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Journal articles on the topic 'Polycentric knee'

Author: Grafiati

Published: 3 June 2025

Last updated: 13 July 2025

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1

GUNSTON, FRANK H., and RICHARD S. BRYAN. "Polycentric Knee Arthroplasty." Clinical Orthopaedics and Related Research &NA;, no. 205 (1986): 4. http://dx.doi.org/10.1097/00003086-198604000-00002.

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2

Lee, Wen-Tzong, Kevin Russell, and Raj S. Sodhi. "On Transfemoral Prosthetic Knee Design for Natural Human Knee Motion." Recent Patents on Mechanical Engineering 13, no. 1 (2020): 49–59. http://dx.doi.org/10.2174/2212797613666191219154947.

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Background: A transfemoral prosthetic knee is an artificial knee used by above-the-knee amputees. There are two major categories of transfemoral prosthetic knee designs: pin joint-based and polycentric designs. While pin joint-based knee designs only allow pure rotation of the knee, polycentric knee designs allow a combination of rotational and translational knee motion which is exhibited in natural knee motion. Objective: This work presents both the recently-patented design process and the resulting design of a polycentric transfemoral prosthetic knee that approximates natural spatial human knee motion during flexion and extension. Methods: The design process includes tibial motion acquisition, Revolute-Revolute-Spherical-Spherical linkage (or RRSS) motion generation, RRSS linkage axode generation and circle fitting. The polycentric transfemoral prosthetic knee design produced from this process includes a gear joint with a specific spatial orientation to approximate natural spatial human knee motion. Results: Using the design process, a polycentric transfemoral prosthetic knee was designed to replicate a group of five tibial positions over 37.5° of knee flexion (the amount of knee flexion in a standard human gait cycle) with a minimal structural error. Conclusion: The circular gear-based knee design accurately replicated natural spatial knee motion over the tibial position data given for a standard human gait cycle. The knee design method must be implemented over a broader sampling of tibial position data to determine if a circular gear-based knee design is consistently accurate.

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3

Kadhim, Fahad Mohanad, Jumaa Salman Chiad, and Maryam Abdul Salam Enad. "Evaluation and Analysis of Different Types of Prosthetic Knee Joint Used by above Knee Amputee." Defect and Diffusion Forum 398 (January 2020): 34–40. http://dx.doi.org/10.4028/www.scientific.net/ddf.398.34.

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Four prosthetic knee joints (polycentric knee weight activating-4bar and friction, extension assist controlled),(single axis knee weight activating and friction, internal extension assist controlled), (single axis knee weight activating-4bar and hydraulically, controlled) and (polycentric knee geometric locking-6bar, hydraulically controlled) for a trans-femoral patient were tested. The tests were conducted to find the maximum velocity as well as discussing the most comfortable prosthetic forthe patient and walking stability for these prosthetic knees by examining the gait cycle and measuring the ground reaction force (GRF), using force a plate device. Also, the interface pressure was measured between socket and stump muscles by using F-socket device to get the stress distribution during walking with a prosthetic knee. Results manifested that the polycentric knee geometric locking - 6bar, hydraulically controlled is the best because of the good homogenous distribution of GRF between the healthy and prosthetic limb, during which the difference between both the healthy and prosthetic limb is with the least value (4%).And, K4 gives the minimum value of differences in contact pressure between the left and right limb with a value of (24%), it alsoimparts the maximum symmetry between the left and right limb according to the gait cycle parameters.The best results of the interface pressures and kinovea velocity are achieved whenK4 is used with (132.4KPa, 0.71m/s), respectively. Finally, the polycentric knee geometric locking - 6bar, hydraulically controlled is the best according to the ANSYS results during which it yields the minimum values of Von-Mises stress with 14.24MPa and a maximum factor of safety of 3.11.

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4

Anand, TS, and S. Sujatha. "A method for performance comparison of polycentric knees and its application to the design of a knee for developing countries." Prosthetics and Orthotics International 41, no. 4 (2016): 402–11. http://dx.doi.org/10.1177/0309364616652017.

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Background:Polycentric knees for transfemoral prostheses have a variety of geometries, but a survey of literature shows that there are few ways of comparing their performance.Objectives:Our objective was to present a method for performance comparison of polycentric knee geometries and design a new geometry.Study design:In this work, we define parameters to compare various commercially available prosthetic knees in terms of their stability, toe clearance, maximum flexion, and so on and optimize the parameters to obtain a new knee design.Methods:We use the defined parameters and optimization to design a new knee geometry that provides the greater stability and toe clearance necessary to navigate uneven terrain which is typically encountered in developing countries.Results:Several commercial knees were compared based on the defined parameters to determine their suitability for uneven terrain. A new knee was designed based on optimization of these parameters. Preliminary user testing indicates that the new knee is very stable and easy to use.Conclusion:The methodology can be used for better knee selection and design of more customized knee geometries.Clinical relevanceThe method provides a tool to aid in the selection and design of polycentric knees for transfemoral prostheses.

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5

Gunston, Frank H. "THE CLASSIC: Polycentric Knee Arthroplasty." Clinical Orthopaedics and Related Research 446 (May 2006): 11–12. http://dx.doi.org/10.1097/01.blo.0000214423.59829.04.

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6

Bopp, Florian, Jens Stecher, Ingomar Lorenz, and Ulrich Holz. "The Unicompartmental Polycentric Knee Arthroplasty." Orthopaedics and Traumatology 9, no. 3 (2001): 207–17. http://dx.doi.org/10.1007/s065-001-8355-0.

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7

Memisoglu, Kaya. "Revision of the Gunston polycentric knee arthroplasty with total knee arthroplasty." Acta Orthopaedica et Traumatologica Turcica 44, no. 5 (2010): 410–12. http://dx.doi.org/10.3944/aott.2010.2317.

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8

MOHANTY, RAJESH KUMAR, STHIRPRANJYAN BISWAL, PABITRA KUMAR SAHOO, SAKTI PRASAD DAS, R. C. MOHANTY, and SUKANTA KUMAR SABUT. "CLINICAL GAIT ANALYSIS OF SUBJECTS WITH TRANS-FEMORAL AMPUTATION USING POLYCENTRIC FOUR-BAR LINKAGE PROSTHETIC KNEE JOINT." Journal of Mechanics in Medicine and Biology 20, no. 05 (2020): 2050021. http://dx.doi.org/10.1142/s0219519420500219.

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Background: Adequate research is not reported so far to underline the influence of commonly used polycentric knee joints on gait performance of subjects with trans-femoral amputation. Objective: The intent of this investigation is to analyze prosthetic gait of unilateral traumatic trans-femoral amputees with polycentric four-bar linkage knee and compare it with normal subjects for evaluating any asymmetry in gait performance. Methods: Objective three-dimensional gait analysis of 15 subjects [mean (age): 36.4 (10.7) years] were performed in gait lab through force plate and optoelectronic devices to measure temporal-spatial parameters, kinematic and kinetic performances. Gait patterns of amputees were compared with those of 15 individuals with normal gait to analyze distinct functionalities of existing polycentric knee. Results: Asymmetry in gait was observed between amputees and normal subjects for all variables concerned ([Formula: see text]). Amputee gait was with significantly lesser velocity, cadence with shorter step and stride length. There was significantly less hip, knee and pelvic motions, however, pelvic obliquity and rotation did not show significant difference from the normal subjects. The vertical component of the ground reaction force differed significantly between prosthetic and intact limb [49.7 (8.5)% and 90.4 (7.4)% body weight] and also from normal subjects [107.5 (2.4)% body weight] during stance ([Formula: see text]). Interpretation and Conclusion: This difference may be attributed to nonproportionate loading of limbs and mechanical adaptations for counteracting deficiencies of prosthetic side. This study will help to explain gait asymmetry in trans-femoral amputees and to identify underlying mechanisms to enhance the quality of the existing design of prosthetic knee through optimizing design parameters and utilizing appropriate materials.

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9

Koçak, Mertcan, and Erkin Gezgin. "Unified Design Methodology for a Polycentric Transfemoral Knee Prosthesis Using Kinematic Synthesis." Machines 13, no. 1 (2024): 20. https://doi.org/10.3390/machines13010020.

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This study introduces a novel single-degree-of-freedom polycentric knee mechanism specifically designed for transfemoral prostheses to address dual challenges of stability during the stance phase and biomimetic motion during the swing phase. Leveraging analytical kinematic synthesis, the proposed mechanism integrates separate kinematic designs for each of the gait phases into a combined structure that prevents singularity issues during full knee flexion, which is a significant limitation in conventional active designs. The stance phase mechanism emphasizes stability through precise control of the instantaneous center of rotation (ICR) and weight-bearing support, while the swing phase mechanism adopts a biomimetic motion trajectory. In order to validate the proposed methodology, kinematic synthesis, numerical simulations, and visual analyses were conducted. Incorporating insights from polycentric prostheses and orthotic applications, the proposed mechanism achieves a seamless transition between two different configurations by keeping its overall mobility. Additionally, its possible compatibility with motorized actuation offers a foundation for active prosthesis systems, paving the way for adapting the advantages of polycentric prosthesis to active devices. This innovative approach offers a scientifically grounded pathway for improving transfemoral prosthetic systems, advancing both their biomechanical utility and user comfort.

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10

Hoseini, Saman, and Mohammad Reza S. Noorani. "FEM-based Fatigue Analysis on a 4-Bar Polycentric Knee of Above-Knee Prostheses." International Journal of Biomedical Engineering and Technology 1, no. 1 (2023): 1. http://dx.doi.org/10.1504/ijbet.2023.10056453.

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11

Noorani, Mohammad Reza Sayyed, and Saman Hoseini. "FEM-based fatigue analysis on a four-bar polycentric knee of above-knee prostheses." International Journal of Biomedical Engineering and Technology 44, no. 2 (2024): 120–32. http://dx.doi.org/10.1504/ijbet.2024.136917.

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12

Nagesh Saraf, Makarand, Sangita Nayak, and R. Ravindran. "Comparison between Weight Activated and Polycentric Knee Joints on the Gait Performance of Transfemoral Amputees." International Journal of Science and Research (IJSR) 11, no. 5 (2022): 325–36. http://dx.doi.org/10.21275/mr22503063257.

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13

JERGESEN, HARRY E., FRANKLIN T. HOAGLUND, RUTH A. ROBERTS, LEIGH A. WILSON, LARRY W. LAMOREUX, and CHARLES W. RADCLIFFE. "The University of California Biomechanics Laboratory Four-Bar Polycentric Knee Linkage." Clinical Orthopaedics and Related Research &NA;, no. 204 (1986): 184???192. http://dx.doi.org/10.1097/00003086-198603000-00021.

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14

Mangera, Taahirah, Frank Kienhöfer, Kristian Carlson, Mariette Conning, Tamsin Purkis, and Gonasagren Govender. "Design for manufacture and assembly of a polycentric paediatric prosthetic knee." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 14 (2019): 2566–76. http://dx.doi.org/10.1177/0954405419840555.

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Design for manufacture and assembly is a critical step in the product design life cycle. In this study, design for manufacture and assembly theory was applied to the design of a polycentric paediatric prosthetic knee to resolve assembly and manufacture issues prior to product prototyping. Assembly time and efficiency prior and subsequent to design for assembly analysis was calculated. By combining redundant parts and improving the ease of alignment, orientation, and insertion of various parts through modification of part features, a 10.1% increase in assembly efficiency was achieved. Design for manufacture analysis was then performed for die casting of the component. Undercut features were removed and replaced with the use of standard components, reducing the assembly time of the component by reducing the complexity of parts. Proposed design changes were verified using finite element analysis to simulate the loading conditions of a polycentric prosthetic knee as per the ISO10328:2006 standard for methods of testing prostheses. An overall improvement of 13.6% in assembly efficiency was achieved after the design for manufacture and assembly analysis. The improvement is due to the decrease in assembly insertion time and eliminating small parts and parts in areas that were difficult to access. The reduction in assembly time will directly reduce the labour cost for assembly of the manufactured product. This case study illustrates how design for manufacture and assembly theory can be applied to the design of biomedical equipment to reduce the need for prototype re-work and the consequent costs.

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15

Imran, A., JJ O'Connor, and DW Murray. "Shape of the femoral component in knee replacement: Polycentric or circular?" Journal of Biomechanics 31 (July 1998): 25. http://dx.doi.org/10.1016/s0021-9290(98)80052-3.

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16

Galey, Lucas, and Roger V. Gonzalez. "Design and Initial Evaluation of a Low-Cost Microprocessor-Controlled Above-Knee Prosthesis: A Case Report of 2 Patients." Prosthesis 4, no. 1 (2022): 60–72. http://dx.doi.org/10.3390/prosthesis4010007.

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For prosthesis users, knee units can range from simple devices costing $2000 up to $45,000 for high-end, microprocessor-controlled systems. These higher-end electronic knees provide significant advantages in stability, gait, and metabolic rate compared to their passive or mechanical counterparts. However, the high cost of such systems makes them inaccessible to most amputees. In this study, it was hypothesized that a microprocessor knee could be manufactured for less than $1000, with comparable stability and user experience to a high-end industry standard device. A prototype (E-Knee) was designed with a specific emphasis on stance stability, and was tested during patient gait trials. The gait trials used a repeated measures design to compare three knee devices (a simple passive knee, the prototype E-Knee, and a high-end knee). Ground reaction forces and a functionality questionnaire were used to compare devices. A microprocessor locking test was used to evaluate the prototype’s ability to prevent falls. Building on the LIMBS M3, a passive four-bar polycentric device, the E-Knee added sensing, computing, and controlling capabilities for a material cost of $507. Initial data from a two-subject trial served as proof-of-concept to validate the prototype and found that it improved gait by providing more stability than the M3 and had more gait-pattern similarities to the Ottobock C-Leg than to the M3. Patients reported no perceived differences in stability between the E-Knee and the C-Leg. Patient trials supported that the E-Knee prototype behaved more naturally than the low-end M3 device and had similar ground reaction forces to the C-Leg.

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17

Jergesen, Harry E., Franklin T. Hoaglund, and Ruth A. Roberts. "Subjective Evaluation of the UCBL Polycentric Knee Linkage by Active Above Knee Amputees: A Prospective Trial." Orthopedics 8, no. 2 (1985): 237–41. http://dx.doi.org/10.3928/0147-7447-19850201-12.

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18

Bapat, Ganesh M., and S. Sujatha. "A Method for Optimal Synthesis of a Biomimetic Four-Bar Linkage Knee Joint for a Knee-Ankle-Foot Orthosis." Journal of Biomimetics, Biomaterials and Biomedical Engineering 32 (May 2017): 20–28. http://dx.doi.org/10.4028/www.scientific.net/jbbbe.32.20.

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A Knee-Ankle-Foot orthosis (KAFO) is used as a supportive device by individuals with lower limb disability. A type of KAFO that allows knee flexion-extension is prescribed for people who need knee stability in the transverse and frontal planes. In such an orthosis, mimicking the human knee motion is vital to avoid relative motion (called pistoning) between the limb and the orthosis. A four-bar mechanism, owing to its polycentric nature, simplicity and ease of fabrication can provide a customizable, biomimetic solution. This paper presents an improved and robust optimization approach to synthesize a four-bar mechanism to closely mimic the anatomical knee motion. The reference human knee centrode is obtained from literature. A genetic algorithm is used for optimal synthesis of the fourbar mechanism. Results show that the average error between the reference centrode and the centrode of the synthesized four-bar mechanism is very small (0.2 mm). Thus, the synthesized crossed four-bar linkage can reproduce better anthropomorphic characteristics of the knee joint. The methodology can be used for the design of customized orthotic knee joints for KAFOs and knee braces.

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19

Lee, Taesik, Dongyoung Lee, Buchun Song, and Yoon Su Baek. "Design and Control of a Polycentric Knee Exoskeleton Using an Electro-Hydraulic Actuator." Sensors 20, no. 1 (2019): 211. http://dx.doi.org/10.3390/s20010211.

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An exoskeleton robot helps the wearer with mechanical forces by identifying the wearer’s intentions and requires high energy efficiency, sufficient load capacity, and a comfortable fit. However, since it is difficult to implement complex anatomical movements of the human body, most exoskeleton robots are designed simply, unlike the anatomy of real humans. This forces the wearer to accept the robot’s stiffness entirely, and to use energy inefficiently from the power source. In this paper, a simple 1 degree of freedom (DoF) structure, which was mainly used in the knees of exoskeleton robots, was designed with a polycentric (multi-axial) structure to minimize the misalignment between wearer and robot, so that torque transfer could be carried out efficiently. In addition, the overall robot system was constructed by using an electro-hydraulic actuator (EHA) to solve the problems of the energy inefficiency of conventional hydraulic actuators and the low load capacity of conventional electric actuators. After the configuration of the hardware system, the sliding mode controller was designed to address the EHA nonlinear models and the uncertainty of the plant design. This was configured as Simulink for the first verification, and the experiment was conducted by applying it to the actual model to demonstrate the performance of the sliding mode control. In this process, an optical rotary encoder was used as the main feedback sensor of the controller. The proposed polycentric knee exoskeleton robot system using the EHA was able to reach the desired target value well despite the presence of many model uncertainties.

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20

Bernal-Torres, Mario G., Hugo I. Medellín-Castillo, and Juan C. Arellano-González. "Design and Control of a New Biomimetic Transfemoral Knee Prosthesis Using an Echo-Control Scheme." Journal of Healthcare Engineering 2018 (2018): 1–16. http://dx.doi.org/10.1155/2018/8783642.

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Passive knee prostheses require a significant amount of additional metabolic energy to carry out a gait cycle, therefore affecting the natural human walk performance. Current active knee prostheses are still limited because they do not reply with accuracy of the natural human knee movement, and the time response is relatively large. This paper presents the design and control of a new biomimetic-controlled transfemoral knee prosthesis based on a polycentric-type mechanism. The aim was to develop a knee prosthesis able to provide additional power and to mimic with accuracy of the natural human knee movement using a stable control strategy. The design of the knee mechanism was obtained from the body-guidance kinematics synthesis based on real human walking patterns obtained from computer vision and 3D reconstruction. A biomechanical evaluation of the synthesized prosthesis was then carried out. For the activation and control of the prosthesis, an echo-control strategy was proposed and developed. In this echo-control strategy, the sound side leg is sensed and synchronized with the activation of the knee prosthesis. An experimental prototype was built and evaluated in a test rig. The results revealed that the prosthetic knee is able to mimic the biomechanics of the human knee.

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21

Séguin, Émélie, and Marc Doumit. "Kinematic and Kinetic Assessment of a Novel Polycentric Knee Joint for Powered Walking Assist Exoskeletons." Journal of Physical Medicine and Rehabilitation 5, no. 1 (2023): 6–15. http://dx.doi.org/10.33696/rehabilitation.5.034.

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Loss of mobility and independence directly affects the quality of life of many vulnerable individuals. In order to address this, researchers have been developing wearable walking assist exoskeletons to aid users with their daily activities. While this technology has advanced tremendously in the past decade, current exoskeletons are yet to be ergonomic, causing discomfort and injuries to the user, leading to early device rejection. This research intends to assess the kinematic and kinetic compatibility of a novel knee joint suitable for exoskeletons. The proposed knee design can be adapted to accommodate a kinematic offset and optimize force delivery. This is achieved by ensuring that the mechanical and biological joint rotation axes are aligned and that the moment arm can be varied to mimic the mechanical characteristics of a biological knee. Model simulations and mechanical testing of fabricated prototypes were achieved to analyze and validate the design. Results confirmed the compatibility of the design, which demonstrated kinematic absolute error values of 1.68 and 0.32 mm for the offset and aligned joints, respectively. It was shown that the moment arm can be varied throughout flexion, allowing future iterations to achieve optimal and effective moment transfer.

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22

Al-Maliky, Firas Thair, and Jumaa Salman Chiad. "A Review Study for Measurement, Analysis and Evaluation Four Bar Polycentric Knee." IOP Conference Series: Materials Science and Engineering 1094, no. 1 (2021): 012113. http://dx.doi.org/10.1088/1757-899x/1094/1/012113.

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23

Bonnet, X., H. Pillet, P. Fodé, F. Lavaste, and W. Skalli. "Gait analysis of a transfemoral amputee with a hydraulic polycentric knee prosthesis." Computer Methods in Biomechanics and Biomedical Engineering 12, sup1 (2009): 59–60. http://dx.doi.org/10.1080/10255840903065530.

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24

Arun, S., Balaphrang Marbaniang, Bhaskar Borgohain, and S. Kanagaraj. "Rehabilitation evaluation of the newly developed polymeric based passive polycentric knee joint." Disability and Rehabilitation: Assistive Technology 15, no. 8 (2019): 871–77. http://dx.doi.org/10.1080/17483107.2019.1621955.

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25

Blumentritt, Slegmar, Hans Werner Scherer, Ulf Wellershaws, and John W. Michael. "Design Principles, Biomeclianical Data and Clinical Experience with a Polycentric Knee Offering Controlled Stance Phase Knee Flexion." JPO Journal of Prosthetics and Orthotics 9, no. 1 (1997): 18???24. http://dx.doi.org/10.1097/00008526-199700910-00005.

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26

Blumentritt, Siegmar, Hans Werner Scherer, Ulf Wellershaus, and John W. Michael. "Design Principles, Biomechanical Data and Clinical Experience with a Polycentric Knee Offering Controlled Stance Phase Knee Flexion." JPO Journal of Prosthetics and Orthotics 9, no. 1 (1997): 18???24. http://dx.doi.org/10.1097/00008526-199710000-00005.

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27

Yokogushi, Kazutoshi, Hiroshi Narita, Eiichi Uchiyama, Susumu Chiba, Toshiya Nosaka, and Ken-ichi Yamakoshi. "Biomechanical and clinical evaluation of a newly designed polycentric knee of transfemoral prosthesis." Journal of Rehabilitation Research and Development 41, no. 5 (2004): 675. http://dx.doi.org/10.1682/jrrd.2003.05.0076.

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28

KITTISARES, Sarin, Hiroyuki NABAE, Gen ENDO, and Koichi SUZUMORI. "Knee Support Device with Polycentric Joint Mechanism Driven by Bundled Thin Soft Muscles." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2019 (2019): 2P1—M03. http://dx.doi.org/10.1299/jsmermd.2019.2p1-m03.

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29

Bertomeu, José María Baydal, Juan Manuel Belda Lois, Ricard Barberà Guillem, et al. "Development of a hinge compatible with the kinematics of the knee joint." Prosthetics and Orthotics International 31, no. 4 (2007): 371–83. http://dx.doi.org/10.1080/03093640601095842.

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This study aims to present a new concept of a knee hinge based on a crossed four-bar linkage mechanism which has been designed to optimally follow a motion curve representing the knee kinematics in the position at which the knee hinge should be placed. The methodology used to determine the optimal knee hinge is based on the optimization of certain variables of the crossed four-bar mechanism using genetic algorithms in order to follow a certain motion curve, which was determined using a biomechanical model of the knee motion. Two current, commercially available knee hinges have been used to theoretically determine their motion by means of the path performed by their instantaneous helical axis. Comparison between these two different knee hinges, Optimal Knee Hinge and the theoretical motion performed by a human knee reveals that a common monocentric hinge has a maximum misalignment of up to 27.2 mm; a polycentric hinge has a maximum misalignment of 23.9 mm. In contrast, the maximum misalignment produced by the Optimal Knee Hinge is 1.99 mm. The orthotic joint presented significantly improves the kinematical compatibility and the adjustment between orthotic and human joint motion, and should provide several advantages in terms of comfort and safety. Furthermore, the determination of the instantaneous helical axis for a particular user, by means of human movement measurement techniques, will enable the optimal crossed four-bar mechanisms to be determined in a customized and personalized manner. As a consequence, this new concept of orthotic knee joint design may improve the adaptability of lower limb orthoses for the user, and may lead to significant advantages in the field of orthotics for the lower limb.

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Nayak, Sushree Sangita, Aswini Kumar Mohapatra, Srikanta Maharana, Biswaranjan Mishra, Bijay Kishor Shishir Sekhar Pattanaik, and Bijay Kumar Paikaray. "Computational analysis of gait patterns in transfemoral amputees: polycentric and weight-activated knee joints." International Journal of Computational Biology and Drug Design 16, no. 2 (2024): 147–66. http://dx.doi.org/10.1504/ijcbdd.2024.142282.

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31

Patil, K. M., and J. K. Chakraborty. "Analysis of a new polycentric above-knee prosthesis with a pneumatic swing phase control." Journal of Biomechanics 24, no. 3-4 (1991): 223–33. http://dx.doi.org/10.1016/0021-9290(91)90180-u.

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32

Blumentritt, Siegmar, Hans Werner Scherer, Ulf Wellershaus, and John W. Michael. "Design Principles, Biomechanical Data and Clinical Experience with a Polycentric Knee Offering Controlled Stance Phase Knee Flexion: A Preliminary Report." JPO Journal of Prosthetics and Orthotics 9, no. 1 (1997): 18–24. http://dx.doi.org/10.1097/00008526-199701000-00005.

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33

Mohanty, Rajesh Kumar, R. C. Mohanty, and Sukanta Kumar Sabut. "A systematic review on design technology and application of polycentric prosthetic knee in amputee rehabilitation." Physical and Engineering Sciences in Medicine 43, no. 3 (2020): 781–98. http://dx.doi.org/10.1007/s13246-020-00882-3.

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34

POLIAKOV, A. M., P. K. SOPIN, V. B. LAZAREV, A. I. RYZHKOV, M. A. KOLESOVA, and P. A. BUGAYOV. "PROTOTYPE OF TRANSFEMORAL PROSTHESIS WITH AN ACTIVE ARTIFICIAL KNEE." Fundamental and Applied Problems of Engineering and Technology 4, no. 1 (2020): 172–80. http://dx.doi.org/10.33979/2073-7408-2020-342-4-1-172-180.

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This article presents a transfemoral prosthesis prototype with active control of an artificial knee joint. One of the main criteria used in the design of the prosthesis was to achieve the maximum biological similarity of this device in order to provide optimal conditions conducive to user natural walking. The artificial knee joint, designed on the basis of a polycentric higed mechanism with intersecting links, provides such conditions at the design level, and a three-level hierarchical control system, built on the basis of an intelligent-synergetic concept, at the control level. To recognize user's intentions, the intelligent subsystem uses algorithms for comparing graphic images of user's walking phases by the method of estimating the invariant moments of Hu. After that, prosthesis elements movements are planned in the synergistic subsystem in accordance with the synergistic quality criteria. The algorithms used in the control system are adjusted depending on what type of artificial foot is used in the prosthesis: active, semi-active or passive (purely mechanical). Mathematical modeling of the prosthesis operation shows that the nature of its functioning corresponds to the quality criteria adopted in the design.

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35

Sudeesh, S., S. Sujatha, and M. S. Shunmugam. "The Effects of Polycentric Knee Design and Alignment on Swing Phase Gait Parameters: A Simulation Approach." JPO Journal of Prosthetics and Orthotics 33, no. 4 (2021): 266–78. http://dx.doi.org/10.1097/jpo.0000000000000384.

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36

Imran, Amer, Mohammad Reza Haghjoo, and Borhan Beigzadeh. "Design of a novel above-knee prosthetic leg with a passive energy-saving mechanism." Engineering Solid Mechanics 11, no. 4 (2023): 339–52. http://dx.doi.org/10.5267/j.esm.2023.5.009.

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The push-off phase is a critical part of initiating movement during walking, and it requires a significant amount of energy. Recent research has shown that the passive use of springs in parallel with the leg can harvest the push-off energy and reduce the total metabolic energy of walking for healthy subjects. In this study, we present the design of a prosthetic leg with a passive-based mechanism to reduce walking energy consumption for above-knee amputees. The mechanism stores energy during the stance phase of the gait cycle and releases it to support the prosthetic leg during locomotion. The known polycentric knee joint 3R36 and the ankle-foot joint ESAR were chosen and adopted for this study. We also utilized a ratchet clutch that connects with a spring and rope from the pylon to the foot which regulates movement and saves energy. Our simulations demonstrate that the spring stores elastic energy from approximately 22% of the gait cycle and reaches its maximum energy storage at approximately 50% of the walking cycle. The energy is then released at approximately 58% of the stride cycle during the push-off phase. The motion of the proposed prosthetic leg for individuals with transfemoral amputations mimics the normal walking pattern of healthy individuals well.

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Miller, Laura A., and Dudley S. Childress. "Problems associated with the use of inverse dynamics in prosthetic applications: An example using a polycentric prosthetic knee." Robotica 23, no. 3 (2005): 329–35. http://dx.doi.org/10.1017/s0263574704001353.

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Arun, S., and S. Kanagaraj. "Mechanical characterization and validation of poly (methyl methacrylate)/multi walled carbon nanotube composite for the polycentric knee joint." Journal of the Mechanical Behavior of Biomedical Materials 50 (October 2015): 33–42. http://dx.doi.org/10.1016/j.jmbbm.2015.06.002.

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Bachtiar, Emilio O., Tatacipta Dirgantara, Sandro Mihradi, and Andi Isra Mahyuddin. "Design and Fabrication of an Affordable Transfemoral Prosthetic Leg." Applied Mechanics and Materials 842 (June 2016): 435–44. http://dx.doi.org/10.4028/www.scientific.net/amm.842.435.

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An invalid is a person with physical or mental abnormalities which hinders their ability of doing normal human activities. One of the aforementioned abnormalities is the loss or malfunction of a body part or organ, such as the human leg. Problems brought about by this disability could be alleviated by the use of prosthetic limbs to restore normal bodily functions [1]. While there are many needs for leg prosthetics in Indonesia, the price of commercially available prosthetic is prohibitively high for most amputees. The current available affordable prosthetics are very basic and employ monocentric knee joints. Here an attempt is made towards acquiring an optimal design of an affordable prosthetic leg using previously developed four-bar knee joint [2,3]. The design is carried out by implementing a systematic design method to arrive at an affordable, yet ones with better performances. The procedure involves a rubric and analyzing various alternatives to arrive at an optimal design conclusion. The evaluation objective is to maximize the performance of the leg and knee prosthetics through an extensive analysis with considerations from various stakeholders, including the potential users, fabricator, and hospitals in Indonesia [4]. The final design of the leg consists of a composite socket, an aluminum pylon, and a solid-ankle cushioned-heel foot design. Its components are modular and compatible with prosthetic industry standards. The knee is made of a combination of polymers and stainless steel and employs a polycentric mechanism in order to satisfy design requirements while keeping costs low [4,5]. The leg and knee were then fabricated according to the analysis results. The total cost of fabrication is approximately 5.5 million IDR, significantly cheaper than commercial prosthetics. The prototype is then tested and examined using a gait analysis system previously developed at Institut Teknologi Bandung by the Biomechanics Research Team [6]. The results show satisfactory performance, albeit with a host of potential improvements.

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Al-Maliky, Firas Thair, and Jumaa Salman Chiad. "Study and evaluation of four bar polycentric knee used in the prosthetic limb for transfemoral amputee during the gait cycle." Materials Today: Proceedings 42 (2021): 2706–12. http://dx.doi.org/10.1016/j.matpr.2020.12.709.

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Sudeesh, S., S. Sujatha, and M. S. Shunmugam. "On the Possibility of Achieving Near-Normal Swing Phase of Walking with Passive Single-Axis and Polycentric Knees." Journal of Prosthetics and Orthotics 32, no. 2 (2020): 121–33. http://dx.doi.org/10.1097/jpo.0000000000000251.

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Toderita, Diana, Clement D. Favier, Giovanni S. Milandri, Vasiliki Vardakastani, David P. Henson, and Anthony MJ Bull. "The biomechanical effect of different spring extension assist mechanisms in mechanical 4-bar polycentric prosthetic knees for unilateral above/through-knee amputees." Prosthetics & Orthotics International, April 9, 2025. https://doi.org/10.1097/pxr.0000000000000448.

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Background: Passive prosthetic knees incorporate extension assist mechanisms to enhance the swing phase of the gait cycle for persons with above/through-knee amputations. In conventional polycentric knees using a 4-bar linkage, the extension assist mechanism connects one of the bars to the body of the prosthesis. However, this design introduces a singularity in the spring action delivery, causing the spring to push the knee into flexion beyond a certain angle. In contrast, polycentric prosthetic knees with an extension assist mechanism that links the upper and lower parts of the knee eliminate the singularity feature, ensuring that the knee is pushed toward extension throughout the full range of motion. Objective: This study aims to investigate the effects of different spring extension assist mechanisms in polycentric knees on the walking capacity of unilateral above/through-knee amputees. Study Design: Repeated measures. Methods: Gait data were collected at self-selected and fast speeds from 8 unilateral above/through-knee traumatic amputees using a 10-camera motion capture system. Participants trialed 2 different polycentric prosthetic knees with and without the singularity feature, both coupled with a solid-ankle-cushioned-heel prosthetic foot. They underwent gait analysis with both prosthetic knees, and a comparison analysis was conducted to examine the trial conditions. Results: The symmetry between the prosthetic and intact knee flexion angles was higher for the design without singularity by 5.2% (p = 0.025) at self-selected speeds and by 7.7% (p = 0.003) at fast speeds. Also, peak prosthetic knee flexion angles were lower for the design without singularity by 9.4° (p < 0.001) at self-selected speeds and by 9.6° (p = 0.012) at fast speeds. Conclusions: The extension assist mechanism without singularity improved the symmetry between the intact and prosthetic knee flexion angles by preventing excessive prosthetic knee flexion in the swing phase of the gait cycle.

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Köhler, Thomas Maximilian, Malte Bellmann, and Siegmar Blumentritt. "POLYCENTRIC EXOPROSTHETIC KNEE JOINTS – EXTENT OF SHORTENING DURING SWING PHASE." Canadian Prosthetics & Orthotics Journal 3, no. 1 (2020). https://doi.org/10.33137/cpoj.v3i1.33768.

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Abstract BACKGROUND: An often assumed advantage of polycentric knee joints compared to monocentric ones is the improved ground clearance during swing phase due to the geometric shortening of the lower leg segment (LLS). OBJECTIVE: To investigate whether polycentric knee joints considerably improve ground clearance and to evaluate the influence of prosthetic alignment on the extent of ground clearance. METHODOLOGY: 11 polycentric and 2 monocentric knee joints were attached to a rigid, stationary testing device. Shortening of the LLS and the resulting ground clearance during knee flexion were measured. Prosthetic components were mounted at the same height and the anterior-posterior position was in accordance with the manufacturer's alignment recommendations. FINDINGS: Shortening of up to 14.7 (SD=0.0) mm at the instance of minimal ground clearance during swing phase was measured. One knee joint elongated by 4.4 (SD=0.0) mm. Measurements of the ground clearance demonstrated differences up to 25.4 (SD=0.0) mm. One monocentric knee joint provided more ground clearance when compared to 8 of the polycentric knee joints investigated.   CONCLUSION: Only some polycentric knee joints shorten appreciably during swing phase. With an optimized prosthetic alignment and a well-designed swing phase control, a monocentric knee joint may generate greater ground clearance compared to a polycentric knee joint. <strong>LAYMAN’S ABSTRACT </strong> Tripping is a safety risk for amputees and it is mainly affected by ground clearance during swing phase. An often assumed advantage of polycentric knee joints compared to monocentric ones is the improved ground clearance during swing phase due to the geometric shortening of the lower leg segment (LLS). Based on this statement safety benefits for above knee-amputees due to reduced danger of stumbling are discussed commonly for the entire group of polycentric knee joints. We believe that this statement is not true for all polycentric knee joint designs. Therefore, we analyzed 11 polycentric and two monocentric knee joints in a rigid, stationary testing device with their individual prosthetic alignments according to the manufacturer’s alignment recommendations. Shortening of the LLS and the resulting ground clearance during knee flexion were measured. The results showed shortening effects of up to 15 mm. One knee joint elongated by 4 mm. One monocentric knee joint provided more ground clearance when compared to 8 of the polycentric knee joints investigated. We conclude, that only some polycentric knee joints shorten appreciably during swing phase. With an optimized prosthetic alignment a monocentric knee joint may generate greater ground clearance compared to a polycentric knee joint.

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Köhler, Thomas Maximilian, Malte Bellmann, and Siegmar Blumentritt. "POLYCENTRIC EXOPROSTHETIC KNEE JOINTS – EXTENT OF SHORTENING DURING SWING PHASE." CANADIAN PROSTHETICS & ORTHOTICS JOURNAL 3, no. 1 (2020). http://dx.doi.org/10.33137/cpoj.v3i1.33768.

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BACKGROUND: An often assumed advantage of polycentric knee joints compared to monocentric ones is the improved ground clearance during swing phase due to the geometric shortening of the lower leg segment (LLS). OBJECTIVE: To investigate whether polycentric knee joints considerably improve ground clearance and to evaluate the influence of prosthetic alignment on the extent of ground clearance. METHODOLOGY: 11 polycentric and 2 monocentric knee joints were attached to a rigid, stationary testing device. Shortening of the LLS and the resulting ground clearance during knee flexion were measured. Prosthetic components were mounted at the same height and the anterior-posterior position was in accordance with the manufacturer's alignment recommendations. FINDINGS: Shortening of up to 14.7 (SD=0.0) mm at the instance of minimal ground clearance during swing phase was measured. One knee joint elongated by 4.4 (SD=0.0) mm. Measurements of the ground clearance demonstrated differences up to 25.4 (SD=0.0) mm. One monocentric knee joint provided more ground clearance when compared to 8 of the polycentric knee joints investigated.  CONCLUSION: Only some polycentric knee joints shorten appreciably during swing phase. With an optimized prosthetic alignment and a well-designed swing phase control, a monocentric knee joint may generate greater ground clearance compared to a polycentric knee joint. LAYMAN’S ABSTRACT  Tripping is a safety risk for amputees and it is mainly affected by ground clearance during swing phase. An often assumed advantage of polycentric knee joints compared to monocentric ones is the improved ground clearance during swing phase due to the geometric shortening of the lower leg segment (LLS). Based on this statement safety benefits for above knee-amputees due to reduced danger of stumbling are discussed commonly for the entire group of polycentric knee joints. We believe that this statement is not true for all polycentric knee joint designs. Therefore, we analyzed 11 polycentric and two monocentric knee joints in a rigid, stationary testing device with their individual prosthetic alignments according to the manufacturer’s alignment recommendations. Shortening of the LLS and the resulting ground clearance during knee flexion were measured. The results showed shortening effects of up to 15 mm. One knee joint elongated by 4 mm. One monocentric knee joint provided more ground clearance when compared to 8 of the polycentric knee joints investigated. We conclude, that only some polycentric knee joints shorten appreciably during swing phase. With an optimized prosthetic alignment a monocentric knee joint may generate greater ground clearance compared to a polycentric knee joint. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/33768/26547 How To Cite: Köhler T.M, Bellmann M, Blumentritt S. Polycentric Exoprosthetic Knee Joints – Extent of Shortening during Swing Phase. Canadian Prosthetics & Orthotics Journal. 2020;Volume3, Issue1, No.5. https://doi.org/10.33137/cpoj.v3i1.33768 Corresponding Author: Thomas Maximilian Köhler, MScOttobock: Hermann-Rein-Straße 2a, 37075, Göttingen.E-mail: thomasmaximilian.koehler@ottobock.deORCID: https://orcid.org/0000-0002-5063-121X

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Oleksandr, Poliakov, Chepenyuk Olena, Pashkov Yevgen, Kalinin Mykhaylo, and Kramar Vadym. "Multicriteria Synthesis of a Polycentric Knee Prosthesis For Transfemoral Amputees." May 27, 2012. https://doi.org/10.5281/zenodo.1055869.

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In one of the prosthesis designs for lower limb transfemoral amputations artificial knee joints with polycentric mechanisms are used. Such prostheses are characterized by high stability during the stance phase of the movement. The existing variety of polycentric mechanisms indicates the possibility of finding the optimal prosthesis design satisfying several quality criteria.In this paper we present a multicriteria method for the synthesis of the artifical polycentric knee mechanism based on the uniform systematic study of the design parameters space and on the analysis of Pareto optimal solutions.

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Syafitri, Ismi Dwi, and Nur Rachmat. "Gambaran Proses Pembuatan Transfemoral Prosthesis Menggunakan Polycentric Knee Joint Untuk Pasien Amputasi Atas Lutut." Jurnal Keterapian Fisik 3, no. 1 (2018). http://dx.doi.org/10.37341/jkf.v3i1.103.

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Abstract : Transfemoral Amputasi, Transfemoral Prosthesis, Polycentric Knee Joint. World Health Organization (WHO) estimated that there are 40 million amputees throughout the developing countries. Amputation in the lower limbs reached 85% -90% of all amputations. Transfemoral amputation because of this amputation occurs in the thigh that passed through the femur bone. Amputation causes significant gait abnormalities. amputation levels increased, the functional level is reduced, and the characteristic of the gait abnormality is immediately apparent. Transfemoral Prosthesis is artificial limb that made for above knee amputation. making process of transfemoral prosthesis includes assessment, measurement, casting, fabrication, fitting, finishing. Of all components for transfemoral patients, prosthetic knee joints are the most important components that can affect to gait stability. The choice for the type of popular passive knee mechanism is polycentric knee. The polycentric knee joint mechanism, linkage of 4 and 6 bar mechanisms have been used to increase stability during the stance and kinematic phase of the swing phase.

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Phoengsongkhro, Santiphap, Pairat Tangpornprasert, Pattarapol Yotnuengnit, Manunchaya Samala, and Chanyaphan Virulsri. "Development of four-bar polycentric knee joint with stance-phase knee flexion." Scientific Reports 13, no. 1 (2023). http://dx.doi.org/10.1038/s41598-023-49879-4.

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AbstractA conventional 4-bar polycentric knee and solid ankle cushion heel foot (SACH foot) have been commonly used in developing countries. However, they cannot perform stance-phase knee flexion, which makes a person with an amputation walk unnaturally and with less stability. This research proposes a novel design of a 4-bar polycentric knee with stance-phase knee flexion ability (4BSF), which can perform both stance and swing-phase knee flexion, like able-bodied gait. In the proposed conceptual design, the instantaneous center of rotation (ICR) path is repositioned during the stance phase. The ICR was placed in front of the ground reaction force (GRF) to initiate knee flexion during the loading response. The prototype was validated by a single-subject pilot study at the Gait analysis laboratory. The results showed that a person with an amputation walks with stance-phase knee flexion using the proposed 4BSF. The maximum knee flexion angle is more than 10° during the stance phase. Furthermore, when the 4BSF was used with a SACH foot, the amount of time to achieve the foot flat was shorter, and the foot flat duration time was twice as long as the conventional 4-bar polycentric knee.

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Patrick, Shawanee', Namita Anil Kumar, and Pilwon Hur. "Evaluating Knee Mechanisms for Assistive Devices." Frontiers in Neurorobotics 16 (May 30, 2022). http://dx.doi.org/10.3389/fnbot.2022.790070.

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State-of-the-art knee braces use a polycentric mechanism with a predefined locus of the instantaneous center of rotation (centrode) and most exoskeleton devices use a knee mechanism with a single axis of rotation. However, human knees do not share a common centrode nor do they have a single axis. This leads to misalignment between the assistive device's joint axis and the user's knee axis, resulting in device migration and interaction forces, which can lead to sores, pain, and abandonment of the device over time. There has been some research into self-aligning knee mechanisms; however, there is a lack of consensus on the benefit of these mechanisms. There is no research that looked purely at the impact of the knee mechanisms, either. In this article, we compare three different knee brace mechanisms: single axis (SA), polycentric with predefined centrode (PPC), and polycentric with a self-aligning center of rotation (PSC). We designed and conducted an experiment to evaluate different joint mechanisms on device migration and interaction forces. Brace material, weight, size, cuff design, fitment location, and tightness were consistent across trials, making the knee joint mechanism the sole variable. The brace mechanisms had no significant effect on walking kinematics or kinetics. However, the PPC brace had greater interaction forces on the top brace strap than the SA and PSC. The PSC and SA had significantly lower interaction forces on the bottom strap compared to the PPC brace. The PSC had significantly less migration than both the SA and PPC braces. These results show that a PPC mechanism may not be beneficial for a wide range of users. This also shows that the PSC mechanisms may improve mechanism alignment and lessen device migration.

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Niznan, P., M. Csekei, J. Sido, P. Kostal, and R. Zelnik. "GEOMETRIC ANALYSIS AND MATHEMATICAL MODEL OF A POLYCENTRIC KNEE MECHANISM." MM Science Journal 2025, no. 1 (2025). https://doi.org/10.17973/mmsj.2025_03_2025016.

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This paper focuses on calculating the central distances of polycentric joints designed to replicate the natural motion of the human knee. A key aspect is the shortening of the central distance during the swing phase, which reduces tripping risk and improves gait stability. Using mathematical modeling, the study analyzes the dynamic changes in instantaneous centers of rotation and their impact on knee biomechanics. The results enable a more precise design of polycentric prosthetic joints, enhancing their functionality and adaptability for users.

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Sudeesh, S., MS Shunmugam, and S. Sujatha. "Equivalent system based inverse dynamics analysis of transfemoral prosthetic legs: Validation and application." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, February 28, 2023, 095441192311571. http://dx.doi.org/10.1177/09544119231157144.

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Inverse dynamics analysis of prosthetic legs with polycentric knees is complex due to increased number of links. The present work proposes a simple and general method called equivalent system (ES) analysis. The ES analysis provides forces and moment at hip joint as well as at the functional knee centre (FKC), the instant centre of the polycentric knee. The input to the ES analysis is the motion data. For validation of the proposed method, synthetic motion data for the swing phase of walking with prosthetic legs having different knees are generated by simulations using ADAMS. The hip kinetics evaluated by the proposed method is compared with that from ADAMS. The root mean square errors of the ES analysis are lower than 17 (10−6) N for hip reaction forces and 2.6 (10−6) Nm for the hip moments, thereby validating the proposed method. In order to demonstrate the application of the proposed methodology, the motion data of two transfemoral amputees using single-axis and four-bar knee prostheses are obtained during gait trials. The hip kinetics as well as kinetics at FKC are computed using ES analysis. Hip power during the swing phase is also evaluated and compared. The results are presented in this paper and discussed. The ES analysis is shown to be a versatile tool to provide insights into the human-mechanism interaction.

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