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Elkington RJ, Hall RM, Beadling AR, Pandit H, Bryant MG. Brushing Up on Cartilage Lubrication: Polyelectrolyte-Enhanced Tribological Rehydration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:10648-10662. [PMID: 38712915 PMCID: PMC11112737 DOI: 10.1021/acs.langmuir.4c00598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/14/2024] [Accepted: 04/18/2024] [Indexed: 05/08/2024]
Abstract
This study presents new insights into the potential role of polyelectrolyte interfaces in regulating low friction and interstitial fluid pressurization of cartilage. Polymer brushes composed of hydrophilic 3-sulfopropyl methacrylate potassium salt (SPMK) tethered to a PEEK substrate (SPMK-g-PEEK) are a compelling biomimetic solution for interfacing with cartilage, inspired by the natural lubricating biopolyelectrolyte constituents of synovial fluid. These SPMK-g-PEEK surfaces exhibit a hydrated compliant layer approximately 5 μm thick, demonstrating the ability to maintain low friction coefficients (μ ∼ 0.01) across a wide speed range (0.1-200 mm/s) under physiological loads (0.75-1.2 MPa). A novel polyelectrolyte-enhanced tribological rehydration mechanism is elucidated, capable of recovering up to ∼12% cartilage strain and subsequently facilitating cartilage interstitial fluid recovery, under loads ranging from 0.25 to 2.21 MPa. This is attributed to the combined effects of fluid confinement within the contact gap and the enhanced elastohydrodynamic behavior of polymer brushes. Contrary to conventional theories that emphasize interstitial fluid pressurization in regulating cartilage lubrication, this work demonstrates that SPMK-g-PEEK's frictional behavior with cartilage is independent of these factors and provides unabating aqueous lubrication. Polyelectrolyte-enhanced tribological rehydration can occur within a static contact area and operates independently of known mechanisms of cartilage interstitial fluid recovery established for converging or migrating cartilage contacts. These findings challenge existing paradigms, proposing a novel polyelectrolyte-cartilage tribological mechanism not exclusively reliant on interstitial fluid pressurization or cartilage contact geometry. The implications of this research extend to a broader understanding of synovial joint lubrication, offering insights into the development of joint replacement materials that more accurately replicate the natural functionality of cartilage.
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Affiliation(s)
- Robert J. Elkington
- Institute
of Functional Surfaces, Mechanical Engineering, University of Leeds, Leeds LS2 9JT, Yorkshire, U.K.
| | - Richard M. Hall
- School
of Engineering College of Engineering and Physical Sciences, University of Birmingham, Birmingham B15 2TT, West
Midlands, U.K.
| | - Andrew R. Beadling
- Institute
of Functional Surfaces, Mechanical Engineering, University of Leeds, Leeds LS2 9JT, Yorkshire, U.K.
| | - Hemant Pandit
- Leeds
Institute of Rheumatic and Musculoskeletal Medicine, Chapel Allerton Hospital, Chapeltown Road, Leeds LS7 4SA, Yorkshire, U.K.
| | - Michael G. Bryant
- School
of Engineering College of Engineering and Physical Sciences, University of Birmingham, Birmingham B15 2TT, West
Midlands, U.K.
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2
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Chen T, Zou H, Wu X, Chen Y, Situ B, Zheng L, Yang G. Fullerene-like MoS 2 Nanoparticles as Cascade Catalysts Improving Lubricant and Antioxidant Abilities of Artificial Synovial Fluid. ACS Biomater Sci Eng 2019; 5:3079-3088. [PMID: 33405540 DOI: 10.1021/acsbiomaterials.9b00372] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Intraarticular injection of hyaluronic acid (HA) for viscosupplementation is a nonsurgical therapy for osteoarthritis (OA). However, HA fails to lubricate under a significant load and tends to be depolymerized by the overproduction of reactive oxygen species (ROS) in inflammation. Here, we for the first time reported that fullerene-like MoS2 (F-MoS2) nanoparticles are efficient lubricants and antioxidants for artificial synovial fluid. A model of arthrosis was built, to evaluate the tribological behavior of F-MoS2 nanoparticles. The tests showed that they significantly improve the antiwear and friction-reducing abilities of the artificial synovial fluid. More importantly, the F-MoS2 nanoparticles possess intrinsic dual-enzyme-like activity, mimicking superoxide dismutases (SOD) and catalases (CAT) under physiological conditions (pH 7.4, 25 °C). By coupling of these unique properties, a self-organized cascade catalytic system was constructed, which includes the disproportionation of superoxide radicals (O2•-) to hydrogen peroxide (H2O2) and subsequently the disproportionation of H2O2 into oxygen (O2). The effectiveness of the detox system was evaluated by human umbilical vein endothelial cells (HUVEC) models exposed to oxidative stress. After that, F-MoS2 nanoparticles were used to regulate the ROS level in artificial synovial fluid containing HA. Relative viscosity measurements showed the excellent protective effect of F-MoS2 nanoparticles against HA oxidative damage offered by O2•-. These results indicate that F-MoS2 nanoparticles are promising candidates for treatment of OA and other diseases caused by lubrication deficiency or oxidative stress.
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Affiliation(s)
- Tongming Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science & Engineering, School of Physics, Sun Yat-sen University, Guangzhou 510275, Guangdong, People's Republic of China
| | - Hang Zou
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University/The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Xiaoju Wu
- State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science & Engineering, School of Physics, Sun Yat-sen University, Guangzhou 510275, Guangdong, People's Republic of China
| | - Yuan Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science & Engineering, School of Physics, Sun Yat-sen University, Guangzhou 510275, Guangdong, People's Republic of China
| | - Bo Situ
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University/The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Lei Zheng
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University/The First School of Clinical Medicine, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Guowei Yang
- State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science & Engineering, School of Physics, Sun Yat-sen University, Guangzhou 510275, Guangdong, People's Republic of China
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3
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Inyang AO, Abdalrahman T, Bezuidenhout D, Bowen J, Vaughan CL. Suitability of developed composite materials for meniscal replacement: Mechanical, friction and wear evaluation. J Mech Behav Biomed Mater 2018; 89:217-226. [PMID: 30296703 DOI: 10.1016/j.jmbbm.2018.09.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/17/2018] [Indexed: 11/19/2022]
Abstract
The meniscus is a complex and frequently damaged tissue which requires a substitute capable of reproducing similar biomechanical functions. This study aims to develop a synthetic meniscal substitute that can mimic the function of the native meniscus. Medical grade silicones reinforced with nylon were fabricated using compression moulding and evaluated for mechanical and tribological properties. The optimal properties were obtained with tensile modulus increased considerably from 10.7 ± 2.9 MPa to 114.6 ± 20.9 MPa while compressive modulus was found to reduce from 2.5 ± 0.6 MPa to 0.7 ± 0.3 MPa. Using a tribometer, the coefficient of friction of 0.08 ± 0.02 was measured at the end of the 100,000 cycles. The developed composite could be an auspicious substitute for the native meniscus and the knowledge gained from this study is useful as it enhances the understanding of a potentially suitable material for meniscal implants.
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Affiliation(s)
- Adijat Omowumi Inyang
- Division of Biomedical Engineering, Human Biology Department, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, Cape Town, South Africa.
| | - Tamer Abdalrahman
- Division of Biomedical Engineering, Human Biology Department, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, Cape Town, South Africa.
| | - Deon Bezuidenhout
- Cardiovascular Research Unit, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, Cape Town, South Africa.
| | - James Bowen
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Chistopher Leonard Vaughan
- Division of Biomedical Engineering, Human Biology Department, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, Cape Town, South Africa.
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4
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O’Donnell JM, Devitt BM, Arora M. The role of the ligamentum teres in the adult hip: redundant or relevant? A review. J Hip Preserv Surg 2018; 5:15-22. [PMID: 29423246 PMCID: PMC5798146 DOI: 10.1093/jhps/hnx046] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 08/21/2017] [Accepted: 12/12/2017] [Indexed: 12/14/2022] Open
Abstract
The ligamentum teres (LT) has traditionally been described as a redundant structure with no contribution to hip biomechanics or function. There has been renewed interest in the LT as a source of hip pathology due to the high prevalence of LT pathology observed at the time of hip arthroscopy. The LT acts a secondary stabilizer to supplement the work of the capsular ligaments and works in a sling-like manner to prevent subluxation of the hip at the extremes of motion. The presence of free nerve endings within the LT indicates a definite role in pain generation, with the LT undergoing various mechanical and histological adaptations to hip pathology.
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Affiliation(s)
- John M O’Donnell
- Hip Arthroscopy Australia, 21 Erin Street, Richmond, VIC 3121, Australia
| | - Brian M Devitt
- Orthosport Victoria, 89 Bridge Road, Richmond, VIC 3121, Australia
| | - Manit Arora
- Hip Arthroscopy Australia, 21 Erin Street, Richmond, VIC 3121, Australia
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5
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Abstract
The major synovial joints such as hips and knees are uniquely efficient tribological systems, able to articulate over a wide range of shear rates with a friction coefficient between the sliding cartilage surfaces as low as 0.001 up to pressures of more than 100 atm. No human-made material can match this. The means by which such surfaces maintain their very low friction has been intensively studied for decades and has been attributed to fluid-film and boundary lubrication. Here, we focus especially on the latter: the reduction of friction by molecular layers at the sliding cartilage surfaces. In particular, we discuss such lubrication in the light of very recent advances in our understanding of boundary effects in aqueous media based on the paradigms of hydration lubrication and of the synergism between different molecular components of the synovial joints (namely hyaluronan, lubricin, and phospholipids) in enabling this lubrication.
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Affiliation(s)
- Sabrina Jahn
- Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Jasmine Seror
- Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Jacob Klein
- Weizmann Institute of Science, Rehovot 76100, Israel;
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6
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Medley JB, Dowson D, Wright V. Transient Elastohydrodynamic Lubrication Models for the Human Ankle Joint. ACTA ACUST UNITED AC 2016; 13:137-51. [PMID: 6542885 DOI: 10.1243/emed_jour_1984_013_035_02] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An equivalent bearing was proposed to represent the normal human ankle joint. The geometry was based on measurements of dissected ankle joints and tissue properties were obtained from the work of previous investigators. Theoretical models were developed to estimate the cyclic variation in lubricant film thickness and coefficient of friction during repetitive activities such as walking. Solutions were obtained for various combinations of input parameters. For the conditions representing the walking cycle, film thicknesses of about 0.7 μm were calculated. Although this value was smaller than most previous measurements of the rms roughness of cartilage, it was not much smaller and suggested that transient elastohydrodynamic lubrication played a role in synovial joint lubrication. The possibility of full fluid film lubrication was supported only when a very high input viscosity was employed, based on values estimated from the previous experimental studies of the boosted lubrication mechanism. Also, an attempt was made to link the current findings to a published experimental study of whole joint lubrication.
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7
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Abstract
In order to study the joint contact and joint space of statically loaded human knee and hip joints, observations of serial slices of joint specimens which were frozen during the application of a load were carried out. In the intact joints, the articular cartilage surfaces did not come into direct contact with each other even under a load of more than twice that of the body weight. The minimum distance between cartilage surfaces in each specimen ranged from 0.2 to 0.6 mm. The Indian ink which was injected into the joints before the load application was squeezed out of some areas of the remaining joint space, but a dye-free fluid apparently remained in this space. Based on our findings, the definition of joint contact and the lubrication mechanism in the intact human joint have been discussed.
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Affiliation(s)
- K Terayama
- Associate Professor, Department of Orthopaedic Surgery, Faculty of Medicine, Shinshu University, Japan
| | - T Takei
- Clinical Associate, Department of Orthopaedic Surgery, Faculty of Medicine, Shinshu University, Japan
| | - K Nakada
- Clincial Associate, Department of Orthopaedic Surgery, Faculty of Medicine, Shinshu University, Japan
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8
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Ellis MI, Seedhom BB, Wright V, Dowson D. An Evaluation of the Ratio between the Tensions along the Quadriceps Tendon and the Patellar Ligament. ACTA ACUST UNITED AC 2016. [DOI: 10.1243/emed_jour_1980_009_049_02] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An experiment was devised whereby physiological loads could be applied to the quadriceps tendon of cadaveric knee joints so that the ratio of tensions in the quadriceps tendon and the patellar ligament could be determined. On two knee joints, radiographs were taken before testing, so that the theoretical ratio of the tensions could be evaluated and compared with the experimental results. As the knee was flexed, the ratio of the tensions, frequently assumed to be unity, reduced by up to fifty per cent.
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Affiliation(s)
- M I Ellis
- Rheumatism Research Unit, University of Leeds
| | - B B Seedhom
- Departments of Medicine and Mechanical Engineering, University of Leeds
| | - V Wright
- University Department of Medicine, General Infirmary, Leeds
| | - D Dowson
- Department of Mechanical Engineering, University of Leeds
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9
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Jones BK, Durney KM, Hung CT, Ateshian GA. The friction coefficient of shoulder joints remains remarkably low over 24 h of loading. J Biomech 2015; 48:3945-9. [PMID: 26472306 DOI: 10.1016/j.jbiomech.2015.09.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 09/11/2015] [Accepted: 09/24/2015] [Indexed: 11/18/2022]
Abstract
The frictional response of whole human joints over durations spanning activities of daily living has not been reported previously. This study measured the friction of human glenohumeral joints during 24 h of reciprocal loading in a pendulum testing device, at moderate (0.2 mm/s, 4320 cycles) and low (0.02 mm/s, 432 cycles) sliding speeds, under a 200 N load. The effect of joint congruence was also investigated by testing human humeral heads against significantly larger mature bovine glenoids. Eight human joints and six bovine joints were tested in four combinations: human joints tested at moderate (hHCMS, n=6) and low speed (hHCLS, n=3), human humeral heads tested against bovine glenoids at moderate speed (LCMS, n=3), and bovine joints tested at moderate speed (bHCMS, n=3). In the first half hour the mean±standard deviation of the friction coefficient was hHCMS: 0.0016±0.0011, hHCLS: 0.0012±0.0002, LCMS: 0.0008±0.0002 and bHCMS: 0.0024±0.0008; in the last four hours it was hHCMS: 0.0057±0.0025, hHCLS: 0.0047±0.0017, LCMS: 0.0012±0.0003 and bHCMS: 0.0056±0.0016. The initial value was lower than the final value (p<0.0001). The value in LCMS was significantly lower than in hHCMS and bHCMS (p<0.01). No visual damage was observed in any of the specimens. These are the first results to demonstrate that the friction coefficient of natural human shoulders remains remarkably low (averaging as little as 0.0015 and no greater than 0.006) for up to 24 h of continuous loading. The sustained low friction coefficients observed in incongruent joints (~0.001) likely represent rolling rather than sliding friction.
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Affiliation(s)
- Brian K Jones
- Columbia University, Departments of Mechanical Engineering, Biomedical Engineering, and Orthopaedic Surgery, 500 West 120th Street, MC 4703, New York, NY 10027, USA
| | - Krista M Durney
- Columbia University, Departments of Mechanical Engineering, Biomedical Engineering, and Orthopaedic Surgery, 500 West 120th Street, MC 4703, New York, NY 10027, USA
| | - Clark T Hung
- Columbia University, Departments of Mechanical Engineering, Biomedical Engineering, and Orthopaedic Surgery, 500 West 120th Street, MC 4703, New York, NY 10027, USA
| | - Gerard A Ateshian
- Columbia University, Departments of Mechanical Engineering, Biomedical Engineering, and Orthopaedic Surgery, 500 West 120th Street, MC 4703, New York, NY 10027, USA.
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10
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Thomas JMC, Beevers D, Dowson D, Jones MD, King P, Theobald PS. The Bio-Tribological Characteristics of Synthetic Tissue Grafts. Proc Inst Mech Eng H 2010; 225:141-8. [DOI: 10.1243/09544119jeim796] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The use of synthetic connective tissue grafts became popular in the mid-1980s, particularly for anterior cruciate ligament reconstruction; however, this trend was soon changed given the high failure rate due to abrasive wear. More than 20 years later, a vast range of grafts are available to the orthopaedic surgeon for augmenting connective tissue following rupture or tissue loss. While the biomechanical properties of these synthetic grafts become ever closer to the natural tissue, there have been no reports of their bio-tribological (i.e. bio-friction) characteristics. In this study, the bio-tribological performance of three clinically available synthetic tissue grafts, and natural tendon, was investigated. It was established that the natural tissue exhibits fluid-film lubrication characteristics and hence is highly efficient when sliding against opposing tissues. Conversely, all the synthetic tissues demonstrated boundary or mixed lubrication regimes, resulting in surface—surface contact, which will subsequently cause third body wear. The tribological performance of the synthetic tissue, however, appeared to be dependent on the macroscopic structure. This study indicates that there is a need for synthetic tissue designs to have improved frictional characteristics or to use a scaffold structure that encourages tissue in-growth. Such a development would optimize the bio-tribological properties of the synthetic tissue and thereby maximize longevity.
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Affiliation(s)
- J M C Thomas
- Department of Trauma and Orthopaedics, The Royal London Hospital, Whitechapel, London, UK
| | - D Beevers
- Xiros, Springfield House, Whitehouse Lane, Leeds, UK
| | - D Dowson
- Trauma Biomechanics Research Group, Institute of Medical Engineering and Medical Physics, Cardiff University, Cardiff, UK
| | - M D Jones
- Trauma Biomechanics Research Group, Institute of Medical Engineering and Medical Physics, Cardiff University, Cardiff, UK
| | - P King
- Trauma Biomechanics Research Group, Institute of Medical Engineering and Medical Physics, Cardiff University, Cardiff, UK
| | - P S Theobald
- Trauma Biomechanics Research Group, Institute of Medical Engineering and Medical Physics, Cardiff University, Cardiff, UK
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11
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Theobald P, Byrne C, Oldfield SF, Dowson D, Benjamin M, Dent C, Pugh N, Nokes LDM. Lubrication regime of the contact between fat and bone in bovine tissue. Proc Inst Mech Eng H 2007; 221:351-6. [PMID: 17605392 DOI: 10.1243/09544119jeim176] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fat pads are masses of encapsulated adipose tissue located throughout the human body. Whilst a number of studies describe these soft tissues anatomically little is known about their biomechanics, and surgeons may excise them arthroscopically if they hinder visual inspection of the joint or bursa. By measuring the coefficient of friction between, and performing Sommerfeld analysis of, the surfaces approximating the in vivo conjuncture, this contact has been shown to have a coefficient of friction of the order of 0.01. The system appears to be lubricated hydrodynamically, thus possibly promoting low levels of wear. It is suggested that one of the functions of fat pads associated with subtendinous bursae and synovial joints is to generate a hydrodynamic lubricating layer between the opposing surfaces.
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Affiliation(s)
- P Theobald
- Institute of Medical Engineering and Medical Physics, Cardiff University, Cardiff, UK.
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12
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Müller LP, Degreif J, Rudig L, Mehler D, Hely H, Rommens PM. Friction of ceramic and metal hip hemi-endoprostheses against cadaveric acetabula. Arch Orthop Trauma Surg 2004; 124:681-7. [PMID: 15449077 DOI: 10.1007/s00402-004-0734-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Studies of hip arthroplasty have dealt mainly with total endoprosthesis, while tribology measurement values of hemi-endoprosthetic implants are rare. The small amount of experimental tribological data concerning materials of hemi-endoprosthetic implants in the form of pendulum trials, animal experiments, in vivo measurements on human hip joints and pin on disc studies report friction coefficients between 0.014 and 0.57; the friction coefficients measured in fresh human cadaver hip joints were determined between 0.001 and 0.08. MATERIALS AND METHODS The HEPFlEx-hip simulator was constructed to test the friction coefficients of unipolar femur head hemi-endoprostheses made of metal or ceramic against fresh cadaveric acetabula. Its plane of movement is uniaxial with a flexion-extension movement of +30/-18 degrees . The force is produced pneumatically dynamic with amounts of 2.5 kN. Newborn calf serum serves as a lubricant. We mounted 20 fresh porcine acetabula and 10 fresh human cadaver acetabula in the HEPFlEx-hip simulator and compared the two unipolar femur head hemi-endoprostheses (metal vs. ceramic). RESULTS The mean friction coefficients against porcine acetabula were micro=0.017-0.082 for ceramic and micro=0.020-0.101 for metal; against human cadaver acetabula micro=0.017-0.083 for ceramic and micro=0.019-0.118 for metal. The frictional coefficient deltas (metal-ceramic) values of all measurements were Deltamicro=0.004 for porcine acetabula and Deltamicro=0.001 for cadaver acetabula. Box-plots graphics document significantly lower frictional coefficients of the ceramics. CONCLUSIONS The lower frictional coefficients of ceramic compared to metal against fresh cadaveric acetabula may have a clinical impact on the process of the protrusion of the corresponding femoral head through the acetabulum.
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Affiliation(s)
- L P Müller
- Department of Traumatology, Johannes Gutenberg University Hospital, Langenbeckstrasse 1, 55101 Mainz, Germany.
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13
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Mller LP, Degreif J, Hely H, Mehler D, Otto M, Rommens PM. Friction in hip hemiendoprostheses. Review of literature and own model using cadaveric acetabula. Hip Int 2002; 12:126-134. [PMID: 28124355 DOI: 10.1177/112070000201200219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The science of tribology concerning hip arthroplasty has mainly dealt with total endoprosthesis, whereas measurement values of hemiendoprosthetic implants are rare. The small amount of experimental tribologic data concerning hemiendoprosthetic implants in the form of pendulum trials, animal experiments, in vivo measurements on human hip joints and pin on disc studies will be reviewed in the following work. The reported frictional coefficients in these studies were between 0.014-0.57. In order to test the friction coefficients of different femur head hemiendoprostheses (unipolar ceramic- and metal heads) against fresh cadaveric acetabula, the HEPFlEx-hip simulator (Hemi-EndoProsthesis Flexion Extension) was developed. In the simulator, the various hemiendoprosthetic heads are placed on a special cone and tested against a cadaver acetabulum cast in MCP 47 woodmetal. The plane of movement of the apparatus is uniaxial with a flexion-extension movement of 35 degrees. The force is produced pneumatically with amounts of up to 5 kN. Newborn calf serum serves as a lubricant. A PC collects the data from torque-, force-, and angle-sensors on-line and allows the simultaneous processing and visualization of the data. The frictional coefficients produced by the different head materials and the relevance of the play between the hemiendoprothesis head size and acetabulum can be determined. Preliminary results showed that the mean friction coefficient at 1 kN loading was =0.024-0.063 for ceramic against cartilage and =0.033-0.075 for metal against cartilage. (Hip International 2002; 2: 126-34).
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Affiliation(s)
- L P Mller
- Department of Traumatology, Johannes Gutenberg-University Hospital, Mainz - Germany
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14
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Abstract
OBJECTIVE The aim of the study is to investigate the labrum's ability to seal a pressurised layer of synovial fluid within the joint, and to study the influence of this sealing mechanism on cartilage deformation, interstitial fluid pressure and collagen solid matrix stresses. BACKGROUND Cartilage degeneration has been observed in conjunction with labrum pathology. However, little is known about the function of the labrum. Experimental observations have been reported which are consistent with a sealing function of the labrum. METHODS The model was an axisymmetric geometric approximation of the acetabular and femoral cartilage layers and the surrounding labrum. A poroelastic formulation was used to account for the solid and fluid components of these hydrated tissues. A sensitivity analysis of the labrum material properties was carried out. RESULTS With a compressive load of 1200 N applied across the joint model, the labrum could seal a layer of pressurised fluid between the femur and acetabulum, thus preventing contact of the articulating surfaces. With this sealing effect, loads were transferred across the joint predominantly by uniform pressurisation of the interstitial fluid of the cartilage layers. In the absence of this sealing, strains within the solid matrix of the cartilage layers were higher (e.g. 20% vs. 3%). CONCLUSIONS The labrum can seal against fluid expression from the joint space. This sealing function protects the cartilage layers of the hip. RELEVANCE Current treatments for labrum damage and early arthrosis may compromise the sealing function of the labrum. With continued study of the function and importance of the labrum, new surgical repair strategies can be developed to maintain the overall function of the hip joint.
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Affiliation(s)
- S J Ferguson
- AO-ASIF Research Institute, Clavadelerstrasse, Davos Platz, Switzerland.
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15
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Scholes SC, Unsworth A. Comparison of friction and lubrication of different hip prostheses. Proc Inst Mech Eng H 2000; 214:49-57. [PMID: 10718050 DOI: 10.1243/0954411001535237] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
It is well documented that an important cause of osteolysis and subsequent loosening of replacement hip joints is polyethylene wear debris. To avoid this, interest has been renewed in metal-on-metal and ceramic-on-ceramic prostheses. Various workers have assessed the lubrication modes of different joints by measuring the friction at the bearing surfaces, using different lubricants. Measurements of friction factors of a series of hip prostheses were undertaken using carboxymethyl cellulose (CMC) fluids, silicone fluids, synovial fluid and different concentrations of bovine serum as the lubricant. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing CMC fluids or silicone fluids as the lubricant. Mixed lubrication was found to occur in the metal-on-metal (CoCrMo/CoCrMo) joints with all lubricants at a viscosity within the physiological range. This was also the case for the metal-on-plastic (CoCrMo/ultra-high molecular weight polyethylene) joints. The ceramic-on-ceramic (Al2O3/Al2O3) joints, however, exhibited full fluid film lubrication with the synthetic lubricants but mixed lubrication with the biological lubricants. Employing a biological fluid as the lubricant affected the friction to varying degrees when compared with the synthetic lubricants. In the case of the ceramic-on-ceramic joints it acted to increase the friction factor tenfold; however, for the metal-on-metal joints, biological fluids gave slightly lower friction than the synthetic lubricants did. This suggests that, when measuring friction and wear of artificial joints, a standard lubricant should be used.
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Affiliation(s)
- S C Scholes
- Centre for Biomedical Engineering, University of Durham, UK
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16
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Abstract
Although the reduction of frictional torques was the driving force behind the design of the Charnley prosthesis, later concerns about wear and subsequent loosening of this and other hip replacements have dominated debate within the bioengineering community. To stimulate discussion on the role of friction in loosening, a review of the frictional characteristics of different prostheses was undertaken. The use of simple laboratory screening-type machines in the frictional assessment of different material combinations is discussed together with experiments performed on single axis simulators using both conventional and experimental prostheses. In particular, recent developments in the use of soft layer components are highlighted. Further, the possible link between excessively high frictional torques and loosening is discussed in the light of current results obtained from explanted prostheses.
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Affiliation(s)
- R M Hall
- Centre for Biomedical Engineering, School of Engineering, University of Durham, UK
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17
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Forster H, Fisher J. The influence of loading time and lubricant on the friction of articular cartilage. Proc Inst Mech Eng H 1996; 210:109-19. [PMID: 8688115 DOI: 10.1243/pime_proc_1996_210_399_02] [Citation(s) in RCA: 212] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Friction of cartilage on metal, metal on cartilage and cartilage on cartilage contact configurations, within a mixed lubrication regime, was measured using synovial fluid, Ringer's solution or with no lubricant present. The main test variable was the period of stationary loading which ranged from 5 s to 45 min, prior to sliding and consequently measuring friction. The coefficient of friction rose gradually with increasing stationary loading time, up to a value of approximately 0.3 at 45 min for all the contact configurations. Following the re-application of load, after short periods of load removal, friction was also found to drop sharply. The flow of liquid in the biphasic cartilage and load carriage by the fluid phase was highlighted as being an important factor in reducing friction within the mixed or boundary lubrication regime. Movement of the contact zone over the cartilage counterface ensured very low friction as the slider moved over fully hydrated cartilage. For the cartilage--cartilage contacts synovial fluid significantly reduced friction compared to Ringer's solution. This was attributed to an effective boundary lubrication action, which was not as effective for the cartilage--metal contacts.
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Affiliation(s)
- H Forster
- Department of Mechanical Engineering, University of Leeds
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18
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The effect of stationary loading on the friction and boundary lubrication of articular cartilage in the mixed lubrication regime. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0167-8922(08)70618-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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19
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Abstract
The asperity lubrication in human joints is examined in the present paper, with particular reference to the tertiary undulation with wavelengths of around 20-45 microns. It was found that, under dynamic physiological loading conditions, the secondary waviness of the cartilaginous surface (typically 0.5 mm wavelength) could be effectively flattened to sustain a fluid film of 0.1-0.3 micron thick, while the tertiary waviness could be squashed to sustain a much thinner fluid film of 0.01 micron (10 nm) thick with normal synovial fluid as the lubricant. The calculated film thickness for the tertiary undulation was less than 5 nm when the ankle joint was lubricated by Ringer's solution or pathological synovial fluids, or when only quasi-static loading conditions were considered, while a sufficiently thick fluid film could still be formed when the secondary undulations were considered alone. It was thus suggested that the fluid film lubrication mechanism was operative for human joints with normal synovial fluid as the lubricant under physiological dynamic loading conditions and the mixed lubrication mechanism could take over when static loading conditions prevailed or when watery lubricants (eta approximately 0.001 Pa s) were used.
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Affiliation(s)
- J Q Yao
- School of Engineering and Computer Science, University of Durham
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20
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Williams PF, Powell GL, LaBerge M. Sliding friction analysis of phosphatidylcholine as a boundary lubricant for articular cartilage. Proc Inst Mech Eng H 1993; 207:59-66. [PMID: 8363698 DOI: 10.1243/pime_proc_1993_207_268_02] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Dipalmitoyl phosphatidylcholine (DPPC), the major lipidic component of the synovial fluid (45 per cent), has been implicated in previous studies in synovial joint lubrication as a potential boundary lubricant for articular cartilage. The purpose of this study was to evaluate the effectiveness of DPPC as a boundary lubricant at physiological stresses experienced by weight-bearing joints (up to 7.5 MPa). The sliding coefficients of static and kinetic friction for glass surfaces coated with DPPC layers of physiological thickness (70 nm) were measured as a function of average contact stress, contact geometry (point and line), applied load and relative velocity (from 25 to 0 mm/s) and compared to the coefficient of friction for clean glass in the same conditions. The coefficient of friction for DPPC-lubricated surfaces was dependent on contact geometry, obeyed Amonton's law (not dependent on axial load or contact area), was dependent on relative velocity within the range stated and was an effective lubricant at physiological stresses. This study showed that dipalmitoyl phosphatidylcholine can be an effective boundary lubricant at stresses observed in load-bearing joints. Because of their surface-active nature, these adsorbed molecules might also act as a protective layer for the articular surfaces.
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Affiliation(s)
- P F Williams
- Department of Bioengineering, Clemson University, South Carolina
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21
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Auger DD, Dowson D, Fisher J, Jin ZM. Friction and lubrication in cushion form bearings for artificial hip joints. Proc Inst Mech Eng H 1993; 207:25-33. [PMID: 8363695 DOI: 10.1243/pime_proc_1993_207_265_02] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Two hip joint prostheses were designed and constructed to be elastohydrodynamically equivalent producing approximately equal initial contact areas and theoretical film thicknesses. One was made from conventional UHMWPE (ultra-high molecular weight polyethylene) and the other was a cushion component which had a low modulus layer introduced into the joint space. Friction measurements were carried out on a pendulum simulator apparatus and the two joints were compared. In addition the experimental results were compared with theoretical values of friction predicted from elastohydrodynamic lubrication theory. Values for the friction factor at peak load and peak velocity in the cushion cup (0.003-0.009) were much lower than in the UHMWPE cup (0.017-0.042). The low friction values in the cushion cup are consistent with fluid film lubrication in the contact with the thin lubricating film being preserved by microelastohydrodynamic action.
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Affiliation(s)
- D D Auger
- Department of Mechanical Engineering, University of Leeds
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22
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Friction of Cylindrical Cushion form Bearings for Artificial Joints. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0167-8922(08)70421-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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23
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Abstract
Studies of human joint lubrication mechanisms have led to the conclusion that under normal healthy conditions they are fluid film lubricated. The main features responsible for allowing this mechanism to operate are the dynamic nature of the loading and the compliance of the bearing surfaces (articular cartilage). In contrast, artificial joints, being made of much more rigid materials, have been demonstrated to be lubricated by a mixed regime, where some load is carried by the fluid film and some by solid to solid contact. Since some surface contact takes place then wear remains a problem and friction is much higher than in human joints. The use of compliant surface bearings for artificial joints has been explored and shown to be of great advantage, reproducing the effects of natural joints. However, elastomeric materials are known to degrade in aqueous solutions so this aspect has been examined to ensure a reasonable life in the human body. Joints of the lower limb--hip, knee, and ankle--have similar load and motion patterns and behave in a similar way in terms of lubrication. Joints of the hand are not in any way similar in their behaviour and so a typical upper limb joint, the finger, has been studied to see if improvements can be made to the design of replacement artificial joints. Novel suggestions like plastic on plastic joints have been shown to be an alternative which is worthy of further consideration.
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Affiliation(s)
- A Unsworth
- Centre for Biomedical Engineering, University of Durham
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24
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Blamey J, Rajan S, Unsworth A, Dawber R. Soft layered prostheses for arthritic hip joints: a study of materials degradation. JOURNAL OF BIOMEDICAL ENGINEERING 1991; 13:180-4. [PMID: 1870325 DOI: 10.1016/0141-5425(91)90123-o] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A great deal of interest is being shown in complaint bearing surfaces for artificial joints. These produce very low friction because of the fluid-film lubrication that they exhibit, and therefore should produce lower wear than current prosthetic materials as the two surfaces of the joint are completely separated by a film of synovial fluid. However, one problem with soft elastic materials in vivo is that the elastomers may degrade with time. Specimens of four polyurethanes were kept in Ringer's solution at 37 degrees C for about 4 months to investigate changes in mechanical properties and the mode of lubrication with time of immersion. The materials tested were a polyether-urethane (E57), a polyester-urethane (E58), an aromatic polyether-urethane (P1) and an aliphatic polyether-urethane (A1). Samples of E57 showed a decrease in hardness and elastic modulus of 21% and 28% respectively. This was much better than E58 which showed decreases of 32% and 42% respectively. Better results were achieved with A1 (hardness change 2%) and P1 (decrease in hardness of 14% and modulus 17%). When tested in a hip-function simulator, A1 showed virtually no change in its very low coefficient of friction (0.004), P1 showed an increase of 60%, while E57 and and E58 both showed a doubling in friction over the course of the study. The modes of in vitro degradation were considered and surface effects determined to be most damaging. Currently the best candidate for a compliant material in hip replacement is the aliphatic polyether-urethane which maintains fluid-film lubrication.
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Affiliation(s)
- J Blamey
- Centre for Biomedical Engineering, School of Engineering and Applied Science, University of Durham, UK
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25
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Abstract
This paper presents a review of the biomechanics of the patello-femoral joint. The evolution of sagittal plane models of the joint from that of a simple pulley is explained. The importance of other biomechanical factors, such as the Q-angle and the cartilage structure, and their relationship to chondromalacia are also discussed. A hypothesis relating to collagen fibre orientation in cartilage is presented.
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26
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Unsworth A, Pearcy MJ, White EF, White G. Frictional properties of artificial hip joints. ENGINEERING IN MEDICINE 1988; 17:101-4. [PMID: 3181586 DOI: 10.1243/emed_jour_1988_017_029_02] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A new generation of hip replacements has been designed incorporating compliant layers to promote fluid film lubrication when the joints are implanted in patients. Tests in the Durham hip function simulator show that the friction in these joints is up to an order of magnitude lower than in currently used prostheses, and because this is due to complete separation of the rubbing surfaces, wear ought to be vastly reduced. Experiments have shown that the best results are achieved with compliant surfaces of hardness between 4 and 8 N/mm2. Such surfaces produce coefficients of friction of the order of 5 × 10-3.
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27
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Grigoriadou-Koukis M. State variable approach to the function of the muscular system supporting the hip joint during normal walking. JOURNAL OF BIOMEDICAL ENGINEERING 1987; 9:88-93. [PMID: 3795910 DOI: 10.1016/0141-5425(87)90106-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In Figures 6 and 7, the results of the forces Fk and Fm are analytically represented. The signs of these forces show the direction of the corresponding moment which emanates from this force, since this sign is stable throughout the entire duration of the interval. The resultant moment, included in the equation 7 or 8, is expressed as Fkdk or Fmdm respectively. The direction of this moment is positive if F1 or F3 is operational, and negative if F2 or F4 is operational, therefore the sign attached to this force must follow the sign of the corresponding moment. The results show that this is satisfied for all values, except for those at the 65 and 75% point of the period. This is probably because the value of the corresponding moment is very small, about 0.1, and the resultant force is primarily due to the effect of the moment Mx. In this work, the flexion-extension and abduction-adduction forces, Fk, Fm respectively, were found to take their maximum and minimum values at times which are proximal to those found by Paul and other authors. On the other side there is a difference in values which fluctuates between 15 and 35% at various points; this divergence should be generally acceptable, given that it concerns models describing biological systems. These results seem to lend encouraging support to our method and suggest that the model should be reliable and effective and could be further enhanced if the time intervals were shorter but more numerous.
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28
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Ellis MI, Seedhom BB, Wright V. A comparison of knee joint and muscle forces in women 36 weeks pregnant and four weeks after delivery. ENGINEERING IN MEDICINE 1985; 14:95-9. [PMID: 4043501 DOI: 10.1243/emed_jour_1985_014_019_02] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Knee joint and muscle forces were determined for three women when they were 36 weeks pregnant and again four weeks after delivery, for the activity of rising from a seated position. The knee joint forces were determined by kinesiological techniques using a high speed cine camera, a force platform, a specially constructed dynamometerized chair, and emg recorders. A comparison of knee joint and muscle forces was made for rising from a normal chair both with and without the aid of arms for the same three women Before Childbirth (b.c.) and After Delivery (a.d.). For rising from the seated position without the aid of arms, the knee joint forces parallel to the long axis of the tibia at the point of contact between the tibia and the femur, were found to be 33 per cent greater b.c. compared to those a.d. Other knee joint and muscle forces were also dramatically increased due to pregnancy.
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29
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Ellis MI, Seedhom BB, Wright V. Forces in the knee joint whilst rising from a seated position. JOURNAL OF BIOMEDICAL ENGINEERING 1984; 6:113-20. [PMID: 6708484 DOI: 10.1016/0141-5425(84)90053-0] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Knee joint forces were determined by kinesiological techniques, using a high speed cine camera, a force platform, a specially constructed dynamometerized chair, and EMG recorders; so that a comparison could be made for rising from a normal chair with and without the aid of arms, and for rising from high and low chairs. For rising from the seated position, the knee joint forces parallel to the long axis of the tibia at the point of contact between the tibia and femur were found to be up to seven times body weight at about the time when the body left contact with the chair. When rising from a chair with the aid of arms, the knee joint forces were reduced to less than three times body weight. Knee joint and muscle forces were also reduced when rising from a high seat compared with rising from a low seat.
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30
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Wright V, Dowson D. Education in bioengineering: experience at the University of Leeds. ENGINEERING IN MEDICINE 1983; 12:151-3. [PMID: 6685069 DOI: 10.1243/emed_jour_1983_012_040_02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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31
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Chapter 3 The Lubrication of Natural Joints. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0167-8922(08)71011-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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