Comparison of the Power Knee and C-Leg during step-up and sit-to-stand tasks

Physical performance and self-report outcomes associated with use of passive, adaptive, and active prosthetic knees in persons with unilateral, transfemoral amputation: Randomized crossover trial

“…Future research with an instrumented TUG [93] may reveal which subtasks (e.g., sit-to-stand, walking, turning, and stand-to-sit) are most affected by adaptive knee control. Reduced TUG times in the active compared with the passive conditions appear to conflict with reports of increased knee power provided by the Power Knee II reported by Wolf and colleagues [51]. However, data here are corroborated by our participants' spontaneous reports that they were often unable to activate the sit and/or stand functions in the Power Knee II.…”

“…A key limitation to the existing adaptive knee literature is that the majority of findings to date have been based on a single model (i.e., Ottobock C-Leg) (Ottobock; Duderstadt, Germany) that uses a specific microprocessorcontrolled hydraulic control system [37]. Other adaptive or active knee technologies, such as the MR system present in the Össur Rheo Knee II (Össur hf; Reykjavík, Iceland), or the harmonic drive system present in the Össur Power Knee have not been well studied, with a few notable exceptions [39,[47][48][49][50][51]. These prior studies have primarily focused on evaluation of laboratory-based biomechanical outcomes (e.g., kinetics and kinematics) and have not directly evaluated users' functional outcomes over longer periods.…”

First-in-man demonstration of a fully implanted myoelectric sensors system to control an advanced electromechanical prosthetic hand

“…Even advanced microprocessor controlled variable dampening prosthetic knees (such as the Genium, X3, and Rheo Knee) are “passive” systems that are unable to generate active power to propel an individual during walking, climbing stairs, or rising out of a chair. (Wolf et al, 2013) Therefore, individuals with above knee amputation must rely on the activity of more proximal muscles such as the hip, pelvis and lower back to generate power, which not only limits their function, but decreases intuitive control and biomechanical efficiency, likely contributing to long-term complications. (Gailey et al, 2008)…”

Persons with unilateral transfemoral amputation have altered lumbosacral kinetics during sitting and standing movements

“…Following approval by the local Institutional Review Board, biomechanical data collected during sit-to-stand and stand-to sit movements were retrospectively analyzed from nine males with unilateral TFA -5 initially fit with the PK and 4 with the C-Leg (cross-over design) -and nine male uninjured controls (for more information, see [17]). All participants were military personnel, with no self-reported neurologic or other musculoskeletal conditions or pain that may have adversely affected the results.…”

“…and importance to completion of the sit-to-stand and stand-to-sit task, there remain no studies examining lumbosacral kinetics during these movements among persons with unilateral LLA. A recent investigation evaluated functional performance, using sit-to-stand and stand-to-sit movements, in persons with unilateral transfemoral amputation (TFA) wearing passive (C-Leg; Otto Bock Healthcare, Duderstadt, Germany) and powered (Power Knee TM ; Ö ssur, Reykjavík, Iceland) microprocessor knee devices [17]. Although these authors noted larger mediolateral trunk displacements among persons with TFA compared to uninjured controls, regardless of knee device, no further (kinetic) trunk analyses were performed.…”