arcs placed above each other. Just under the knee is a calf strap. This calf strap has an elastic that runs to the lower arch of the Genux (just above the ankle). This is how the Genux is attached to the calf band.

      Because the rolls allow the skin to move up and down easily under the Genux, the knee bending does not pull the orthosis downwards. The calf strap keeps the Genux in its place. The Genux itself can make, thanks to the elastic, micro-movements up and down and the skin can migrate freely below the Genux. Those three elements (the rolls, calf band and elastic) make sure the Genux does not slip down.

      In the GENUX 2 we’ve replaced the roller arcs with pelottes with a very low coefficient of friction, which means that they slide very easily, over the GENUX 2 sleeve or over your pants. With the Genux we found that very few people actually wear the brace directly on the skin. Therefore we’ve provided your GENUX 2 with a sleeve that you can wear under the brace if you choose to wear the brace under your clothing.

      Furthermore the smart coupling of the straps just above and below the knee lead to these straps getting loose in flexion, reducing the contact forces at the front side of the knee and therewith the possibility of the skin to pull the brace down with it.

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