Studies-Outcomes

In the 21st Century we are sending rockets to Mars but prosthetists are still fitting you in buckets!?!?
Where is the science people?

Our HiFi Interface and Imager™ system, with patented and patents-pending technology, is the most advanced design available because we focus on body biomechanics, responsiveness, shear forces, pressure, bone positioning and control, tissue management, efficiency of movement, gait symmetry, rotational control, range of motion, proprioception, energy saving, and overall user embodiment, all while ensuring superior comfort. In other words, obtaining a comfortable fit is just the beginning. Functional outcomes are the end game.

We know the attachment platform is the core factor in determining success or failure of attached devices and is in direct proportion to wear times, walking speeds, balance confidence, falls, comfort, and overall function. In our opinion there has been an overwhelming misappropriation of research dollars allocated to the components that are being attached to the prosthetic user and little financial consideration to the connection itself. The components today are highly effective and functional, yet they are being attached to inefficient socket platforms. You wouldn’t trust your Ferrari or Lamborghini if it was built on a rickety chassis with faulty suspension and flat tires. No one would. But you are forced to trust a socket that is inherently biomechanically flawed with not only your hard earned dollars, but with your life.
66

Yearly fall rates are as high as 66%. 

Did you know, falling and the fear of falling is prevalent among the amputee population, especially for AK amputees?

I don’t know about you, but at biodesigns we don’t think this is an acceptable risk for the prosthetic wearer. And we would bet that a significant factor in these falls is an unstable socket that allows far too much bone movement inside. Not to mention falls are very expensive, costing over $23.3 billion annually. Wouldn’t it be great if that money was going into research and technology that prevents falls instead?
Our HiFi Interface, also referred to as Compression Release Stabilized or CRS, is based on judicious application of our OsseostabilizationTM principles which results in a synching of the interface, and hence the external device connected to it, to skeletal motion, an effect dubbed Osseosynchronization™.
The High-Fidelity Interface System is not experimental and has been used successfully in prosthetic practices for nearly a decade with thousands of patients fit. The HiFi socket/interface platform is based off proven biomechanical principles and is backed by clinical evidence. The HiFi technology was also utilized in two DARPA/VA studies, as well as being the primary focus of biodesigns’ Direct to Phase II DARPA/SBIR contract, “Adaptive Tooling for Customized Upper Limb Prosthetic Socket Fitment” (D15PC00174), and is now being utilized in a US Army Exoskeleton contract.
However, the HiFi is more than just a revolutionary socket design. It has shown promise far beyond traditional outcome measures and is embarking on the phenomenon of embodiment, i.e. being one with whatever device or gear is attached. Our prosthetic wearers not only report improved comfort and function but state their prostheses feel like a part of them and feel connected to them.

“The HiFi makes me feel more secure and makes mobility more comfortable and easier. It is less and lighter – but I can get more out of it. It feels better all the way around. It feels more like a part of me. It moves with me. I’m not fighting it. There is not as much effort to get the movement I’m looking for. This is the feeling I’ve been looking for. It’s the anatomical extension of my limb.” – Jeff Fabry, 2012 Paralympic gold medalist, archery

In fact, many report previously lost phantom sensations returning to their limb, allowing users to “feel” the ground and prevent falls and stumbles, one of the biggest challenges currently with prosthetics and orthotics. This degree of acceptance and embodiment breaks the boundaries on what many thought was possible in a non-surgical, non-sensorized attachment design, and is the basis for all of our work.
High levels of sound side overuse and breakdown is another common side effect for those missing limbs. This is caused by many things including improper alignment or a poorly fitting and functioning socket, however we believe your confidence in your prosthesis is a main determinant. If you don’t believe your prosthesis will hold your body’s weight or you feel it is unstable of simply not a part of you, you will compensate with your sound side and this results in gait asymmetry. Gait asymmetry could be the most insidious yet least understood problem for amputees as it creates a snowball effect leading to sound-side break down of your “good” limb.
Our bodies endure a lot of stress and strain, especially our knees. Osteoarthritis (OA) is a major concern for unilateral amputees, especially those who have lost limbs at an early age. This results in knee pain making it harder to walk.
Data show intact limb knee pain is twice as common in unilateral lower extremity amputees as in able-bodied individuals and is the primary complaint among longtime prosthesis users (average prosthesis wear time of 24 years). Pain is also more common among those with higher amputations; one study by Mussman et al found 46% of transtibial amputees had knee pain versus 75% of people with transfemoral amputation.
If you are a woman, you will face even higher levels of OA. Unfortunately, a double whammy – amputee and a woman over 45. We do not find these OA numbers acceptable. Part of our HiFi Interface research shows improved gait symmetry AND balance confidence, among many other benefits. Imagine how such an interface might improve not only your quality of life, but your life expectancy. It’s that simple. Descend into immobility due to pain and fear of falling and you will shorten your life. Who wants that?

HiFi Interface Theory and Biomechanics

Summary: HiFi Interface/Socket platform integrating superior biomechanics is more stable than traditional designs/approaches.
Randy Alley, et al published a journal article describing the theory and superior biomechanics of the HiFi design in upper and lower limb amputees. The article details how the HiFi’s compression and tissue release technology reduces unwanted motion of the bone within the interface and increases socket stability, while increasing the wearer’s capability to handle greater loads. This article was published in the Journal of Rehabilitation Research and Development, 48(6), pp. 679-696, “Prosthetic Sockets Stabilized by Alternating Areas of Tissue Compression and Release.”
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X-Ray Visualization of HiFi Osseostabilized Socket vs. IRC Socket

Summary: X-ray visualization of HiFi Interface/Socket shows improved control of femur, and reduced lag when moving the prosthesis. Patients are able to use less effort to move their prosthesis, saving energy with every step.
A preliminary study was performed using x-rays to visualize the bone position relative to the socket or interface in both an ischial containment socket and a HiFi Interface. When the patient stood equally weighted in a comfortable stance, the femur was found to be abducted and positioned laterally within the soft tissue in an ischial containment socket, whereas in a HiFi Interface the femur is centered within the soft tissue and lies more naturally in adduction. The x-ray analysis of the patient with his prosthetic side hip flexed to 90 degrees and unsupported while wearing the prosthesis shows very little skeletal motion is lost in the translation and movement of the prosthesis while wearing the HiFi Interface. A greater discrepancy was found between the angle of the femur relative to the angle of the socket using an ischial containment socket. The HiFi’s claims of skeletal control, stabilization, and synchronization were imaged and confirmed. With greater control patients are able to use less effort to move their prosthesis, saving energy with every step.

Gait Symmetry Case Study - Subischial HiFi Suction Socket vs. Elevated Vacuum

Summary: HiFi Interface/Socket’s enhanced positional control was most likely due to the improved proprioception gained from a more direct linkage and synchronization with skeletal movements, which in turn results in more precise and repeatable step placement. A trend toward greater overall gait symmetry between prosthetic and sound side was concluded.
Using a BTS G-Walk system, step variability-or the level of differentiation of the same side step as compared to its predecessors and successors-was compared between a subischial HiFi Interface with a simple expulsion valve.and a subischial elevated vacuum socket. Graphical analysis showed that the HiFi Interface had a significantly reduced step variability.

Eastern Michigan University Biomechanics Comparative Case Study of Subischial HiFi Interface vs. IRC Socket

Summary: EMU study documents that HiFi Interface improves gait stability, symmetry, and function, while decreasing pain, fatigue, fall risk, and self-reported disability.
This study was conducted with IRB oversight under the guidance of Professor Jeff Ropp, BSc, CP and Tyler Klenow, MSOP, CPO, CPT and included self-report standardized clinical outcome measures and gait analysis conducted with a Vicon Motion Capture System. The study concluded the HiFi Interface increased stability which further resulted in decreased, pain, fatigue, and marked increases in function. Gains were seen in both self-selected walking velocity and overall gait symmetry between the prosthetic and sound sides with the HiFi Interface. Center of mass deviations decreased vertically and laterally with the HiFi Interface, which correlates to greater stability during ambulation and reduced fall risk. In subjective measures, the patient improved from a category of Severe to Moderate in amputation-related disability per the Oswestry Questionnaire and reported a nearly 20% increase in functional ease per the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The Eastern Michigan University Study is ongoing and seeking additional subjects. The results of this study were published in the Journal of Prosthetics and Orthotics, 29(3), pp. 130-136, entitled “Comparative Efficacy of Transfemoral Prosthetic Interfaces.”
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Blatchford-Endolite Prosthesis Evaluation Questionnaire (PEQ) Study - Subischial HiFi Interface vs. IRC Socket

Summary: Blatchford’s UK study of Prosthesis Evaluation Questionnaires filled out by amputees pre and post HiFi, shows improvements of 20-110% in functional and subjective measures.
Blatchford conducted an exploratory study of patients fit with the HiFi Interface at their Crystal Palace and Charing Cross facilities. The patients were asked to complete Prosthesis Evaluation Questionnaires before and after being fit with the HiFi Interface. With the HiFi Interface patients reported an average improvement of 48.6% in ambulation, 49.8% in utility, 19.0% in transfers, 74.9% in well-being, 109.4% in prosthesis satisfaction, and 90.9% in walking satisfaction.  Additionally, the subjects generally noted that they had increased sitting comfort with the subischial HiFi Interface, a general feeling of being more connected to the knee joint and componentry, and greater proprioception transmitted through the prosthesis.

California State University Northridge Physical Therapist Case Study

Summary: PT Case Study documented HiFi Interface provides greater comfort, stability, function, quality of life and significant improvement in fall risk. Additionally, the subject’s activity level improved from a K2 to a K3 while wearing a HiFi Interface as determined by the Amputee Mobility Predictor (AMP).
At California State University Northridge, Physical Therapist Victoria Graham completed examinations both pre- and post-HiFi fitting. Subjective reports using the Socket Comfort Scale (SCS), Activities Balance Confidence Scale (ABC), Prosthesis Evaluation Questionnaire (PEQ), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) showed the subject reporting significantly greater comfort, stability, perceived function, and quality of life with the HiFi Interface. A point of interest was the ABC indicated improvement of over 60%, which put the user within 1 pt. of the fall risk threshold when using the HiFi Interface.   Functional measures saw improvements of 20-50% across tests such as the Four Square Step Test, Timed Up and Go, (TUG) L-Test, and Amputee Mobility Predictor (AMP). The AMP tested noted the subject’s activity level improved from a K2 using a traditional socket to a K3 while wearing a HiFi Interface.

Effect on Gait Speed and Risk of Falls - Subischial HiFi Interface vs. IRC Socket

Summary: Data generated by Sampson et al and analyzed by Kahle et al concluded the HiFi Interface significantly outperformed IRC sockets in all objective and subjective tests employed in study. Notable findings include HiFi interface allowed wearers to walk faster, farther, and with greater balance and energy savings.
Bill Sampson, Sampson Prosthetics and Orthotics, engaged a physical therapist to study and report on the comparative effects of subischial HiFi interface to ischial ramus containment (IRC) sockets. Components were kept consistent with the only variable being the interface design. He and his research team concluded that the HiFi interface significantly outperformed IRC sockets in all objective and subjective tests. While using the HiFi interface increased walking capability was observed in terms of being able to walk faster, farther, and with greater energy savings. Increased balance confidence was also observed as users in the HiFi interface saw less falls and greater stability.   Additionally, the lower trim lines offered in the subischial HiFi interface provided greater levels of comfort and range of motion. The results were published in Technology & Innovation, 18(2) pp. 167-173, “The Effects of Transfemoral Interface Design on Gait Speed and Risk of Falls.”
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Femur Bone Control in Water - Therapy Case Report

Summary: Cutler’s study indicated that the HiFi interface does provide a substantial improvement in femoral control and that improved rehabilitation can be accomplished with the combination of HiFi interface and aquatic therapy.
HiFi Authorized Provider Tom Cutler, CPO, reported on his case study of a patient rehabilitating through aquatic ambulation while utilizing the HiFi interface. The study indicated that the HiFi interface has significant control of the femur and concluded improved rehabilitation of the patient can be accomplished with the combination of a HiFi Interface and aquatic therapy. This case study can be found in the Journal of Prosthetics and Orthotics, 29(4), pp. 206-212, “Rehabilitation of an Individual with Transfemoral Amputation Combining Aquatic Ambulation with Prosthetic Socket Incorporating High-Fidelity Skeletal Capture: Case Report.”
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VA Research on Transhumeral HiFi Interface (Compression Release Socket) vs Traditional Socket

Summary: After numerous fittings of the CRS/HiFi Interface paired with the DARPA/DEKA LUKE Arm, the principal investigator reports that the HiFi Interface provides better control of the residual limb within the socket and had less slippage.
The researchers determined the Transhumeral Compression Release Socket (CRS/HiFi) provided better control of the residual limb within the socket and had less slippage. The results of this study can be found in Disability and Rehabilitation: Assistive Technology, pp.1-10, Comparison of Transhumeral Socket Designs Utilizing Patient Assessment and in-vivo Skeletal and Socket Motion Tracking: a Case Study.”

Pistoning Comparison Between HiFi Interfaces and IRC Sockets

Summary: Blatchford Technical Director Saeed Zahedi study showed HiFi Interfaces reduce pistoning by 50% as compared to IRC sockets.
Saeed Zahedi, Technical Director, from Blatchford Endolite performed a comparison between IRC sockets and HiFi Interfaces. It was found that the HiFi Interface reduced pistoning by 50%. Mr. Zahedi’s study results were presented in the Royal Overseas League, “London Shear Force in External Limb Prosthetics.”

Transradial Biomechanical Design Considerations

Summary: HiFi Interface/Socket is based on proven biomechanical principles that will yield greater comfort and safety.
Sang et al, stated that biomechanics can help determine better efficiency and safety for interface designs, and that force and motion transferred together with comfort and safety are two main aspects of prosthetic interface designs. The authors concluded load distribution and transmission should rely on achieving skeletal control through targeted soft tissue relief, which is a core design principle of the HiFi Interface. The article was published in the Journal of Engineering Medicine, 230(3), pp. 239-250, “Biomechanical Design Considerations for transradial prosthetic Interface: A Review.” 
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Ischial Ramus Containment vs. Vacuum Assisted Suspension

Summary: HiFi Interface/Socket is the only socket design that has the needed stability that allows it to be subischial with or without vacuum. Thus patient preferences for subischial are met with the HiFi and would likely lead patients toward a greater acceptance of HiFi versus traditional socket designs.
Jason Kahle, researcher, compared Ischial Ramus Containment (IRC) sockets to Vacuum-Assisted Suspension (VAS) and determined that except for medical proximal pressure, no other measures reached statistical evidence. However, all subjects preferred subischial sockets. The Journal of Rehabilitation Research and Development, 50(9), pp. 1241-1252, “Transfemoral Sockets with Vacuum-assisted suspension comparison of hip kinematics, socket position, contact pressure, and preference: ischial containment versus brimless.”
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Research with biodesigns

RESEARCH / STUDIES
Several additional studies, not mentioned, are currently in progress with many not yet started. Please contact us if interested in working with biodesigns on research and/or socket studies.

Real Outcomes

Don’t believe us? Too good to be true? We invite you to read our many testimonials. See what our users and other allied health professions have to say about the HiFi.

Bam! HiFi is validated by clinical evidence.

Don’t let anyone hold you back.