scholarly journals Modular Design of a Passive, Low-Cost Prosthetic Knee Mechanism to Enable Able-Bodied Kinematics for Users With Transfemoral Amputation

2017 ◽  
Author(s):  
Molly A. Berringer ◽  
Paige J. Boehmcke ◽  
Jason Z. Fischman ◽  
Athena Y. Huang ◽  
Youngjun Joh ◽  
...  
Keyword(s):  
High Performance ◽  
Stance Phase ◽  
Modular Design ◽  
Low Cost ◽  
Metabolic Cost ◽  
User Testing ◽  
Transfemoral Amputation ◽  
Prosthetic Knee ◽  
Adjustable Mechanism ◽  
Transfemoral Amputees

There is a significant need for low-cost, high-performance prosthetic knee technology for transfemoral amputees in India. Replicating able-bodied gait in amputees is biomechanically necessary to reduce the metabolic cost, and it is equally important to mitigate the socio-economic discrimination faced by amputees in developing countries due to their conspicuous gait deviations. This paper improves upon a previous study of a fully passive knee mechanism, addressing the issues identified in its user testing in India. This paper presents the design, analysis and bench-level testing of the three major functional modules of the new prosthetic knee architecture: (i) a four-bar latch mechanism for achieving stability during stance phase of walking, (ii) an early stance flexion module designed by implementing a fully adjustable mechanism, and (iii) a hydraulic rotary damping system for achieving smooth and reliable swing-phase control.

scholarly journals Design of Mechanism and Preliminary Field Validation of Low-Cost, Passive Prosthetic Knee for Users With Transfemoral Amputation in India

2015 ◽  
Author(s):  
V. N. Murthy Arelekatti ◽  
Amos G. Winter
Keyword(s):  
Early Stage ◽  
Low Cost ◽  
Metabolic Cost ◽  
Functional Requirements ◽  
Transfemoral Amputation ◽  
Prosthetic Knee ◽  
Gait Kinematics ◽  
Flexion Extension ◽  
Economic Constraints ◽  
Kinetics Of

An estimated 230,000 above-knee amputees in India are currently in need of prosthetic care, a majority of them facing severe socio-economic constraints. However, only few passive prosthetic knee devices in the market have been designed for facilitation of normative gait kinematics and for meeting the specific daily life needs of above-knee amputees in the developing world. Based on the results of our past studies, this paper establishes a framework for the design of a low-cost prosthetic knee device, which aims to facilitate able-bodied kinematics at a low metabolic cost. Based on an exhaustive set of functional requirements, we present a prototype mechanism design for the low-cost prosthetic knee. The mechanism is implemented using an early stance lock for stability and two friction dampers for achieving able-bodied kinematics and kinetics of walking. For early-stage validation of the prosthesis design, we carry out a preliminary field trial on four above-knee amputees in India and collect qualitative user feedback. Future iterations of the mechanism prototype will incorporate an additional spring component for enabling early stance flexion-extension.

scholarly journals Design of Mechanism and Preliminary Field Validation of Low-Cost Transfemoral Rotator for Use in the Developing World

2016 ◽  
Author(s):  
Matthew L. Cavuto ◽  
Matthew Chun ◽  
Nora Kelsall ◽  
Karl Baranov ◽  
Keriann Durgin ◽  
...  
Keyword(s):  
Developing World ◽  
Low Cost ◽  
Field Studies ◽  
Field Validation ◽  
User Testing ◽  
Common Solution ◽  
Locking Mechanism ◽  
Medial Rotation ◽  
Transfemoral Amputees ◽  
And Function

Transfemoral (above-knee) amputees face a unique and challenging set of restrictions to movement and function. Most notably, they are unable to medially rotate their lower-leg and subsequently cross their legs. The best and most common solution to this issue today is a transfemoral rotator, which allows medial rotation of the leg distal to the knee through a lockable turntable mechanism. However, currently available transfemoral rotators can cost thousands of dollars, and few equivalent technologies exist in the developing world. This paper, supported by the results of field studies and user testing, establishes a framework for the design of a low-cost and easily manufacturable transfemoral rotator for use in the developing world. Two prototypes are presented, each with a unique internal locking mechanism and form. A preliminary field study was conducted on six transfemoral amputees in India and qualitative user and prosthetist feedback was collected. Both prototypes successfully allowed all subjects to complete tasks such as crossing legs, putting on pants, and tying shoes while maintaining functionality of walking and standing. Future iterations of the mechanism will be guided by a combination of the most positively received features of the prototypes and general feedback suggestions from the users.

Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints

2020 ◽  
Vol 44 (5) ◽  
pp. 314-322
Author(s):  
Jan Andrysek ◽  
Daniela García ◽  
Claudio Rozbaczylo ◽  
Carlos Alvarez-Mitchell ◽  
Rebeca Valdebenito ◽  
...  
Keyword(s):  
Young Adults ◽  
Knee Joint ◽  
Stance Phase ◽  
Pelvic Tilt ◽  
Swing Phase ◽  
Knee Joints ◽  
Transfemoral Amputation ◽  
Phase Duration ◽  
Prosthetic Knee ◽  
Stance Control

Background: Prosthetic knee joint function is important in the rehabilitation of individuals with transfemoral amputation. Objectives: The objective of this study was to assess the gait patterns associated with two types of mechanical stance control prosthetic knee joints—weight-activated braking knee and automatic stance-phase lock knee. It was hypothesized that biomechanical differences exist between the two knee types, including a prolonged swing-phase duration and exaggerated pelvic movements for the weight-activated braking knee during gait. Study design: Prospective crossover study. Methods: Spatiotemporal, kinematic, and kinetic parameters were obtained via instrumented gait analysis for 10 young adults with a unilateral transfemoral amputation. Discrete gait parameters were extracted based on their magnitudes and timing. Results: A 1.01% ± 1.14% longer swing-phase was found for the weight-activated braking knee (p < 0.05). The prosthetic ankle push-off also occurred earlier in the gait cycle for the weight-activated braking knee. Anterior pelvic tilt was 3.3 ± 3.0 degrees greater for the weight-activated braking knee. This range of motion was also higher (p < 0.05) and associated with greater hip flexion angles. Conclusions: Stance control affects biomechanics primarily in the early and late stance associated with prosthetic limb loading and unloading. The prolonged swing-phase time for the weight-activated braking knee may be associated with the need for knee unloading to initiate knee flexion during gait. The differences in pelvic tilt may be related to knee stability and possibly the different knee joint stance control mechanisms. Clinical relevance Understanding the influence of knee function on gait biomechanics is important in selecting and improving treatments and outcomes for individuals with lower-limb amputations. Weight-activated knee joints may result in undesired gait deviations associated with stability in early stance-phase, and swing-phase initiation in the late stance-phase of gait.

scholarly journals The Effects of the Inertial Properties of Above-Knee Prostheses on Optimal Stiffness, Damping, and Engagement Parameters of Passive Prosthetic Knees

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Yashraj S. Narang ◽  
V. N. Murthy Arelekatti ◽  
Amos G. Winter
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Knee Prostheses ◽  
Joint Power ◽  
Prosthetic Knee ◽  
Constant Friction ◽  
Linear Spring ◽  
Mechanical Elements ◽  
Prosthetic Knees ◽  
Optimal Stiffness

Our research aims to design low-cost, high-performance, passive prosthetic knees for developing countries. In this study, we determine optimal stiffness, damping, and engagement parameters for a low-cost, passive prosthetic knee that consists of simple mechanical elements and may enable users to walk with the normative kinematics of able-bodied humans. Knee joint power was analyzed to divide gait into energy-based phases and select mechanical components for each phase. The behavior of each component was described with a polynomial function, and the coefficients and polynomial order of each function were optimized to reproduce the knee moments required for normative kinematics of able-bodied humans. Sensitivity of coefficients to prosthesis mass was also investigated. The knee moments required for prosthesis users to walk with able-bodied normative kinematics were accurately reproduced with a mechanical system consisting of a linear spring, two constant-friction dampers, and three clutches (R2=0.90 for a typical prosthetic leg). Alterations in upper leg, lower leg, and foot mass had a large influence on optimal coefficients, changing damping coefficients by up to 180%. Critical results are reported through parametric illustrations that can be used by designers of prostheses to select optimal components for a prosthetic knee based on the inertial properties of the amputee and his or her prosthetic leg.

Lower extremity joint kinematics of stair ascent in transfemoral amputees

2011 ◽  
Vol 35 (4) ◽  
pp. 467-472 ◽  
Author(s):  
Hiroaki Hobara ◽  
Yoshiyuki Kobayashi ◽  
Takashi Nakamura ◽  
Nobuya Yamasaki ◽  
Kimitaka Nakazawa ◽  
...  
Keyword(s):  
Knee Joint ◽  
Lower Extremity ◽  
Stance Phase ◽  
Reaction Force ◽  
Joint Kinematics ◽  
Whole Body ◽  
Prosthetic Knee ◽  
Stair Ascent ◽  
Transfemoral Amputees ◽  
Prosthetic Knee Joint

Background: Stair ascent is a very demanding task for transfemoral amputees (TFAs). The purpose of this study was to investigate the lower extremity joint kinematics of TFAs who can climb stairs using a step-over-step gait pattern without an active artificial prosthetic knee joint or handrail use. Case Description and Methods: Case series. Participants were two traumatic TFAs and 10 control participants. Both TFAs used a single-axis prosthetic knee joint in daily living. Sagittal plane joint kinematics were recorded at 60 Hz using an eight-camera motion analysis system and digital video camera. Findings and Outcomes: From the instant of touchdown, the prosthetic knee joint was rapidly extended and remained fully extended until toe-off. In the latter half of the stance phase, the knee and ankle joints of the sound limb simultaneously showed rapid joint flexion during continuous extension. Further, the ankle joint of the sound limb showed greater plantarflexion at the end of the stance phase. Conclusion: These results suggest that the TFA in the present study would (1) extend the prosthetic knee joint to prevent the knee flexion generated by the bodyweight (plus ground reaction force and/or joint moment), and (2) lift the whole body in an upward direction using strong counter-movements and greater joint extension during the stance phase.

scholarly journals Feasibility and Design of a Low-Cost Prosthetic Knee Joint Using a Compliant Member for Stance-Phase Control

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Daniel G. Harrison ◽  
Jan Andrysek ◽  
William L. Cleghorn
Keyword(s):  
Knee Joint ◽  
Stance Phase ◽  
Low Cost ◽  
Phase Locking ◽  
Phase Control ◽  
Prosthetic Knee ◽  
Engineering Software ◽  
Qualitative Feedback ◽  
Locking Mechanism ◽  
Prosthetic Knee Joint

This paper is concerned with the feasibility and design of a low-cost prosthetic knee joint that uses a compliant member for stance-phase control. A mechanical locking mechanism was used in conjunction with a compliant control axis to achieve automatic stance-phase locking. The concept was developed with the aid of computer-aided engineering software and was validated through the fabrication and testing of a simplified prototype made of an injection moldable polymer. A prosthetic knee joint was then designed, incorporating the compliant member concept. After modeling, fabrication, and laboratory testing, a pilot study was conducted in a clinical setting. A simple gait analysis showed asymmetric gait patterns that demonstrated the need for improved swing-phase control and damping, while qualitative feedback indicated the desire to reduce the noise produced by the knee. The knee provided the automatic stance-phase control for which it was designed and shows significant potential to evolve into a highly functioning, low-cost knee.

scholarly journals Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
V. N. Murthy Arelekatti ◽  
Amos G. Winter
Keyword(s):  
Low Cost ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Biomechanical Analysis ◽  
Functional Requirements ◽  
Timely Initiation ◽  
Prosthetic Devices ◽  
Prosthetic Knee ◽  
Flexion Extension ◽  
Economic Constraints

An estimated 230,000 above-knee amputees in India are currently in need of prosthetic devices, a majority of them facing severe socio-economic constraints. However, only a few passive prosthetic knee devices in the market have been designed for facilitation of normative gait kinematics and for meeting the specific daily life needs of above-knee amputees in the developing world. Based on the results of our past studies, this paper establishes a framework for designing a potentially low-cost, fully passive prosthetic knee device, which aims to facilitate able-bodied kinematics at a low metabolic cost. Based on a comprehensive set of functional requirements and biomechanical analysis from our past work, we present an early prototype mechanism for the prosthetic knee joint that is primarily focused on enabling able-bodied kinematics. The mechanism is implemented using two functional modules: an automatic early stance lock for stability and a differential friction damping system for late stance and swing control. For preliminary, qualitative validation of the knee mechanism, we carried out a field trial on four above-knee amputees in India, which showed satisfactory performance of the early stance lock. The prototype enabled smooth stance-to-swing transition by timely initiation of late stance flexion. Possible methods of incorporating an additional spring module for further refinement of the design are also discussed, which can enable flexion-extension during the early-stance phase of the gait cycle and potentially reduce the metabolic energy expenditure of the user further.

Comparison of UV- and Derivative-Spectrophotometric and HPTLC UVDensitometric Methods for the Determination of Amrinone and Milrinone in Bulk Drugs

2020 ◽  
Vol 16 (3) ◽  
pp. 246-253
Author(s):  
Marcin Gackowski ◽  
Marcin Koba ◽  
Stefan Kruszewski
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Low Cost ◽  
Uv Spectra ◽  
Derivative Spectrophotometry ◽  
Therapeutic Monitoring ◽  
Bulk Drug ◽  
Layer Chromatography ◽  
Standard Solutions

Background: Spectrophotometry and thin layer chromatography have been commonly applied in pharmaceutical analysis for many years due to low cost, simplicity and short time of execution. Moreover, the latest modifications including automation of those methods have made them very effective and easy to perform, therefore, the new UV- and derivative spectrophotometry as well as high performance thin layer chromatography UV-densitometric (HPTLC) methods for the routine estimation of amrinone and milrinone in pharmaceutical formulation have been developed and compared in this work since European Pharmacopoeia 9.0 has yet incorporated in an analytical monograph a method for quantification of those compounds. Methods: For the first method the best conditions for quantification were achieved by measuring the lengths between two extrema (peak-to-peak amplitudes) 252 and 277 nm in UV spectra of standard solutions of amrinone and a signal at 288 nm of the first derivative spectra of standard solutions of milrinone. The linearity between D252-277 signal and concentration of amironone and 1D288 signal of milrinone in the same range of 5.0-25.0 μg ml/ml in DMSO:methanol (1:3 v/v) solutions presents the square correlation coefficient (r2) of 0,9997 and 0.9991, respectively. The second method was founded on HPTLC on silica plates, 1,4-dioxane:hexane (100:1.5) as a mobile phase and densitometric scanning at 252 nm for amrinone and at 271 nm for milrinone. Results: The assays were linear over the concentration range of 0,25-5.0 μg per spot (r2=0,9959) and 0,25-10.0 μg per spot (r2=0,9970) for amrinone and milrinone, respectively. The mean recoveries percentage were 99.81 and 100,34 for amrinone as well as 99,58 and 99.46 for milrinone, obtained with spectrophotometry and HPTLC, respectively. Conclusion: The comparison between two elaborated methods leads to the conclusion that UV and derivative spectrophotometry is more precise and gives better recovery, and that is why it should be applied for routine estimation of amrinone and milrinone in bulk drug, pharmaceutical forms and for therapeutic monitoring of the drug.

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