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Our Technology

While our mission is a social one, our innovative solutions are made possible by pushing the boundaries of science and technology. We rely on extensive scientific investigation to help us ensure that our products are truly going to make a difference for people around the world.


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Linkages and axes defined. Assembly view (left), Section view (right)

The All-Terrain Knee utilizes a proprietary stance-phase control mechanism (the AutoLock) and swing-phase control mechanism (Variable Cadence Controller or VCC). The mechanisms comprise a 4-linkage (4 bar) kinematic chain.

The AutoLock technology is based on a knee lock that is automatically engaged in late-swing-phase for extra safety. The knee remains securely locked until mid-to-late stance-phase when it is disengaged for an effortless swing‐phase initiation.

The VCC utilizes a variable friction system with an optimized extension assist spring for efficient gait at multiple walking speeds.

The 4 bar kinematic arrangement of the All-Terrain Knee mechanism results in polycentric kinematics and swing-phase foot-clearance comparable to 4 and 6 bar polycentric knee mechanisms.

AutoLock Technology operation in a 4 bar knee design

Variable Cadence Controller Demonstrations


Andrysek J, Wright FV, Rotter K, Garcia D, Valdebenito R, Mitchel CA, Rozbaczylo C, Cubillos R. "Functional and biomechanical differences between weight-activated brake (wab) and automatic stance-phase lock (aspl) prosthetic knee joint mechanisms"

Andrysek J, Wright FV, Rotter K, Garcia D, Valdebenito R, Mitchel CA, Rozbaczylo C, Cubillos R. "Long-term clinical evaluation of the automatic stance-phase lock-controlled prosthetic knee joint in young adults with unilateral above-knee amputation." Disability and Rehabilitation Assistive Technology. 2016 Jul 4:1-7.

Andrysek J, Klejman S, Heim W, Torres Moreno R, Steinnagel B, Glasford, S. "Mobility function of a prosthetic knee joint with an automatic stance-phase lock." Prosth Orth Int. 35(2), 163-170, 2011.

Furse A, Cleghorn W, Andrysek J. "Improving the gait performance of non-fluid-based swing-phase control mechanisms in above-knee prostheses." IEEE Trans Biomed Eng. May 16, 2011(epub).

Furse A, Cleghorn W, Andrysek J. "Development of a low-technology prosthetic swing-phase mechanism." J Med Biomed Eng. 31(2), 145-150, 2011.

Wyss D, Lindsay S, Cleghorn WL, Andrysek J. "Priorities in lower limb prosthetic service delivery based on an international survey of prosthetists in low- and high-income countries." Prosth Orth Int. 2013 Dec.

Andrysek J. "Lower-limb prosthetic technologies in the developing world: a review of literature from 1994 to 2010." Prosth Orth Int. 34(4), 378-398, 2010.

Wyss D, Cleghorn WL, Andrysek J. "Application of Quality Function Deployment for the development of a prosthetic knee joint." AES Technical Reviews Part C: International Journal of Advances and Trends in Engineering Materials and their Applications (IJATEMA). 1 (1) 2013, 67 – 75.

  • Abstract available here.

Andrysek JNaumann S, Cleghorn WL. "Design and quantitative evaluation of a stance-phase controlled prosthetic knee joint for children." IEEE Trans Neural Syst Rehabil Eng. 2005 Dec;13(4):437-43.

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