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Ankle prosthesis

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https://www.readbyqxmd.com/read/28885156/the-vspa-foot-a-quasi-passive-ankle-foot-prosthesis-with-continuously-variable-stiffness
#1
Max K Shepherd, Elliott J Rouse
Most commercially available prosthetic feet do not exhibit a biomimetic torque-angle relationship, and are unable to modulate their mechanics to assist with other mobility tasks, such as stairs and ramps. In this work, we present a quasi-passive ankle-foot prosthesis with a customizable torque-angle curve and an ability to quickly modulate ankle stiffness between tasks. The customizable torque-angle curve is obtained with a cam-based transmission and a fiberglass leaf spring. To achieve variable stiffness, the leaf spring's support conditions can be actively modulated by a small motor, shifting the torque-angle curve to be more or less stiff...
September 7, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28871360/the-aes-total-ankle-arthroplasty-analysis-of-failures-and-survivorship-at-ten-years
#2
Alexandre Di Iorio, Anthony Viste, Michel Henry Fessy, Jean Luc Besse
BACKGROUND: AES mobile-bearing total ankle replacement was developed from the Buechel Pappas model. It was withdrawn in 2009, after identification of a higher than expected complication rate. The purpose of the current study was to analyse clinical outcomes, failures and survival of the initial series of 50 AES published in 2009. METHODS: In this single-centre continuous prospective study (2003-2006), 50 AES prostheses were included. Pre-operative osteoarthritis was mainly post-traumatic (50%) and secondary to instability (36%)...
September 4, 2017: International Orthopaedics
https://www.readbyqxmd.com/read/28869812/the-effects-of-prosthetic-foot-stiffness-on-transtibial-amputee-walking-mechanics-and-balance-control-during-turning
#3
Courtney E Shell, Ava D Segal, Glenn K Klute, Richard R Neptune
BACKGROUND: Little evidence exists regarding how prosthesis design characteristics affect performance in tasks that challenge mediolateral balance such as turning. This study assesses the influence of prosthetic foot stiffness on amputee walking mechanics and balance control during a continuous turning task. METHODS: Three-dimensional kinematic and kinetic data were collected from eight unilateral transtibial amputees as they walked overground at self-selected speed clockwise and counterclockwise around a 1-meter circle and along a straight line...
August 15, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28867058/complex-total-ankle-arthroplasty
#4
REVIEW
Stephen A Brigido, Scott C Carrington, Nicole M Protzman
Total ankle arthroplasty is a viable surgical technique for the treatment of end-stage degenerative joint disease. With continued advancement in prosthetic design, refined surgical techniques, and improved outcomes, the indications for total ankle replacement have expanded to include cases of increasing complexity. With meticulous preoperative planning and exacting execution, many frontal plane deformities and cases of avascular necrosis can now be successfully addressed at the time of prosthesis implantation or in a staged procedure...
October 2017: Clinics in Podiatric Medicine and Surgery
https://www.readbyqxmd.com/read/28865584/bone-block-arthrodesis-procedure-in-failures-of-first-metatarsophalangeal-joint-replacement
#5
Federico Giuseppe Usuelli, Jacopo Tamini, Camilla Maccario, Miriam Grassi, Eric W Tan
BACKGROUND: The treatment for the failure of a first metatarsophalangeal joint (MTP1) prosthesis can be complex. There is no consensus regarding the ideal treatment. One of the main issues is the available bone stock after prosthesis removal. The aim of the study was to report the clinical and radiographic results for MTP1 arthrodesis with autologous calcaneus bone graft (bone-block fusion) as a revision procedure of a previous MTP1 implant failure. METHODS: This study included 12 patients diagnosed with failure of a MTP1 prosthesis...
September 2017: Foot and Ankle Surgery: Official Journal of the European Society of Foot and Ankle Surgeons
https://www.readbyqxmd.com/read/28854938/the-assessment-of-femoral-shaft-morphology-in-the-sagittal-plane-in-chinese-patients-with-osteoarthritis-a-radiographic-analysis
#6
Zhengyuan Bao, Liang Qiao, Jianghui Qin, Jiacheng Xu, Sheng Zhou, Dongyang Chen, Dongquan Shi, Jin Dai, Yao Yao, Qing Jiang, Zhihong Xu
BACKGROUND: The purpose of this study was to analyze femoral shaft sagittal parameters in Chinese osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA) and identify whether the parameters in the coronal plane could be predictors of those in the sagittal plane. METHODS: Standard long-standing anteroposterior and femoral lateral radiographs of 50 lower limbs in 50 Chinese OA patients were included. Sagittal femoral bowing angle (sFBA), angle between femoral distal anterior cortex axis and sagittal mechanical axis (DACSMA), angle between femoral distal anterior cortex axis and sagittal distal anatomic axis (DACSDAA), and angle between femoral sagittal mechanical axis and sagittal distal anatomic axis (SMADAA) were measured...
August 30, 2017: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/28814050/segmental-contributions-to-sagittal-plane-whole-body-angular-momentum-when-using-powered-compared-to-passive-ankle-foot-prostheses-on-ramps
#7
Nathaniel T Pickle, Anne K Silverman, Jason M Wilken, Nicholas P Fey
Understanding the effects of an assistive device on dynamic balance is crucial, particularly for robotic leg prostheses. Analyses of dynamic balance commonly evaluate the range of whole-body angular momentum (H). However, the contributions of individual body segments to overall H throughout gait may yield futher insights, specifically for people with transtibial amputation using powered prostheses. We evaluated segment contributions to H using Statistical Parametric Mapping to assess the effects of prosthesis type (powered vs passive) and ramp angle on segmental coordination...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28814045/across-user-adaptation-for-a-powered-lower-limb-prosthesis
#8
John A Spanias, Ann M Simon, Levi J Hargrove
Pattern recognition algorithms have been used to control powered lower limb prostheses because they are capable of identifying the intent of the amputee user and therefore can provide a method for seamlessly transitioning between the different locomotion modes of the prosthesis. However, one major limitation of current algorithms is that they require subject-specific data from the individual user. These data are difficult and time-consuming to collect and consequently these algorithms do not generalize well across users...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28814037/design-of-a-power-asymmetric-actuator-for-a-transtibial-prosthesis
#9
Harrison L Bartlett, Brian E Lawson, Michael Goldfarb
This paper presents the design and characterization of a power-asymmetric actuator for a transtibial prosthesis. The device is designed to provide the combination of: 1) joint locking, 2) high power dissipation, and 3) low power generation. This actuator functionality allows for a prosthesis to be designed with minimal mass and power consumption relative to a fully-powered robotic prosthesis while maintaining much of the functionality necessary for activities of daily living. The actuator achieves these design characteristics while maintaining a small form factor by leveraging a combination of electromechanical and hydraulic components...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28814020/piecewise-and-unified-phase-variables-in-the-control-of-a-powered-prosthetic-leg
#10
Dario J Villarreal, David Quintero, Robert D Gregg
Many control methods have been proposed for powered prosthetic legs, ranging from finite state machines that switch between discrete phases of gait to unified controllers that have a continuous sense of phase. In particular, recent work has shown that a mechanical phase variable can parameterize the entire gait cycle for controlling a prosthetic leg during steady rhythmic locomotion. However, the unified approach does not provide voluntary control over non-rhythmic motions like stepping forward and back. In this paper we present a phasing algorithm that uses the amputee's hip angle to control both rhythmic and non-rhythmic motion through two modes: 1) a piecewise (PW) function that provides users voluntary control over stance and swing in a piecewise manner, and 2) a unified function that continuously synchronizes the motion of the prosthetic leg with the amputee user at different walking speeds...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28814001/design-of-an-energy-efficient-transfemoral-prosthesis-using-lockable-parallel-springs-and-electrical-energy-transfer
#11
Francois Heremans, Renaud Ronsse
Over the last decade, active lower-limb prostheses demonstrated their ability to restore a normal gait for transfemoral amputees by supplying the required positive energy balance [1]. However, the added-value of such devices is significantly impacted by their limited energetic autonomy preventing their full appropriation by the patients. There is thus a strong incentive to reduce the overall power consumption of active prostheses. Addressing this need requires to revisit the electromechanical design. For both the ankle and the knee, the present paper demonstrates that both the use of a lockable parallel spring and the transfer of electrical energy between joints can significantly improve the energetic performance for overground walking...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28814000/preliminary-study-of-a-robotic-foot-ankle-prosthesis-with-active-alignment
#12
Andrew K LaPre, Ryan D Wedge, Brian R Umberger, Frank C Sup
Robotic prosthetic foot-ankle prostheses typically aim to replace the lost joint with revolute joints aimed at replicating normal joint biomechanics. In this paper, a previously developed robotic ankle prosthesis with active alignment is evaluated. It uses a four-bar mechanism to inject positive power into the gait cycle while altering the kinematics of the ankle joint and pylon segment to reduce loading on the residual limb. In a single-subject biomechanics analysis, there was a 10% reduction in peak limb pressures and evidence of greater gait symmetry in ground reaction forces when active alignment was implemented compared to walking with the daily use prosthesis...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813983/modeling-and-control-of-a-transfemoral-prosthesis-embedding-two-infinitely-variable-transmissions
#13
Renaud Ronsse, Matthias Tummers, Christophe Everarts
In this paper, we report the model of an original actuation concept for a transfemoral prosthesis, relying on the combination of a single power motor, a compliant element (a spring), a mechanical differential, and two infinitely variable transmissions. It allows to manage the mechanical power flows through the device in both directions (i.e. when energy should be produced or dissipated by the knee and ankle), so that the power motor does not face the sharp load power fluctuations. The paper further reports a preliminary approach to synthesize a closed-loop controller for this device, and simulation results of this closed-loop behavior for three locomotion tasks: level-ground walking and stair ascent/descent...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813975/a-lightweight-robotic-ankle-prosthesis-with-non-backdrivable-cam-based-transmission
#14
Tommaso Lenzi, Marco Cempini, Jeremy Newkirk, Levi J Hargrove, Todd A Kuiken
Below-knee level amputation significantly impacts the ability of an individual to ambulate. Transtibial amputees are typically prescribed energetically passive ankle-foot prostheses that behave as a spring or controlled damper, and therefore cannot fully replace the function of the missing limb. More recently, fully-powered devices have been proposed to more closely match the power generation ability of intact limbs. However, these fully-powered devices are significantly heavier than passive devices, thus increasing the stress on the socket-residual limb interface...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28756766/accuracy-assessment-of-measuring-component-position-after-total-ankle-arthroplasty-using-a-conventional-method
#15
Kyoung-Jai Lee, Shao-Hua Wang, Gun-Woo Lee, Keun-Bae Lee
BACKGROUND: This study was to assess the accuracy of measuring the tibial and talar components position and to investigate the outlier rate of each component and predisposing factors related to component malalignment after total ankle arthroplasty (TAA) using a conventional method. METHODS: One hundred fifty consecutive primary total ankle arthroplasty were performed using the three-component HINTEGRA prosthesis for ankle end-stage osteoarthritis. Radiographic analysis for the accuracy of component position in coronal and sagittal plane was conducted at postoperative 6 months...
July 31, 2017: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/28755611/fixed-and-mobile-bearing-total-ankle-prostheses-effect-on-tibial-bone-strain
#16
Alexandre Terrier, Caroline Sieger Fernandes, Maïka Guillemin, Xavier Crevoisier
BACKGROUND: Total ankle replacement is associated to a high revision rate. To improve implant survival, the potential advantage of prostheses with fixed bearing compared to mobile bearing is unclear. The objective of this study was to test the hypothesis that fixed and mobile bearing prostheses are associated with different biomechanical quantities typically associated to implant failure. METHODS: With a validated finite element model, we compared three cases: a prosthesis with a fixed bearing, a prosthesis with a mobile bearing in a centered position, and a prosthesis with mobile bearing in an eccentric position...
July 19, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28750586/a-controlled-clinical-trial-of-a-clinically-tuned-powered-ankle-prosthesis-in-people-with-transtibial-amputation
#17
Emily S Gardinier, Brian M Kelly, Jeffrey Wensman, Deanna H Gates
OBJECTIVE: To determine whether there are changes in level walking performance for people using a powered ankle prosthesis that was tuned by an independent, manufacturer-certified prosthetist in accordance with device recommendations. DESIGN: Intervention study with cross-over design. SETTING: Laboratory. PARTICIPANTS: Convenience sample of 10 individuals with unilateral, transtibial amputation, and 10 age- and gender-matched control participants...
July 1, 2017: Clinical Rehabilitation
https://www.readbyqxmd.com/read/28750551/midterm-results-of-the-salto-talaris-total-ankle-arthroplasty
#18
Matthew G Stewart, Cindy L Green, Samuel B Adams, James K DeOrio, Mark E Easley, James A Nunley
BACKGROUND: The Salto Talaris total ankle replacement is a modern fixed-bearing implant used to treat symptomatic ankle arthritis with the goals of providing pain relief, restoring mechanical alignment, and allowing motion of the ankle joint. The goal of this study was to report the midterm clinical results of one of the largest cohort of patients in the United States who underwent ankle replacement with this prosthesis. METHODS: This is a review of patients with a minimum of 5 years up to 10 years' follow-up...
July 1, 2017: Foot & Ankle International
https://www.readbyqxmd.com/read/28744802/survival-of-the-scandinavian-total-ankle-replacement-star-results-of-ten-to-nineteen%C3%A2-years-follow-up
#19
Arno Frigg, Ursula Germann, Martin Huber, Monika Horisberger
PURPOSE: The purpose of this study was to evaluate survival and clinical outcome of the Scandinavian total ankle replacement (STAR) prosthesis after a minimum of ten years up to a maximum of 19 years. METHODS: Fifty STAR prostheses in 46 patients with end stage ankle osteoarthritis operated between 1996 and 2006 by the same surgeon (MH) were included. Minimal follow-up was ten years (median 14.6 years, 95% confidence interval [CI] 12.9-16.4). Clinical (Kofoed score) and radiological assessments were taken before the operation and at one, ten (+2), and 16 (±3) years after implantation...
July 26, 2017: International Orthopaedics
https://www.readbyqxmd.com/read/28650802/translational-motion-tracking-of-leg-joints-for-enhanced-prediction-of-walking-tasks
#20
Roman Mark Stolyarov, Gary Burnett, Hugh Herr
OBJECTIVE: Prediction of walking tasks in powered leg prostheses is an important problem in the development of biomimetic prosthesis controllers. This article proposes a novel method to predict upcoming walking tasks by estimating the translational motion of leg joints using an inertial measurement unit. METHODS: We asked six subjects with unilateral transtibial amputations to traverse flat ground, ramps, and stairs using a powered prosthesis while inertial signals were remotely collected...
June 22, 2017: IEEE Transactions on Bio-medical Engineering
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