HiFi Technology

We haven’t just broken the mold, we’ve destroyed it!

The HiFi is unlike anything you have tried. It captures and controls your underlying bone through our patented and patents-pending compression and tissue release technology. No more sloppy sockets or wasted energy, now you have something that moves with you and feels more like a part of you.

Traditional “bucket” sockets simply focus on fitting the surface of your limb, which results in numerous socket and sound side issues. The HiFi is the world’s first biomechanically-based, skeletally focused, volume adjustable, bone-positing interface that gives you the closest thing to a direct skeletal connection, in a non-surgical, removable design. If you thought surgery was your only open, think again. When motion and force are captured closer to the bone, the prosthesis reacts more precisely and the brain reacts more instinctively. The result is dramatically enhanced performance, energy efficiency, comfort, confidence, enabling amputees of all activity levels and ages to do more.

The HiFi is the brain child of Randy Alley who is best known as a connection pioneer due to his many innovative, biomechanically based, interface designs, inside and outside of prosthetics. In prosthetics, Randall has dedicated years to bringing the focus away from the components and instead to the socket/interface as the primary force in determining the success of a prosthetic system.

We all know you can have the most advanced knee, foot or hand, but if the socket or interface isn’t comfortable or doesn’t function well, you probably won’t wear it.

The HiFi is a game changer. With the HiFi Prosthetic Interface System the benefits are numerous as it is a radically, yet proven, approach to help you achieve better outcomes…because we think you desire it. The HiFi also gives you flexibility as it works with all suspension techniques (i.e. elevated vacuum, pin & liners, straight suction) and can be an open frame or closed design.

Good enough is not enough. Do you like wearing your socket? We think you should.

Superior Comfort

  • Lowest trim lines in the industry
  • Subischial design for above knee wearers
  • Sit evenly on a chair
  • Better posture/less pain
  • Keep your leg(s) on when going to the bathroom
  • No pinching (especially ideal for women)
  • Lighter feeling prosthesis/ability to tolerate weight of components better
  • Reduced skin shear/reduced chafing/reduced skin irritations
  • Increased wear times

Superior Performance

  • Increased stability
  • Improved balance
  • Greater range of motion
  • Improved rotational control
  • Reduced energy expenditure
  • Lighter feeling prosthesis
  • Improved stability
  • Decreased pistoning
  • Greater gait symmetry/improved walking/running
  • Increased step uniformity
  • Faster response times

 Superior Connection

  • Wearer feedback and design input during casting/scanning
  • More intimate design
  • Triggers your muscles when walking/lifting
  • Reduces/stops muscle atrophy
  • Greater proprioception
  • Ability to rely on prosthetic side more/help save sound side
  • Reduction in volume changes/limb fluctuations
  • Adjustable (globally and targeted)
  • Believed to improve neurological connections
  • Believed to help improve circulation



Amputee/prosthetist testimonials with images and/or video




Q: Who is a candidate for the HiFi Interface?

A: We have had great success fitting both upper and lower limb wearers. And while this design benefits individuals of all activity levels, it is extremely effective for those who are very active and demanding on their prosthesis, especially above-knee and upper limb amputees who are looking for greater stability and comfort. If you are unsure if you are a candidate for this design or if you have questions regarding your specific needs, contact us for an initial, complimentary in-person or remote evaluation.

Q: What are the benefits of the HiFi Interface?

A: Better control, less energy expenditure, greater comfort, reduced heat, greater range of motion- overall a better fitting socket that will give you more confidence each and every day. These are just a few of the benefits of the High-Fidelity Interface. But don’t take our word for it. Check out a few of our patient and practitioner testimonials.

Q: I’ve seen frame-style sockets before – what’s different about the HiFi Interface?

A: Having an inner flexible interface surrounded by a frame with struts and windows is a common approach that has been used for a long time. A traditional frame style socket is designed to save a small amount of weight while theoretically allowing some room for contracting muscles to bulge against the flexible material not backed by the rigid frame. It applies a global compression to the entire limb. This is not the same as applying the biomechanical principles of alternating compression and release, a hallmark of the High-Fidelity design. In the High-Fidelity Interface the level of compression imparted by the struts     displaces a significant amount of your limb’s soft tissue out through the windows or release areas depending on the style of High-Fidelity Interface chosen. The reduced volume of tissue “left behind” allows the compression struts to get closer to the underlying bone because there is simply less soft tissue in the way. By being closer to the underlying bone, there is less ability for the bone to move within the interface itself, a common problem with traditional sockets.

Q: What’s so important about a socket anyway, aren’t the components more critical?

A: Absolutely not! The interface forms your connection with everything else on the prosthesis. It is where all motion begins and is where all information from the outside world is ultimately received. It is quite literally the interface between man and machine. Traditional sockets with their “limb stuffed into a tube” design reflect the general feeling that as long as you’re comfortable and the prosthesis stays on, this is all you can hope for. We know you deserve more, which is why we created the High-Fidelity Interface. It captures your movements with absolute precision, extracting maximum energy from your input, whether you’re walking or reaching, running or throwing, dancing or lifting. The High-Fidelity Interface locks your bone in place and ensures the maximum amount of energy you spend is transferred to the rest of the prosthesis rather than being absorbed by a freely moving bone inside the socket. Make sure you get the most out of your prosthesis by understanding it all starts with the right interface.

Q: What type of suspension can I use with the HiFi Interface?

A: The HiFi Interface works with all currently available suspension techniques (i.e. skin fit, roll on liners, elevated vacuum, anatomical)

Q: My above knee socket comes up really high in the back and the sides, does the High-Fidelity Interface have the same trim lines?

A: Because the High-Fidelity Interface stabilizes the shaft of the bone and doesn’t rely on its upper portion for stability, the trim lines can be significantly lower than any socket design currently available, including elevated vacuum sockets.

Q: I’ve heard elevated vacuum is the way to go. Is the High-Fidelity Interface System better?

A: Before answering this, please understand that elevated vacuum is a suspension technique, and although it influences interface design, it is, by itself not a socket or interface. Also keep in mind that elevated vacuum can be used with the High-Fidelity Interface design. This being said, elevated vacuum sockets work by drawing additional fluid into the limb from elsewhere in your body. It essentially keeps your limb tight inside the socket so the connection, or linkage as it is often called, is maintained. While this is certainly an improvement over traditional approaches, it doesn’t come close to creating the level of linkage the High-Fidelity Interface offers. By creating a biomechanical “lock” of your underlying bone via an alternating series of compression and release zones, wearers the world over state the High-Fidelity Interface makes their prosthesis feel like it’s a part of their body. It’s as close as you can come to osseointegration without the surgery. Now that’s linkage!

Q: My socket is always rotating on my leg, does the HiFi help this?

A: Yes it certainly does! The alternating series of compression and release zones not only lock your bone in place but because of the unique shape these zones create, it is very difficult for the interface to rotate on the limb. It is just another benefit the High-Fidelity Interface has over traditional sockets as well as those sockets with elevated vacuum.

Q: My bone is always hitting inside the socket and it hurts. Does the HiFi Interface prevent this?

A: By controlling the underlying bone, it no longer strikes the socket wall during walking or standing, or for upper limb prosthesis wearers, during lifting. Rather than allowing the bone to move freely within the confines of the socket, in the High-Fidelity Interface, unwanted bone motion is held to an absolute minimum, so the only thing that moves when you want it to is the prosthesis itself.

Q: It looks like the High-Fidelity might be uncomfortable. Is it?

A: The High-Fidelity Interface is much more comfortable than traditional sockets because it makes you and your prosthesis feel connected, rather than simply hanging off of you. While the compression zones look aggressive, by combining them with alternating areas of tissue release, the design actually eliminates all of the issues associated with an uncomfortable socket. The main issue for just about everyone is the fact that the bone moves inside a traditional socket far too much. If this doesn’t result in pain or discomfort from striking the wall of the socket, then at best the moving bone wastes energy, and makes the prosthesis feel heavy and unresponsive. The socket trim lines can be much lower than traditional designs because the High-Fidelity Interface stabilizes the shaft of the bone and doesn’t rely on the height of the socket for stability. If an open window design is used it can be considerably cooler, even if using a silicone liner, all contributing to a more positive, more functional and much more comfortable experience.

Q: I saw a casting/scanning device in your HiFi Interface video. How does this device work?

A: In order to ensure the best result during the casting process Biodesigns has created a specialized casting device. The High-Fidelity Imager compresses your limb in specific areas during the casting process to ensure that the optimum compression and tissue release is transferred to your new socket. Patients upon feeling the compression and release imparted by the Imager are immediately able to feel the advantages of the HiFi design.