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Sample records for 3d knee joint

  1. Functional calibration procedure for 3D knee joint angle description using inertial sensors.

    PubMed

    Favre, J; Aissaoui, R; Jolles, B M; de Guise, J A; Aminian, K

    2009-10-16

    Measurement of three-dimensional (3D) knee joint angle outside a laboratory is of benefit in clinical examination and therapeutic treatment comparison. Although several motion capture devices exist, there is a need for an ambulatory system that could be used in routine practice. Up-to-date, inertial measurement units (IMUs) have proven to be suitable for unconstrained measurement of knee joint differential orientation. Nevertheless, this differential orientation should be converted into three reliable and clinically interpretable angles. Thus, the aim of this study was to propose a new calibration procedure adapted for the joint coordinate system (JCS), which required only IMUs data. The repeatability of the calibration procedure, as well as the errors in the measurement of 3D knee angle during gait in comparison to a reference system were assessed on eight healthy subjects. The new procedure relying on active and passive movements reported a high repeatability of the mean values (offset<1 degrees) and angular patterns (SD<0.3 degrees and CMC>0.9). In comparison to the reference system, this functional procedure showed high precision (SD<2 degrees and CC>0.75) and moderate accuracy (between 4.0 degrees and 8.1 degrees) for the three knee angle. The combination of the inertial-based system with the functional calibration procedure proposed here resulted in a promising tool for the measurement of 3D knee joint angle. Moreover, this method could be adapted to measure other complex joint, such as ankle or elbow.

  2. Development and validation of a 3-D model to predict knee joint loading during dynamic movement.

    PubMed

    McLean, S G; Su, A; van den Bogert, A J

    2003-12-01

    The purpose of this study was to develop a subject-specific 3-D model of the lower extremity to predict neuromuscular control effects on 3-D knee joint loading during movements that can potentially cause injury to the anterior cruciate ligament (ACL) in the knee. The simulation consisted of a forward dynamic 3-D musculoskeletal model of the lower extremity, scaled to represent a specific subject. Inputs of the model were the initial position and velocity of the skeletal elements, and the muscle stimulation patterns. Outputs of the model were movement and ground reaction forces, as well as resultant 3-D forces and moments acting across the knee joint. An optimization method was established to find muscle stimulation patterns that best reproduced the subject's movement and ground reaction forces during a sidestepping task. The optimized model produced movements and forces that were generally within one standard deviation of the measured subject data. Resultant knee joint loading variables extracted from the optimized model were comparable to those reported in the literature. The ability of the model to successfully predict the subject's response to altered initial conditions was quantified and found acceptable for use of the model to investigate the effect of altered neuromuscular control on knee joint loading during sidestepping. Monte Carlo simulations (N = 100,000) using randomly perturbed initial kinematic conditions, based on the subject's variability, resulted in peak anterior force, valgus torque and internal torque values of 378 N, 94 Nm and 71 Nm, respectively, large enough to cause ACL rupture. We conclude that the procedures described in this paper were successful in creating valid simulations of normal movement, and in simulating injuries that are caused by perturbed neuromuscular control.

  3. Principal component analysis in construction of 3D human knee joint models using a statistical shape model method.

    PubMed

    Tsai, Tsung-Yuan; Li, Jing-Sheng; Wang, Shaobai; Li, Pingyue; Kwon, Young-Min; Li, Guoan

    2015-01-01

    The statistical shape model (SSM) method that uses 2D images of the knee joint to predict the three-dimensional (3D) joint surface model has been reported in the literature. In this study, we constructed a SSM database using 152 human computed tomography (CT) knee joint models, including the femur, tibia and patella and analysed the characteristics of each principal component of the SSM. The surface models of two in vivo knees were predicted using the SSM and their 2D bi-plane fluoroscopic images. The predicted models were compared to their CT joint models. The differences between the predicted 3D knee joint surfaces and the CT image-based surfaces were 0.30 ± 0.81 mm, 0.34 ± 0.79 mm and 0.36 ± 0.59 mm for the femur, tibia and patella, respectively (average ± standard deviation). The computational time for each bone of the knee joint was within 30 s using a personal computer. The analysis of this study indicated that the SSM method could be a useful tool to construct 3D surface models of the knee with sub-millimeter accuracy in real time. Thus, it may have a broad application in computer-assisted knee surgeries that require 3D surface models of the knee.

  4. Robust 2D/3D registration for fast-flexion motion of the knee joint using hybrid optimization.

    PubMed

    Ohnishi, Takashi; Suzuki, Masahiko; Kobayashi, Tatsuya; Naomoto, Shinji; Sukegawa, Tomoyuki; Nawata, Atsushi; Haneishi, Hideaki

    2013-01-01

    Previously, we proposed a 2D/3D registration method that uses Powell's algorithm to obtain 3D motion of a knee joint by 3D computed-tomography and bi-plane fluoroscopic images. The 2D/3D registration is performed consecutively and automatically for each frame of the fluoroscopic images. This method starts from the optimum parameters of the previous frame for each frame except for the first one, and it searches for the next set of optimum parameters using Powell's algorithm. However, if the flexion motion of the knee joint is fast, it is likely that Powell's algorithm will provide a mismatch because the initial parameters are far from the correct ones. In this study, we applied a hybrid optimization algorithm (HPS) combining Powell's algorithm with the Nelder-Mead simplex (NM-simplex) algorithm to overcome this problem. The performance of the HPS was compared with the separate performances of Powell's algorithm and the NM-simplex algorithm, the Quasi-Newton algorithm and hybrid optimization algorithm with the Quasi-Newton and NM-simplex algorithms with five patient data sets in terms of the root-mean-square error (RMSE), target registration error (TRE), success rate, and processing time. The RMSE, TRE, and the success rate of the HPS were better than those of the other optimization algorithms, and the processing time was similar to that of Powell's algorithm alone.

  5. Estimation of three-dimensional knee joint movement using bi-plane x-ray fluoroscopy and 3D-CT

    NASA Astrophysics Data System (ADS)

    Haneishi, Hideaki; Fujita, Satoshi; Kohno, Takahiro; Suzuki, Masahiko; Miyagi, Jin; Moriya, Hideshige

    2005-04-01

    Acquisition of exact information of three-dimensional knee joint movement is desired in plastic surgery. Conventional X-ray fluoroscopy provides dynamic but just two-dimensional projected image. On the other hand, three-dimensional CT provides three-dimensional but just static image. In this paper, a method for acquiring three-dimensional knee joint movement using both bi-plane, dynamic X-ray fluoroscopy and static three-dimensional CT is proposed. Basic idea is use of 2D/3D registration using digitally reconstructed radiograph (DRR) or virtual projection of CT data. Original ideal is not new but the application of bi-plane fluoroscopy to natural bones of knee is reported for the first time. The technique was applied to two volunteers and successful results were obtained. Accuracy evaluation through computer simulation and phantom experiment with a knee joint of a pig were also conducted.

  6. Hip and knee joints are more stabilized than driven during the stance phase of gait: an analysis of the 3D angle between joint moment and joint angular velocity.

    PubMed

    Dumas, R; Cheze, L

    2008-08-01

    Joint power is commonly used in orthopaedics, ergonomics or sports analysis but its clinical interpretation remains controversial. Some basic principles on muscle actions and energy transfer have been proposed in 2D. The decomposition of power on 3 axes, although questionable, allows the same analysis in 3D. However, these basic principles have been widely criticized, mainly because bi-articular muscles must be considered. This requires a more complex computation in order to determine how the individual muscle force contributes to drive the joint. Conversely, with simple 3D inverse dynamics, the analysis of both joint moment and angular velocity directions is essential to clarify when the joint moment can contribute or not to drive the joint. The present study evaluates the 3D angle between the joint moment and the joint angular velocity and investigates when the hip, knee and ankle joints are predominantly driven (angle close to 0 degrees and 180 degrees ) or stabilized (angle close to 90 degrees ) during gait. The 3D angle curves show that the three joints are never fully but only partially driven and that the hip and knee joints are mainly stabilized during the stance phase. The notion of stabilization should be further investigated, especially for subjects with motion disorders or prostheses.

  7. Gender Dimorphic ACL Strain In Response to Combined Dynamic 3D Knee Joint Loading: Implications for ACL Injury Risk

    PubMed Central

    Mizuno, Kiyonori; Andrish, Jack T.; van den Bogert, Antonie J.; McLean, Scott G.

    2009-01-01

    While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (~10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as a function of the combined 6 DOF knee loads. Following individual model verifications, generalized gender-specific models were generated and subjected to 6 DOF external load scenarios consistent with both a clinical examination and a dynamic sports maneuver. The ensuing model-based strain predictions were subsequently examined for gender-based discrepancies. Male and female specimen specific models predicted ACL strain within 0.51% ± 0.10% and 0.52% ± 0.07% of the measured data respectively, and explained more than 75% of the associated variance in each case. Predicted female ACL strains were also significantly larger than respective male values for both of simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities. PMID:19464897

  8. Correlation between 3D microstructural and 2D histomorphometric properties of subchondral bone with healthy and degenerative cartilage of the knee joint.

    PubMed

    Lahm, Andreas; Kasch, Richard; Spank, Heiko; Erggelet, Christoph; Esser, Jan; Merk, Harry; Mrosek, Eike

    2014-11-01

    Cartilage degeneration of the knee joint is considered to be a largely mechanically driven process. We conducted a microstructural and histomorphometric analysis of subchondral bone samples of intact cartilage and in samples with early and higher- grade arthritic degeneration to compare the different states and correlate the findings with the condition of hyaline cartilage. These findings will enable us to evaluate changes in biomechanical properties of subchondral bone during the evolution of arthritic degeneration, for which bone density alone is an insufficient parameter. From a continuous series of 80 patients undergoing implantation of total knee endoprosthesis 30 osteochondral samples with lesions macroscopically classified as ICRS grade 1b (group A) and 30 samples with ICRS grade 3a or 3b lesions (group B) were taken. The bone samples were assessed by 2D histomorphometry (semiautomatic image analysis system) and 3D microstructural analysis (high-resolution micro-CT system). The cartilage was examined using the semiquantitative real-time PCR gene expression of collagen type I and II and aggrecan. Both histomorphometry and microstructural and biomechanical analysis of subchondral bone in groups A and B consistently revealed progressive changes of both bone and cartilage compared with healthy controls. The severity of cartilage degeneration as assessed by RT PCR was significantly correlated with BV/TV (Bone Volume Fraction), Tb.Th (Trabecular Thickness) showed a slight increase. Tb.N (Trabecular Number), Tb.Sp (Trabecular separation) SMI (Structure Model Index), Conn.D (Connectivity Density) and DA (Degree of Anisotropy) were inversely correlated. We saw sclerotic transformation and phagocytic reticulum cells. Bone volume fraction decreased with an increasing distance from the cartilage with the differences compared with healthy controls becoming greater in more advanced cartilage damage. The density of subchondral bone alone is considered an unreliable

  9. Correlation between 3D microstructural and 2D histomorphometric properties of subchondral bone with healthy and degenerative cartilage of the knee joint.

    PubMed

    Lahm, Andreas; Kasch, Richard; Spank, Heiko; Erggelet, Christoph; Esser, Jan; Merk, Harry; Mrosek, Eike

    2014-11-01

    Cartilage degeneration of the knee joint is considered to be a largely mechanically driven process. We conducted a microstructural and histomorphometric analysis of subchondral bone samples of intact cartilage and in samples with early and higher- grade arthritic degeneration to compare the different states and correlate the findings with the condition of hyaline cartilage. These findings will enable us to evaluate changes in biomechanical properties of subchondral bone during the evolution of arthritic degeneration, for which bone density alone is an insufficient parameter. From a continuous series of 80 patients undergoing implantation of total knee endoprosthesis 30 osteochondral samples with lesions macroscopically classified as ICRS grade 1b (group A) and 30 samples with ICRS grade 3a or 3b lesions (group B) were taken. The bone samples were assessed by 2D histomorphometry (semiautomatic image analysis system) and 3D microstructural analysis (high-resolution micro-CT system). The cartilage was examined using the semiquantitative real-time PCR gene expression of collagen type I and II and aggrecan. Both histomorphometry and microstructural and biomechanical analysis of subchondral bone in groups A and B consistently revealed progressive changes of both bone and cartilage compared with healthy controls. The severity of cartilage degeneration as assessed by RT PCR was significantly correlated with BV/TV (Bone Volume Fraction), Tb.Th (Trabecular Thickness) showed a slight increase. Tb.N (Trabecular Number), Tb.Sp (Trabecular separation) SMI (Structure Model Index), Conn.D (Connectivity Density) and DA (Degree of Anisotropy) were inversely correlated. We saw sclerotic transformation and phagocytic reticulum cells. Bone volume fraction decreased with an increasing distance from the cartilage with the differences compared with healthy controls becoming greater in more advanced cartilage damage. The density of subchondral bone alone is considered an unreliable

  10. Knee joint replacement

    MedlinePlus

    ... is used to attach this part. Repair your muscles and tendons around the new joint and close the surgical cut. The surgery takes about 2 hours. Most artificial knees have both metal and plastic parts. Some ...

  11. 3D visual presentation of shoulder joint motion.

    PubMed

    Totterman, S; Tamez-Pena, J; Kwok, E; Strang, J; Smith, J; Rubens, D; Parker, K

    1998-01-01

    The 3D visual presentation of biodynamic events of human joints is a challenging task. Although the 3D reconstruction of high contrast structures from CT data has been widely explored, then there is much less experience in reconstructing the small low contrast soft tissue structures from inhomogeneous and sometimes noisy MR data. Further, there are no algorithms for tracking the motion of moving anatomic structures through MR data. We represent a comprehensive approach to 3D musculoskeletal imagery that addresses these challenges. Specific imaging protocols, segmentation algorithms and rendering techniques are developed and applied to render complex 3D musculoskeletal systems for their 4D visual presentation. Applications of our approach include analysis of rotational motion of the shoulder, the knee flexion, and other complex musculoskeletal motions, and the development of interactive virtual human joints.

  12. Computational Poromechanics of Human Knee Joint

    NASA Astrophysics Data System (ADS)

    Kazemi, Mojtaba; Li, LePing

    2012-02-01

    Extensive computer modeling has been performed in the recent decade to investigate the mechanical response of the healthy and repaired knee joints. Articular cartilages and menisci have been commonly modeled as single-phase elastic materials in the previous 3D simulations. A comprehensive study considering the interplay of the collagen fibers and fluid pressurization in the tissues in situ remains challenging. We have developed a 3D model of the human knee accounting for the mechanical function of collagen fibers and fluid flow in the cartilages and menisci. An anatomically accurate structure of the human knee was used for this purpose including bones, articular cartilages, menisci and ligaments. The fluid pressurization in the femoral cartilage and menisci under combined creep loading was investigated. Numerical results showed that fluid flow and pressure in the tissues played an important role in the mechanical response of the knee joint. The load transfer in the joint was clearly seen when the fluid pressure was considered.

  13. Effects of radial tears and partial meniscectomy of lateral meniscus on the knee joint mechanics during the stance phase of the gait cycle--A 3D finite element study.

    PubMed

    Mononen, Mika E; Jurvelin, Jukka S; Korhonen, Rami K

    2013-08-01

    The purpose of the current study was to evaluate influences of radial tears and partial meniscectomy of lateral meniscus on the knee joint mechanics during normal walking by using computational modeling. A 3D geometry of a knee joint of a healthy patient was obtained from our previous study, whereas the data of normal walking were taken from the literature. Cartilage tissue was modeled as a fibril reinforced poroviscoelastic material, whereas meniscal tissue was modeled as a transverse isotropic elastic material. The realistic gait cycle data were implemented into the computational model and the effects of radial tears and partial meniscectemy of lateral meniscus on the knee joint mechanics were simulated. Middle, posterior, and anterior radial tears in lateral meniscus increased stresses by 300%, 430%, and 1530%, respectively, at the ends of tears compared to corresponding areas in the model with intact lateral meniscus. Meniscus tears did not alter stresses and strains at the tibial cartilage surface, whereas partial meniscectomy increased contact pressures, stresses, strains and pore pressures in the tibial cartilage by 50%, 44%, 21%, and 43%, respectively. Increased stresses and strains were observed primarily during the first ∼50% of the stance phase of the gait cycle. The present study suggests that anterior radial tear causes the highest risk for the development of total meniscal rupture, whereas partial meniscectomy increases the risk for the development of OA in lateral tibial cartilage. Highest risks for meniscus and cartilage failures are suggested to occur during the loading response and mid-stance of the gait cycle. In the future, the present modeling may be further developed to offer a clinical tool for aid in decision making of clinical interventions for patients with knee joint injuries.

  14. Exercise and the Knee Joint.

    ERIC Educational Resources Information Center

    Clarke, H. Harrison, Ed.

    1976-01-01

    This report by the President's Council on Physical Fitness and Sports examines the effects of various forms of physical exercise on the knee joint which, because of its vulnerability, is especially subject to injury. Discussion centers around the physical characteristics of the joint, commonly used measurements for determining knee stability,…

  15. Spacesuit mobility knee joints

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C. (Inventor)

    1979-01-01

    Pressure suit mobility joints are for use in interconnecting adjacent segments of an hermetically sealed spacesuit in which low torques, low leakage and a high degree of reliability are required. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics and includes linkages which restrain the joint from longitudinal distension and includes a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

  16. 3D joint dynamics analysis of healthy children's gait.

    PubMed

    Samson, William; Desroches, Guillaume; Cheze, Laurence; Dumas, Raphaël

    2009-11-13

    The 3D joint moments and 2D joint powers have been largely explored in the literature of healthy children's gait, in particular to compare them with pathologic subjects' gait. However, no study reported on 3D joint power in children which could be due to the difficulties in interpreting the results. Recently, the analysis of the 3D angle between the joint moment and the joint angular velocity vectors has been proposed in order to help 3D joint power interpretation. Our hypothesis is that this 3D angle may help in characterizing the level of gait maturation. The present study explores 3D joint moments, 3D joint power and the proposed 3D angle for both children's and adults' gaits to highlight differences in the strategies used. The results seem to confirm that children have an alternative strategy of mainly ankle stabilization and hip propulsion compared to the adults' strategy of mainly ankle resistance and propulsion and hip stabilization. In the future, the same 3D angle analysis should be applied to different age groups for better describing the evolution of the 3D joint dynamic strategies during the growth.

  17. Rothia prosthetic knee joint infection.

    PubMed

    Trivedi, Manish N; Malhotra, Prashant

    2015-08-01

    Rothia species - Gram-positive pleomorphic bacteria that are part of the normal oral and respiratory flora - are commonly associated with dental cavities and periodontal disease although systemic infections have been described. We describe a 53-year-old female with rheumatoid arthritis complicated by prosthetic knee joint infection due to Rothia species, which was successfully treated by surgical removal of prosthesis and prolonged antimicrobial therapy. The issue of antibiotic prophylaxis before dental procedures among patients with prosthetic joint replacements is discussed.

  18. Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1994-01-01

    Proposed orthotic knee joint locks and unlocks automatically, at any position within range of bend angles, without manual intervention by wearer. Includes tang and clevis, locks whenever wearer transfers weight to knee and unlocks when weight removed. Locking occurs at any angle between 45 degrees knee bend and full extension.

  19. Automatic locking knee brace joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce (Inventor)

    1995-01-01

    This invention is an apparatus for controlling the pivotal movement of a knee brace comprising a tang-and-clevis joint that has been uniquely modified. Both the tang and the clevis have a set of teeth that, when engaged, can lock the tang and the clevis together. In addition, the tang is biased away from the clevis. Consequently, when there is no axial force (i.e., body weight) on the tang, the tang is free to pivot within the clevis. However, when an axial force is exerted on the tang, the tang is pushed into the clevis, both sets of teeth engage, and the tang and the clevis lock together.

  20. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  1. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  2. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  3. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  4. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  5. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  6. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  7. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  8. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  9. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  10. Characterization of 3D joint space morphology using an electrostatic model (with application to osteoarthritis)

    NASA Astrophysics Data System (ADS)

    Cao, Qian; Thawait, Gaurav; Gang, Grace J.; Zbijewski, Wojciech; Reigel, Thomas; Brown, Tyler; Corner, Brian; Demehri, Shadpour; Siewerdsen, Jeffrey H.

    2015-02-01

    Joint space morphology can be indicative of the risk, presence, progression, and/or treatment response of disease or trauma. We describe a novel methodology of characterizing joint space morphology in high-resolution 3D images (e.g. cone-beam CT (CBCT)) using a model based on elementary electrostatics that overcomes a variety of basic limitations of existing 2D and 3D methods. The method models each surface of a joint as a conductor at fixed electrostatic potential and characterizes the intra-articular space in terms of the electric field lines resulting from the solution of Gauss’ Law and the Laplace equation. As a test case, the method was applied to discrimination of healthy and osteoarthritic subjects (N = 39) in 3D images of the knee acquired on an extremity CBCT system. The method demonstrated improved diagnostic performance (area under the receiver operating characteristic curve, AUC > 0.98) compared to simpler methods of quantitative measurement and qualitative image-based assessment by three expert musculoskeletal radiologists (AUC = 0.87, p-value = 0.007). The method is applicable to simple (e.g. the knee or elbow) or multi-axial joints (e.g. the wrist or ankle) and may provide a useful means of quantitatively assessing a variety of joint pathologies.

  11. Characterization of 3D Joint Space Morphology Using an Electrostatic Model (with Application to Osteoarthritis)

    PubMed Central

    Cao, Qian; Thawait, Gaurav; Gang, Grace J.; Zbijewski, Wojciech; Reigel, Thomas; Brown, Tyler; Corner, Brian; Demehri, Shadpour; Siewerdsen, Jeffrey H.

    2015-01-01

    Joint space morphology can be indicative of the risk, presence, progression, and/or treatment response of disease or trauma. We describe a novel methodology of characterizing joint space morphology in high-resolution 3D images [e.g., cone-beam CT (CBCT)] using a model based on elementary electrostatics that overcomes a variety of basic limitations of existing 2D and 3D methods. The method models each surface of a joint as a conductor at fixed electrostatic potential and characterizes the intra-articular space in terms of the electric field lines resulting from the solution of Gauss’ Law and the Laplace equation. As a test case, the method was applied to discrimination of healthy and osteoarthritic subjects (N = 39) in 3D images of the knee acquired on an extremity CBCT system. The method demonstrated improved diagnostic performance (area under the receiver operating characteristic curve, AUC > 0.98) compared to simpler methods of quantitative measurement and qualitative image-based assessment by three expert musculoskeletal radiologists (AUC = 0.87, p-value = 0.007). The method is applicable to simple (e.g., the knee or elbow) or multi-axial joints (e.g., the wrist or ankle) and may provide a useful means of quantitatively assessing a variety of joint pathologies. PMID:25575100

  12. 3D MRI volume sizing of knee meniscus cartilage.

    PubMed

    Stone, K R; Stoller, D W; Irving, S G; Elmquist, C; Gildengorin, G

    1994-12-01

    Meniscal replacement by allograft and meniscal regeneration through collagen meniscal scaffolds have been recently reported. To evaluate the effectiveness of a replaced or regrown meniscal cartilage, a method for measuring the size and function of the regenerated tissue in vivo is required. To solve this problem, we developed and evaluated a magnetic resonance imaging (MRI) technique to measure the volume of meniscal tissues. Twenty-one intact fresh cadaver knees were evaluated and scanned with MRI for meniscal volume sizing. The sizing sequence was repeated six times for each of 21 lateral and 12 medial menisci. The menisci were then excised and measured by water volume displacement. Each volume displacement measurement was repeated six times. The MRI technique employed to measure the volume of the menisci was shown to correspond to that of the standard measure of volume and was just as precise. However, the MRI technique consistently underestimated the actual volume. The average of the coefficient of variation for lateral volumes was 0.04 and 0.05 for the water and the MRI measurements, respectively. For medial measurements it was 0.04 and 0.06. The correlation for the lateral menisci was r = 0.45 (p = 0.04) and for the medial menisci it was r = 0.57 (p = 0.05). We conclude that 3D MRI is precise and repeatable but not accurate when used to measure meniscal volume in vivo and therefore may only be useful for evaluating changes in meniscal allografts and meniscal regeneration templates over time.

  13. Cryotherapy impairs knee joint position sense.

    PubMed

    Oliveira, R; Ribeiro, F; Oliveira, J

    2010-03-01

    The effects of cryotherapy on joint position sense are not clearly established; however it is paramount to understand its impact on peripheral feedback to ascertain the safety of using ice therapy before resuming exercise on sports or rehabilitation settings. Thus, the aim of the present study was to determine the effects of cryotherapy, when applied over the quadriceps and over the knee joint, on knee position sense. This within-subjects repeated-measures study encompassed fifteen subjects. Knee position sense was measured by open kinetic chain technique and active positioning at baseline and after cryotherapy application. Knee angles were determined by computer analysis of the videotape images. Twenty-minute ice bag application was applied randomly, in two sessions 48 h apart, over the quadriceps and the knee joint. The main effect for cryotherapy application was significant (F (1.14)=7.7, p=0.015) indicating an increase in both absolute and relative angular errors after the application. There was no significant main effect for the location of cryotherapy application, indicating no differences between the application over the quadriceps and the knee joint. In conclusion, cryotherapy impairs knee joint position sense in normal knees. This deleterious effect is similar when cryotherapy is applied over the quadriceps or the knee joint.

  14. Cryotherapy impairs knee joint position sense.

    PubMed

    Oliveira, R; Ribeiro, F; Oliveira, J

    2010-03-01

    The effects of cryotherapy on joint position sense are not clearly established; however it is paramount to understand its impact on peripheral feedback to ascertain the safety of using ice therapy before resuming exercise on sports or rehabilitation settings. Thus, the aim of the present study was to determine the effects of cryotherapy, when applied over the quadriceps and over the knee joint, on knee position sense. This within-subjects repeated-measures study encompassed fifteen subjects. Knee position sense was measured by open kinetic chain technique and active positioning at baseline and after cryotherapy application. Knee angles were determined by computer analysis of the videotape images. Twenty-minute ice bag application was applied randomly, in two sessions 48 h apart, over the quadriceps and the knee joint. The main effect for cryotherapy application was significant (F (1.14)=7.7, p=0.015) indicating an increase in both absolute and relative angular errors after the application. There was no significant main effect for the location of cryotherapy application, indicating no differences between the application over the quadriceps and the knee joint. In conclusion, cryotherapy impairs knee joint position sense in normal knees. This deleterious effect is similar when cryotherapy is applied over the quadriceps or the knee joint. PMID:20221997

  15. Parametric modelling of a knee joint prosthesis.

    PubMed

    Khoo, L P; Goh, J C; Chow, S L

    1993-01-01

    This paper presents an approach for the establishment of a parametric model of knee joint prosthesis. Four different sizes of a commercial prosthesis are used as an example in the study. A reverse engineering technique was employed to reconstruct the prosthesis on CATIA, a CAD (computer aided design) system. Parametric models were established as a result of the analysis. Using the parametric model established and the knee data obtained from a clinical study on 21 pairs of cadaveric Asian knees, the development of a prototype prosthesis that suits a patient with a very small knee joint is presented. However, it was found that modification to certain parameters may be inevitable due to the uniqueness of the Asian knee. An avenue for rapid modelling and eventually economical production of a customized knee joint prosthesis for patients is proposed and discussed.

  16. Knee joint forces: prediction, measurement, and significance

    PubMed Central

    D’Lima, Darryl D.; Fregly, Benjamin J.; Patil, Shantanu; Steklov, Nikolai; Colwell, Clifford W.

    2011-01-01

    Knee forces are highly significant in osteoarthritis and in the survival and function of knee arthroplasty. A large number of studies have attempted to estimate forces around the knee during various activities. Several approaches have been used to relate knee kinematics and external forces to internal joint contact forces, the most popular being inverse dynamics, forward dynamics, and static body analyses. Knee forces have also been measured in vivo after knee arthroplasty, which serves as valuable validation of computational predictions. This review summarizes the results of published studies that measured knee forces for various activities. The efficacy of various methods to alter knee force distribution, such as gait modification, orthotics, walking aids, and custom treadmills are analyzed. Current gaps in our knowledge are identified and directions for future research in this area are outlined. PMID:22468461

  17. Alterations in walking knee joint stiffness in individuals with knee osteoarthritis and self-reported knee instability.

    PubMed

    Gustafson, Jonathan A; Gorman, Shannon; Fitzgerald, G Kelley; Farrokhi, Shawn

    2016-01-01

    Increased walking knee joint stiffness has been reported in patients with knee osteoarthritis (OA) as a compensatory strategy to improve knee joint stability. However, presence of episodic self-reported knee instability in a large subgroup of patients with knee OA may be a sign of inadequate walking knee joint stiffness. The objective of this work was to evaluate the differences in walking knee joint stiffness in patients with knee OA with and without self-reported instability and examine the relationship between walking knee joint stiffness with quadriceps strength, knee joint laxity, and varus knee malalignment. Overground biomechanical data at a self-selected gait velocity was collected for 35 individuals with knee OA without self-reported instability (stable group) and 17 individuals with knee OA and episodic self-reported instability (unstable group). Knee joint stiffness was calculated during the weight-acceptance phase of gait as the change in the external knee joint moment divided by the change in the knee flexion angle. The unstable group walked with lower knee joint stiffness (p=0.01), mainly due to smaller heel-contact knee flexion angles (p<0.01) and greater knee flexion excursions (p<0.01) compared to their knee stable counterparts. No significant relationships were observed between walking knee joint stiffness and quadriceps strength, knee joint laxity or varus knee malalignment. Reduced walking knee joint stiffness appears to be associated with episodic knee instability and independent of quadriceps muscle weakness, knee joint laxity or varus malalignment. Further investigations of the temporal relationship between self-reported knee joint instability and walking knee joint stiffness are warranted.

  18. The effect of foot progression angle on knee joint compression force during walking.

    PubMed

    Koblauch, Henrik; Heilskov-Hansen, Thomas; Alkjær, Tine; Simonsen, Erik B; Henriksen, Marius

    2013-06-01

    It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study was to investigate the knee joint compressive forces during walking with internal, external and normal foot rotation and to determine if the frontal plane knee joint moment is an adequate surrogate for the compression forces in the medial and lateral knee joint compartments under such gait modifications. Ten healthy males walked at a fixed speed of 4.5 km/h under three conditions: Normal walking, internally rotated and externally rotated. All gait trials were recorded by six infrared cameras. Net joint moments were calculated by 3D inverse dynamics. The results revealed that the medial knee joint compartment compression force increased during external foot rotation and the lateral knee joint compartment compression force increased during internal foot rotation. The increases in joint loads may be a result of increased knee flexion angles. Further, these data suggest that the frontal plane knee joint moment is not a valid surrogate measure for knee joint compression forces but rather indicates the medial- to-lateral load distribution.

  19. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  20. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  1. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  2. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  3. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  4. Biomechanics of knee joint — A review

    NASA Astrophysics Data System (ADS)

    Madeti, Bhaskar Kumar; Chalamalasetti, Srinivasa Rao; Bolla Pragada, S. K. Sundara siva rao

    2015-06-01

    The present paper is to know how the work is carried out in the field of biomechanics of knee. Various model formulations are discussed and further classified into mathematical model, two-dimensional model and three-dimensional model. Knee geometry is a crucial part of human body movement, in which how various views of knee is shown in different planes and how the forces act on tibia and femur are studied. It leads to know the forces acting on the knee joint. Experimental studies of knee geometry and forces acting on knee shown by various researchers have been discussed, and comparisons of results are made. In addition, static and dynamic analysis of knee has been also discussed respectively to some extent.

  5. Action and gait recognition from recovered 3-D human joints.

    PubMed

    Gu, Junxia; Ding, Xiaoqing; Wang, Shengjin; Wu, Youshou

    2010-08-01

    A common viewpoint-free framework that fuses pose recovery and classification for action and gait recognition is presented in this paper. First, a markerless pose recovery method is adopted to automatically capture the 3-D human joint and pose parameter sequences from volume data. Second, multiple configuration features (combination of joints) and movement features (position, orientation, and height of the body) are extracted from the recovered 3-D human joint and pose parameter sequences. A hidden Markov model (HMM) and an exemplar-based HMM are then used to model the movement features and configuration features, respectively. Finally, actions are classified by a hierarchical classifier that fuses the movement features and the configuration features, and persons are recognized from their gait sequences with the configuration features. The effectiveness of the proposed approach is demonstrated with experiments on the Institut National de Recherche en Informatique et Automatique Xmas Motion Acquisition Sequences data set.

  6. Determination of representative dimension parameter values of Korean knee joints for knee joint implant design.

    PubMed

    Kwak, Dai Soon; Tao, Quang Bang; Todo, Mitsugu; Jeon, Insu

    2012-05-01

    Knee joint implants developed by western companies have been imported to Korea and used for Korean patients. However, many clinical problems occur in knee joints of Korean patients after total knee joint replacement owing to the geometric mismatch between the western implants and Korean knee joint structures. To solve these problems, a method to determine the representative dimension parameter values of Korean knee joints is introduced to aid in the design of knee joint implants appropriate for Korean patients. Measurements of the dimension parameters of 88 male Korean knee joint subjects were carried out. The distribution of the subjects versus each measured parameter value was investigated. The measured dimension parameter values of each parameter were grouped by suitable intervals called the "size group," and average values of the size groups were calculated. The knee joint subjects were grouped as the "patient group" based on "size group numbers" of each parameter. From the iterative calculations to decrease the errors between the average dimension parameter values of each "patient group" and the dimension parameter values of the subjects, the average dimension parameter values that give less than the error criterion were determined to be the representative dimension parameter values for designing knee joint implants for Korean patients.

  7. Motion analysis of knee joint using dynamic volume images

    NASA Astrophysics Data System (ADS)

    Haneishi, Hideaki; Kohno, Takahiro; Suzuki, Masahiko; Moriya, Hideshige; Mori, Sin-ichiro; Endo, Masahiro

    2006-03-01

    Acquisition and analysis of three-dimensional movement of knee joint is desired in orthopedic surgery. We have developed two methods to obtain dynamic volume images of knee joint. One is a 2D/3D registration method combining a bi-plane dynamic X-ray fluoroscopy and a static three-dimensional CT, the other is a method using so-called 4D-CT that uses a cone-beam and a wide 2D detector. In this paper, we present two analyses of knee joint movement obtained by these methods: (1) transition of the nearest points between femur and tibia (2) principal component analysis (PCA) of six parameters representing the three dimensional movement of knee. As a preprocessing for the analysis, at first the femur and tibia regions are extracted from volume data at each time frame and then the registration of the tibia between different frames by an affine transformation consisting of rotation and translation are performed. The same transformation is applied femur as well. Using those image data, the movement of femur relative to tibia can be analyzed. Six movement parameters of femur consisting of three translation parameters and three rotation parameters are obtained from those images. In the analysis (1), axis of each bone is first found and then the flexion angle of the knee joint is calculated. For each flexion angle, the minimum distance between femur and tibia and the location giving the minimum distance are found in both lateral condyle and medial condyle. As a result, it was observed that the movement of lateral condyle is larger than medial condyle. In the analysis (2), it was found that the movement of the knee can be represented by the first three principal components with precision of 99.58% and those three components seem to strongly relate to three major movements of femur in the knee bend known in orthopedic surgery.

  8. [Biomechanics of the knee joint].

    PubMed

    Witzel, U

    1993-01-01

    The capsular and ligamentous structures as control system of a healthy knee-joint supported by the muscular system are responsible for the rolling and gliding motion of the femoral condyles on the tibial plateau. Both the condyles and the tibial plateau have individually developed but to each other adjusted shapes and fine structures thereby. These structures consist of hyaline cartilage at their three-dimensional surfaces and of closely packed fibrils (lamina splendens) as the final gliding zone for tensile load. The orientation of the collagenous fibres can be made visible by split lines. The chondral surfaces are indirectly in contact to each other and orthogonally stressed at the particular point of contact. The indirect contact of the cartilaginous surfaces happens under interposition of the menisci. The meniscus serves to reduce and equalize the surface pressure by its own projected surface on the one hand and by maintaining of a hydraulic pressure of the synovial fluid on the other hand. Deviations of the condylar position as a result on ligamentous instabilities or ruptures with a following occurring loss of congruence, meniscal lesions or traumatic ruptures lead to a rapid discharge of the synovial fluid under load. The result is a hydraulic head loss with direct contact of the chondral surfaces under stress leading to arthrotic deformations. Severe arthrotic deformations or very much every meniscectomy produce intraarticular lumped loads resulting in a hyper-physiologic chondral pressure and malnutrition thereby. Further on there develop subchondral stress concentrations (caused by the lumped loads) leading to osseous damages, too. MR-pictures can make visible these damages. Chondromalacia, fissure or even chondrolysis are arthroscopically detectable sometimes. As after-effects of deficient knee ligaments occur pathological deviations of the femoral condyles and resulting destructions of the articular surfaces under stress enormously intensified by

  9. Effect of soccer shoe cleats on knee joint loads.

    PubMed

    Gehring, D; Rott, F; Stapelfeldt, B; Gollhofer, A

    2007-12-01

    Noncontact injuries frequently occur during soccer matches and training. The purpose of this study was to examine the influences of different soccer shoe studs to kinematic, kinetic and electromyographic parameters in the knee joint. Six male soccer players performed complex turning movements (180 degrees ) with bladed and round studded soccer shoes. Ground reaction forces, 3-D kinematics and electromyographic activity of the lower leg muscles were recorded. Calculated external knee joint moments were similar with both stud configurations, although there was a trend towards increased vertical and anterior-posterior ground reaction forces with blades. Electromyography evidenced significantly higher activation of m. quadriceps femoris (p = 0.02) with round studs during initial phase of stance. In conclusion, comparison of soccer shoes with round and bladed studs showed no significant differences in externally applied knee joint loads during a complex injury related movement. The significant increased activation of m. quadriceps femoris with round studs during the critical weight acceptance can be associated with an additional internal load on the anterior cruciate ligament. Therefore, results revealed no higher risk of getting noncontact knee joint injuries with bladed soccer shoes. PMID:17455123

  10. Mobile Biplane X-Ray Imaging System for Measuring 3D Dynamic Joint Motion During Overground Gait.

    PubMed

    Guan, Shanyuanye; Gray, Hans A; Keynejad, Farzad; Pandy, Marcus G

    2016-01-01

    Most X-ray fluoroscopy systems are stationary and impose restrictions on the measurement of dynamic joint motion; for example, knee-joint kinematics during gait is usually measured with the subject ambulating on a treadmill. We developed a computer-controlled, mobile, biplane, X-ray fluoroscopy system to track human body movement for high-speed imaging of 3D joint motion during overground gait. A robotic gantry mechanism translates the two X-ray units alongside the subject, tracking and imaging the joint of interest as the subject moves. The main aim of the present study was to determine the accuracy with which the mobile imaging system measures 3D knee-joint kinematics during walking. In vitro experiments were performed to measure the relative positions of the tibia and femur in an intact human cadaver knee and of the tibial and femoral components of a total knee arthroplasty (TKA) implant during simulated overground gait. Accuracy was determined by calculating mean, standard deviation and root-mean-squared errors from differences between kinematic measurements obtained using volumetric models of the bones and TKA components and reference measurements obtained from metal beads embedded in the bones. Measurement accuracy was enhanced by the ability to track and image the joint concurrently. Maximum root-mean-squared errors were 0.33 mm and 0.65° for translations and rotations of the TKA knee and 0.78 mm and 0.77° for translations and rotations of the intact knee, which are comparable to results reported for treadmill walking using stationary biplane systems. System capability for in vivo joint motion measurement was also demonstrated for overground gait.

  11. Improved Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1995-01-01

    Proposed orthotic knee joint improved version of one described in "Automatically Locking/Unlocking Orthotic Knee Joint" (MFS-28633). Locks automatically upon initial application of radial force (wearer's weight) and unlocks automatically, but only when all loads (radial force and bending) relieved. Joints lock whenever wearer applies weight to knee at any joint angle between full extension and 45 degree bend. Both devices offer increased safety and convenience relative to conventional orthotic knee joints.

  12. Uncertainty of knee joint muscle activity during knee joint torque exertion: the significance of controlling adjacent joint torque.

    PubMed

    Nozaki, Daichi; Nakazawa, Kimitaka; Akai, Masami

    2005-09-01

    In the single-joint torque exertion task, which has been widely used to control muscle activity, only the relevant joint torque is specified. However, the neglect of the neighboring joint could make the procedure unreliable, considering our previous result that even monoarticular muscle activity level is indefinite without specifying the adjacent joint torque. Here we examined the amount of hip joint torque generated with knee joint torque and its influence on the activity of the knee joint muscles. Twelve healthy subjects were requested to exert various levels of isometric knee joint torque. The knee and hip joint torques were obtained by using a custom-made device. Because no information about hip joint torque was provided to the subjects, the hip joint torque measured here was a secondary one associated with the task. The amount of hip joint torque varied among subjects, indicating that they adopted various strategies to achieve the task. In some subjects, there was a considerable internal variability in the hip joint torque. Such variability was not negligible, because the knee joint muscle activity level with respect to the knee joint torque, as quantified by surface electromyography (EMG), changed significantly when the subjects were requested to change the strategy. This change occurred in a very systematic manner: in the case of the knee extension, as the hip flexion torque was larger, the activity of mono- and biarticular knee extensors decreased and increased, respectively. These results indicate that the conventional single knee joint torque exertion has the drawback that the intersubject and/or intertrial variability is inevitable in the relative contribution among mono- and biarticular muscles because of the uncertainty of the hip joint torque. We discuss that the viewpoint that both joint torques need to be considered will bring insights into various controversial problems such as the shape of the EMG-force relationship, neural factors that help

  13. Joint 3d Estimation of Vehicles and Scene Flow

    NASA Astrophysics Data System (ADS)

    Menze, M.; Heipke, C.; Geiger, A.

    2015-08-01

    driving. While much progress has been made in recent years, imaging conditions in natural outdoor environments are still very challenging for current reconstruction and recognition methods. In this paper, we propose a novel unified approach which reasons jointly about 3D scene flow as well as the pose, shape and motion of vehicles in the scene. Towards this goal, we incorporate a deformable CAD model into a slanted-plane conditional random field for scene flow estimation and enforce shape consistency between the rendered 3D models and the parameters of all superpixels in the image. The association of superpixels to objects is established by an index variable which implicitly enables model selection. We evaluate our approach on the challenging KITTI scene flow dataset in terms of object and scene flow estimation. Our results provide a prove of concept and demonstrate the usefulness of our method.

  14. Observer variation in examination of knee joints.

    PubMed

    Marks, J S; Palmer, M K; Burke, M J; Smith, P

    1978-08-01

    The knees of 20 patients with rheumatoid arthritis were each examined on two occasions on the same morning by three observers. Assessments were made of joint warmth, synovial thickening, effusion, instability, quadriceps power, bony enlargement, range of movement, and knee circumference, and were graded on a scale of 0-4. Analysis of the results shows close intraobserver agreement for all measurements but considerable interobserver variation for all subjective measurements.

  15. Knee joint arthroplasty after tibial osteotomy

    PubMed Central

    Fosco, Matteo; Cenni, Elisabetta; Tigani, Domenico

    2009-01-01

    A total of 29 consecutive knee joint arthroplasties in 24 patients who underwent previous high tibial osteotomy (HTO) for medial unicompartment osteoarthritis of the knee and followed up for a mean of 97 months were compared with a control group of 28 patients with 29 primary total knee arthroplasty (TKA) without previous HTO. Results for the osteotomy group were satisfactory in 96.5% of cases. In one patient loosening of the implant occurred after 37 months, which required prosthesis revision. Three patients underwent a further operation of secondary patella resurfacing for patella pain. The group without osteotomy reported a similar percentage of satisfactory results. PMID:19882155

  16. Techniques for assessing knee joint pain in arthritis.

    PubMed

    Neugebauer, Volker; Han, Jeong S; Adwanikar, Hita; Fu, Yu; Ji, Guangchen

    2007-03-28

    The assessment of pain is of critical importance for mechanistic studies as well as for the validation of drug targets. This review will focus on knee joint pain associated with arthritis. Different animal models have been developed for the study of knee joint arthritis. Behavioral tests in animal models of knee joint arthritis typically measure knee joint pain rather indirectly. In recent years, however, progress has been made in the development of tests that actually evaluate the sensitivity of the knee joint in arthritis models. They include measurements of the knee extension angle struggle threshold, hind limb withdrawal reflex threshold of knee compression force, and vocalizations in response to stimulation of the knee. A discussion of pain assessment in humans with arthritis pain conditions concludes this review.

  17. 3D superimposition and understanding temporomandibular joint arthritis

    PubMed Central

    Cevidanes, LHS; Gomes, LR; Jung, BT; Gomes, MR; Ruellas, ACO; Goncalves, JR; Schilling, J; Styner, M; Nguyen, T; Kapila, S; Paniagua, B

    2015-01-01

    Objectives To investigate the 3D morphological variations in 169 Temporomandibular Joint (TMJ) condyles, using novel imaging statistical modeling approaches. Setting and Sample Population The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Cone beam CT scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA, mean age 39.1 ± 15.7 years), 15 subjects at initial consult diagnosis of OA (mean age 44.9 ± 14.8 years) and 7 healthy controls (mean age 43 ± 12.4 years). Material & Methods 3D surface models of the condyles were constructed and homologous correspondent points on each model were established. The statistical framework included Direction-Projection-Permutation (DiProPerm) for testing statistical significance of the differences between healthy controls and the OA groups determined by clinical and radiographic diagnoses. Results Condylar morphology in OA and healthy subjects varied widely with categorization from mild to severe bone degeneration or overgrowth. DiProPerm statistics supported a significant difference between the healthy control group and the initial diagnosis of OA group (t=6.6, empirical p-value = 0.006), and between healthy and long term-diagnosis of OA group (t = 7.2, empirical p-value = 0). Compared with healthy controls, the average condyle in OA subjects was significantly smaller in all dimensions, except its anterior surface, even in subjects with initial diagnosis of OA. Conclusion This new statistical modeling of condylar morphology allows the development of more targeted classifications of this condition than previously possible. PMID:25865530

  18. Joint Line Reconstruction in Navigated Total Knee Arthroplasty Revision

    ClinicalTrials.gov

    2012-05-16

    Revision Total Knee Arthroplasty Because of; Loosening; Instability; Impingement; or Other Reasons Accepted as Indications for TKA Exchange.; The Focus is to Determine the Precision of Joint Line Restoration in Navigated vs. Conventional Revision Total Knee Arthroplasty

  19. Complex function of the knee joint: the current understanding of the knee.

    PubMed

    Hirschmann, Michael T; Müller, Werner

    2015-10-01

    Since the early years of orthopaedics, it is a well-known fact that anatomy follows function. During the evolution of mankind, the knee has been optimally adapted to the forces and loads acting at and through the knee joint. However, anatomy of the knee joint is variable and the only constant is its complex function. In contrast to the time of open surgery, nowadays the majority of reconstructive knee surgery is done arthroscopically. Keyhole surgery is less invasive, but on the backside, the knee surgeon lacks daily visualisation of the complex open anatomy. As open anatomical knowledge is less present in our daily practice, it is even more important to highlight this complex anatomy and function of the knee. It is the purpose of this review to perform a systematic review of knee anatomy, highlight the complex function of the knee joint and present an overview about recent and current knowledge about knee function. Level of evidence Systematic review, Level IV.

  20. Kinematic and dynamic analysis of an anatomically based knee joint.

    PubMed

    Lee, Kok-Meng; Guo, Jiajie

    2010-05-01

    This paper presents a knee-joint model to provide a better understanding on the interaction between natural joints and artificial mechanisms for design and control of rehabilitation exoskeletons. The anatomically based knee model relaxes several commonly made assumptions that approximate a human knee as engineering pin-joint in exoskeleton design. Based on published MRI data, we formulate the kinematics of a knee-joint and compare three mathematical approximations; one model bases on two sequential circles rolling a flat plane; and the other two are mathematically differentiable ellipses-based models with and without sliding at the contact. The ellipses-based model taking sliding contact into accounts shows that the rolling-sliding ratio of a knee-joint is not a constant but has an average value consistent with published measurements. This knee-joint kinematics leads to a physically more accurate contact-point trajectory than methods based on multiple circles or lines, and provides a basis to derive a knee-joint kinetic model upon which the effects of a planar exoskeleton mechanism on the internal joint forces and torque during flexion can be numerically investigated. Two different knee-joint kinetic models (pin-joint approximation and anatomically based model) are compared against a condition with no exoskeleton. The leg and exoskeleton form a closed kinematic chain that has a significant effect on the joint forces in the knee. Human knee is more tolerant than pin-joint in negotiating around a singularity but its internal forces increase with the exoskeleton mass-to-length ratio. An oversimplifying pin-joint approximation cannot capture the finite change in the knee forces due to the singularity effect.

  1. Taking care of your new knee joint

    MedlinePlus

    Knee arthroplasty - precautions; Knee replacement - precautions ... After you have knee replacement surgery , you will need to be careful about how you move your knee, especially for the first few ...

  2. Pure Varus Injury to the Knee Joint.

    PubMed

    Yoo, Jae Ho; Lee, Jung Ha; Chang, Chong Bum

    2015-06-01

    A 30-year-old male was involved in a car accident. Radiographs revealed a depressed marginal fracture of the medial tibial plateau and an avulsion fracture of the fibular head. Magnetic resonance imaging showed avulsion fracture of Gerdy's tubercle, injury to the posterior cruciate ligament (PCL), posterior horn of the medial meniscus, and the attachments of the lateral collateral ligament and the biceps femoris tendon. The depressed fracture of the medial tibial plateau was elevated and stabilized using a cannulated screw and washer. The injured lateral and posterolateral corner (PLC) structures were repaired and augmented by PLC reconstruction. However, the avulsion fracture of Gerdy's tubercle was not fixed because it was minimally displaced and the torn PCL was also not repaired or reconstructed. We present a unique case of pure varus injury to the knee joint. This case contributes to our understanding of the mechanism of knee injury and provides insight regarding appropriate treatment plans for this type of injury. PMID:26217477

  3. A volumetric model-based 2D to 3D registration method for measuring kinematics of natural knees with single-plane fluoroscopy

    SciTech Connect

    Tsai, Tsung-Yuan; Lu, Tung-Wu; Chen, Chung-Ming; Kuo, Mei-Ying; Hsu, Horng-Chaung

    2010-03-15

    Purpose: Accurate measurement of the three-dimensional (3D) rigid body and surface kinematics of the natural human knee is essential for many clinical applications. Existing techniques are limited either in their accuracy or lack more realistic experimental evaluation of the measurement errors. The purposes of the study were to develop a volumetric model-based 2D to 3D registration method, called the weighted edge-matching score (WEMS) method, for measuring natural knee kinematics with single-plane fluoroscopy to determine experimentally the measurement errors and to compare its performance with that of pattern intensity (PI) and gradient difference (GD) methods. Methods: The WEMS method gives higher priority to matching of longer edges of the digitally reconstructed radiograph and fluoroscopic images. The measurement errors of the methods were evaluated based on a human cadaveric knee at 11 flexion positions. Results: The accuracy of the WEMS method was determined experimentally to be less than 0.77 mm for the in-plane translations, 3.06 mm for out-of-plane translation, and 1.13 deg. for all rotations, which is better than that of the PI and GD methods. Conclusions: A new volumetric model-based 2D to 3D registration method has been developed for measuring 3D in vivo kinematics of natural knee joints with single-plane fluoroscopy. With the equipment used in the current study, the accuracy of the WEMS method is considered acceptable for the measurement of the 3D kinematics of the natural knee in clinical applications.

  4. Translational and rotational knee joint stability in anterior and posterior cruciate-retaining knee arthroplasty.

    PubMed

    Lo, JiaHsuan; Müller, Otto; Dilger, Torsten; Wülker, Nikolaus; Wünschel, Markus

    2011-12-01

    This study investigated passive translational and rotational stability properties of the intact knee joint, after bicruciate-retaining bi-compartmental knee arthroplasty (BKA) and after posterior cruciate retaining total knee arthroplasty (TKA). Fourteen human cadaveric knee specimens were used in this study, and a robotic manipulator with six-axis force/torque sensor was used to test the joint laxity in anterior-posterior translation, valgus-varus, and internal-external rotation. The results show the knee joint stability after bicruciate-retaining BKA is similar to that of the native knee. On the other hand, the PCL-retaining TKA results in inferior joint stability in valgus, varus, external rotation, anterior and, surprisingly, posterior directions. Our findings suggest that, provided functional ligamentous structures, bicruciate-retaining BKA is a biomechanically attractive treatment for joint degenerative disease.

  5. Pathological Knee Joint Motion Analysis By High Speed Cinephotography

    NASA Astrophysics Data System (ADS)

    Baumann, Jurg U.

    1985-02-01

    The use of cinephotography for evaluation of disturbed knee joint function was compared in three groups of patients. While a sampling rate of 50 images per second was adequate for patients with neuromuscular disorders, a higher frequency of around 300 i.p.s. is necessary in osteoarthritis and ligamentous knee joint injuries, but the task of digitizing is prohibitive unless automated.

  6. Does Success Of Arthroscopic Laser Surgery In The Knee Joint Warrant Its Extension To "Non-Knee" Joints?

    NASA Astrophysics Data System (ADS)

    Smith, Chadwick F.; Johansen, W. Edward; Vangness, C. Thomas; Yamaguchi, Ken; McEleney, Emmett T.; Bales, Peter

    1987-03-01

    One of the authors has performed 162 arthroscopic laser surgeries in the knee joint without any major complication. Other investigators have recently proposed diagnostic arthroscopy and arthroscopic surgery for "non-knee" joints. The authors have proposed that arthroscopic laser surgery he extended to "non-knee" joints. The authors have performed arthroscopic laser surgery on "non-knee" joints of twelve cadavers. One of the authors have performed one successful arthroscopic surgery on a shoulder joint with only a minor, transient complication of subcutaneous emphysema. Is laser arthroscopic surgery safe and effective in "non-knee" joints? The evolving answer appears to be a qualified "Yes," which needs to be verified by a multicenter trial.

  7. Aspiration and injection of the knee joint: approach portal.

    PubMed

    Douglas, Robert J

    2014-03-01

    Aspiration and injection of the knee joint is a commonly performed medical procedure. Injection of corticosteroid for the treatment of osteoarthritis is the most common reason for knee joint injection, and is performed as an office procedure. Debate exists among practitioners as to the 'best' approach portal for knee injection. This paper examines the various approach portals for injection and/or aspiration of the knee joint, as well as the accuracy of each approach. Searches were made of electronic databases, and appropriate papers were identified and hand-searched. Although there is some evidence that particular approach portals may be more efficacious in the presence of specific knee joint pathologies, generally, in experienced hands, it is of no clinical consequence as to which approach portal is utilised for aspiration or injection of the knee joint. No approach portal is 100% accurate, and the accuracy of injection of the knee joint may be enhanced by the use of techniques such as ultrasound. Practitioners are reminded that they should continuously refine and practice their preferred technique. Knee joint aspiration and injection is a common, simple, and generally safe office procedure.

  8. Diagnostic Performance of 3D Standing CT Imaging For Detection of Knee Osteoarthritis Features

    PubMed Central

    Segal, Neil A; Nevitt, Michael C.; Lynch, John A; Niu, Jingbo; Torner, James C; Guermazi, Ali

    2016-01-01

    Objective To determine the diagnostic performance of standing computerized tomography (SCT) of the knee for osteophytes and subchondral cysts compared to fixed-flexion radiography, using magnetic resonance imaging (MRI) as the reference standard. Methods Twenty participants were recruited from the Multicenter Osteoarthritis Study (MOST). Participants' knees were imaged with SCT while standing in a knee-positioning frame, and with PA fixed-flexion radiography and 1T MRI. Medial and lateral marginal osteophytes and subchondral cysts were scored on bilateral radiographs and coronal SCT images using the OARSI grading system and on coronal MRI using Whole Organ MRI Scoring (WORMS). Imaging modalities were read separately with images in random order. Sensitivity, specificity, and accuracy for the detection of lesions were calculated and differences between modalities were tested using McNemar's test. Results Participants' mean age was 66.8 years, BMI was 29.6kg/m2 and 50% were women. Of the 160 surfaces (medial and lateral femur and tibia for 40 knees), MRI revealed 84 osteophytes and 10 subchondral cysts. In comparison with osteophytes and subchondral cysts detected by MRI, SCT was significantly more sensitive (93% and 100%; p<0.004) and accurate (95% and 99%; p<0.001 for osteophytes) than plain radiographs (sensitivity: 60% and 10% and accuracy 79% and 94% respectively). For osteophytes, differences in sensitivity and accuracy were greatest at the medial femur (p=0.002). Conclusions In comparison with MRI, SCT imaging was more sensitive and accurate for detection of osteophytes and subchondral cysts than conventional fixed-flexion radiography. Additional study is warranted to assess diagnostic performance of SCT measures of joint space width, progression of OA features and the patellofemoral joint. PMID:26313455

  9. Active knee joint flexibility and sports activity.

    PubMed

    Hahn, T; Foldspang, A; Vestergaard, E; Ingemann-Hansen, T

    1999-04-01

    The aim of the study was to estimate active knee flexion and active knee extension in athletes and to investigate the potential association of each to different types of sports activity. Active knee extension and active knee flexion was measured in 339 athletes. Active knee extension was significantly higher in women than in men and significantly positively associated with weekly hours of swimming and weekly hours of competitive gymnastics. Active knee flexion was significantly positively associated with participation in basketball, and significantly negatively associated with age and weekly hours of soccer, European team handball and swimming. The results point to sport-specific adaptation of active knee flexion and active knee extension.

  10. Evaluation of RSA set-up from a clinical biplane fluoroscopy system for 3D joint kinematic analysis

    PubMed Central

    BONANZINGA, TOMMASO; SIGNORELLI, CECILIA; BONTEMPI, MARCO; RUSSO, ALESSANDRO; ZAFFAGNINI, STEFANO; MARCACCI, MAURILIO; BRAGONZONI, LAURA

    2016-01-01

    Purpose dinamic roentgen stereophotogrammetric analysis (RSA), a technique currently based only on customized radiographic equipment, has been shown to be a very accurate method for detecting three-dimensional (3D) joint motion. The aim of the present work was to evaluate the applicability of an innovative RSA set-up for in vivo knee kinematic analysis, using a biplane fluoroscopic image system. To this end, the Authors describe the set-up as well as a possible protocol for clinical knee joint evaluation. The accuracy of the kinematic measurements is assessed. Methods the Authors evaluated the accuracy of 3D kinematic analysis of the knee in a new RSA set-up, based on a commercial biplane fluoroscopy system integrated into the clinical environment. The study was organized in three main phases: an in vitro test under static conditions, an in vitro test under dynamic conditions reproducing a flexion-extension range of motion (ROM), and an in vivo analysis of the flexion-extension ROM. For each test, the following were calculated, as an indication of the tracking accuracy: mean, minimum, maximum values and standard deviation of the error of rigid body fitting. Results in terms of rigid body fitting, in vivo test errors were found to be 0.10±0.05 mm. Phantom tests in static and kinematic conditions showed precision levels, for translations and rotations, of below 0.1 mm/0.2° and below 0.5 mm/0.3° respectively for all directions. Conclusions the results of this study suggest that kinematic RSA can be successfully performed using a standard clinical biplane fluoroscopy system for the acquisition of slow movements of the lower limb. Clinical relevance a kinematic RSA set-up using a clinical biplane fluoroscopy system is potentially applicable and provides a useful method for obtaining better characterization of joint biomechanics. PMID:27602352

  11. Biomechanical measures of knee joint mobilization

    PubMed Central

    Silvernail, Jason L; Gill, Norman W; Teyhen, Deydre S; Allison, Stephen C

    2011-01-01

    Background and purpose The purpose of this study was to quantify the biomechanical properties of specific manual therapy techniques in patients with symptomatic knee osteoarthritis. Methods Twenty subjects (7 female/13 male, age 54±8 years, ht 1·7±0·1 m, wt 94·2±21·8 kg) participated in this study. One physical therapist delivered joint mobilizations (tibiofemoral extension and flexion; patellofemoral medial–lateral and inferior glide) at two grades (Maitland’s grade III and grade IV). A capacitance-based pressure mat was used to capture biomechanical characteristics of force and frequency during 2 trials of 15 second mobilizations. Statistical analysis included intraclass correlation coefficient (ICC3,1) for intrarater reliability and 2×4 repeated measures analyses of variance and post-hoc comparison tests. Results Force (Newtons) measurements (mean, max.) for grade III were: extension 45, 74; flexion 39, 61; medial–lateral glide 20, 34; inferior glide 16, 27. Force (Newtons) measurements (mean, max.) for grade IV were: extension 57, 76; flexion 47, 68; medial–lateral glide 23, 36; inferior glide 18, 35. Frequency (Hz) measurements were between 0·9 and 1·2 for grade III, and between 2·1 and 2·4 for grade IV. ICCs were above 0·90 for almost all measures. Discussion and conclusion Maximum force measures were between the ranges reported for cervical and lumbar mobilization at similar grades. Mean force measures were greater at grade IV than III. Oscillation frequency and peak-to-peak amplitude measures were consistent with the grade performed (i.e. greater frequency at grade IV, greater peak-to-peak amplitude at grade III). Intrarater reliability for force, peak-to-peak amplitude and oscillation frequency for knee joint mobilizations was excellent. PMID:22851879

  12. The behavior of reinforced concrete knee joints under earthquake loads

    NASA Astrophysics Data System (ADS)

    Angelakos, Bill

    The poor performance of knee joint connections during recent earthquakes motivated a number of experimental investigations of knee joint behavior under reversed cyclic loading. In this work the knee joint design problem is studied through a collective evaluation of the available experimental results and analytical modeling. The objective is to identify the critical response variables controlling the mechanics of knee joints under earthquake loads and to quantify the influence they have on the strength and deformation capacity of the joint. A knee joint model is derived from simple mechanical constructs of equilibrium and compatibility. The parametric dependence of knee joint behavior is investigated for critical design parameters such as concrete strength, amounts and yield strengths of horizontal and vertical transverse reinforcement, and bond demand. Three different limiting equations are developed from the model limiting the joint shear resistance according with the three alternative modes of joint shear failure. These are: (i) yielding of horizontal and vertical transverse reinforcement, (ii) and (iii) yielding in either of the two principal reinforcing directions accompanied by crushing of the concrete in compression (here the softening influence of orthogonal tensile deformations is considered). For those test specimens from the experimental database that experienced a joint shear failure, the simple knee joint model predicts their joint shear capacity well. Consistent with observations from interior connections it is shown that anchorage of the main reinforcement in the knee joint region prevails as the determining factor of the response of the joint panel. In addition, the same basic physical model that describes the source of resistance in interior connections also applies to knee joints; truss action, and diagonal strut action. By favorably anchoring the beam and column bars it is possible to develop the joint shear strength which is associated with one

  13. Regional 3D superimposition to assess temporomandibular joint condylar morphology

    PubMed Central

    Schilling, J; Gomes, L C R; Benavides, E; Nguyen, T; Paniagua, B; Styner, M; Boen, V; Gonçalves, J R; Cevidanes, L H S

    2014-01-01

    Objectives: To investigate the reliability of regional three-dimensional registration and superimposition methods for assessment of temporomandibular joint condylar morphology across subjects and longitudinally. Methods: The sample consisted of cone beam CT scans of 36 patients. The across-subject comparisons included 12 controls, mean age 41.3 ± 12.0 years, and 12 patients with temporomandibular joint osteoarthritis, mean age 41.3 ± 14.7 years. The individual longitudinal assessments included 12 patients with temporomandibular joint osteoarthritis, mean age 37.8 ± 16.7 years, followed up at pre-operative jaw surgery, immediately after and one-year post-operative. Surface models of all condyles were constructed from the cone beam CT scans. Two previously calibrated observers independently performed all registration methods. A landmark-based approach was used for the registration of across-subject condylar models, and temporomandibular joint osteoarthritis vs control group differences were computed with shape analysis. A voxel-based approach was used for registration of longitudinal scans calculated x, y, z degrees of freedom for translation and rotation. Two-way random intraclass correlation coefficients tested the interobserver reliability. Results: Statistically significant differences between the control group and the osteoarthritis group were consistently located on the lateral and medial poles for both observers. The interobserver differences were ≤0.2 mm. For individual longitudinal comparisons, the mean interobserver differences were ≤0.6 mm in translation errors and 1.2° in rotation errors, with excellent reliability (intraclass correlation coefficient >0.75). Conclusions: Condylar registration for across-subjects and longitudinal assessments is reliable and can be used to quantify subtle bony differences in the three-dimensional condylar morphology. PMID:24170802

  14. The influence of joint line position on knee stability after condylar knee arthroplasty.

    PubMed

    Martin, J W; Whiteside, L A

    1990-10-01

    Using a special knee-testing device, ten knees obtained at autopsy were subjected to varus-valgus, anterior-posterior, and flexion-rotation analysis in the intact state and after total knee arthroplasty. The ten knees showed no significant change in stability after knee replacement when the joint line was maintained in its natural position. When the femoral component was repositioned 5 mm proximally and 5 mm anteriorly, a significant increase in laxity occurred during midflexion. When the joint line was shifted 5 mm distal and 5 mm posterior to its anatomic location, significant tightening occurred in midrange of motion. Coupled rotation of the tibia with knee flexion was decreased after surgery in all knees with no specific relationship to joint line position. Coupled rotation with varus-valgus testing, however, remained within the normal range through the first 30 degrees of flexion only when the joint line was restored to its normal anatomic position. Stability in condylar knee arthroplasty is in part dependent on position of the joint line. Surgical techniques that rely on restoring the flexion and extension gap without regard to joint line position may result in alteration of varus-valgus or anterior-posterior displacement in midrange flexion. PMID:2208849

  15. 21 CFR 888.3480 - Knee joint femorotibial metallic constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metallic constrained... Knee joint femorotibial metallic constrained cemented prosthesis. (a) Identification. A knee joint... knee joint. The device prevents dislocation in more than one anatomic plane and has components that...

  16. 21 CFR 888.3480 - Knee joint femorotibial metallic constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metallic constrained... Knee joint femorotibial metallic constrained cemented prosthesis. (a) Identification. A knee joint... knee joint. The device prevents dislocation in more than one anatomic plane and has components that...

  17. 21 CFR 888.3480 - Knee joint femorotibial metallic constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metallic constrained... Knee joint femorotibial metallic constrained cemented prosthesis. (a) Identification. A knee joint... knee joint. The device prevents dislocation in more than one anatomic plane and has components that...

  18. 21 CFR 888.3480 - Knee joint femorotibial metallic constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metallic constrained... Knee joint femorotibial metallic constrained cemented prosthesis. (a) Identification. A knee joint... knee joint. The device prevents dislocation in more than one anatomic plane and has components that...

  19. Interpolation function for approximating knee joint behavior in human gait

    NASA Astrophysics Data System (ADS)

    Toth-Taşcǎu, Mirela; Pater, Flavius; Stoia, Dan Ioan

    2013-10-01

    Starting from the importance of analyzing the kinematic data of the lower limb in gait movement, especially the angular variation of the knee joint, the paper propose an approximation function that can be used for processing the correlation among a multitude of knee cycles. The approximation of the raw knee data was done by Lagrange polynomial interpolation on a signal acquired using Zebris Gait Analysis System. The signal used in approximation belongs to a typical subject extracted from a lot of ten investigated subjects, but the function domain of definition belongs to the entire group. The study of the knee joint kinematics plays an important role in understanding the kinematics of the gait, this articulation having the largest range of motion in whole joints, in gait. The study does not propose to find an approximation function for the adduction-abduction movement of the knee, this being considered a residual movement comparing to the flexion-extension.

  20. Abnormal loading of the major joints in knee osteoarthritis and the response to knee replacement.

    PubMed

    Metcalfe, Andrew; Stewart, Caroline; Postans, Neil; Barlow, David; Dodds, Alexander; Holt, Cathy; Whatling, Gemma; Roberts, Andrew

    2013-01-01

    Knee osteoarthritis is common and patients frequently complain that they are 'overloading' the joints of the opposite leg when they walk. However, it is unknown whether moments or co-contractions are abnormal in the unaffected joints of patients with single joint knee osteoarthritis, or how they change following treatment of the affected knee. Twenty patients with single joint medial compartment knee osteoarthritis were compared to 20 asymptomatic control subjects. Gait analysis was performed for normal level gait and surface EMG recordings of the medial and lateral quadriceps and hamstrings were used to investigate co-contraction. Patients were followed up 12 months post-operatively and the analysis was repeated. Results are presented for the first 14 patients who have attended follow-up. Pre-operatively, adduction moment impulses were elevated at both knees and the contra-lateral hip compared to controls. Co-contraction of hamstrings and quadriceps was elevated bilaterally. Post-operatively, moment waveforms returned to near-normal levels at the affected knee and co-contraction fell in the majority of patients. However, abnormalities persisted in the contra-lateral limb with partial or no recovery of both moment waveforms and co-contraction in the majority. Patients with knee osteoarthritis do experience abnormal loads of their major weight bearing joints bilaterally, and abnormalities persist despite treatment of the affected limb. Further treatment may be required if we are to protect the other major joints following joint arthroplasty.

  1. [Magnetic resonance imaging in the diagnosis of knee joint sarcomas].

    PubMed

    Shubkin, V N; Gunicheva, N V; Akhadov, T A; Puzhitskiĭ, L B; Keshishian, R A

    2007-01-01

    The purpose of the investigation was to study the potentialities of magnetic resonance imaging (MRI) in the diagnosis of knee joint sarcomas. The paper presents the results of examining 13 patients of different age, shows the potentialities of the technique in the identification of knee joint sarcomas, and describes the MRI semiotics of sarcomas in both the routine study and that using contrast enhancement in lesions of bone and soft tissue elements in the presence of regional metastases.

  2. Complex function of the knee joint: the current understanding of the knee.

    PubMed

    Hirschmann, Michael T; Müller, Werner

    2015-10-01

    Since the early years of orthopaedics, it is a well-known fact that anatomy follows function. During the evolution of mankind, the knee has been optimally adapted to the forces and loads acting at and through the knee joint. However, anatomy of the knee joint is variable and the only constant is its complex function. In contrast to the time of open surgery, nowadays the majority of reconstructive knee surgery is done arthroscopically. Keyhole surgery is less invasive, but on the backside, the knee surgeon lacks daily visualisation of the complex open anatomy. As open anatomical knowledge is less present in our daily practice, it is even more important to highlight this complex anatomy and function of the knee. It is the purpose of this review to perform a systematic review of knee anatomy, highlight the complex function of the knee joint and present an overview about recent and current knowledge about knee function. Level of evidence Systematic review, Level IV. PMID:25962963

  3. Is Lifelong Knee Joint Force from Work, Home, and Sport Related to Knee Osteoarthritis?

    PubMed Central

    Ratzlaff, Charles R.; Koehoorn, Mieke; Cibere, Jolanda; Kopec, Jacek A.

    2012-01-01

    Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the “cumulative peak force index”, a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio's ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA. PMID:22848225

  4. Evaluation of the gait performance of above-knee amputees while walking with 3R20 and 3R15 knee joints

    PubMed Central

    Taheri, AliReza; Karimi, Mohammad Taghi

    2012-01-01

    Background: The performance of the subjects with above-knee amputation is noticeably poorer than normal subjects. Various types of components have been designed to compensate their performance. Among various prosthetic components, the knee joint has great influence on the function. Two types of knee joints (3R15, 3R20) have been used broadly for above-knee prostheses. However, there is not enough research to highlight the influence of these joints on the gait performance of the subjects. Therefore, an aim of this research was to investigate the performance of the above-knee amputees while walking with 3R15 and 3R20 knee joints. Materials and Methods: 7 above-knee amputees were recruited in this research study. They were asked to walk with a comfortable speed to investigate the gait function of the subjects with 3 cameras 3D motion analysis system (Kinematrix system). The difference between the performances of the subjects with these joints was compared by use of paired t-test. Results: The results of this study showed that, the performances of the subjects with 3R20 were better than that with 3R15. The walking speed of the subjects with 3R20 was 66.7 m/min compared to 30.4 m/min (P-value = 0.045). Moreover; the symmetry of walking with 3R20 was more than that with 3R15, based on the spatio- temporal gait parameters values (P-value <0.05). Conclusion: The difference between the performances of the subjects with 3R20 and 3R15 knee joints was related to the walking speed, which improved while walking with 3R20 joint. PMID:23267378

  5. Implementation of a gait cycle loading into healthy and meniscectomised knee joint models with fibril-reinforced articular cartilage.

    PubMed

    Mononen, Mika E; Jurvelin, Jukka S; Korhonen, Rami K

    2015-01-01

    Computational models can be used to evaluate the functional properties of knee joints and possible risk locations within joints. Current models with fibril-reinforced cartilage layers do not provide information about realistic human movement during walking. This study aimed to evaluate stresses and strains within a knee joint by implementing load data from a gait cycle in healthy and meniscectomised knee joint models with fibril-reinforced cartilages. A 3D finite element model of a knee joint with cartilages and menisci was created from magnetic resonance images. The gait cycle data from varying joint rotations, translations and axial forces were taken from experimental studies and implemented into the model. Cartilage layers were modelled as a fibril-reinforced poroviscoelastic material with the menisci considered as a transversely isotropic elastic material. In the normal knee joint model, relatively high maximum principal stresses were specifically predicted to occur in the medial condyle of the knee joint during the loading response. Bilateral meniscectomy increased stresses, strains and fluid pressures in cartilage on the lateral side, especially during the first 50% of the stance phase of the gait cycle. During the entire stance phase, the superficial collagen fibrils modulated stresses of cartilage, especially in the medial tibial cartilage. The present computational model with a gait cycle and fibril-reinforced biphasic cartilage revealed time- and location-dependent differences in stresses, strains and fluid pressures occurring in cartilage during walking. The lateral meniscus was observed to have a more significant role in distributing loads across the knee joint than the medial meniscus, suggesting that meniscectomy might initiate a post-traumatic process leading to osteoarthritis at the lateral compartment of the knee joint.

  6. Examination of knee joint moments on the function of knee-ankle-foot orthoses during walking.

    PubMed

    Andrysek, Jan; Klejman, Susan; Kooy, John

    2013-08-01

    The goal of this study was to investigate clinically relevant biomechanical conditions relating to the setup and alignment of knee-ankle-foot orthoses and the influence of these conditions on knee extension moments and orthotic stance control during gait. Knee moments were collected using an instrumented gait laboratory and concurrently a load transducer embedded at the knee-ankle-foot orthosis knee joint of four individuals with poliomyelitis. We found that knee extension moments were not typically produced in late stance-phase of gait. Adding a dorsiflexion stop at the orthotic ankle significantly decreased the knee flexion moments in late stance-phase, while slightly flexing the knee in stance-phase had a variable effect. The findings suggest that where users of orthoses have problems initiating swing-phase flexion with stance control orthoses, an ankle dorsiflexion stop may be used to enhance function. Furthermore, the use of stance control knee joints that lock while under flexion may contribute to more inconsistent unlocking of the stance control orthosis during gait.

  7. Effect of BMI on knee joint torques in ergometer rowing.

    PubMed

    Roemer, Karen; Hortobagyi, Tibor; Richter, Chris; Munoz-Maldonado, Yolanda; Hamilton, Stephanie

    2013-12-01

    Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity biomechanics during rowing in 10 normal weight (BMI 18-25), 10 overweight (BMI 25-30 kg·m⁻²), and 10 obese (BMI > 30 kg·m⁻²) participants. The results showed that BMI affects joint kinematics and primarily knee joint kinetics. The data revealed that high BMI leads to unfavorable knee joint torques, implying increased loads of the medial compartment in the knee joint that could be avoided by allowing more variable foot positioning on future designs of rowing ergometers.

  8. Recent Advances in Computational Mechanics of the Human Knee Joint

    PubMed Central

    Kazemi, M.; Dabiri, Y.; Li, L. P.

    2013-01-01

    Computational mechanics has been advanced in every area of orthopedic biomechanics. The objective of this paper is to provide a general review of the computational models used in the analysis of the mechanical function of the knee joint in different loading and pathological conditions. Major review articles published in related areas are summarized first. The constitutive models for soft tissues of the knee are briefly discussed to facilitate understanding the joint modeling. A detailed review of the tibiofemoral joint models is presented thereafter. The geometry reconstruction procedures as well as some critical issues in finite element modeling are also discussed. Computational modeling can be a reliable and effective method for the study of mechanical behavior of the knee joint, if the model is constructed correctly. Single-phase material models have been used to predict the instantaneous load response for the healthy knees and repaired joints, such as total and partial meniscectomies, ACL and PCL reconstructions, and joint replacements. Recently, poromechanical models accounting for fluid pressurization in soft tissues have been proposed to study the viscoelastic response of the healthy and impaired knee joints. While the constitutive modeling has been considerably advanced at the tissue level, many challenges still exist in applying a good material model to three-dimensional joint simulations. A complete model validation at the joint level seems impossible presently, because only simple data can be obtained experimentally. Therefore, model validation may be concentrated on the constitutive laws using multiple mechanical tests of the tissues. Extensive model verifications at the joint level are still crucial for the accuracy of the modeling. PMID:23509602

  9. Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement.

    PubMed

    Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A; Cates, Harold E; Zhang, Songning

    2016-01-01

    Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

  10. Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement

    PubMed Central

    Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A.; Cates, Harold E.

    2016-01-01

    Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

  11. Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement.

    PubMed

    Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A; Cates, Harold E; Zhang, Songning

    2016-01-01

    Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups.

  12. Knee and ankle joint torque-angle relationships of multi-joint leg extension.

    PubMed

    Hahn, Daniel; Olvermann, Matthias; Richtberg, Jan; Seiberl, Wolfgang; Schwirtz, Ansgar

    2011-07-28

    The force-length-relation (F-l-r) is an important property of skeletal muscle to characterise its function, whereas for in vivo human muscles, torque-angle relationships (T-a-r) represent the maximum muscular capacity as a function of joint angle. However, since in vivo force/torque-length data is only available for rotational single-joint movements the purpose of the present study was to identify torque-angle-relationships for multi-joint leg extension. Therefore, inverse dynamics served for calculation of ankle and knee joint torques of 18 male subjects when performing maximum voluntary isometric contractions in a seated leg press. Measurements in increments of 10° knee angle from 30° to 100° knee flexion resulted in eight discrete angle configurations of hip, knee and ankle joints. For the knee joint we found an ascending-descending T-a-r with a maximum torque of 289.5° ± 43.3 Nm, which closely matches literature data from rotational knee extension. In comparison to literature we observed a shift of optimum knee angle towards knee extension. In contrast, the T-a-r of the ankle joint vastly differed from relationships obtained for isolated plantar flexion. For the ankle T-a-r derived from multi-joint leg extension subjects operated over different sections of the force-length curve, but the ankle T-a-r derived from isolated joint efforts was over the ascending limb for all subjects. Moreover, mean maximum torque of 234.7 ± 56.6 Nm exceeded maximal strength of isolated plantar flexion (185.7 ± 27.8 Nm). From these findings we conclude that muscle function between isolated and more physiological multi-joint tasks differs. This should be considered for ergonomic and sports optimisation as well as for modelling and simulation of human movement.

  13. Registration of knee joint surfaces for the in vivo study of joint injuries based on magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cheng, Rita W. T.; Habib, Ayman F.; Frayne, Richard; Ronsky, Janet L.

    2006-03-01

    In-vivo quantitative assessments of joint conditions and health status can help to increase understanding of the pathology of osteoarthritis, a degenerative joint disease that affects a large population each year. Magnetic resonance imaging (MRI) provides a non-invasive and accurate means to assess and monitor joint properties, and has become widely used for diagnosis and biomechanics studies. Quantitative analyses and comparisons of MR datasets require accurate alignment of anatomical structures, thus image registration becomes a necessary procedure for these applications. This research focuses on developing a registration technique for MR knee joint surfaces to allow quantitative study of joint injuries and health status. It introduces a novel idea of translating techniques originally developed for geographic data in the field of photogrammetry and remote sensing to register 3D MR data. The proposed algorithm works with surfaces that are represented by randomly distributed points with no requirement of known correspondences. The algorithm performs matching locally by identifying corresponding surface elements, and solves for the transformation parameters relating the surfaces by minimizing normal distances between them. This technique was used in three applications to: 1) register temporal MR data to verify the feasibility of the algorithm to help monitor diseases, 2) quantify patellar movement with respect to the femur based on the transformation parameters, and 3) quantify changes in contact area locations between the patellar and femoral cartilage at different knee flexion angles. The results indicate accurate registration and the proposed algorithm can be applied for in-vivo study of joint injuries with MRI.

  14. 3D kinematics of the tarsal joints from magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Hirsch, Bruce E.; Udupa, Jayaram K.; Okereke, Enyi; Hillstrom, Howard J.; Siegler, Sorin; Ringleb, Stacie I.; Imhauser, Carl W.

    2001-09-01

    We have developed a method for analyzing motion at skeletal joints based on the 3D reconstruction of magnetic resonance (MR) image data. Since the information about each voxel in MR images includes its location in the scanner, it follows that information is available for each organ whose 3D surface is computed from a series of MR slices. In addition, there is information on the shape and orientation of each organ, and the contact areas of adjacent bones. By collecting image data in different positions we can calculate the motion of the individual bones. We have used this method to study human foot bones, in order to understand normal and abnormal foot function. It has been used to evaluate patients with tarsal coalitions, various forms of pes planus, ankle sprains, and several other conditions. A newly described feature of this system is the ability to visualize the contact area at a joint, as determined by the region of minimum distance. The display of contact area helps understand abnormal joint function. Also, the use of 3D imaging reveals motions in joints which cannot otherwise be visualized, such as the subtalar joint, for more accurate diagnosis of joint injury.

  15. Consideration of equilibrium equations at the hip joint alongside those at the knee and ankle joints has mixed effects on knee joint response during gait.

    PubMed

    Adouni, M; Shirazi-Adl, A

    2013-02-01

    Accurate estimation of muscle forces during daily activities such as walking is critical for a reliable evaluation of loads on the knee joint. To evaluate knee joint muscle forces, the importance of the inclusion of the hip joint alongside the knee and ankle joints when treating the equilibrium equations remains yet unknown. An iterative kinematics-driven finite element model of the knee joint that accounts for the synergy between passive structures and active musculature is employed. The knee joint muscle forces and biomechanical response are predicted and compared with our earlier results that did not account for moment equilibrium equations at the hip joint. This study indicates that inclusion of the hip joint in the optimization along the knee and ankle joints only slightly (<10%) influences total forces in quadriceps, lateral hamstrings and medial hamstrings. As a consequence, even smaller differences are found in predicted ligament forces, contact forces/areas, and cartilage stresses/strains during the stance phase of gait. The distribution of total forces between the uni- and bi-articular muscle components in quadriceps and in lateral hamstrings; however, substantially alter at different stance phases.

  16. Three-dimensional dynamic analysis of knee joint during gait in medial knee osteoarthritis using loading axis of knee.

    PubMed

    Nishino, Katsutoshi; Omori, Go; Koga, Yoshio; Kobayashi, Koichi; Sakamoto, Makoto; Tanabe, Yuji; Tanaka, Masaei; Arakawa, Masaaki

    2015-07-01

    We recently developed a new method for three-dimensional evaluation of mechanical factors affecting knee joint in order to help identify factors that contribute to the progression of knee osteoarthritis (KOA). This study aimed to verify the clinical validity of our method by evaluating knee joint dynamics during gait. Subjects were 41 individuals (14 normal knees; 8 mild KOAs; 19 severe KOAs). The positions of skin markers attached to the body were captured during gait, and bi-planar X-ray images of the lower extremities were obtained in standing position. The positional relationship between the markers and femorotibial bones was determined from the X-ray images. Combining this relationship with gait capture allowed for the estimation of relative movement between femorotibial bones. We also calculated the point of intersection of loading axis of knee on the tibial proximal surface (LAK point) to analyze knee joint dynamics. Knee flexion range in subjects with severe KOA during gait was significantly smaller than that in those with normal knees (p=0.011), and knee adduction in those with severe KOA was significantly larger than in those with mild KOA (p<0.000). LAK point was locally loaded on the medial compartment of the tibial surface as KOA progressed, with LAK point of subjects with severe KOA rapidly shifting medially during loading response. Local loading and medial shear force were applied to the tibial surface during stance phase as medial KOA progressed. Our findings suggest that our method is useful for the quantitative evaluation of mechanical factors that affect KOA progression.

  17. Three-dimensional dynamic analysis of knee joint during gait in medial knee osteoarthritis using loading axis of knee.

    PubMed

    Nishino, Katsutoshi; Omori, Go; Koga, Yoshio; Kobayashi, Koichi; Sakamoto, Makoto; Tanabe, Yuji; Tanaka, Masaei; Arakawa, Masaaki

    2015-07-01

    We recently developed a new method for three-dimensional evaluation of mechanical factors affecting knee joint in order to help identify factors that contribute to the progression of knee osteoarthritis (KOA). This study aimed to verify the clinical validity of our method by evaluating knee joint dynamics during gait. Subjects were 41 individuals (14 normal knees; 8 mild KOAs; 19 severe KOAs). The positions of skin markers attached to the body were captured during gait, and bi-planar X-ray images of the lower extremities were obtained in standing position. The positional relationship between the markers and femorotibial bones was determined from the X-ray images. Combining this relationship with gait capture allowed for the estimation of relative movement between femorotibial bones. We also calculated the point of intersection of loading axis of knee on the tibial proximal surface (LAK point) to analyze knee joint dynamics. Knee flexion range in subjects with severe KOA during gait was significantly smaller than that in those with normal knees (p=0.011), and knee adduction in those with severe KOA was significantly larger than in those with mild KOA (p<0.000). LAK point was locally loaded on the medial compartment of the tibial surface as KOA progressed, with LAK point of subjects with severe KOA rapidly shifting medially during loading response. Local loading and medial shear force were applied to the tibial surface during stance phase as medial KOA progressed. Our findings suggest that our method is useful for the quantitative evaluation of mechanical factors that affect KOA progression. PMID:26002602

  18. Knee Joint Dysfunctions That Influence Gait in Cerebrovascular Injury

    PubMed Central

    Lucareli, Paulo Roberto Garcia; Greve, Julia Maria D’Andrea

    2008-01-01

    INTRODUCTION There is still no consensus among different specialists on the subject of kinematic variation during the hemiparetic gait, including the main changes that take place during the gait cycle and whether the gait velocity changes the patterns of joint mobility. One of the most frequently discussed joints is the knee. OBJECTIVES This study aims to evaluate the variables found in the angular kinematics of knee joint, and to describe the alterations found in the hemiparetic gait resulting from cerebrovascular injury. METHODS This study included 66 adult patients of both genders with a diagnosis of either right or left hemiparesis resulting from ischemic cerebrovascular injury. All the participants underwent three-dimensional gait evaluation, an the angular kinematics of the joint knee were selected for analysis. RESULTS The results were distributed into four groups formed based on the median of the gait speed and the side of hemiparesis. CONCLUSIONS The relevant clinical characteristics included the important mechanisms of loading response in the stance, knee hyperextension in single stance, and reduction of the peak flexion and movement amplitude of the knee in the swing phase. These mechanisms should be taken into account when choosing the best treatment. We believe that the findings presented here may aid in preventing the occurrence of the problems found, and also in identifying the origin of these problems. PMID:18719753

  19. Mechanical performance and parameter sensitivity analysis of 3D braided composites joints.

    PubMed

    Wu, Yue; Nan, Bo; Chen, Liang

    2014-01-01

    3D braided composite joints are the important components in CFRP truss, which have significant influence on the reliability and lightweight of structures. To investigate the mechanical performance of 3D braided composite joints, a numerical method based on the microscopic mechanics is put forward, the modeling technologies, including the material constants selection, element type, grid size, and the boundary conditions, are discussed in detail. Secondly, a method for determination of ultimate bearing capacity is established, which can consider the strength failure. Finally, the effect of load parameters, geometric parameters, and process parameters on the ultimate bearing capacity of joints is analyzed by the global sensitivity analysis method. The results show that the main pipe diameter thickness ratio γ, the main pipe diameter D, and the braided angle α are sensitive to the ultimate bearing capacity N.

  20. Mechanical Performance and Parameter Sensitivity Analysis of 3D Braided Composites Joints

    PubMed Central

    Wu, Yue; Nan, Bo; Chen, Liang

    2014-01-01

    3D braided composite joints are the important components in CFRP truss, which have significant influence on the reliability and lightweight of structures. To investigate the mechanical performance of 3D braided composite joints, a numerical method based on the microscopic mechanics is put forward, the modeling technologies, including the material constants selection, element type, grid size, and the boundary conditions, are discussed in detail. Secondly, a method for determination of ultimate bearing capacity is established, which can consider the strength failure. Finally, the effect of load parameters, geometric parameters, and process parameters on the ultimate bearing capacity of joints is analyzed by the global sensitivity analysis method. The results show that the main pipe diameter thickness ratio γ, the main pipe diameter D, and the braided angle α are sensitive to the ultimate bearing capacity N. PMID:25121121

  1. Alpha 5 Integrin Mediates Osteoarthritic Changes in Mouse Knee Joints

    PubMed Central

    Candela, Maria Elena; Wang, Chao; Gunawardena, Aruni T.; Zhang, Kairui; Cantley, Leslie; Yasuhara, Rika; Usami, Yu; Francois, Noelle; Iwamoto, Masahiro; van der Flier, Arjan; Zhang, Yejia; Qin, Ling; Han, Lin; Enomoto-Iwamoto, Motomi

    2016-01-01

    Osteoarthritis (OA) is one of most common skeletal disorders and can affect synovial joints such as knee and ankle joints. α5 integrin, a major fibronectin receptor, is expressed in articular cartilage and has been demonstrated to play roles in synovial joint development and in the regulation of chondrocyte survival and matrix degradation in articular cartilage. We hypothesized that α5 integrin signaling is involved in pathogenesis of OA. To test this, we generated compound mice that conditionally ablate α5 integrin in the synovial joints using the Gdf5Cre system. The compound mice were born normally and had an overall appearance similar to the control mice. However, when the mutant mice received the OA surgery, they showed stronger resistance to osteoarthritic changes than the control. Specifically the mutant knee joints presented lower levels of cartilage matrix and structure loss and synovial changes and showed stronger biomechanical properties than the control knee joints. These findings indicate that α5 integrin may not be essential for synovial joint development but play a causative role in induction of osteoarthritic changes. PMID:27280771

  2. Alpha 5 Integrin Mediates Osteoarthritic Changes in Mouse Knee Joints.

    PubMed

    Candela, Maria Elena; Wang, Chao; Gunawardena, Aruni T; Zhang, Kairui; Cantley, Leslie; Yasuhara, Rika; Usami, Yu; Francois, Noelle; Iwamoto, Masahiro; van der Flier, Arjan; Zhang, Yejia; Qin, Ling; Han, Lin; Enomoto-Iwamoto, Motomi

    2016-01-01

    Osteoarthritis (OA) is one of most common skeletal disorders and can affect synovial joints such as knee and ankle joints. α5 integrin, a major fibronectin receptor, is expressed in articular cartilage and has been demonstrated to play roles in synovial joint development and in the regulation of chondrocyte survival and matrix degradation in articular cartilage. We hypothesized that α5 integrin signaling is involved in pathogenesis of OA. To test this, we generated compound mice that conditionally ablate α5 integrin in the synovial joints using the Gdf5Cre system. The compound mice were born normally and had an overall appearance similar to the control mice. However, when the mutant mice received the OA surgery, they showed stronger resistance to osteoarthritic changes than the control. Specifically the mutant knee joints presented lower levels of cartilage matrix and structure loss and synovial changes and showed stronger biomechanical properties than the control knee joints. These findings indicate that α5 integrin may not be essential for synovial joint development but play a causative role in induction of osteoarthritic changes. PMID:27280771

  3. A study of Chinese knee joint geometry for prosthesis design.

    PubMed

    Wang, S W; Feng, C H; Lu, H S

    1992-03-01

    This study for the first time provides the geometric parameters of the knee joint of Chinese, which is indispensible to the design of knee prosthesis used for compatriotic patients. Thirty-five items, including linear, radial and angular measurements, were taken from 105 cadaveric knees and knee X-ray films of 1,100 subjects. The method and calculation for proper correction of the X-ray image magnification and joint cartilage space was established. Correlation was found to exist between the X-ray correction coefficients and the body weight, which formed the basis for individualized correction of X-ray measurements. Statistical analysis revealed that most of the linear and radial measurements were highly related while the angular measurements were independent of others. Principal component analysis showed that the width of femoral condyle might be taken as the leading index in determining the dimension of the knee, and regression functions were established to supply the serial parameters for prosthetic design. Multivariate discriminate functions could aid the selection of knee prosthesis.

  4. Focal cartilage defect compromises fluid-pressure dependent load support in the knee joint.

    PubMed

    Dabiri, Yaghoub; Li, LePing

    2015-06-01

    A focal cartilage defect involves tissue loss or rupture. Altered mechanics in the affected joint may play an essential role in the onset and progression of osteoarthritis. The objective of the present study was to determine the compromised load support in the human knee joint during defect progression from the cartilage surface to the cartilage-bone interface. Ten normal and defect cases were simulated with a previously tested 3D finite element model of the knee. The focal defects were considered in both condyles within high load-bearing regions. Fluid pressurization, anisotropic fibril-reinforcement, and depth-dependent mechanical properties were considered for the articular cartilages and menisci. The results showed that a small cartilage defect could cause 25% reduction in the load support of the knee joint due to a reduced capacity of fluid pressurization in the defect cartilage. A partial-thickness defect could cause a fluid pressure decrease or increase in the remaining underlying cartilage depending on the defect depth. A cartilage defect also increased the shear strain at the cartilage-bone interface, which was more significant with a full-thickness defect. The effect of cartilage defect on the fluid pressurization also depended on the defect sites and contact conditions. In conclusion, a focal cartilage defect causes a fluid-pressure dependent load reallocation and a compromised load support in the joint, which depend on the defect depth, site, and contact condition.

  5. Focal cartilage defect compromises fluid-pressure dependent load support in the knee joint.

    PubMed

    Dabiri, Yaghoub; Li, LePing

    2015-06-01

    A focal cartilage defect involves tissue loss or rupture. Altered mechanics in the affected joint may play an essential role in the onset and progression of osteoarthritis. The objective of the present study was to determine the compromised load support in the human knee joint during defect progression from the cartilage surface to the cartilage-bone interface. Ten normal and defect cases were simulated with a previously tested 3D finite element model of the knee. The focal defects were considered in both condyles within high load-bearing regions. Fluid pressurization, anisotropic fibril-reinforcement, and depth-dependent mechanical properties were considered for the articular cartilages and menisci. The results showed that a small cartilage defect could cause 25% reduction in the load support of the knee joint due to a reduced capacity of fluid pressurization in the defect cartilage. A partial-thickness defect could cause a fluid pressure decrease or increase in the remaining underlying cartilage depending on the defect depth. A cartilage defect also increased the shear strain at the cartilage-bone interface, which was more significant with a full-thickness defect. The effect of cartilage defect on the fluid pressurization also depended on the defect sites and contact conditions. In conclusion, a focal cartilage defect causes a fluid-pressure dependent load reallocation and a compromised load support in the joint, which depend on the defect depth, site, and contact condition. PMID:25727068

  6. Effects of proprioceptive circuit exercise on knee joint pain and muscle function in patients with knee osteoarthritis.

    PubMed

    Ju, Sung-Bum; Park, Gi Duck; Kim, Sang-Soo

    2015-08-01

    [Purpose] This study applied proprioceptive circuit exercise to patients with degenerative knee osteoarthritis and examined its effects on knee joint muscle function and the level of pain. [Subjects] In this study, 14 patients with knee osteoarthritis in two groups, a proprioceptive circuit exercise group (n = 7) and control group (n = 7), were examined. [Methods] IsoMed 2000 (D&R Ferstl GmbH, Hemau, Germany) was used to assess knee joint muscle function, and a Visual Analog Scale was used to measure pain level. [Results] In the proprioceptive circuit exercise group, knee joint muscle function and pain levels improved significantly, whereas in the control group, no significant improvement was observed. [Conclusion] A proprioceptive circuit exercise may be an effective way to strengthen knee joint muscle function and reduce pain in patients with knee osteoarthritis.

  7. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  8. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a...

  9. 21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device...

  10. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  11. 21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended...

  12. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace...

  13. 21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended...

  14. 21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a...

  15. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  16. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace...

  17. 21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended...

  18. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace...

  19. 21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device...

  20. 21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a...

  1. 21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a...

  2. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a...

  3. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a...

  4. 21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device...

  5. 21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a...

  6. 21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a...

  7. 21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a...

  8. 21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a...

  9. 21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a...

  10. 21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a...

  11. 21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a...

  12. 21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a...

  13. 21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a...

  14. 21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a...

  15. 21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a...

  16. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace...

  17. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a...

  18. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a...

  19. 21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a...

  20. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  1. 21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device...

  2. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace...

  3. 21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device...

  4. 21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended...

  5. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a...

  6. 21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended...

  7. Experimental joint immobilization in guinea pigs. Effects on the knee joint

    NASA Technical Reports Server (NTRS)

    Marcondesdesouza, J. P.; Machado, F. F.; Sesso, A.; Valeri, V.

    1980-01-01

    In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints were examined macro and microscopically. Findings included: (1) muscular hypotrophy and joint stiffness in all animals, directly proportional to the length of immobilization; (2) haemoarthrosis in the first week; (3) intra-articular fibrous tissue proliferation ending up with fibrous ankylosis; (4) hyaline articular cartilage erosions; (5) various degrees of destructive menisci changes. A tentative explanation of the fibrous tissue proliferation and of the cartilage changes is offered.

  8. Electrical noise to a knee joint stabilizes quiet bipedal stance.

    PubMed

    Kimura, Tetsuya; Kouzaki, Motoki

    2013-04-01

    Studies have shown that a minute, noise-like electrical stimulation (ES) of a lower limb joint stabilizes one-legged standing (OS), possibly due to the noise-enhanced joint proprioception. To demonstrate the practical utility of this finding, we assessed whether the bipedal stance (BS), relatively stable and generally employed in daily activities, is also stabilized by the same ES method. Twelve volunteers maintained quiet BS with or without an unperceivable, noise-like ES of a knee joint. The results showed that the average amplitude, peak-to-peak amplitude, and standard deviation of the foot center of pressure in the anteroposterior direction were significantly attenuated by the ES (P<0.05). These results indicate that the BS also can be stabilized by an unperceivable, noise-like ES of a knee joint. PMID:23044409

  9. Elbow and knee joint for hard space suits

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C.

    1986-01-01

    An elbow or knee joint for a hard space suit or similar usage is formed of three serially connected rigid sections which have truncated spherical configurations. The ends of each section form solid geometric angles, and the sections are interconnected by hermetically sealed ball bearings. The outer two sections are fixed together for rotation in a direction opposite to rotation of the center section. A preferred means to make the outer sections track each other in rotation comprises a rotatable continuous bead chain which engages sockets circumferentially spaced on the facing sides of the outer races of the bearings. The joint has a single pivot point and the bearing axes are always contained in a single plane for any articulation of the joint. Thus flexure of the joint simulates the coplanar flexure of the knee or elbow and is not susceptible to lockup.

  10. The effect of knee joint angle on torque control.

    PubMed

    Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T

    2010-01-01

    The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque.

  11. An improved OpenSim gait model with multiple degrees of freedom knee joint and knee ligaments.

    PubMed

    Xu, Hang; Bloswick, Donald; Merryweather, Andrew

    2015-08-01

    Musculoskeletal models are widely used to investigate joint kinematics and predict muscle force during gait. However, the knee is usually simplified as a one degree of freedom joint and knee ligaments are neglected. The aim of this study was to develop an OpenSim gait model with enhanced knee structures. The knee joint in this study included three rotations and three translations. The three knee rotations and mediolateral translation were independent, with proximodistal and anteroposterior translations occurring as a function of knee flexion/extension. Ten elastic elements described the geometrical and mechanical properties of the anterior and posterior cruciate ligaments (ACL and PCL), and the medial and lateral collateral ligaments (MCL and LCL). The three independent knee rotations were evaluated using OpenSim to observe ligament function. The results showed that the anterior and posterior bundles of ACL and PCL (aACL, pACL and aPCL, pPCL) intersected during knee flexion. The aACL and pACL mainly provided force during knee flexion and adduction, respectively. The aPCL was slack throughout the range of three knee rotations; however, the pPCL was utilised for knee abduction and internal rotation. The LCL was employed for knee adduction and rotation, but was slack beyond 20° of knee flexion. The MCL bundles were mainly used during knee adduction and external rotation. All these results suggest that the functions of knee ligaments in this model approximated the behaviour of the physical knee and the enhanced knee structures can improve the ability to investigate knee joint biomechanics during various gait activities.

  12. A reciprocal connection factor for assessing knee-joint function.

    PubMed

    Kim, Wangdo; Kohles, Sean S

    2012-01-01

    In the knee joint, interactions between instantaneous kinetics and kinematics associated with ligamentous and articular tissues are not fully understood. These structures may be represented by the instantaneous screw axis ($) (ISA) and static force vectors ($'). Geometric changes to the joint structure affecting motion have not been fully explained, especially after surgical reconstruction and replacement procedures. The ISA offers a joint-characterisation approach, which is dependent on the combined forces of ligaments, articular contacts and muscles. The standard four-bar linkage model in the sagittal plane demonstrates that the normal contact force and the lines of action of the cruciate ligaments always intersect at the centre of rotation of the joint. A kinematic knee model in which the articular surfaces in the lateral and medial compartments as well as the isometric fascicles in the engaged ligaments may be represented as five constraints in a one-degree-of-freedom parallel spatial mechanism. This study provides a theoretical foundation to elucidate the role of each of these elements in the control of the ISA. A recourse to the principle of virtual work explained through d'Alembert's principle for reducing a dynamics problem to an instantaneous static scenario allows screws to be applied to the biomechanics of human motion. The principle of reciprocity links these approaches together to explain the transmitting load between the tibia and the femur as well as the relative motion within the knee joint. A principal clinical implication of this study is the introduction of the reciprocal connection factor to evaluate knee kinematics and kinetics in one simple term, allowing the quantitative assessment of the outcome of knee-joint treatment and rehabilitation methods.

  13. Review: Modelling of meniscus of knee joint during soccer kicking

    NASA Astrophysics Data System (ADS)

    Azrul Hisham Mohd Adib, Mohd; Firdaus Jaafar, Mohd

    2013-12-01

    Knee is a part of the body that located between thigh and shank is one of the most complicated and largest joints in the human body. The common injuries that occur are ligaments, meniscus or bone fracture. During soccer games, the knee is the most critical part that will easily injure due to the shock from an external impact. Torn meniscus is one of the effects. This study will investigate the effect towards the meniscus within the knee joint during soccer ball kicking. We conduct a literary review of 14 journals that discuss the general view of meniscus and also soccer kicking. The selected topics for this review paper are meniscal function, meniscal movement, meniscal tears and also instep kick. As a finding, statistics show that most meniscal tears (73%) occurred in athletes who were soccer players, basketball players or skiers. The tear is frequently happening at the medial side rather than lateral side with a percentage of 70%.

  14. Decreased Knee Joint Loading Associated With Early Knee Osteoarthritis After Anterior Cruciate Ligament Injury

    PubMed Central

    Wellsandt, Elizabeth; Gardinier, Emily S.; Manal, Kurt; Axe, Michael J.; Buchanan, Thomas S.; Snyder-Mackler, Lynn

    2015-01-01

    Background Anterior cruciate ligament (ACL) injury predisposes individuals to early-onset knee joint osteoarthritis (OA). Abnormal joint loading is apparent after ACL injury and reconstruction. The relationship between altered joint biomechanics and the development of knee OA is unknown. Hypothesis Altered knee joint kinetics and medial compartment contact forces initially after injury and reconstruction are associated with radiographic knee OA 5 years after reconstruction. Study Design Case-control study; Level of evidence, 3. Methods Individuals with acute, unilateral ACL injury completed gait analysis before (baseline) and after (posttraining) preoperative rehabilitation and at 6 months, 1 year, and 2 years after reconstruction. Surface electromyographic and knee biomechanical data served as inputs to an electromyographically driven musculoskeletal model to estimate knee joint contact forces. Patients completed radiographic testing 5 years after reconstruction. Differences in knee joint kinetics and contact forces were compared between patients with and those without radiographic knee OA. Results Patients with OA walked with greater frontal plane interlimb differences than those without OA (nonOA) at baseline (peak knee adduction moment difference: 0.00 ± 0.08 N·m/kg·m [nonOA] vs −0.15 ± 0.09 N·m/kg·m [OA], P = .014; peak knee adduction moment impulse difference: −0.001 ± 0.032 N·m·s/kg·m [nonOA] vs −0.048 ± 0.031 N·m·s/kg·m [OA], P = .042). The involved limb knee adduction moment impulse of the group with osteoarthritis was also lower than that of the group without osteoarthritis at baseline (0.087 ± 0.023 N·m·s/kg·m [nonOA] vs 0.049 ± 0.018 N·m·s/kg·m [OA], P = .023). Significant group differences were absent at posttraining but reemerged 6 months after reconstruction (peak knee adduction moment difference: 0.02 ± 0.04 N·m/kg·m [nonOA] vs −0.06 ± 0.11 N·m/kg·m [OA], P = .043). In addition, the OA group walked with lower peak

  15. Joint stiffness of the ankle and the knee in running.

    PubMed

    Günther, Michael; Blickhan, Reinhard

    2002-11-01

    The spring-mass model is a valid fundament to understand global dynamics of fast legged locomotion under gravity. The underlying concept of elasticity, implying leg stiffness as a crucial parameter, is also found on lower motor control levels, i.e. in muscle-reflex and muscle-tendon systems. Therefore, it seems reasonable that global leg stiffness emerges from local elasticity established by appropriate joint torques. A recently published model of an elastically operating, segmented leg predicts that proper adjustment of joint elasticities to the leg geometry and initial conditions of ground contact provides internal leg stability. Another recent study suggests that in turn the leg segmentation and the initial conditions may be a consequence of metabolic and bone stress constraints. In this study, the theoretical predictions were verified experimentally with respect to initial conditions and elastic joint characteristics in human running. Kinematics and kinetics were measured and the joint torques were estimated by inverse dynamics. Stiffnesses and elastic nonlinearities describing the resulting joint characteristics were extracted from parameter fits. Our results clearly support the theoretical predictions: the knee joint is always stiffer and more extended than the ankle joint. Moreover, the knee torque characteristic on the average shows the higher nonlinearity. According to literature, the leg geometry is a consequence of metabolic and material stress limitations. Adapted to this given geometry, the initial joint angle conditions in fast locomotion are a compromise between metabolic and control effort minimisation. Based on this adaptation, an appropriate joint stiffness ratio between ankle and knee passively safeguards the internal leg stability. The identified joint nonlinearities contribute to the linearisation of the leg spring.

  16. Soft tissue artifact compensation in knee kinematics by multi-body optimization: Performance of subject-specific knee joint models.

    PubMed

    Clément, Julien; Dumas, Raphaël; Hagemeister, Nicola; de Guise, Jaques A

    2015-11-01

    Soft tissue artifact (STA) distort marker-based knee kinematics measures and make them difficult to use in clinical practice. None of the current methods designed to compensate for STA is suitable, but multi-body optimization (MBO) has demonstrated encouraging results and can be improved. The goal of this study was to develop and validate the performance of knee joint models, with anatomical and subject-specific kinematic constraints, used in MBO to reduce STA errors. Twenty subjects were recruited: 10 healthy and 10 osteoarthritis (OA) subjects. Subject-specific knee joint models were evaluated by comparing dynamic knee kinematics recorded by a motion capture system (KneeKG™) and optimized with MBO to quasi-static knee kinematics measured by a low-dose, upright, biplanar radiographic imaging system (EOS(®)). Errors due to STA ranged from 1.6° to 22.4° for knee rotations and from 0.8 mm to 14.9 mm for knee displacements in healthy and OA subjects. Subject-specific knee joint models were most effective in compensating for STA in terms of abduction-adduction, inter-external rotation and antero-posterior displacement. Root mean square errors with subject-specific knee joint models ranged from 2.2±1.2° to 6.0±3.9° for knee rotations and from 2.4±1.1 mm to 4.3±2.4 mm for knee displacements in healthy and OA subjects, respectively. Our study shows that MBO can be improved with subject-specific knee joint models, and that the quality of the motion capture calibration is critical. Future investigations should focus on more refined knee joint models to reproduce specific OA knee geometry and physiology.

  17. Osteochondral grafting of knee joint using mosaicplasty.

    PubMed

    Wajid, Muhammad Abdul; Shah, Muhammad Idrees; Mohsin-e-Azam; Ahmad, Tashfeen

    2011-03-01

    Focal cartilage defects of articular surface-traumatic and degenerative are difficult to treat, thus a variety of surgical techniques have been developed and reported for treatment of such defects. Procedures such as Priddies perforations, microfracture, abrasion chondroplasty have shown long-term results which are often less than adequate. One of the reasons is that all these techniques lead to the formation of fibrocartilage which has inferior mechanical properties as compared to the native hyaline cartilage. Mosaicplasty is a procedure which aims at replacing the lost articular cartilage with hyaline cartilage including underlying bone support, thus providing adequate stability to the cartilage and better cartilage/bone integration. A young man underwent this procedure for recalcitrant knee pain at our institution. At 2 years follow-up, his knee pain has significantly improved. We hereby present medium term results (2 years) of this first case report in local literature.

  18. Mathematical modeling of the human knee joint

    SciTech Connect

    Ricafort, Juliet

    1996-05-01

    A model was developed to determine the forces exerted by several flexor and extensor muscles of the human knee under static conditions. The following muscles were studied: the gastrocnemius, biceps femoris, semitendinosus, semimembranosus, and the set of quadricep muscles. The tibia and fibula were each modeled as rigid bodies; muscles were modeled by their functional lines of action in space. Assumptions based on previous data were used to resolve the indeterminacy.

  19. Visualization of a newborn's hip joint using 3D ultrasound and automatic image processing

    NASA Astrophysics Data System (ADS)

    Overhoff, Heinrich M.; Lazovic, Djordje; von Jan, Ute

    1999-05-01

    Graf's method is a successful procedure for the diagnostic screening of developmental dysplasia of the hip. In a defined 2-D ultrasound (US) scan, which virtually cuts the hip joint, landmarks are interactively identified to derive congruence indicators. As the indicators do not reflect the spatial joint structure, and the femoral head is not clearly visible in the US scan, here 3-D US is used to gain insight to the hip joint in its spatial form. Hip joints of newborns were free-hand scanned using a conventional ultrasound transducer and a localizer system fixed on the scanhead. To overcome examiner- dependent findings the landmarks were detected by automatic segmentation of the image volume. The landmark image volumes and an automatically determined virtual sphere approximating the femoral head were visualized color-coded on a computer screen. The visualization was found to be intuitive and to simplify the diagnostic substantially. By the visualization of the 3-D relations between acetabulum and femoral head the reliability of diagnostics is improved by finding the entire joint geometry.

  20. Self-adjusting, isostatic exoskeleton for the human knee joint.

    PubMed

    Cai, Viet Anh Dung; Bidaud, Philippe; Hayward, Vincent; Gosselin, Florian; Desailly, Eric

    2011-01-01

    A knee-joint exoskeleton design that can apply programmable torques to the articulation and that self-adjusts to its physiological movements is described. Self-adjustment means that the articular torque is automatically produced around the rotational axis of the joint. The requirements are first discussed and the conditions under which the system tracks the spatial relative movements of the limbs are given. If these conditions are met, the torque applied to the joint takes into account the possible relative movements of the limbs without introducing constraints. A prototype was built to demonstrate the applicability of these principles and preliminary tests were carried out to validate the design.

  1. Self-adjusting, isostatic exoskeleton for the human knee joint.

    PubMed

    Cai, Viet Anh Dung; Bidaud, Philippe; Hayward, Vincent; Gosselin, Florian; Desailly, Eric

    2011-01-01

    A knee-joint exoskeleton design that can apply programmable torques to the articulation and that self-adjusts to its physiological movements is described. Self-adjustment means that the articular torque is automatically produced around the rotational axis of the joint. The requirements are first discussed and the conditions under which the system tracks the spatial relative movements of the limbs are given. If these conditions are met, the torque applied to the joint takes into account the possible relative movements of the limbs without introducing constraints. A prototype was built to demonstrate the applicability of these principles and preliminary tests were carried out to validate the design. PMID:22254384

  2. Sex Differences in Proximal Control of the Knee Joint

    PubMed Central

    Mendiguchia, Jurdan; Ford, Kevin R.; Quatman, Carmen E.; Alentorn-Geli, Eduard; Hewett, Timothy E.

    2014-01-01

    Following the onset of maturation, female athletes have a significantly higher risk for anterior cruciate ligament (ACL) injury compared with male athletes. While multiple sex differences in lower-extremity neuromuscular control and biomechanics have been identified as potential risk factors for ACL injury in females, the majority of these studies have focused specifically on the knee joint. However, increasing evidence in the literature indicates that lumbopelvic (core) control may have a large effect on knee-joint control and injury risk. This review examines the published evidence on the contributions of the trunk and hip to knee-joint control. Specifically, the sex differences in potential proximal controllers of the knee as risk factors for ACL injury are identified and discussed. Sex differences in trunk and hip biomechanics have been identified in all planes of motion (sagittal, coronal and transverse). Essentially, female athletes show greater lateral trunk displacement, altered trunk and hip flexion angles, greater ranges of trunk motion, and increased hip adduction and internal rotation during sport manoeuvres, compared with their male counterparts. These differences may increase the risk of ACL injury among female athletes. Prevention programmes targeted towards trunk and hip neuromuscular control may decrease the risk for ACL injuries. PMID:21688868

  3. Bio-inspired design of geometrically interlocked 3D printed joints

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Oliva, Noel; Kumar's Lab Team

    The morphology of the adhesive-adherend interface significantly affects the mechanical behavior of adhesive joints. As seen in some biocomposites like human skull, or the nacre of some bivalve molluscs' shells, a geometrically interlocking architecture of interfaces creates toughening and strengthening mechanisms enhancing the mechanical properties of the joint. In an attempt to characterize this mechanical interlocking mechanism, this study is focused on computational and experimental investigation of a single-lap joint with a very simple geometrically interlocked interface design in which both adherends have a square waveform configuration of the joining surfaces. This square waveform configuration contains a positive and a negative rectangular teeth per cycle in such a way that the joint is symmetric about the mid-bondlength. Both physical tests performed on 3D printed prototypes of joints and computational results indicate that the joints with square waveform design have higher strength and damage tolerance than those of joints with flat interface. In order to identify an optimal design configuration of this interface, a systematic parametric study is conducted by varying the geometric and material properties of the non-flat interface. This work was supported by Lockheed Martin (Award No: 12NZZ1).

  4. Fungal prosthetic joint infection after total knee arthroplasty

    PubMed Central

    Reddy, Kankanala J; Shah, Jay D; Kale, Rohit V; Reddy, T Jayakrishna

    2013-01-01

    Fungal prosthetic joint infection after total knee arthroplasty (TKA) is a rare complication. Lacunae exist in the management of this complication. 62 year old lady presented with pain and swelling in left knee and was diagnosed as Candida tropicalis fungal infection after TKA. She underwent debridement, resection arthroplasty and antifungal plus antibiotic loaded cement spacer insertion, antifungal therapy with fluconazole followed by delayed revision TKA and further fluconazole therapy. Total duration of fluconazole therapy was 30 weeks. At 2 year followup, she has pain less range of motion of 10°-90° and there is no evidence of recurrence of infection. PMID:24133317

  5. Fatigue effects on knee joint stability during two jump tasks in women.

    PubMed

    Ortiz, Alexis; Olson, Sharon L; Etnyre, Bruce; Trudelle-Jackson, Elaine E; Bartlett, William; Venegas-Rios, Heidi L

    2010-04-01

    Dynamic knee joint stability may be affected by the onset of metabolic fatigue during sports participation that could increase the risk for knee injury. The purpose of this investigation was to determine the effects of metabolic fatigue on knee muscle activation, peak knee joint angles, and peak knee internal moments in young women during 2 jumping tasks. Fifteen women (mean age: 24.6 +/- 2.6 years) participated in one nonfatigued session and one fatigued session. During both sessions, peak knee landing flexion and valgus joint angles, peak knee extension and varus/valgus internal moments, electromyographic (EMG) muscle activity of the quadriceps and hamstrings, and quadriceps/hamstring EMG cocontraction ratio were measured. The tasks consisted of a single-legged drop jump from a 40-cm box and a 20-cm, up-down, repeated hop task. The fatigued session included a Wingate anaerobic protocol followed by performance of the 2 tasks. Although participants exhibited greater knee injury-predisposing factors during the fatigued session, such as lesser knee flexion joint angles, greater knee valgus joint angles, and greater varus/valgus internal joint moments for both tasks, only knee flexion during the up-down task was statistically significant (p = 0.028). Metabolic fatigue may perhaps predispose young women to knee injuries by impairing dynamic knee joint stability. Training strength-endurance components and the ability to maintain control of body movements in either rested or fatigued situations might help reduce injuries in young women athletes. PMID:20300024

  6. Instrumented knee joint implants: innovations and promising concepts.

    PubMed

    Torrão, João N D; Dos Santos, Marco P Soares; Ferreira, Jorge A F

    2015-01-01

    This article focuses on in vivo implementations of instrumented knee implants and recent prototypes with highly innovative potential. An in-depth analysis of the evolution of these systems was conducted, including three architectures developed by two research teams for in vivo operation that were implanted in 13 patients. The specifications of their various subsystems: sensor/transducers, power management, communication and processing/control units are presented, and their features are compared. These systems were designed to measure biomechanical quantities to further assist in rehabilitation and physical therapy, to access proper implant placement and joint function and to help predicting aseptic loosening. Five prototype systems that aim to improve their operation, as well as include new abilities, are also featured. They include technology to assist proper ligament tensioning and ensure self-powering. One can conclude that the concept of instrumented active knee implant seems the most promising trend for improving the outcomes of knee replacements.

  7. Analysis of controlling parameters for shear behavior of rock joints with FLAC3D

    NASA Astrophysics Data System (ADS)

    Tiwari, Prasoon

    The research investigation is conducted to perform an analysis of sensitivity of parameters affecting the strength of joints in rock mass. Friction angle, normal stiffness, shear stiffness and shear displacement are the parameters analyzed with respect to shear strength of rock joints. Discontinuities have an important influence on the deformational behavior of rock systems; hence, proper consideration of the physical and mechanical properties of discontinuities is necessary during experimental investigation, in order to correctly evaluate the shear behavior. These parameters are utilized to simulate the in situ stress condition in numerical modeling, which is important for safe and economical design of various engineering constructions. These concerns require accurate quantification of shear strength of unfilled and in-filled joints, proper understanding of the basic mechanics of discontinuity and the principals involved in their shear deformation. This can be achieved through laboratory testing on natural rock core samples. In the present work, the detailed account of test results of direct shear tests performed on rock joints is presented. Rock samples are obtained by core drilling in an underground mine, in Nevada. These rock samples, containing joint, are used to perform direct shear strength test. Calibration of numerical model is done on average values obtained from direct shear strength test. Analysis of sensitivity of parameters effecting shear strength of rock is done in FLAC3D shear test environment. A numerical parametric study is done, according to the Mohr-Coulomb constitutive model, and results obtained are plotted to estimate performance of rock joints.

  8. Role of Agnikarma in Sandhigata Vata (osteoarthritis of knee joint)

    PubMed Central

    Jethava, Nilesh G.; Dudhamal, Tukaram S.; Gupta, Sanjay Kumar

    2015-01-01

    Introduction: Sandhigata Vata is one of Vata Vyadhi characterized by the symptoms such as Sandhishoola (joint pain) and Sandhishopha (swelling of joint). Osteoarthritis (OA) is degenerative joint disorder, represents failure of the diarthrodial (movable, synovial-lined) joint. OA of knee joint comes under the inflammatory group which is almost identical to Sandhigata Vata described in Ayurveda with respect to etiology, pathology, and clinical features. Agnikarma (therapeutic heat burn) is one which gives instant relief from pain by balancing local Vata and Kapha Dosha without any untoward effects. Aim: To evaluate the efficacy of Agnikarma with Rajata and Loha Dhatu Shalaka in the management of Janugata Sandhivata (OA of knee joint). Materials and Methods: A total of 28 diagnosed patients of Janugata Sandhivata were registered and randomly divided into two groups. In Group-A, Agnikarma was done with Rajata Shalaka while in Group-B Agnikarma was performed by Loha Shalaka in four sittings. Assessment in relief of signs and symptoms was done by weekly interval, and Student's t-test was applied for statistical analysis. Results: Group-A provided 76.31% relief in pain while Group-B provided 83.77% relief. Relief from crepitus was observed in 57.13% of patients of Group-A, while 57.92% of patients of Group-B. There was statistically insignificant difference between both the groups. Loha Shalaka provided better result in pain relief than Rajata Shalaka. Conclusion: Agnikarma is effective nonpharmacological, parasurgical procedure for pain management in Sandhigata Vata (OA of knee joint). PMID:26730134

  9. Shea Nut Oil Triterpene Concentrate Attenuates Knee Osteoarthritis Development in Rats: Evidence from Knee Joint Histology

    PubMed Central

    Lin, Sheng-Hsiung; Lai, Chun-Fu; Lin, Yu-Chieh; Kong, Zwe-Ling; Wong, Chih-Shung

    2016-01-01

    Background Shea nut oil triterpene concentrate is considered to have anti-inflammatory and antioxidant properties. Traditionally, it has been used to treat arthritic conditions in humans. This study aimed to investigate the effect of attenuating osteoarthritis (OA)-induced pain and joint destruction in rats by administering shea nut oil triterpene concentrate (SheaFlex75, which is more than 50% triterpenes). Methods An anterior cruciate ligament transaction (ACLT) with medial meniscectomy (MMx) was used to induce OA in male Wistar rats. Different doses of SheaFlex75 (111.6 mg/kg, 223.2 mg/kg, and 446.4 mg/kg) were then intragastrically administered daily for 12 weeks after surgery. Body weight and the width of the knee joint were measured weekly. Additionally, incapacitance tests were performed at weeks 2, 4, 6, 8, 10 and 12 to measure the weight bearing of the hind limbs, and the morphology and histopathology of the medial femoral condyles were examined and were evaluated using the Osteoarthritis Research Society International (OARSI) scoring system. Results This study showed that SheaFlex75 reduced the swelling of the knee joint with OA and rectified its weight bearing after ACLT plus MMx surgery in rats. Treatment with SheaFlex75 also decreased ACLT plus MMx surgery-induced knee joint matrix loss and cartilage degeneration. Conclusion SheaFlex75 relieves the symptoms of OA and protects cartilage from degeneration. SheaFlex75 thus has the potential to be an ideal nutraceutical supplement for joint protection, particularly for injured knee joints. PMID:27583436

  10. Development and validation of a computational model of the knee joint for the evaluation of surgical treatments for osteoarthritis

    PubMed Central

    Mootanah, R.; Imhauser, C.W.; Reisse, F.; Carpanen, D.; Walker, R.W.; Koff, M.F.; Lenhoff, M.W.; Rozbruch, S.R.; Fragomen, A.T.; Dewan, Z.; Kirane, Y.M.; Cheah, Pamela A.; Dowell, J.K.; Hillstrom, H.J.

    2014-01-01

    A three-dimensional (3D) knee joint computational model was developed and validated to predict knee joint contact forces and pressures for different degrees of malalignment. A 3D computational knee model was created from high-resolution radiological images to emulate passive sagittal rotation (full-extension to 65°-flexion) and weight acceptance. A cadaveric knee mounted on a six-degree-of-freedom robot was subjected to matching boundary and loading conditions. A ligament-tuning process minimised kinematic differences between the robotically loaded cadaver specimen and the finite element (FE) model. The model was validated by measured intra-articular force and pressure measurements. Percent full scale error between EE-predicted and in vitro-measured values in the medial and lateral compartments were 6.67% and 5.94%, respectively, for normalised peak pressure values, and 7.56% and 4.48%, respectively, for normalised force values. The knee model can accurately predict normalised intra-articular pressure and forces for different loading conditions and could be further developed for subject-specific surgical planning. PMID:24786914

  11. Intensity of joints associated with an extensional fault zone: an estimation by poly3d .

    NASA Astrophysics Data System (ADS)

    Minelli, G.

    2003-04-01

    The presence and frequency of joints in sedimentary rocks strongly affects the mechanical and fluid flow properties of the host layers. Joints intensity is evaluated by spacing, S, the distance between neighbouring fractures, or by density, D = 1/S. Joint spacing in layered rocks is often linearly related to layer thickness T, with typical values of 0.5 T < S < 2.0 T . On the other hand, some field cases display very tight joints with S << T and nonlinear relations between spacing and thickness , most of these cases are related to joint system “genetically” related to a nearby fault zone. The present study by using the code Poly3D (Rock Fracture Project at Stanford), numerically explores the effect of the stress distribution in the neighbour of an extensional fault zone with respect to the mapped intensity of joints both in the hanging wall and in the foot wall of it (WILLEMSE, E. J. M., 1997; MARTEL, S. J, AND BOGER, W. A,; 1998). Poly3D is a C language computer program that calculates the displacements, strains and stresses induced in an elastic whole or half-space by planar, polygonal-shaped elements of displacement discontinuity (WILLEMSE, E. J. M., POLLARD, D. D., 2000) Dislocations of varying shapes may be combined to yield complex three-dimensional surfaces well-suited for modeling fractures, faults, and cavities in the earth's crust. The algebraic expressions for the elastic fields around a polygonal element are derived by superposing the solution for an angular dislocation in an elastic half-space. The field data have been collected in a quarry located close to Noci town (Puglia) by using the scan line methodology. In this quarry a platform limestone with a regular bedding with very few shale or marly intercalations displaced by a normal fault are exposed. The comparison between the mapped joints intensity and the calculated stress around the fault displays a good agreement. Nevertheless the intrinsic limitations (isotropic medium and elastic behaviour

  12. Accurate 3D kinematic measurement of temporomandibular joint using X-ray fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Yamazaki, Takaharu; Matsumoto, Akiko; Sugamoto, Kazuomi; Matsumoto, Ken; Kakimoto, Naoya; Yura, Yoshiaki

    2014-04-01

    Accurate measurement and analysis of 3D kinematics of temporomandibular joint (TMJ) is very important for assisting clinical diagnosis and treatment of prosthodontics and orthodontics, and oral surgery. This study presents a new 3D kinematic measurement technique of the TMJ using X-ray fluoroscopic images, which can easily obtain the TMJ kinematic data in natural motion. In vivo kinematics of the TMJ (maxilla and mandibular bone) is determined using a feature-based 2D/3D registration, which uses beads silhouette on fluoroscopic images and 3D surface bone models with beads. The 3D surface models of maxilla and mandibular bone with beads were created from CT scans data of the subject using the mouthpiece with the seven strategically placed beads. In order to validate the accuracy of pose estimation for the maxilla and mandibular bone, computer simulation test was performed using five patterns of synthetic tantalum beads silhouette images. In the clinical applications, dynamic movement during jaw opening and closing was conducted, and the relative pose of the mandibular bone with respect to the maxilla bone was determined. The results of computer simulation test showed that the root mean square errors were sufficiently smaller than 1.0 mm and 1.0 degree. In the results of clinical application, during jaw opening from 0.0 to 36.8 degree of rotation, mandibular condyle exhibited 19.8 mm of anterior sliding relative to maxillary articular fossa, and these measurement values were clinically similar to the previous reports. Consequently, present technique was thought to be suitable for the 3D TMJ kinematic analysis.

  13. Rapid object indexing using locality sensitive hashing and joint 3D-signature space estimation.

    PubMed

    Matei, Bogdan; Shan, Ying; Sawhney, Harpreet S; Tan, Yi; Kumar, Rakesh; Huber, Daniel; Hebert, Martial

    2006-07-01

    We propose a new method for rapid 3D object indexing that combines feature-based methods with coarse alignment-based matching techniques. Our approach achieves a sublinear complexity on the number of models, maintaining at the same time a high degree of performance for real 3D sensed data that is acquired in largely uncontrolled settings. The key component of our method is to first index surface descriptors computed at salient locations from the scene into the whole model database using the Locality Sensitive Hashing (LSH), a probabilistic approximate nearest neighbor method. Progressively complex geometric constraints are subsequently enforced to further prune the initial candidates and eliminate false correspondences due to inaccuracies in the surface descriptors and the errors of the LSH algorithm. The indexed models are selected based on the MAP rule using posterior probability of the models estimated in the joint 3D-signature space. Experiments with real 3D data employing a large database of vehicles, most of them very similar in shape, containing 1,000,000 features from more than 365 models demonstrate a high degree of performance in the presence of occlusion and obscuration, unmodeled vehicle interiors and part articulations, with an average processing time between 50 and 100 seconds per query.

  14. Numerical Investigation of T-joints with 3D Four Directional Braided Composite Fillers Under Tensile Loading

    NASA Astrophysics Data System (ADS)

    Li, Xiao-kang; Liu, Zhen-guo; Hu, Long; Wang, Yi-bo; Lei, Bing; Huang, Xiang

    2016-08-01

    Numerical studied on T-joints with three-dimensional four directional (3D4D) braided composite fillers was presented in this article. Compared with conventional unidirectional prepreg fillers, the 3D braided composite fillers have excellent ability to prevent crack from penetrating trigone fillers, which constantly occurred in the conventional fillers. Meanwhile, the 3D braided composite fillers had higher fiber volume fraction and eliminated the fiber folding problem in unidirectional prepreg fillers. The braiding technology and mechanical performance of 3D4D braided fillers were studied. The numerical model of carbon fiber T-joints with 3D4D braided composite fillers was built by finite element analysis software. The damage formation, extension and failing process of T-joints with 3D4D braided fillers under tensile load were investigated. Further investigation was extended to the effect of 3D4D braided fillers with different braiding angles on mechanical behavior of the T-joints. The study results revealed that the filling area was the weakest part of the T-joints where the damage first appeared and the crack then rapidly spread to the glue film around the filling area and the interface between over-laminate and soleplate. The 3D4D braided fillers were undamaged and the braiding angle change induced a little effect on the bearing capacity of T-joints.

  15. Research on Joint Parameter Inversion for an Integrated Underground Displacement 3D Measuring Sensor

    PubMed Central

    Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

    2015-01-01

    Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0 ~ 30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor. PMID:25871714

  16. Research on joint parameter inversion for an integrated underground displacement 3D measuring sensor.

    PubMed

    Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

    2015-01-01

    Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0~30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor. PMID:25871714

  17. Analysis of knee-joint forces during flexed-knee stance.

    PubMed

    Perry, J; Antonelli, D; Ford, W

    1975-10-01

    Using an instrumented cadaver lower extremity, the forces in the quadriceps, patella, and tibia during flexed-knee stance were measured and the calculated and experimental data were found to correlate with an average discrepancy of 6 per cent. The quadriceps force required to stabilize the knee was 75 per cent of the load on the femoral head at 15 degrees of knee flexion, 210 per cent at 30 degrees, and 410 per cent at 60 degrees. Stresses at the tibiofemoral and patellofemoral joint surfaces increased in similar fashion. The quadriceps force was equivalent to 20 per cent of average maximum quadriceps strength at 15 degrees and to 50 per cent at 30 degrees, as determined from torque tests on five normal subjects.

  18. [Ski shoe versus knee joint--3: Risk for falling backward].

    PubMed

    Schaff, P; Hauser, W

    1990-12-01

    In contrast to the drop in the incidence of fractures of the lower leg that has been observed in recent years, the incidence of knee injuries has not decreased in skiing. There has even been a relative increase of severe knee lesions and isolated ACL ruptures, prompting us to conduct a comprehensive study of the causes of this phenomena. The goal of the study was to develop a new measuring device for alpine skiing research by combining motion analysis, pressure and force measurement, comprehensive examine the forward/backward movement in skiboots in the lab and by means of telemetry on the slope (Skiboot versus knee joint part 1/Sportverlerletzung. Sportschaden 3, 1989, pp. 149-161) and to come up with a proposal for a new safety concept to reduce the high number of knee injuries in alpine skiing in the future. The first study was devoted to the forward movement in skiboots (Skiboot versus knee joint part 2/Sportverletzung. Sportschaden 4, 1990, pp. 1-13). The results showed that a skiing style in backward lean position was adopted by skiers wearing boots with a stiff forward flexion and was supported by the fixed backward spoiler. In order to quantify the influence of the backward spoiler a special skiboot was constructed allowing the rear spoiler to give way at a variable, defined stiffness and register the angular displacement and horizontal force Fh. The results showed most clearly that even a medium rear spoiler resistance will sign, reduce the peak force values by a factor of 5.5. The acceleration at the knee joint level is significantly higher (factor 1.6, p less than 0.05) in case of a rigid spoiler. The lab tests could be confirmed on the slope (sign. reduction of max. force by factor 8). It also proved that normal skiing can be performed in such a boot without limitations. In consideration of our facts it is concluded that the principle of safety bindings must definitely apply in future in equal measure also to the ski boot. As a proposal for future

  19. Effect of static stretching of muscles surrounding the knee on knee joint position sense

    PubMed Central

    Ghaffarinejad, Farahnaz; Taghizadeh, Shohreh; Mohammadi, Farshid

    2007-01-01

    Background Muscle stretching is widely used in sport training and in rehabilitation. Considering the important contribution of joint position sense (JPS) to knee joint stability and function, it is legitimate to question if stretching might alter the knee JPS. Objective To evaluate if a stretch regimen consisting of three 30 s stretches alters the knee JPS. Design and setting A blinded, randomised design with a washout time of 24 h was used. Subjects 39 healthy students (21 women, 18 men) volunteered to participate in this study. Methods and main outcome measures JPS was estimated by the ability to reproduce the two target positions (20° and 45° of flexion) in the dominant knee. The absolute angular error (AAE) was defined as the absolute difference between the target angle and the subject perceived angle of knee flexion. AAE values were measured before and immediately after the static stretch. Measurements were repeated three times. The static stretch comprised a 30 s stretch followed by a 30 s pause, three times for each muscle. Results The AAE decreased significantly after the stretching protocols for quadriceps (3.5 (1.3) vs 0.7 (2.4); p<0.001), hamstring (3.6 (2.2) vs 1.6 (3.1); p = 0.016) and adductors (3.7 (2.8) vs 1.7 (2.4); p = 0.016) in 45° of flexion, but no differences were found for values of the gastrocnemius and popliteus muscles in this angle and for the values of all muscles in 20° of flexion (p>0.05). Conclusion The accuracy of the knee JPS in 45° of flexion is improved subsequent to a static stretch regimen of quadriceps, hamstring and adductors in healthy subjects. PMID:17510229

  20. Behavioral effect of knee joint motion on body's center of mass during human quiet standing.

    PubMed

    Yamamoto, Akio; Sasagawa, Shun; Oba, Naoko; Nakazawa, Kimitaka

    2015-01-01

    The balance control mechanism during upright standing has often been investigated using single- or double-link inverted pendulum models, involving the ankle joint only or both the ankle and hip joints, respectively. Several studies, however, have reported that knee joint motion during quiet standing cannot be ignored. This study aimed to investigate the degree to which knee joint motion contributes to the center of mass (COM) kinematics during quiet standing. Eight healthy adults were asked to stand quietly for 30s on a force platform. Angular displacements and accelerations of the ankle, knee, and hip joints were calculated from kinematic data obtained by a motion capture system. We found that the amplitude of the angular acceleration was smallest in the ankle joint and largest in the hip joint (ankle < knee < hip). These angular accelerations were then substituted into three biomechanical models with or without the knee joint to estimate COM acceleration in the anterior-posterior direction. Although the "without-knee" models greatly overestimated the COM acceleration, the COM acceleration estimated by the "with-knee" model was similar to the actual acceleration obtained from force platform measurement. These results indicate substantial effects of knee joint motion on the COM kinematics during quiet standing. We suggest that investigations based on the multi-joint model, including the knee joint, are required to reveal the physiologically plausible balance control mechanism implemented by the central nervous system. PMID:25248799

  1. Behavioral effect of knee joint motion on body's center of mass during human quiet standing.

    PubMed

    Yamamoto, Akio; Sasagawa, Shun; Oba, Naoko; Nakazawa, Kimitaka

    2015-01-01

    The balance control mechanism during upright standing has often been investigated using single- or double-link inverted pendulum models, involving the ankle joint only or both the ankle and hip joints, respectively. Several studies, however, have reported that knee joint motion during quiet standing cannot be ignored. This study aimed to investigate the degree to which knee joint motion contributes to the center of mass (COM) kinematics during quiet standing. Eight healthy adults were asked to stand quietly for 30s on a force platform. Angular displacements and accelerations of the ankle, knee, and hip joints were calculated from kinematic data obtained by a motion capture system. We found that the amplitude of the angular acceleration was smallest in the ankle joint and largest in the hip joint (ankle < knee < hip). These angular accelerations were then substituted into three biomechanical models with or without the knee joint to estimate COM acceleration in the anterior-posterior direction. Although the "without-knee" models greatly overestimated the COM acceleration, the COM acceleration estimated by the "with-knee" model was similar to the actual acceleration obtained from force platform measurement. These results indicate substantial effects of knee joint motion on the COM kinematics during quiet standing. We suggest that investigations based on the multi-joint model, including the knee joint, are required to reveal the physiologically plausible balance control mechanism implemented by the central nervous system.

  2. Estimating total knee replacement joint load ratios from kinematics.

    PubMed

    Fitzpatrick, Clare K; Rullkoetter, Paul J

    2014-09-22

    Accurate prediction of loads acting at the joint in total knee replacement (TKR) patients is key to developing experimental or computational simulations which evaluate implant designs under physiological loading conditions. In vivo joint loads have been measured for a small number of telemetric TKR patients, but in order to assess device performance across the entire patient population, a larger patient cohort is necessary. This study investigates the accuracy of predicting joint loads from joint kinematics. Specifically, the objective of the study was to assess the accuracy of internal-external (I-E) and anterior-posterior (A-P) joint load predictions from I-E and A-P motions under a given compressive load, and to evaluate the repeatability of joint load ratios (I-E torque to compressive force (I-E:C), and A-P force to compressive force (A-P:C)) for a range of compressive loading profiles. A tibiofemoral finite element model was developed and used to simulate deep knee bend, chair-rise and step-up activities for five patients. Root-mean-square (RMS) differences in I-E:C and A-P:C load ratios between telemetric measurements and model predictions were less than 1.10e-3 Nm/N and 0.035 N/N for all activities. I-E:C and A-P:C load ratios were consistently reproduced regardless of the compressive force profile applied (RMS differences less than 0.53e-3 Nm/N and 0.010 N/N, respectively). When error in kinematic measurement was introduced to the model, joint load predictions were forgiving to kinematic measurement error when conformity between femoral and tibial components was low. The prevalence of kinematic data, in conjunction with the analysis presented here, facilitates determining the scope of A-P and I-E joint loading ratios experienced by the TKR population.

  3. Time And Temperature Dependent Micromechanical Properties Of Solder Joints For 3D-Package Integration

    NASA Astrophysics Data System (ADS)

    Roellig, Mike; Meier, Karsten; Metasch, Rene

    2010-11-01

    The recent development of 3D-integrated electronic packages is characterized by the need to increase the diversity of functions and to miniaturize. Currently many 3D-integration concepts are being developed and all of them demand new materials, new designs and new processing technologies. The combination of simulation and experimental investigation becomes increasingly accepted since simulations help to shorten the R&D cycle time and reduce costs. Numerical calculations like the Finite-Element-Method are strong tools to calculate stress conditions in electronic packages resulting from thermal strains due to the manufacturing process and environmental loads. It is essential for the application of numerical calculations that the material data is accurate and describes sufficiently the physical behaviour. The developed machine allows the measurement of time and temperature dependent micromechanical properties of solder joints. Solder joints, which are used to mechanically and electrically connect different packages, are physically measured as they leave the process. This allows accounting for process influences, which may change material properties. Additionally, joint sizes and metallurgical interactions between solder and under bump metallization can be respected by this particular measurement. The measurement allows the determination of material properties within a temperature range of 20° C-200° C. Further, the time dependent creep deformation can be measured within a strain-rate range of 10-31/s-10-81/s. Solder alloys based on Sn-Ag/Sn-Ag-Cu with additionally impurities and joint sizes down to O/ 200 μm were investigated. To finish the material characterization process the material model coefficient were extracted by FEM-Simulation to increase the accuracy of data.

  4. Geophysical monitoring using 3D joint inversion of multi-modal geophysical data with Gramian constraints

    NASA Astrophysics Data System (ADS)

    Zhdanov, M. S.; Gribenko, A.; Wilson, G. A.

    2012-12-01

    Geophysical monitoring of reservoir fluids and rock properties is relevant to oil and gas production, carbon sequestration, and enhanced geothermal systems. Different geophysical fields provide information about different physical properties of the earth. Multiple geophysical surveys spanning gravity, magnetic, electromagnetic, seismic, and thermal methods are often interpreted to infer geology from models of different physical properties. In many cases, the various geophysical data are complimentary, making it natural to consider a formal mathematical framework for their joint inversion to a shared earth model. We introduce a new approach to the 3D joint inversion of multiple geophysical datasets using Gramian spaces of model parameters and Gramian constraints, computed as determinants of the corresponding Gram matrices of the multimodal model parameters and/or their attributes. The basic underlying idea of this approach is that the Gramian provides a measure of correlation between the model parameters. By imposing an additional requirement of the minimum of the Gramian, we arrive at the solution of the joint multimodal inverse problem with the enhanced correlation between the different model parameters and/or their attributes. We demonstrate that this new approach is a generalized technique that can be applied to the simultaneous joint inversion of any number and combination of geophysical datasets. Our approach includes as special cases those extant methods based on correlations and/or structural constraints of different physical properties. We illustrate this approach by a model study of reservoir monitoring using different geophysical data.

  5. Effects of kinesiology taping on repositioning error of the knee joint after quadriceps muscle fatigue.

    PubMed

    Han, Jin Tae; Lee, Jung-Hoon

    2014-06-01

    [Purpose] The purpose of this study was to identify the effects of kinesiology taping on repositioning error of the knee joint after quadriceps muscle fatigue. [Subjects] Thirty healthy adults with no orthopaedic or neurological problems participated in this study. [Methods] The repositioning error of the knee joint was measured using a digital goniometer when the subjects extended their dominant-side knee to a random target angle (30°, 45°, or 60°) with their eyes closed, before and after a quadriceps muscle fatigue protocol, and after application of kinesiology tape. [Results] We found that repositioning errors of the dominant-side knee joint increased after quadriceps fatigue compared with no-fatigue conditions. However, kinesiology taping of the quadriceps muscle and patella after quadriceps fatigue significantly decreased repositioning errors of the knee joint. [Conclusion] These results suggest that quadriceps fatigue increases the repositioning error of the knee joint, whereas application of kinesiology tape decreases fatigue-induced joint repositioning error.

  6. Investigating the Potential of Using Off-Axis 3D Woven Composites in Composite Joints' Applications

    NASA Astrophysics Data System (ADS)

    Saleh, Mohamed Nasr; Wang, Ying; Yudhanto, Arief; Joesbury, Adam; Potluri, Prasad; Lubineau, Gilles; Soutis, Constantinos

    2016-09-01

    The effect of circular notch has been evaluated for three different architectures of three-dimensional (3D) carbon fibre woven composites (orthogonal, ORT; layer-to-layer, LTL; angle interlock, AI) through open-hole quasi-static tension and double-lap bearing strength tests in the off-axis (45°) direction. Damage characterisation is monitored using Digital Image correlation (DIC) for open-hole testing and X-ray Computed Tomography (CT) for double-lap bearing strength test. The off-axis notched 3D woven composites exhibits minor reduction (less than 10 %) of the notched strength compared to the un-notched strength. DIC strain contour clearly show stress/strain localisation regions around the hole periphery and stress/strain redistribution away from the whole due to the z-binder existence, especially for ORT architecture. Up to 50 % bearing strain, no significant difference in the bearing stress/bearing strain response is observed. However when ORT architecture was loaded up to failure, it demonstrates higher strain to failure (~140 %) followed by AI (~105 %) and lastly LTL (~85 %). X-ray CT scans reveal the effect of the z-binder architecture on damage evolution and delamination resistance. The study suggests that off-axis loaded 3D woven composites, especially ORT architecture, has a great potential of overcoming the current challenges facing composite laminates when used in composite joints' applications.

  7. Computer-aided three dimensional assessment of knee-joint cartilage with magnetic resonance imaging.

    PubMed

    Muensterer, O J; Eckstein, F; Hahn, D; Putz, R

    1996-07-01

    OBJECTIVE: An MRI-based technique for non-invasive assessment of the quantitative distribution of articular cartilage in the knee-joint was to be developed, and its accuracy and reproducibility tested. DESIGN: Three cadaveric specimens and one patient were studied and MRI measurements compared with anatomical sections or arthroscopy. BACKGROUND: Data on articular cartilage thickness is needed for the design of computer models, determination of cartilage material properties from arthroscopy and staging of osteoarthrosis. METHODS: The knees were imaged using strongly T2-weighted spin-echo and FISP-3D sequences. After digital subtraction and automatic segmentation, three-dimensional reconstruction of the cartilages was performed. Surface areas, volumes and the mean cartilage thickness were calculated, and the regional distribution displayed after trigonometric correction. RESULTS: The difference between MRI volumes and those obtained from the sections ranged from 4 to 21% with a reproducibility of +/-4 to +/-12% after repositioning. The thickness maps obtained with MRI were very similar to those from the sections. In the patient, a full-thickness defect demonstrated with MRI was verified by arthroscopy. CONCLUSIONS: Using the technique presented, the quantitative distribution of knee-joint cartilage may be analysed non-invasively, accurately, and in a very time-effective manner, in cadavers and in living subjects. RELEVANCE: To date there exists no accepted method for the accurate, fast and non-invasive assessment of articular cartilage thickness. Such a technique is, however, very helpful for generating computer models of diarthrodial joints, determination of cartilage material properties during arthroscopy, staging of joint disease, and objective control of chondroprotective treatment.

  8. Age and gender differences in the control of vertical ground reaction force by the hip, knee and ankle joints.

    PubMed

    Toda, Haruki; Nagano, Akinori; Luo, Zhiwei

    2015-06-01

    [Purpose] This study examined the relationships between joint moment and the control of the vertical ground reaction force during walking in the elderly and young male and female individuals. [Subjects and Methods] Forty elderly people, 65 years old or older (20 males and 20 females), and 40 young people, 20 to 29 years old (20 males and 20 females), participated in this study. Joint moment and vertical ground reaction force during walking were obtained using a 3D motion analysis system and force plates. Stepwise linear regression analysis determined the joint moments that predict the amplitude of the vertical ground reaction force. [Results] Knee extension moment was related to the vertical ground reaction force in the young males and females. On the other hand, in the elderly females, hip, ankle, and knee joint moments were related to the first peak and second peak forces, and the minimum value of vertical ground reaction force, respectively. [Conclusion] Our results suggest that the young males and females make use of the knee joint moment to control of the vertical ground reaction force. There were differences between the elderly and the young females with regard to the joints used for the control of the vertical ground reaction force.

  9. Age and gender differences in the control of vertical ground reaction force by the hip, knee and ankle joints

    PubMed Central

    Toda, Haruki; Nagano, Akinori; Luo, Zhiwei

    2015-01-01

    [Purpose] This study examined the relationships between joint moment and the control of the vertical ground reaction force during walking in the elderly and young male and female individuals. [Subjects and Methods] Forty elderly people, 65 years old or older (20 males and 20 females), and 40 young people, 20 to 29 years old (20 males and 20 females), participated in this study. Joint moment and vertical ground reaction force during walking were obtained using a 3D motion analysis system and force plates. Stepwise linear regression analysis determined the joint moments that predict the amplitude of the vertical ground reaction force. [Results] Knee extension moment was related to the vertical ground reaction force in the young males and females. On the other hand, in the elderly females, hip, ankle, and knee joint moments were related to the first peak and second peak forces, and the minimum value of vertical ground reaction force, respectively. [Conclusion] Our results suggest that the young males and females make use of the knee joint moment to control of the vertical ground reaction force. There were differences between the elderly and the young females with regard to the joints used for the control of the vertical ground reaction force. PMID:26180331

  10. Effects of wearing ankle weight on knee joint repositioning sense in the elderly

    PubMed Central

    Kim, Sooyoung; Jung, Daeun; Han, Jintae; Jung, Jaemin

    2016-01-01

    [Purpose] To investigate the effects of different ankle weights on knee joint repositioning sense in elderly individuals. [Subjects and Methods] Twenty-one subjects were divided for assessment as follows: young (20–30 years, n=10) and elderly (60–70 years, n=11). Knee joint repositioning error was measured by asking the subjects to reposition the target angle of their knee joints while wearing different ankle weights (0%, 0.5%, 1%, and 1.5%) in an open kinetic chain. The Hawk Digital System (60 Hz; Motion Analysis, Santa Rosa, CA, USA) was used to measure knee joint repositioning error. Differences in knee joint repositioning error between the young and elderly groups according to ankle weight load were examined by using two-way mixed repeated-measures analysis of variance. [Results] The knee joint repositioning error was lower with than without ankle weights in both groups. The error value was lowest with the 1.0% weight, though not significantly. Knee joint repositioning error was significantly higher in the elderly under all the ankle weight conditions. [Conclusion] Knee joint repositioning sense can be improved in elderly individuals by wearing proper ankle weights. However, weights that are too heavy might disturb knee joint positioning sense. PMID:27799664

  11. Analysis of Joint Sounds in the Diagnosis of Knee Disorders

    ClinicalTrials.gov

    2015-07-22

    Healthy Patients; No Knee Complaints; No Knee Injuries; No Knee Surgeries; No Neurological Problems; Patients Undergoing Knee Arthroscopy, Who Has a Pre-op MRI; Age Groups of 20,40 and 60 Years of Age.

  12. Torsional syndromes about the knee joint in classical ballet

    PubMed Central

    Burkett, Donald G.; Kinsman, John G.

    1982-01-01

    Dance-related pain of the lower limb is often treated symptomatically, without consideration of the chronic strains placed on the joints due to improper technique and alignment. Three pathomechanical syndromes of the knee which produce knee, ankle and foot pain are described. Clinical therapeutic approaches are proposed which emphasize the biomechanical nature of the etiology. Much information in regards to the basis of dance-related pain need be elicited before the pain-producing phenomena and its treatment can be definitively described. This paper makes no attempt to outline proper ballet technique but rather to make the chiropractor aware that insufficiencies in dance technique can and do lead to problems in the dancer. ImagesFigure 1aFigure 1bFigure 2aFigure 2bFigure 5aFigure 5bFigure 6Figure 7Figures 7c-7d

  13. A Predictive Model for Knee Joint Replacement in Older Women

    PubMed Central

    Lewis, Joshua R.; Dhaliwal, Satvinder S.; Zhu, Kun; Prince, Richard L.

    2013-01-01

    Knee replacement (KR) is expensive and invasive. To date no predictive algorithms have been developed to identify individuals at high risk of surgery. This study assessed whether patient self-reported risk factors predict 10-year KR in a population-based study of 1,462 women aged over 70 years recruited for the Calcium Intake Fracture Outcome Study (CAIFOS). Complete hospital records of prevalent (1980-1998) and incident (1998-2008) total knee replacement were available via the Western Australian Data Linkage System. Potential risk factors were assessed for predicative ability using a modeling approach based on a pre-planned selection of risk factors prior to model evaluation. There were 129 (8.8%) participants that underwent KR over the 10 year period. Baseline factors including; body mass index, knee pain, previous knee replacement and analgesia use for joint pain were all associated with increased risk, (P < 0.001). These factors in addition to age demonstrated good discrimination with a C-statistic of 0.79 ± 0.02 as well as calibration determined by the Hosmer-Lemeshow Goodness-of-Fit test. For clinical recommendations, three categories of risk for 10-year knee replacement were selected; low < 5%; moderate 5 to < 10% and high ≥ 10% predicted risk. The actual risk of knee replacement was; low 16 / 741 (2.2%); moderate 32 / 330 (9.7%) and high 81 / 391 (20.7%), P < 0.001. Internal validation of this 5-variable model on 6-year knee replacements yielded a similar C-statistic of 0.81 ± 0.02, comparable to the WOMAC weighted score; C-statistic 0.75 ± 0.03, P = 0.064. In conclusion 5 easily obtained patient self-reported risk factors predict 10-year KR risk well in this population. This algorithm should be considered as the basis for a patient-based risk calculator to assist in the development of treatment regimens to reduce the necessity for surgery in high risk groups such as the elderly. PMID:24349541

  14. Proprioceptive impairments associated with knee osteoarthritis are not generalized to the ankle and elbow joints.

    PubMed

    Shanahan, Camille J; Wrigley, Tim V; Farrell, Michael J; Bennell, Kim L; Hodges, Paul W

    2015-06-01

    The mechanisms for proprioceptive changes associated with knee osteoarthritis (OA) remain elusive. Observations of proprioceptive changes in both affected knees and other joints imply more generalized mechanisms for proprioceptive impairment. However, evidence for a generalized effect remains controversial. This study examined whether joint repositioning proprioceptive deficits are localized to the diseased joint (knee) or generalized across other joints (elbow and ankle) in people with knee OA. Thirty individuals with right knee OA (17 female, 66±7 [mean±SD] years) of moderate/severe radiographic disease severity and 30 healthy asymptomatic controls of comparable age (17 female, 65±8years) performed active joint repositioning tests of the knee, ankle and elbow in randomised order in supine. Participants with knee OA had a larger relative error for joint repositioning of the knee than the controls (OA: 2.7±2.1°, control: 1.6±1.7°, p=.03). Relative error did not differ between groups for the ankle (OA: 2.2±2.5°, control: 1.9±1.3°, p=.50) or elbow (OA: 2.5±3.3°, control: 2.9±2.8°, p=.58). These results are consistent with a mechanism for proprioceptive change that is localized to the knee joint. This could be mediated by problems with mechanoreceptors, processing/relay of somatosensory input to higher centers, or joint-specific interference with cognitive processes by pain.

  15. Prevention of Periprosthetic Joint Infections of the Hip and Knee.

    PubMed

    Levy, David M; Wetters, Nathan G; Levine, Brett R

    2016-01-01

    Periprosthetic joint infection (PJI) is a rare but devastating complication of arthroplasty. Research has been dedicated to minimizing the incidence of PJI, leading to the development of a comprehensive perioperative approach. Multiple preoperative, intraoperative, and postoperative factors can increase patient risk. From medical management and skin sterilization to wound sterility and blood management, multiple issues must be considered in a well-rounded prevention protocol. In this literature review, we consolidate the current information that orthopedic surgeons can use to minimize PJI after total knee arthroplasty and total hip arthroplasty. PMID:27552468

  16. [Postoperative knee joint mobilization in catheter peridural anesthesia following arthrolyses of the knee joint].

    PubMed

    Ulrich, C; Burri, C; Wörsdörfer, O

    1985-04-01

    The results of arthrolysis of a stiff knee are often poor due to post-operative pain preventing early active mobilization that is so essential. Adequate analgesia may be ensured by the use of continuous anaesthesia via an epidural catheter, and in combination with continuous passive motion such analgesia is able to maintain, and often improve, the range of movement obtained at surgery. 22 patients treated in this way showed an improvement in the range of movement of between 39 and 120 degrees. Patients with post-traumatic knee stiffness achieved an average improvement in the range of movement of 93%, while those with stiffness following infection only improved by 55% on the average. The pre-operative loss of movement does not appear to determine the end result: the aetiology of the stiffness is more important.

  17. A Study of Knee Joint Kinematics and Mechanics using a Human FE Model.

    PubMed

    Kitagawa, Yuichi; Hasegawa, Junji; Yasuki, Tsuyoshi; Iwamoto, Masami; Miki, Kazuo

    2005-11-01

    Posterior translation of the tibia with respect to the femur can stretch the posterior cruciate ligament (PCL). Fifteen millimeters of relative displacement between the femur and tibia is known as the Injury Assessment Reference Value (IARV) for the PCL injury. Since the anterior protuberance of the tibial plateau can be the first site of contact when the knee is flexed, the knee bolster is generally designed with an inclined surface so as not to directly load the projection in frontal crashes. It should be noted, however, that the initial flexion angle of the occupant knee can vary among individuals and the knee flexion angle can change due to the occupant motion. The behavior of the tibial protuberance related to the knee flexion angle has not been described yet. The instantaneous angle of the knee joint at the timing of restraining the knee should be known to manage the geometry and functions of knee restraint devices. The purposes of this study are first to understand the kinematics of the knee joint during flexion, and second to characterize the mechanics of the knee joint under anterior-posterior loading. A finite element model of the knee joint, extracted from the Total Human Model for Safety (THUMS), was used to analyze the mechanism. The model was validated against kinematics and mechanical responses of the human knee joint. By tracking the relative positions and angles between the patella and the tibia in a knee flexing simulation, the magnitude of the tibial anterior protuberance was described as a function of the knee joint angle. The model revealed that the mechanics of the knee joint was characterized as a combination of stiffness of the patella-femur structure and the PCL It was also found that the magnitude of the tibial anterior protuberance determined the amount of initial stretch of the PCL in anterior-posterior loading. Based on the knee joint kinematics and mechanics, an interference boundary was proposed for different knee flexion angles, so

  18. Evaluation of knee joint forces during kneeling work with different kneepads.

    PubMed

    Xu, Hang; Jampala, Sree; Bloswick, Donald; Zhao, Jie; Merryweather, Andrew

    2017-01-01

    The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors. The results revealed that kneepad design can significantly modify the forces on the knee joint through redistribution. The Professional Gel design was preferred among the five tested kneepads which was confirmed with both force measurements and participants' responses. The extreme reaching locations induced significantly higher joint forces on left knee or right knee depending on task. The conclusion of this study is that a properly selected kneepad for specific tasks and a more neutral working posture can modify the force distribution on the knees and likely decrease the risk of knee disorders from kneeling work. PMID:27633227

  19. Evaluation of knee joint forces during kneeling work with different kneepads.

    PubMed

    Xu, Hang; Jampala, Sree; Bloswick, Donald; Zhao, Jie; Merryweather, Andrew

    2017-01-01

    The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors. The results revealed that kneepad design can significantly modify the forces on the knee joint through redistribution. The Professional Gel design was preferred among the five tested kneepads which was confirmed with both force measurements and participants' responses. The extreme reaching locations induced significantly higher joint forces on left knee or right knee depending on task. The conclusion of this study is that a properly selected kneepad for specific tasks and a more neutral working posture can modify the force distribution on the knees and likely decrease the risk of knee disorders from kneeling work.

  20. A new method to measure post-traumatic joint contractures in the rabbit knee.

    PubMed

    Hildebrand, Kevin A; Holmberg, Michael; Shrive, Nigel

    2003-12-01

    A new device and method to measure rabbit knee joint angles are described. The method was used to measure rabbit knee joint angles in normal specimens and in knee joints with obvious contractures. The custom-designed and manufactured gripping device has two clamps. The femoral clamp sits on a pinion gear that is driven by a rack attached to a materials testing system. A 100 N load cell in series with the rack gives force feedback. The tibial clamp is attached to a rotatory potentiometer. The system allows the knee joint multiple degrees-of-freedom (DOF). There are two independent DOF (compression-distraction and internal-external rotation) and two coupled motions (medial-lateral translation coupled with varus-valgus rotation; anterior-posterior translation coupled with flexion-extension rotation). Knee joint extension-flexion motion is measured, which is a combination of the materials testing system displacement (converted to degrees of motion) and the potentiometer values (calibrated to degrees). Internal frictional forces were determined to be at maximum 2% of measured loading. Two separate experiments were performed to evaluate rabbit knees. First, normal right and left pairs of knees from four New Zealand White (NZW) rabbits were subjected to cyclic loading. An extension torque of 0.2 Nm was applied to each knee. The average change in knee joint extension from the first to the fifth cycle was 1.9 deg +/- 1.5 deg (mean +/- sd) with a total of 49 tests of these eight knees. The maximum extension of the four left knees (tested 23 times) was 14.6 deg +/- 7.1 deg, and of the four right knees (tested 26 times) was 12.0 deg +/- 10.9 deg. There was no significant difference in the maximum extension between normal left and right knees. In the second experiment, nine skeletally mature NZW rabbits had stable fractures of the femoral condyles of the right knee that were immobilized for five, six or 10 weeks. The left knee served as an unoperated control. Loss of knee joint

  1. Design and Evaluation of a Prosthetic Knee Joint Using the Geared Five-Bar Mechanism.

    PubMed

    Sun, Yuanxi; Ge, Wenjie; Zheng, Jia; Dong, Dianbiao

    2015-11-01

    This paper presents the mechanical design, dynamics analysis and ankle trajectory analysis of a prosthetic knee joint using the geared five-bar mechanism. Compared with traditional four-bar or six-bar mechanisms, the geared five-bar mechanism is better at performing diverse movements and is easy to control. This prosthetic knee joint with the geared five-bar mechanism is capable of fine-tuning its relative instantaneous center of rotation and ankle trajectory. The centrode of this prosthetic knee joint, which is mechanically optimized according to the centrode of human knee joint, is better in the bionic performance than that of a prosthetic knee joint using the four-bar mechanism. Additionally, the stability control of this prosthetic knee joint during the swing and stance phase is achieved by a motor. By adjusting the gear ratio of this prosthetic knee joint, the ankle trajectories of both unilateral and bilateral amputees show less deviations from expected than that of the four-bar knee joint.

  2. Septic arthritis caused by Mycobacterium fortuitum and Mycobacterium abscessus in a prosthetic knee joint: case report and review of literature.

    PubMed

    Wang, Shu-Xiang; Yang, Chang-Jen; Chen, Yu-Chuan; Lay, Chorng-Jang; Tsai, Chen-Chi

    2011-01-01

    Nontuberculous mycobacterium (NTM) is an infrequent cause of prosthetic knee joint infections. Simultaneous infection with different NTM species in a prosthetic knee joint has not been previously reported. A case of prosthetic knee joint infection caused by Mycobacterium abscessus and M. fortuitum is described in this report. The patient was successfully treated with adequate antibiotics and surgery. The clinical features of sixteen previously reported cases of prosthetic knee joint infection caused by NTM are reviewed.

  3. Cruciate coupling and screw-home mechanism in passive knee joint during extension--flexion.

    PubMed

    Moglo, K E; Shirazi-Adl, A

    2005-05-01

    The screw-home mechanism and coupling between forces in cruciate ligaments during passive knee joint flexion were investigated for various boundary conditions, flexion axis alignments and posterior cruciate ligaments (PCL)/anterior cruciate ligament (ACL) conditions. A developed non-linear 3D finite element model was used to perform detailed elasto-static response analyses of the human tibiofemoral joint as a function of flexion angle varying from 10 degrees hyper-extension to 90 degrees flexion. The tibia rotated internally as the femur flexed and externally as the femur extended. The re-alignment of the flexion axis by +/-5 degrees rotation about the axial (distal-proximal) axis, transection of the ACL and changes in cruciate ligament initial strains substantially influenced the 'screw-home' motion. On the other hand, restraint on this coupled rotation diminished ACL forces in flexion. A remarkable coupling was predicted between ACL and PCL forces in flexion; forces in both cruciate ligaments increased as the initial strain or pretension in one of them increased whereas they both diminished as one of them was cut or became slack. This has important consequences in joint functional biomechanics following a ligament injury or replacement surgery and, hence, in the proper management of joint disorders. PMID:15797589

  4. The effect of varying the plantarflexion resistance of an ankle-foot orthosis on knee joint kinematics in patients with stroke.

    PubMed

    Kobayashi, Toshiki; Leung, Aaron K L; Akazawa, Yasushi; Hutchins, Stephen W

    2013-03-01

    Ankle-foot orthoses (AFOs) can improve gait in patients with hemiplegia. However, it is anecdotally known that excessive plantarflexion resistance of an AFO could induce undesired knee flexion at early stance. The aim of this study was to systematically investigate the effect of varying the degrees of plantarflexion resistance of an AFO on knee flexion angles at early stance in five subjects with chronic stroke who demonstrated two clear knee flexion peaks at early stance and swing. Each subject wore an experimental AFO constructed with an oil-damper type ankle joint and was instructed to walk at their self-selected walking speed under five plantarflexion resistance conditions. The sagittal plane ankle and knee joint kinematics and gait speed were analyzed using a 3-D Motion Analysis System. A number of significant differences (P<0.005) in maximum knee flexion angles at early stance amongst different plantarflexion resistance conditions were revealed. The knee flexion angle was 23.80 (3.25) degrees under the free hinge joint condition (condition 1), while that was 26.09 (3.79) degrees under the largest resistance condition (condition 5). It was therefore demonstrated that increasing the plantarflexion resistance of an AFO would induce more knee flexion at early stance phase in patients with stroke.

  5. Individual muscle contributions to the axial knee joint contact force during normal walking.

    PubMed

    Sasaki, Kotaro; Neptune, Richard R

    2010-10-19

    Muscles are significant contributors to the high joint forces developed in the knee during human walking. Not only do muscles contribute to the knee joint forces by acting to compress the joint, but they also develop joint forces indirectly through their contributions to the ground reaction forces via dynamic coupling. Thus, muscles can have significant contributions to forces at joints they do not span. However, few studies have investigated how the major lower-limb muscles contribute to the knee joint contact forces during walking. The goal of this study was to use a muscle-actuated forward dynamics simulation of walking to identify how individual muscles contribute to the axial tibio-femoral joint force. The simulation results showed that the vastii muscles are the primary contributors to the axial joint force in early stance while the gastrocnemius is the primary contributor in late stance. The tibio-femoral joint force generated by these muscles was at times greater than the muscle forces themselves. Muscles that do not cross the knee joint (e.g., the gluteus maximus and soleus) also have significant contributions to the tibio-femoral joint force through their contributions to the ground reaction forces. Further, small changes in walking kinematics (e.g., knee flexion angle) can have a significant effect on the magnitude of the knee joint forces. Thus, altering walking mechanics and muscle coordination patterns to utilize muscle groups that perform the same biomechanical function, yet contribute less to the knee joint forces may be an effective way to reduce knee joint loading during walking.

  6. Intra-articular pressures and joint mechanics: should we pay attention to effusion in knee osteoarthritis?

    PubMed

    Rutherford, Derek James

    2014-09-01

    What factors play a role to ensure a knee joint does what it should given the demands of moving through the physical environment? This paper aims to probe the hypothesis that intra-articular joint pressures, once a topic of interest, have been left aside in contemporary frameworks in which we now view knee joint function. The focus on ligamentous deficiencies and the chondrocentric view of osteoarthritis, while important, have left little attention to the consideration of other factors that can impair joint function across the lifespan. Dynamic knee stability is required during every step we take. While there is much known about the role that passive structures and muscular activation play in maintaining a healthy knee joint, this framework does not account for the role that intra-articular joint pressures may have in providing joint stability during motion and how these factors interact. Joint injuries invariably result in some form of intra-articular fluid accumulation. Ultimately, it may be how the knee mechanically responds to this fluid, of which pressure plays a significant role that provides the mechanisms for continued function. Do joint pressures provide an important foundation for maintaining knee function? This hypothesis is unique and argues that we are missing an important piece of the puzzle when attempting to understand implications that joint injury and disease have for joint function.

  7. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    PubMed

    Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

    2016-01-01

    The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  8. Automated bone segmentation from large field of view 3D MR images of the hip joint

    NASA Astrophysics Data System (ADS)

    Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S.; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

    2013-10-01

    Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation.

  9. Automated bone segmentation from large field of view 3D MR images of the hip joint.

    PubMed

    Xia, Ying; Fripp, Jurgen; Chandra, Shekhar S; Schwarz, Raphael; Engstrom, Craig; Crozier, Stuart

    2013-10-21

    Accurate bone segmentation in the hip joint region from magnetic resonance (MR) images can provide quantitative data for examining pathoanatomical conditions such as femoroacetabular impingement through to varying stages of osteoarthritis to monitor bone and associated cartilage morphometry. We evaluate two state-of-the-art methods (multi-atlas and active shape model (ASM) approaches) on bilateral MR images for automatic 3D bone segmentation in the hip region (proximal femur and innominate bone). Bilateral MR images of the hip joints were acquired at 3T from 30 volunteers. Image sequences included water-excitation dual echo stead state (FOV 38.6 × 24.1 cm, matrix 576 × 360, thickness 0.61 mm) in all subjects and multi-echo data image combination (FOV 37.6 × 23.5 cm, matrix 576 × 360, thickness 0.70 mm) for a subset of eight subjects. Following manual segmentation of femoral (head-neck, proximal-shaft) and innominate (ilium+ischium+pubis) bone, automated bone segmentation proceeded via two approaches: (1) multi-atlas segmentation incorporating non-rigid registration and (2) an advanced ASM-based scheme. Mean inter- and intra-rater reliability Dice's similarity coefficients (DSC) for manual segmentation of femoral and innominate bone were (0.970, 0.963) and (0.971, 0.965). Compared with manual data, mean DSC values for femoral and innominate bone volumes using automated multi-atlas and ASM-based methods were (0.950, 0.922) and (0.946, 0.917), respectively. Both approaches delivered accurate (high DSC values) segmentation results; notably, ASM data were generated in substantially less computational time (12 min versus 10 h). Both automated algorithms provided accurate 3D bone volumetric descriptions for MR-based measures in the hip region. The highly computational efficient ASM-based approach is more likely suitable for future clinical applications such as extracting bone-cartilage interfaces for potential cartilage segmentation.

  10. Sodium inversion recovery MRI of the knee joint in vivo at 7T.

    PubMed

    Madelin, Guillaume; Lee, Jae-Seung; Inati, Souheil; Jerschow, Alexej; Regatte, Ravinder R

    2010-11-01

    The loss of proteoglycans (PG) in the articular cartilage is an early signature of osteoarthritis (OA). The ensuing changes in the fixed charge density in the cartilage can be directly linked to sodium concentration via charge balance. Sodium ions in the knee joint appear in two pools: in the synovial fluids or joint effusion where the ions are in free motion and bound within the cartilage tissue where the Na(+) ions have a restricted motion. The ions in these two compartments have therefore different T₁ and T₂ relaxation times. The purpose of this study is to demonstrate the feasibility of a fluid-suppressed 3D ultrashort TE radial sodium sequence by implementing an inversion recovery (IR) preparation of the magnetization at 7T. This method could allow a more accurate and more sensitive quantification of loss of PG in patients with OA. It is shown that adiabatic pulses offer significantly improved performance in terms of robustness to B₁ and B₀ inhomogeneities when compared to the hard pulse sequence. Power deposition considerations further pose a limit to the RF inversion power, and we demonstrate in simulations and experiments how a practical compromise can be struck between clean suppression of fluid signals and power deposition levels. Two IR sequences with different types of inversion pulses (a rectangular pulse and an adiabatic pulse) were tested on a liquid phantom, ex vivo on a human knee cadaver and then in vivo on five healthy volunteers, with a (Nyquist) resolution of ∼3.6 mm and a signal-to-noise ratio of ∼30 in cartilage without IR and ∼20 with IR. Due to specific absorption rate limitations, the total acquisition time was ∼17 min for the 3D radial sequence without inversion or with the rectangular IR, and 24:30 min for the adiabatic IR sequence. It is shown that the adiabatic IR sequence generates a more uniform fluid suppression over the whole sample than the rectangular IR sequence.

  11. Quasi-stiffness of the knee joint in flexion and extension during the golf swing.

    PubMed

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2015-01-01

    Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment-angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment-angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery.

  12. Quasi-stiffness of the knee joint in flexion and extension during the golf swing.

    PubMed

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2015-01-01

    Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment-angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment-angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery. PMID:25651162

  13. Knee-Extension Training with a Single-Joint Hybrid Assistive Limb during the Early Postoperative Period after Total Knee Arthroplasty in a Patient with Osteoarthritis

    PubMed Central

    Sugaya, Hisashi; Kubota, Shigeki; Onishi, Mio; Kanamori, Akihiro; Sankai, Yoshiyuki; Yamazaki, Masashi

    2016-01-01

    The knee range of motion is an important outcome of total knee arthroplasty (TKA). According to previous studies, the knee range of motion temporarily decreases for approximately 1 month after TKA due to postoperative pain and quadriceps dysfunction following surgical invasion into the knee extensor mechanism. We describe our experience with a knee-extension training program based on a single-joint hybrid assistive limb (HAL-SJ, Cyberdyne Inc., Tsukuba, Japan) during the acute recovery phase after TKA. HAL-SJ is a wearable robot suit that facilitates the voluntary control of knee joint motion. A 76-year-old man underwent HAL-SJ-based knee-extension training, which enabled him to perform knee function training during the acute phase after TKA without causing increased pain. Thus, he regained the ability to fully extend his knee postoperatively. HAL-SJ-based knee-extension training can be used as a novel post-TKA rehabilitation modality. PMID:27774330

  14. Three-dimensional (3D) visualization of reflow porosity and modeling of deformation in Pb-free solder joints

    SciTech Connect

    Dudek, M.A.; Hunter, L.; Kranz, S.; Williams, J.J.; Lau, S.H.; Chawla, N.

    2010-04-15

    The volume, size, and dispersion of porosity in solder joints are known to affect mechanical performance and reliability. Most of the techniques used to characterize the three-dimensional (3D) nature of these defects are destructive. With the enhancements in high resolution computed tomography (CT), the detection limits of intrinsic microstructures have been significantly improved. Furthermore, the 3D microstructure of the material can be used in finite element models to understand their effect on microscopic deformation. In this paper we describe a technique utilizing high resolution (< 1 {mu}m) X-ray tomography for the three-dimensional (3D) visualization of pores in Sn-3.9Ag-0.7Cu/Cu joints. The characteristics of reflow porosity, including volume fraction and distribution, were investigated for two reflow profiles. The size and distribution of porosity size were visualized in 3D for four different solder joints. In addition, the 3D virtual microstructure was incorporated into a finite element model to quantify the effect of voids on the lap shear behavior of a solder joint. The presence, size, and location of voids significantly increased the severity of strain localization at the solder/copper interface.

  15. [Repair of skin and soft tissue defects around the knee joints].

    PubMed

    Tan, Qian; Xu, Peng

    2015-10-01

    Skin and soft tissue defects around the knee joints are often accompanied by popliteal artery injury, patellar ligament injury, patellar fracture, and other deep tissue damage or exposure, making them challenging to repair. The principle is to repair the wound, reconstruct anatomical structure of the knee joint, and recover the knee joint function. At present the reconstruction with skin flap or myocutaneous flap is our priority. Local flap or myocutaneous flap can be used for repairing minor defects around the knee joints. Repairing with perforator flap, fascia flap, and free flap are main alternatives for covering larger and complex defects around the knee joints. During the treatment, a joint effort is mandatory, not only to repair the wound, but also to reconstruct vasculature, fix fracture, repair ligament, and finally recover the knee joint function. Therefore, the importance of multidisciplinary cooperation must be emphasized. Moreover, along with the development of new technologies, new methods, and new materials, perforator flap plays an important role in repairing skin and soft tissue defects around the knee joints.

  16. New Advances for a joint 3D inversion of multiple EM methods

    NASA Astrophysics Data System (ADS)

    Meqbel, N. M.; Ritter, O.

    2013-12-01

    Electromagnetic (EM) methods are routinely applied to image the subsurface from shallow to regional structures. Individual EM methods differ in their sensitivities towards resistive and conductive structures as well as in their exploration depths. Joint 3D inversion of multiple EM data sets can result in significantly better resolution of subsurface structures than the individual inversions. Proper weighting between different EM data is essential, however. We present a recently developed weighting algorithm to combine magnetotelluric (MT), controlled source EM (CSEM) and DC-geoelectric (DC) data. It is well known that MT data are mostly sensible to regional conductive structures, whereas, CSEM and DC data are more suitable to recover more shallow and resistive structures. Our new scheme is based on weighting individual components of the total data gradient after each model update. Norms of each data residual are used to assess how much weight individual components of the total data gradient must have to achieve an equal contribution of all data sets in the inverse model. A numerically efficient way to search for appropriate weighting factors could be established by applying a bi-diagonalization procedure to the sensitivity matrix. Thereby, the original inverse problem can be projected onto a smaller dimension in which the search of weighting factors is numerically cheap. We demonstrate the efficiency of the proposed weighting schemes and explore the model domain with synthetic data sets.

  17. Computer-Assisted 3D Kinematic Analysis of All Leg Joints in Walking Insects

    PubMed Central

    Bender, John A.; Simpson, Elaine M.; Ritzmann, Roy E.

    2010-01-01

    High-speed video can provide fine-scaled analysis of animal behavior. However, extracting behavioral data from video sequences is a time-consuming, tedious, subjective task. These issues are exacerbated where accurate behavioral descriptions require analysis of multiple points in three dimensions. We describe a new computer program written to assist a user in simultaneously extracting three-dimensional kinematics of multiple points on each of an insect's six legs. Digital video of a walking cockroach was collected in grayscale at 500 fps from two synchronized, calibrated cameras. We improved the legs' visibility by painting white dots on the joints, similar to techniques used for digitizing human motion. Compared to manual digitization of 26 points on the legs over a single, 8-second bout of walking (or 106,496 individual 3D points), our software achieved approximately 90% of the accuracy with 10% of the labor. Our experimental design reduced the complexity of the tracking problem by tethering the insect and allowing it to walk in place on a lightly oiled glass surface, but in principle, the algorithms implemented are extensible to free walking. Our software is free and open-source, written in the free language Python and including a graphical user interface for configuration and control. We encourage collaborative enhancements to make this tool both better and widely utilized. PMID:21049024

  18. 3D stochastic inversion and joint inversion of potential fields for multi scale parameters

    NASA Astrophysics Data System (ADS)

    Shamsipour, Pejman

    In this thesis we present the development of new techniques for the interpretation of potential field (gravity and magnetic data), which are the most widespread economic geophysical methods used for oil and mineral exploration. These new techniques help to address the long-standing issue with the interpretation of potential fields, namely the intrinsic non-uniqueness inversion of these types of data. The thesis takes the form of three papers (four including Appendix), which have been published, or soon to be published, in respected international journals. The purpose of the thesis is to introduce new methods based on 3D stochastical approaches for: 1) Inversion of potential field data (magnetic), 2) Multiscale Inversion using surface and borehole data and 3) Joint inversion of geophysical potential field data. We first present a stochastic inversion method based on a geostatistical approach to recover 3D susceptibility models from magnetic data. The aim of applying geostatistics is to provide quantitative descriptions of natural variables distributed in space or in time and space. We evaluate the uncertainty on the parameter model by using geostatistical unconditional simulations. The realizations are post-conditioned by cokriging to observation data. In order to avoid the natural tendency of the estimated structure to lay near the surface, depth weighting is included in the cokriging system. Then, we introduce algorithm for multiscale inversion, the presented algorithm has the capability of inverting data on multiple supports. The method involves four main steps: i. upscaling of borehole parameters (It could be density or susceptibility) to block parameters, ii. selection of block to use as constraints based on a threshold on kriging variance, iii. inversion of observation data with selected block densities as constraints, and iv. downscaling of inverted parameters to small prisms. Two modes of application are presented: estimation and simulation. Finally, a novel

  19. Designs and performance of microprocessor-controlled knee joints.

    PubMed

    Thiele, Julius; Westebbe, Bettina; Bellmann, Malte; Kraft, Marc

    2014-02-01

    In this comparative study, three transfemoral amputee subjects were fitted with four different microprocessor-controlled exoprosthetic knee joints (MPK): C-Leg, Orion, Plié2.0, and Rel-K. In a motion analysis laboratory, objective gait measures were acquired during level walking at different velocities. Subsequent technical analyses, which involved X-ray computed tomography, identified the functional mechanisms of each device and enabled corroboration of the performance in the gait laboratory by the engineering design of the MPK. Gait measures showed that the mean increase of the maximum knee flexion angle at different walking velocities was closest in value to the unaffected contralateral knee (6.2°/m/s) with C-Leg (3.5°/m/s; Rel-K 17.0°/m/s, Orion 18.3°/m/s, and Plié2.0 28.1°/m/s). Technical analyses corroborated that only with Plié2.0 the flexion resistances were not regulated by microprocessor control at different walking velocities. The muscular effort for the initiation of the swing phase, measured by the minimum hip moment, was found to be lowest with C-Leg (-82.1±14.1 Nm; Rel-K -83.59±17.8 Nm, Orion -88.0±16.3 Nm, and Plié2.0 -91.6±16.5 Nm). Reaching the extension stop at the end of swing phase was reliably executed with both Plié2.0 and C-Leg. Abrupt terminal stance phase extension observed with Plié2.0 and Rel-K could be attributed to the absence of microprocessor control of extension resistance.

  20. Knee joint biomechanics and neuromuscular control during gait before and after total knee arthroplasty are sex-specific.

    PubMed

    Astephen Wilson, Janie L; Dunbar, Michael J; Hubley-Kozey, Cheryl L

    2015-01-01

    The future of total knee arthroplasty (TKA) surgery will involve planning that incorporates more patient-specific characteristics. Despite known biological, morphological, and functional differences between men and women, there has been little investigation into knee joint biomechanical and neuromuscular differences between men and women with osteoarthritis, and none that have examined sex-specific biomechanical and neuromuscular responses to TKA surgery. The objective of this study was to examine sex-associated differences in knee kinematics, kinetics and neuromuscular patterns during gait before and after TKA. Fifty-two patients with end-stage knee OA (28 women, 24 men) underwent gait and neuromuscular analysis within the week prior to and one year after surgery. A number of sex-specific differences were identified which suggest a different manifestation of end-stage knee OA between the sexes.

  1. Altered Tibiofemoral Joint Contact Mechanics and Kinematics in Patients with Knee Osteoarthritis and Episodic Complaints of Joint Instability

    PubMed Central

    Farrokhi, Shawn; Voycheck, Carrie A.; Klatt, Brian A.; Gustafson, Jonathan A.; Tashman, Scott; Fitzgerald, G. Kelley

    2014-01-01

    Background To evaluate knee joint contact mechanics and kinematics during the loading response phase of downhill gait in knee osteoarthritis patients with self-reported instability. Methods Forty-three subjects, 11 with medial compartment knee osteoarthritis and self-reported instability (unstable), 7 with medial compartment knee osteoarthritis but no reports of instability (stable), and 25 without knee osteoarthritis or instability (control) underwent Dynamic Stereo X-ray analysis during a downhill gait task on a treadmill. Findings The medial compartment contact point excursions were longer in the unstable group compared to the stable (p=0.046) and the control groups (p=0.016). The peak medial compartment contact point velocity was also greater for the unstable group compared to the stable (p=0.047) and control groups (p=0.022). Additionally, the unstable group demonstrated a coupled movement pattern of knee extension and external rotation after heel contact which was different than the coupled motion of knee flexion and internal rotation demonstrated by stable and control groups. Interpretation Our findings suggest that knee joint contact mechanics and kinematics are altered during the loading response phase of downhill gait in knee osteoarthritis patients with self-reported instability. The observed longer medial compartment contact point excursions and higher velocities represent objective signs of mechanical instability that may place the arthritic knee joint at increased risk for disease progression. Further research is indicated to explore the clinical relevance of altered contact mechanics and kinematics during other common daily activities and to assess the efficacy of rehabilitation programs to improve altered joint biomechanics in knee osteoarthritis patients with self-reported instability. PMID:24856791

  2. Knee joint laxity and neuromuscular characteristics of male and female soccer and basketball players.

    PubMed

    Rozzi, S L; Lephart, S M; Gear, W S; Fu, F H

    1999-01-01

    Anterior cruciate ligament injuries are occurring at a higher rate in female athletes compared with their male counterparts. Research in the area of anterior cruciate ligament injury has increasingly focused on the role of joint proprioception and muscle activity in promoting knee joint stability. We measured knee joint laxity, joint kinesthesia, lower extremity balance, the amount of time required to generate peak torque of the knee flexor and extensor musculature, and electromyographically assessed muscle activity in 34 healthy, collegiate-level athletes (average age, 19.6 +/- 1.5 years) who played soccer or basketball or both. Independent t-tests were used to determine significant sex differences. Results revealed that women inherently possess significantly greater knee joint laxity values, demonstrate a significantly longer time to detect the knee joint motion moving into extension, possess significantly superior single-legged balance ability, and produce significantly greater electromyographic peak amplitude and area of the lateral hamstring muscle subsequent to landing a jump. The excessive joint laxity of women appears to contribute to diminished joint proprioception, rendering the knee less sensitive to potentially damaging forces and possibly at risk for injury. Unable to rely on ligamentous structures, healthy female athletes appear to have adopted compensatory mechanisms of increased hamstring activity to achieve functional joint stabilization.

  3. Knee joint laxity and neuromuscular characteristics of male and female soccer and basketball players.

    PubMed

    Rozzi, S L; Lephart, S M; Gear, W S; Fu, F H

    1999-01-01

    Anterior cruciate ligament injuries are occurring at a higher rate in female athletes compared with their male counterparts. Research in the area of anterior cruciate ligament injury has increasingly focused on the role of joint proprioception and muscle activity in promoting knee joint stability. We measured knee joint laxity, joint kinesthesia, lower extremity balance, the amount of time required to generate peak torque of the knee flexor and extensor musculature, and electromyographically assessed muscle activity in 34 healthy, collegiate-level athletes (average age, 19.6 +/- 1.5 years) who played soccer or basketball or both. Independent t-tests were used to determine significant sex differences. Results revealed that women inherently possess significantly greater knee joint laxity values, demonstrate a significantly longer time to detect the knee joint motion moving into extension, possess significantly superior single-legged balance ability, and produce significantly greater electromyographic peak amplitude and area of the lateral hamstring muscle subsequent to landing a jump. The excessive joint laxity of women appears to contribute to diminished joint proprioception, rendering the knee less sensitive to potentially damaging forces and possibly at risk for injury. Unable to rely on ligamentous structures, healthy female athletes appear to have adopted compensatory mechanisms of increased hamstring activity to achieve functional joint stabilization. PMID:10352766

  4. Accuracy of a contour-based biplane fluoroscopy technique for tracking knee joint kinematics of different speeds.

    PubMed

    Giphart, J Erik; Zirker, Christopher A; Myers, Casey A; Pennington, W Wesley; LaPrade, Robert F

    2012-11-15

    While measuring knee motion in all six degrees of freedom is important for understanding and treating orthopaedic knee pathologies, traditional motion capture techniques lack the required accuracy. A variety of model-based biplane fluoroscopy techniques have been developed with sub-millimeter accuracy. However, no studies have statistically evaluated the consistency of the accuracy across motions of varying intensity or between degrees of freedom. Therefore, this study evaluated the bias and precision of a contour-based tracking technique by comparing it to a marker-based method (gold standard) during three movements with increasing intensity. Six cadaveric knees with implanted tantalum markers were used to simulate knee extension, walking and drop landings, while motion was recorded by a custom biplane fluoroscopy system. The 3D geometries of the bones were reconstructed from CT scans and anatomical coordinate systems were assigned. The position and orientation of the bone and marker models were determined for an average of 27 frames for each trial and knee joint kinematics were compared. The average bias and precision was 0.01 ± 0.65° for rotations and 0.01 ± 0.59 mm for joint translations. Rotational precision was affected by motion (p=0.04) and depended on the axis of rotation (p=0.02). However, the difference in average precision among motions or axes was small (≤ 0.13°) and not likely of consequence for kinematic measurements. No other differences were found. The contour-based technique demonstrated sub-millimeter and sub-degree accuracy, indicating it is a highly accurate tool for measuring complex three dimensional knee movements of any intensity.

  5. [Sports-induced epiphyseal injuries of the knee and ankle joint].

    PubMed

    Krüger-Franke, M; Vaeltl, M; Trouillier, H; Pförringer, W

    1994-06-01

    We report on the clinical and radiological follow-up results of 37 patients with epiphyseal injuries of the knee and ankle joint who were treated in our hospital between 1985 and 1990. Most of the ankle joint injuries were sustained during track and field, soccer and basketball, and most of the knee injuries during alpine skiing. The different mechanisms of injuries of the knee and ankle joint are discussed on the basis of our own results. The therapy considers the age of patient as well as localisation and type of the epiphyseal injury. In spite of this, growth disturbances occurred in 12.5% of the ankle joint and in 9.5% of the knee joint injuries.

  6. Effect of knee joint angle on side-to-side strength ratios.

    PubMed

    Krishnan, Chandramouli; Williams, Glenn N

    2014-10-01

    Isometric knee extensor and flexor strength are typically tested at different joint angles due to the differences in length-tension relationships of the quadriceps and hamstring muscles. The efficiency of strength testing can be improved if the same angle can be used to test both the knee extensor and flexor muscle groups. The aim of this study was to determine an optimal angle for isometric knee strength testing by examining the effect of knee angle on side-to-side peak torque ratios. Eighteen active young people (9 males and 9 females) participated in this study. Knee extensor and knee flexor strength were tested on both sides at 30°, 60°, and 90° of knee flexion. The effect of knee flexion angle on side-to-side peak torque ratios, raw torque values, and side-to-side flexor-to-extensor torque ratios were assessed. Side-to-side knee extensor peak torque ratios and knee flexor-to-extensor torque ratios differed significantly by knee flexion angle (p = 0.024 and p = 0.011, respectively), but side-to-side knee flexor peak torque ratios did not differ significantly (p = 0.311). When considering both side-to-side peak torque ratios and flexor-to-extensor torque ratios, the values were more symmetrical (i.e., closer to 100%) only at 60° of knee flexion. Our results indicate that both the knee flexors and the knee extensors can be tested clinically at 60° of knee flexion. Our results also indicate that the hamstrings can be tested at any of the 3 angles if the examiner is interested in side-to-side ratios rather than raw torque values. These results may facilitate more efficient and flexible clinical knee strength testing.

  7. Understanding North Texas Seismicity: A Joint Analysis of Seismic Data and 3D Pore Pressure Modeling

    NASA Astrophysics Data System (ADS)

    DeShon, H. R.; Hornbach, M. J.; Ellsworth, W. L.; Oldham, H. R.; Hayward, C.; Stump, B. W.; Frohlich, C.; Olson, J. E.; Luetgert, J. H.

    2014-12-01

    In November 2013, a series of earthquakes began along a mapped ancient fault system near Azle, Texas. The Azle events are the third felt earthquake sequence in the Fort Worth (Barnett Shale) Basin since 2008, and several production and injection wells in the area are drilled to depths near the recent seismic activity. Understanding if and/or how injection and removal of fluids in the crystalline crust reactivates faults have important implications for seismology, the energy industry, and society. We assessed whether the Azle earthquakes were induced using a joint analysis of the earthquake data, subsurface geology and fault structure, and 3D pore pressure modeling. Using a 12-station temporary seismic deployment, we have recorded and located >300 events large enough to be recorded on multiple stations and 1000s of events during periods of swarm activity. High-resolution locations and focal mechanisms indicate that events occurred on NE-SW trending, steeply dipping normal faults associated with the southern end of the Newark East Fault Zone with hypocenters between 2-8 km depth. We considered multiple causes that might have changed stress along this system. Earthquakes resulting from natural processes, though perhaps unlikely in this historically inactive region, can be neither ruled out nor confirmed due to lack of information on the natural stress state of these faults. Analysis of lake and groundwater variations near Azle showed that no significant stress changes occurred prior to or during the earthquake sequence. In contrast, analysis of pore-pressure models shows that the combination of formation water production and wastewater injection near the fault could have caused pressure increases that induced earthquakes on near-critically stressed faults.

  8. Physiological alterations of maximal voluntary quadriceps activation by changes of knee joint angle.

    PubMed

    Becker, R; Awiszus, F

    2001-05-01

    The purpose of this study was to investigate the influence of different angles of the knee joint on voluntary activation of the quadriceps muscle, estimating the ability of a subject to activate a muscle maximally by means of voluntary contraction. Isometric torque measurement was performed on 6 healthy subjects in 5 degrees intervals between 30 degrees and 90 degrees of knee joint flexion. Superimposed twitches at maximal voluntary contraction (MVC) and at a level of 60% and 40% of the MVC were applied and the voluntary activation estimated. At between 30 degrees and 75 degrees of knee flexion, the maximal extension torque increased at an average rate of 2.67 +/- 0.6 Nm/degree, followed by a decline with further flexion. However, throughout the joint-angle range tested, voluntary activation increased on average by 0.37%/degree with a maximum at 90 degrees of flexion. Due to the influence of joint position it is not possible to generalize results obtained at the knee joint angle of 90 degrees of flexion, which is usually used for the quadriceps twitch-interpolation technique. Consequently, it is useful to investigate voluntary activation deficits in knee joint disorders at a range of knee joint angles that includes, in particular, the more extended joint angles used frequently during daily activity.

  9. Increased joint loads during walking--a consequence of pain relief in knee osteoarthritis.

    PubMed

    Henriksen, Marius; Simonsen, Erik B; Alkjaer, Tine; Lund, Hans; Graven-Nielsen, Thomas; Danneskiold-Samsøe, Bente; Bliddal, Henning

    2006-12-01

    Joint pain is a primary symptom in knee osteoarthritis (OA), but the effect of pain and pain relief on the knee joint mechanics of walking is not clear. In this study, the effects of local knee joint analgesia on knee joint loads during walking were studied in a group of knee osteoarthritis patients. A group of healthy subjects was included as a reference group. The joint loads were calculated from standard gait analysis data obtained with standardised walking speed (4 km/h). The gait analyses were performed before and after pain relief by intra-articular injections of 10 mL lidocaine (1%). Pre-injection measurements revealed lower joint loads in the OA group compared to the reference group. Following injections pain during walking decreased significantly and the joint loads increased in the OA group during the late single support phase to a level comparable to the reference group. Although the patients walked with less compressive knee joint forces compared to the reference group, the effects of pain relief may accelerate the degenerative changes. PMID:17011194

  10. A Practical Strategy for sEMG-Based Knee Joint Moment Estimation During Gait and Its Validation in Individuals With Cerebral Palsy

    PubMed Central

    Kwon, Suncheol; Stanley, Christopher J.; Kim, Jung; Kim, Jonghyun; Damiano, Diane L.

    2013-01-01

    Individuals with cerebral palsy have neurological deficits that may interfere with motor function and lead to abnormal walking patterns. It is important to know the joint moment generated by the patient’s muscles during walking in order to assist the suboptimal gait patterns. In this paper, we describe a practical strategy for estimating the internal moment of a knee joint from surface electromyography (sEMG) and knee joint angle measurements. This strategy requires only isokinetic knee flexion and extension tests to obtain a relationship between the sEMG and the knee internal moment, and it does not necessitate comprehensive laboratory calibration, which typically requires a 3-D motion capture system and ground reaction force plates. Four estimation models were considered based on different assumptions about the functions of the relevant muscles during the isokinetic tests and the stance phase of walking. The performance of the four models was evaluated by comparing the estimated moments with the gold standard internal moment calculated from inverse dynamics. The results indicate that an optimal estimation model can be chosen based on the degree of cocontraction. The estimation error of the chosen model is acceptable (normalized root-mean-squared error: 0.15–0.29, R: 0.71–0.93) compared to previous studies (Doorenbosch and Harlaar, 2003; Doorenbosch and Harlaar, 2004; Doorenbosch, Joosten, and Harlaar, 2005), and this strategy provides a simple and effective solution for estimating knee joint moment from sEMG. PMID:22410952

  11. A practical strategy for sEMG-based knee joint moment estimation during gait and its validation in individuals with cerebral palsy.

    PubMed

    Kwon, Suncheol; Park, Hyung-Soon; Stanley, Christopher J; Kim, Jung; Kim, Jonghyun; Damiano, Diane L

    2012-05-01

    Individuals with cerebral palsy have neurological deficits that may interfere with motor function and lead to abnormal walking patterns. It is important to know the joint moment generated by the patient's muscles during walking in order to assist the suboptimal gait patterns. In this paper, we describe a practical strategy for estimating the internal moment of a knee joint from surface electromyography (sEMG) and knee joint angle measurements. This strategy requires only isokinetic knee flexion and extension tests to obtain a relationship between the sEMG and the knee internal moment, and it does not necessitate comprehensive laboratory calibration, which typically requires a 3-D motion capture system and ground reaction force plates. Four estimation models were considered based on different assumptions about the functions of the relevant muscles during the isokinetic tests and the stance phase of walking. The performance of the four models was evaluated by comparing the estimated moments with the gold standard internal moment calculated from inverse dynamics. The results indicate that an optimal estimation model can be chosen based on the degree of cocontraction. The estimation error of the chosen model is acceptable (normalized root-mean-squared error: 0.15-0.29, R: 0.71-0.93) compared to previous studies (Doorenbosch and Harlaar, 2003; Doorenbosch and Harlaar, 2004; Doorenbosch, Joosten, and Harlaar, 2005), and this strategy provides a simple and effective solution for estimating knee joint moment from sEMG.

  12. Therapeutic Experience on Stance Control Knee-Ankle-Foot Orthosis With Electromagnetically Controlled Knee Joint System in Poliomyelitis

    PubMed Central

    Kim, Jung-Hwan; Ji, Sang-Goo; Jung, Kang-Jae

    2016-01-01

    A 54-year-old man with poliomyelitis had been using a conventional, passive knee-ankle-foot orthosis (KAFO) with a drop ring lock knee joint for about 40 years. A stance control KAFO (SCKAFO) with an electromagnetically controlled (E-MAG) knee joint system was prescribed. To correct his gait pattern, he also underwent rehabilitation therapy, which included muscle re-education, neuromuscular electrical stimulation, strengthening exercises for the lower extremities, and balance training twice a week for about 4 months. Both before and after rehabilitation, we conducted a gait analysis and assessed the physiological cost index in energy expended during walking in a locked-knee state and while he wore a SCKAFO with E-MAG. When compared with the pre-rehabilitation data, the velocity, step length, stride length, and knee kinematic data were improved after rehabilitation. Although the SCKAFO with E-MAG system facilitated the control of knee motion during ambulation, appropriate rehabilitative therapy was also needed to achieve a normal gait pattern. PMID:27152288

  13. Joint immobilization induced hypoxic and inflammatory conditions in rat knee joints.

    PubMed

    Yabe, Yutaka; Hagiwara, Yoshihiro; Suda, Hideaki; Ando, Akira; Onoda, Yoshito; Tsuchiya, Masahiro; Hatori, Kouki; Itoi, Eiji

    2013-01-01

    The purpose of this study was to examine the hypoxic and inflammatory conditions after immobilization in the joint capsule of rat knees. The unilateral knee joints of adult male rats were immobilized with an internal fixator (Im group) for 1 day, 3 days, and 1, 2, 4, 8, and 16 weeks. Sham-operated animals had holes drilled in the femur and tibia and screws inserted without a plate (control group). The number of cells and blood vessels in the capsule were histologically examined. The hypoxic condition in the capsule was histologically examined with a Hypoxyprobe™-1. The gene expressions related to the hypoxic (hypoxia inducible factor-1α, vascular endothelial growth factor, and fibroblast growth factor 2) and inflammatory conditions [interleukin-6 (IL-6), IL-1α, IL-1β, tumor necrosis factor-α, and tumor necrosis factor-β] were evaluated by quantitative reverse transcription polymerase chain reaction. The number of cells was unchanged at 1 day in the two groups; however, the number significantly increased at 3 days in the Im group. The number of blood vessels in the Im group gradually decreased. Strong immunostaining of Hypoxyprobe™-1 around the blood vessels was observed in the Im group. The gene expressions of hypoxia inducible factor-1α and fibroblast growth factor 2 were significantly higher in the Im group compared with those in the control group. The gene expressions of IL-6, IL-1α, IL-1β, and tumor necrosis factor-β were significantly higher in the Im group compared with those in the control group. These data indicated that joint immobilization induced hypoxic and inflammatory conditions in the joint capsule, which might be an initiating factor for joint contracture.

  14. Obesity is not associated with increased knee joint torque and power during level walking.

    PubMed

    DeVita, Paul; Hortobágyi, Tibor

    2003-09-01

    While it is widely speculated that obesity causes increased loads on the knee leading to joint degeneration, this concept is untested. The purpose of the study was to identify the effects of obesity on lower extremity joint kinetics and energetics during walking. Twenty-one obese adults were tested at self-selected (1.29m/s) and standard speeds (1.50m/s) and 18 lean adults were tested at the standard speed. Motion analysis and force platform data were combined to calculate joint torques and powers during the stance phase of walking. Obese participants were more erect with 12% less knee flexion and 11% more ankle plantarflexion in self-selected compared to standard speeds (both p<0.02). Obese participants were still more erect than lean adults with approximately 6 degrees more extension at all joints (p<0.05, for each joint) at the standard speed. Knee and ankle torques were 17% and 11% higher (p<0.034 and p<0.041) and negative knee work and positive ankle work were 68% and 11% higher (p<0.000 and p<0.048) in obese participants at the standard speed compared to the slower speed. Joint torques and powers were statistically identical at the hip and knee but were 88% and 61% higher (both p<0.000) at the ankle in obese compared to lean participants at the standard speed. Obese participants used altered gait biomechanics and despite their greater weight, they had less knee torque and power at their self-selected walking speed and equal knee torque and power while walking at the same speed as lean individuals. We propose that the ability to reorganize neuromuscular function during gait may enable some obese individuals to maintain skeletal health of the knee joint and this ability may also be a more accurate risk indicator for knee osteoarthritis than body weight.

  15. Immediate effect of Masai Barefoot Technology shoes on knee joint moments in women with knee osteoarthritis.

    PubMed

    Tateuchi, Hiroshige; Taniguchi, Masashi; Takagi, Yui; Goto, Yusuke; Otsuka, Naoki; Koyama, Yumiko; Kobayashi, Masashi; Ichihashi, Noriaki

    2014-01-01

    Footwear modification can beneficially alter knee loading in patients with knee osteoarthritis. This study evaluated the effect of Masai Barefoot Technology shoes on reductions in external knee moments in patients with knee osteoarthritis. Three-dimensional motion analysis was used to examine the effect of Masai Barefoot Technology versus control shoes on the knee adduction and flexion moments in 17 women (mean age, 63.6 years) with radiographically confirmed knee osteoarthritis. The lateral and anterior trunk lean values, knee flexion and adduction angles, and ground reaction force were also evaluated. The influence of the original walking pattern on the changes in knee moments with Masai Barefoot Technology shoes was evaluated. The knee flexion moment in early stance was significantly reduced while walking with the Masai Barefoot Technology shoes (0.25±0.14Nm/kgm) as compared with walking with control shoes (0.30±0.19 Nm/kgm); whereas the knee adduction moment showed no changes. Masai Barefoot Technology shoes did not increase compensatory lateral and anterior trunk lean. The degree of knee flexion moment in the original walking pattern with control shoes was correlated directly with its reduction when wearing Masai Barefoot Technology shoes by multiple linear regression analysis (adjusted R2=0.44, P<0.01). Masai Barefoot Technology shoes reduced the knee flexion moment during walking without increasing the compensatory trunk lean and may therefore reduce external knee loading in women with knee osteoarthritis.

  16. 3D joint inversion using seismic data and marine controlled-source electromagnetic data for evaluating gas hydrate concentrations

    NASA Astrophysics Data System (ADS)

    Kim, B.; Byun, J.; Seol, S. J.; Jeong, S.; Chung, Y.; Kwon, T.

    2015-12-01

    For many decades, gas hydrates have been received great attention as a potential source of natural gas. Therefore, the detailed information of structures of buried gas hydrates and their concentrations are prerequisite for the production for the gas hydrate as a reliable source of alternate energy. Recently, for this reason, a lot of gas hydrate assessment methods have been proposed by many researchers. However, it is still necessary to establish as new method for the further improvement of the accuracy of the 3D gas hydrate distribution. In this study, we present a 3D joint inversion method that provides superior quantitative information of gas hydrate distributions using 3D seismic data obtained by ocean-bottom cable (OBC) and marine controlled-source electromagnetic (CSEM) data. To verify our inversion method, we first built the general 3D gas hydrate model containing vertical methane-flow pathways. With the described model, we generated synthetic 3D OBC data and marine CSEM data using finite element modeling algorithms, respectively. In the joint inversion process, to obtain the high-resolution volumetric P-wave velocity structure, we applied the 3D full waveform inversion algorithm to the acquired OBC data. After that, the obtained P-wave velocity model is used as the structure constraint to compute cross-gradients with the updated resistivity model in the EM inversion process. Finally, petrophysical relations were applied to estimate volumetric gas hydrate concentrations. The proposed joint inversion process makes possible to obtain more precise quantitative gas hydrate assessment than inversion processes using only seismic or EM data. This technique can be helpful for accurate decision-making in gas hydrate development as well as in their production monitoring.

  17. Learning Dictionaries of Sparse Codes of 3D Movements of Body Joints for Real-Time Human Activity Understanding

    PubMed Central

    Qi, Jin; Yang, Zhiyong

    2014-01-01

    Real-time human activity recognition is essential for human-robot interactions for assisted healthy independent living. Most previous work in this area is performed on traditional two-dimensional (2D) videos and both global and local methods have been used. Since 2D videos are sensitive to changes of lighting condition, view angle, and scale, researchers begun to explore applications of 3D information in human activity understanding in recently years. Unfortunately, features that work well on 2D videos usually don't perform well on 3D videos and there is no consensus on what 3D features should be used. Here we propose a model of human activity recognition based on 3D movements of body joints. Our method has three steps, learning dictionaries of sparse codes of 3D movements of joints, sparse coding, and classification. In the first step, space-time volumes of 3D movements of body joints are obtained via dense sampling and independent component analysis is then performed to construct a dictionary of sparse codes for each activity. In the second step, the space-time volumes are projected to the dictionaries and a set of sparse histograms of the projection coefficients are constructed as feature representations of the activities. Finally, the sparse histograms are used as inputs to a support vector machine to recognize human activities. We tested this model on three databases of human activities and found that it outperforms the state-of-the-art algorithms. Thus, this model can be used for real-time human activity recognition in many applications. PMID:25473850

  18. Compensatory mechanism involving the knee joint of the intact limb during gait in unilateral below-knee amputees.

    PubMed

    Beyaert, C; Grumillier, C; Martinet, N; Paysant, J; André, J-M

    2008-08-01

    This study evaluated the asymmetry of knee kinetics during uncomfortable gait induced by prosthesis misalignment to further demonstrate the compensatory function of the knee joint of the intact limb during gait. Three-dimensional gait analysis including knee kinematics and kinetics at the beginning of stance phase was conducted in 15 healthy subjects and 17 unilateral trans-tibial amputees (TTA) walking at self-selected speed in three conditions of prosthetic alignment: initial alignment (IA); initial alignment altered either by 6 degrees of internal rotation (IR) or by 6 degrees of external rotation (ER) applied on the pylon. Patients reported best comfort of gait in IA condition and discomfort mainly in IR condition. Maximum knee flexion and knee total work at power phases K0-K2 were significantly higher in intact limbs compared to prosthetic and control limbs. In intact limbs, these variables had significantly higher values (+10-35%, p<0.05) in IR condition than IA condition whereas these were not altered across conditions in prosthetic limbs. In trans-tibial amputees, inducing uncomfortable gait by internally rotating the prosthetic foot did not alter the knee kinetics of the prosthetic limb, which suggests a protective mechanism. Knee kinetics of the intact limb did alter, which suggests a compensatory mechanism.

  19. Intra-Articular Knee Contact Force Estimation During Walking Using Force-Reaction Elements and Subject-Specific Joint Model.

    PubMed

    Jung, Yihwan; Phan, Cong-Bo; Koo, Seungbum

    2016-02-01

    Joint contact forces measured with instrumented knee implants have not only revealed general patterns of joint loading but also showed individual variations that could be due to differences in anatomy and joint kinematics. Musculoskeletal human models for dynamic simulation have been utilized to understand body kinetics including joint moments, muscle tension, and knee contact forces. The objectives of this study were to develop a knee contact model which can predict knee contact forces using an inverse dynamics-based optimization solver and to investigate the effect of joint constraints on knee contact force prediction. A knee contact model was developed to include 32 reaction force elements on the surface of a tibial insert of a total knee replacement (TKR), which was embedded in a full-body musculoskeletal model. Various external measurements including motion data and external force data during walking trials of a subject with an instrumented knee implant were provided from the Sixth Grand Challenge Competition to Predict in vivo Knee Loads. Knee contact forces in the medial and lateral portions of the instrumented knee implant were also provided for the same walking trials. A knee contact model with a hinge joint and normal alignment could predict knee contact forces with root mean square errors (RMSEs) of 165 N and 288 N for the medial and lateral portions of the knee, respectively, and coefficients of determination (R2) of 0.70 and -0.63. When the degrees-of-freedom (DOF) of the knee and locations of leg markers were adjusted to account for the valgus lower-limb alignment of the subject, RMSE values improved to 144 N and 179 N, and R2 values improved to 0.77 and 0.37, respectively. The proposed knee contact model with subject-specific joint model could predict in vivo knee contact forces with reasonable accuracy. This model may contribute to the development and improvement of knee arthroplasty.

  20. Measurement of complex joint trajectories using slice-to-volume 2D/3D registration and cine MR

    NASA Astrophysics Data System (ADS)

    Bloch, C.; Figl, M.; Gendrin, C.; Weber, C.; Unger, E.; Aldrian, S.; Birkfellner, W.

    2010-02-01

    A method for studying the in vivo kinematics of complex joints is presented. It is based on automatic fusion of single slice cine MR images capturing the dynamics and a static MR volume. With the joint at rest the 3D scan is taken. In the data the anatomical compartments are identified and segmented resulting in a 3D volume of each individual part. In each of the cine MR images the joint parts are segmented and their pose and position are derived using a 2D/3D slice-to-volume registration to the volumes. The method is tested on the carpal joint because of its complexity and the small but complex motion of its compartments. For a first study a human cadaver hand was scanned and the method was evaluated with artificially generated slice images. Starting from random initial positions of about 5 mm translational and 12° rotational deviation, 70 to 90 % of the registrations converged successfully to a deviation better than 0.5 mm and 5°. First evaluations using real data from a cine MR were promising. The feasibility of the method was demonstrated. However we experienced difficulties with the segmentation of the cine MR images. We therefore plan to examine different parameters for the image acquisition in future studies.

  1. Footwear affects the gearing at the ankle and knee joints during running.

    PubMed

    Braunstein, Bjoern; Arampatzis, Adamantios; Eysel, Peer; Brüggemann, Gert-Peter

    2010-08-10

    The objective of the study was to investigate the adjustment of running mechanics by wearing five different types of running shoes on tartan compared to barefoot running on grass focusing on the gearing at the ankle and knee joints. The gear ratio, defined as the ratio of the moment arm of the ground reaction force (GRF) to the moment arm of the counteracting muscle tendon unit, is considered to be an indicator of joint loading and mechanical efficiency. Lower extremity kinematics and kinetics of 14 healthy volunteers were quantified three dimensionally and compared between running in shoes on tartan and barefoot on grass. Results showed no differences for the gear ratios and resultant joint moments for the ankle and knee joints across the five different shoes, but showed that wearing running shoes affects the gearing at the ankle and knee joints due to changes in the moment arm of the GRF. During barefoot running the ankle joint showed a higher gear ratio in early stance and a lower ratio in the late stance, while the gear ratio at the knee joint was lower during midstance compared to shod running. Because the moment arms of the counteracting muscle tendon units did not change, the determinants of the gear ratios were the moment arms of the GRF's. The results imply higher mechanical stress in shod running for the knee joint structures during midstance but also indicate an improved mechanical advantage in force generation for the ankle extensors during the push-off phase.

  2. Lipoma arborescens arising in the extra-articular bursa of the knee joint.

    PubMed

    Minami, Shinji; Miyake, Yusuke; Kinoshita, Hirofumi

    2016-01-01

    Lipoma arborescens arising in the extra-articular bursa of the knee joint is extremely rare. We describe an 11-year-old boy who complained of a gradual swelling mass of the lateral knee joint. Magnetic resonance imaging (MRI) showed a high signal intensity tumor on T1- and T2-weighted images with a thickened septa and nodular lesion that showed low signal intensity. The radiologist suggested the possible differential diagnosis of well-differentiated liposarcoma. At operation, the tumor was found under the iliotibial tract and was not in contact with the knee joint. Histopathologically, this lesion was diagnosed as lipoma arborescens arising in the extra-articular bursa of the knee joint. On MRI, the appearance of lipoma arborescens arising in the extra-articular bursa of the knee joint differed from that of conventional intra-articular lipoma arborescens. In this report, we describe a case of extra-articular lipoma arborescens of the knee joint bursa and discuss the diagnosis and etiology. PMID:27382924

  3. Effects of Kinesiology Taping on Repositioning Error of the Knee Joint after Quadriceps Muscle Fatigue

    PubMed Central

    Han, Jin Tae; Lee, Jung-hoon

    2014-01-01

    [Purpose] The purpose of this study was to identify the effects of kinesiology taping on repositioning error of the knee joint after quadriceps muscle fatigue. [Subjects] Thirty healthy adults with no orthopaedic or neurological problems participated in this study. [Methods] The repositioning error of the knee joint was measured using a digital goniometer when the subjects extended their dominant-side knee to a random target angle (30°, 45°, or 60°) with their eyes closed, before and after a quadriceps muscle fatigue protocol, and after application of kinesiology tape. [Results] We found that repositioning errors of the dominant-side knee joint increased after quadriceps fatigue compared with no-fatigue conditions. However, kinesiology taping of the quadriceps muscle and patella after quadriceps fatigue significantly decreased repositioning errors of the knee joint. [Conclusion] These results suggest that quadriceps fatigue increases the repositioning error of the knee joint, whereas application of kinesiology tape decreases fatigue-induced joint repositioning error. PMID:25013297

  4. Lipoma arborescens arising in the extra-articular bursa of the knee joint

    PubMed Central

    Minami, Shinji; Miyake, Yusuke; Kinoshita, Hirofumi

    2016-01-01

    Lipoma arborescens arising in the extra-articular bursa of the knee joint is extremely rare. We describe an 11-year-old boy who complained of a gradual swelling mass of the lateral knee joint. Magnetic resonance imaging (MRI) showed a high signal intensity tumor on T1- and T2-weighted images with a thickened septa and nodular lesion that showed low signal intensity. The radiologist suggested the possible differential diagnosis of well-differentiated liposarcoma. At operation, the tumor was found under the iliotibial tract and was not in contact with the knee joint. Histopathologically, this lesion was diagnosed as lipoma arborescens arising in the extra-articular bursa of the knee joint. On MRI, the appearance of lipoma arborescens arising in the extra-articular bursa of the knee joint differed from that of conventional intra-articular lipoma arborescens. In this report, we describe a case of extra-articular lipoma arborescens of the knee joint bursa and discuss the diagnosis and etiology. PMID:27382924

  5. The effect of total knee arthroplasty on knee joint kinematics and kinetics during gait.

    PubMed

    Hatfield, Gillian L; Hubley-Kozey, Cheryl L; Astephen Wilson, Janie L; Dunbar, Michael J

    2011-02-01

    This study determined how total knee arthroplasty (TKA) altered knee motion and loading during gait. Three-dimensional kinematic and kinetic gait patterns of 42 patients with severe knee osteoarthritis were collected 1 week prior and 1-year post-TKA. Principal component analysis extracted major patterns of variability in the gait waveforms. Overall and midstance knee adduction moment magnitude decreased. Overall knee flexion angle magnitude increased due to an increase during swing. Increases in the early stance knee flexion moment and late stance knee extension moment were found, indicating improved impact attenuation and function. A decrease in the early stance knee external rotation moment indicated alteration in the typical rotation mechanism. Most changes moved toward an asymptomatic pattern and would be considered improvements in motion, function, and loading.

  6. Understanding patellofemoral pain with maltracking in the presence of joint laxity: complete 3D in vivo patellofemoral and tibiofemoral kinematics.

    PubMed

    Sheehan, Frances T; Derasari, Aditya; Brindle, Timothy J; Alter, Katharine E

    2009-05-01

    Patellofemoral pain is widely accepted as one of the most common pathologies involving the knee, yet the etiology of this pain is still an open debate. Generalized joint laxity has been associated with patellofemoral pain, but is not often discussed as a potential source of patellar maltracking. Thus, the objective of this study was to compare the complete 6 degree of freedom patellofemoral and tibiofemoral kinematics from a group of patients diagnosed with patellofemoral pain syndrome and maltracking to those from an asymptomatic population. The following null hypotheses were tested: kinematic alterations in patellofemoral maltracking are limited to the axial plane; knee joint kinematics are the same in maltrackers with and without generalized joint laxity (defined by a clinical diagnosis of Ehlers Danlos Syndrome); and no correlations exist between tibiofemoral and patellofemoral kinematics or within patellofemoral kinematics. This study demonstrated that alterations in patellofemoral kinematics, associated with patellofemoral pain, are not limited to the axial plane, minimal correlations exist between patellofemoral and tibiofemoral kinematics, and distinct subgroups likely exist within the general population of maltrackers. Being able to identify subgroups correctly within the omnibus diagnosis of patellar maltracking is a crucial step in correctly defining the pathophysiology and the eventual treatment of these patients. PMID:19009601

  7. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study

    PubMed Central

    Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

    2016-01-01

    The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a “soft” constraint using a penalty-based method, this elastic joint description challenges the strictness of “hard” constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO. PMID:27314586

  8. Decision making and experience level influence frontal plane knee joint biomechanics during a cutting maneuver.

    PubMed

    Kipp, Kristof; Brown, Tyler N; McLean, Scott G; Palmieri-Smith, Riann M

    2013-12-01

    The purpose of this study was to examine the combined impact of experience and decision making on frontal plane knee joint biomechanics during a cutting maneuver. Kinematic and kinetic data were collected from 12 recreationally active and 18 NCAA Division I female athletes during execution of anticipated and unanticipated single-leg land-and-cut maneuvers. Knee joint abduction angles and external knee joint abduction torques were calculated and discrete peak stance-phase variables were extracted. Angle and torque time-series data were also submitted to separate functional data analyses. Variables derived from the functional data analyses indicated that decision making influenced knee abduction angle and torque time series in the recreational group only. Specifically, these variables pointed to greater knee abduction at the end of stance as well as a greater, albeit delayed peak in knee abduction torque at the beginning of landing in the recreational athletes during the unanticipated condition. In addition, the recreational athletes displayed greater discrete peak knee abduction angles than the Division I athletes regardless of condition. Discrete peak knee abduction torque did not differ between groups or conditions.

  9. Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion

    PubMed Central

    Suehiro, Tadanobu; Mizutani, Masatoshi; Okamoto, Mitsuhisa; Ishida, Hiroshi; Kobara, Kenichi; Fujita, Daisuke; Osaka, Hiroshi; Takahashi, Hisashi; Watanabe, Susumu

    2014-01-01

    [Purpose] This study investigated the selective activation of the gluteus maximus during a prone hip extension with knee flexion exercise, with the hip joint in different positions. [Subjects] The subjects were 21 healthy, male volunteers. [Methods] Activities of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during a prone hip extension with knee flexion exercise. Measurements were made with the hip joint in each of 3 positions: (1) a neutral hip joint position, (2) an abduction hip joint position, and (3) an abduction with external rotation hip joint position. [Results] Gluteus maximus activity was significantly higher when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. Gluteus maximus activity was also significantly higher in the abduction hip joint position than in the neutral hip joint position. Hamstring activity was significantly lower when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion exercise selectively activates the gluteus maximus. PMID:25540492

  10. The Effects of Patellar Taping on Knee Joint Proprioception

    PubMed Central

    Callaghan, Michael J.; Selfe, James; Bagley, Pam J.; Oldham, Jacqueline A.

    2002-01-01

    Objective: To evaluate the effects of patellar taping on knee joint proprioception. Design and Setting: In a research unit, 3 proprioceptive tests were performed. For each of the tests, a standardized patellar taping technique was applied in random order. Subjects: Fifty-two healthy volunteers (27 women, 25 men; age, 23.2 ± 4.6 years; body mass index, 23.3 ± 3.7). Measurements: We measured active angle reproduction, passive angle reproduction, and threshold to detection of passive movement on an isokinetic dynamometer. Results: We found no significant differences between the tape and no-tape conditions in any of the 3 proprioceptive tests (P > .05). However, when the subjects' results for active angle reproduction and passive angle reproduction were graded as good (≤5°) and poor (>5°), taping was found to improve significantly those with poor proprioceptive ability (P < .01). Conclusions: Subjects with good proprioception did not benefit from patellar taping. However, in those healthy subjects with poor proprioceptive ability as measured by active and passive ankle reproduction, patellar taping provided proprioceptive enhancement. Further studies are needed to investigate the effect of patellar taping on the proprioceptive status of patients with patellofemoral pain syndrome. PMID:12937439

  11. Knee joint proprioception in ballet dancers and non-dancers.

    PubMed

    Dieling, Simone; van der Esch, Martin; Janssen, Thomas W J

    2014-01-01

    The aim of this study was to evaluate the influence of upper-leg muscle fatigue on knee joint proprioception in 13 ballet dancers and 13 non-dancer controls. Proprioception acuity, expressed as position and motion sense, was measured with an isokinetic dynamometer. The position and motion sense assessments were prior to and immediately after an isokinetic upper-leg muscle fatigue protocol. Participants wore blindfolds for both tasks to eliminate vision, an inflated air splint on their lower leg to neutralize cutaneous sensation, and headphones with white noise during the motion sense task to eliminate auditory cues. Results showed no significant differences in position and motion sense between dancers and controls in the non-fatigued state. In the fatigued state no significant differences were found in position sense between dancers and controls, while controls increased significantly in motion sense error (p = 0.030) and ballet dancers showed no change in motion sense. It is concluded that position sense and motion sense acuity are not affected by muscle fatigue in dancers, but motion sense is affected by muscle fatigue in non-dancers. PMID:25474293

  12. The Effects of Patellar Taping on Knee Joint Proprioception.

    PubMed

    Callaghan, Michael J; Selfe, James; Bagley, Pam J; Oldham, Jacqueline A

    2002-03-01

    OBJECTIVE: To evaluate the effects of patellar taping on knee joint proprioception. DESIGN AND SETTING: In a research unit, 3 proprioceptive tests were performed. For each of the tests, a standardized patellar taping technique was applied in random order. SUBJECTS: Fifty-two healthy volunteers (27 women, 25 men; age, 23.2 +/- 4.6 years; body mass index, 23.3 +/- 3.7). MEASUREMENTS: We measured active angle reproduction, passive angle reproduction, and threshold to detection of passive movement on an isokinetic dynamometer. RESULTS: We found no significant differences between the tape and no-tape conditions in any of the 3 proprioceptive tests (P >.05). However, when the subjects' results for active angle reproduction and passive angle reproduction were graded as good (5 degrees ), taping was found to improve significantly those with poor proprioceptive ability (P <.01). CONCLUSIONS: Subjects with good proprioception did not benefit from patellar taping. However, in those healthy subjects with poor proprioceptive ability as measured by active and passive ankle reproduction, patellar taping provided proprioceptive enhancement. Further studies are needed to investigate the effect of patellar taping on the proprioceptive status of patients with patellofemoral pain syndrome.

  13. Hip rotation angle is associated with frontal plane knee joint mechanics during running.

    PubMed

    Sakaguchi, Masanori; Shimizu, Norifumi; Yanai, Toshimasa; Stefanyshyn, Darren J; Kawakami, Yasuo

    2015-02-01

    Inability to control lower extremity segments in the frontal and transverse planes resulting in large knee abduction angle and increased internal knee abduction impulse has been associated with patellofemoral pain (PFP). However, the influence of hip rotation angles on frontal plane knee joint kinematics and kinetics remains unclear. The purpose of this study was to explore how hip rotation angles are related to frontal plane knee joint kinematics and kinetics during running. Seventy runners participated in this study. Three-dimensional marker positions and ground reaction forces were recorded with an 8-camera motion analysis system and a force plate while subjects ran along a 25-m runway at a speed of 4m/s. Knee abduction, hip rotation and toe-out angles, frontal plane lever arm at the knee, internal knee abduction moment and impulse, ground reaction forces and the medio-lateral distance from the ankle joint center to the center of pressure (AJC-CoP) were quantified. The findings of this study indicate that greater hip external rotation angles were associated with greater toe-out angles, longer AJC-CoP distances, smaller internal knee abduction impulses with shorter frontal plane lever arms and greater knee abduction angles. Thus, there appears to exist a conflict between kinematic and kinetic risk factors of PFP, and hip external rotation angle may be a key factor to control frontal plane knee joint kinematics and kinetics. These results may help provide an appropriate manipulation and/or intervention on running style to reduce the risk of PFP.

  14. PhotoCloud: Interactive remote exploration of joint 2D and 3D datasets.

    PubMed

    Brivio, Paolo; Benedetti, Luca; Tarini, Marco; Ponchio, Federico; Cignoni, Paolo; Scopigno, Roberto

    2013-01-01

    PhotoCloud is a real-time client-server system for interactive visualization and exploration of large datasets comprising thousands of calibrated 2D photographs of a scene and a complex 3D description of the scene. The system isn't tailored to any specific data acquisition process; it aims at generality and flexibility. PhotoCloud achieves scalability through a multiresolution dynamic hierarchical representation of the data, which is remotely stored and accessed by the client through an efficient cache system. The system includes a compact image browser and a multiresolution model renderer. PhotoCloud employs iconic visualization of the images in the 3D space and projects images onto the 3D scene on the fly. Users can navigate the 2D and 3D spaces with smooth, integrated, seamless transitions between them. A study with differently skilled users confirms PhotoCloud's effectiveness and communication power. The Web extras at http://www.youtube.com/playlist?list=PLHJB2bhmgB7cmYD0ST9CEDMRv1JlX4xPH are videos demonstrating PhotoCloud, a real-time client-server system for interactive exploration of large datasets comprising 2D photos and 3D models.

  15. Joint contact forces can be reduced by improving joint moment symmetry in below-knee amputee gait simulations.

    PubMed

    Koelewijn, Anne D; van den Bogert, Antonie J

    2016-09-01

    Despite having a fully functional knee and hip in both legs, asymmetries in joint moments of the knee and hip are often seen in gait of persons with a unilateral transtibial amputation (TTA), possibly resulting in excessive joint loading. We hypothesize that persons with a TTA can walk with more symmetric joint moments at the cost of increased effort or abnormal kinematics. The hypothesis was tested using predictive simulations of gait. Open loop controls of one gait cycle were found by solving an optimization problem that minimizes a combination of walking effort and tracking error in joint angles, ground reaction force and gait cycle duration. A second objective was added to penalize joint moment asymmetry, creating a multi-objective optimization problem. A Pareto front was constructed by changing the weights of the objectives and three solutions were analyzed to study the effect of increasing joint moment symmetry. When the optimization placed more weight on moment symmetry, walking effort increased and kinematics became less normal, confirming the hypothesis. TTA gait improved with a moderate increase in joint moment symmetry. At a small cost of effort and abnormal kinematics, the peak hip extension moment in the intact leg was decreased significantly, and so was the joint contact force in the knee and hip. Additional symmetry required a significant increase in walking effort and the joint contact forces in both hips became significantly higher than in able-bodied gait.

  16. Stair ascent with an innovative microprocessor-controlled exoprosthetic knee joint.

    PubMed

    Bellmann, Malte; Schmalz, Thomas; Ludwigs, Eva; Blumentritt, Siegmar

    2012-12-01

    Climbing stairs can pose a major challenge for above-knee amputees as a result of compromised motor performance and limitations to prosthetic design. A new, innovative microprocessor-controlled prosthetic knee joint, the Genium, incorporates a function that allows an above-knee amputee to climb stairs step over step. To execute this function, a number of different sensors and complex switching algorithms were integrated into the prosthetic knee joint. The function is intuitive for the user. A biomechanical study was conducted to assess objective gait measurements and calculate joint kinematics and kinetics as subjects ascended stairs. Results demonstrated that climbing stairs step over step is more biomechanically efficient for an amputee using the Genium prosthetic knee than the previously possible conventional method where the extended prosthesis is trailed as the amputee executes one or two steps at a time. There is a natural amount of stress on the residual musculoskeletal system, and it has been shown that the healthy contralateral side supports the movements of the amputated side. The mechanical power that the healthy contralateral knee joint needs to generate during the extension phase is also reduced. Similarly, there is near normal loading of the hip joint on the amputated side.

  17. Joint Cross-Range Scaling and 3D Geometry Reconstruction of ISAR Targets Based on Factorization Method.

    PubMed

    Lei Liu; Feng Zhou; Xue-Ru Bai; Ming-Liang Tao; Zi-Jing Zhang

    2016-04-01

    Traditionally, the factorization method is applied to reconstruct the 3D geometry of a target from its sequential inverse synthetic aperture radar images. However, this method requires performing cross-range scaling to all the sub-images and thus has a large computational burden. To tackle this problem, this paper proposes a novel method for joint cross-range scaling and 3D geometry reconstruction of steadily moving targets. In this method, we model the equivalent rotational angular velocity (RAV) by a linear polynomial with time, and set its coefficients randomly to perform sub-image cross-range scaling. Then, we generate the initial trajectory matrix of the scattering centers, and solve the 3D geometry and projection vectors by the factorization method with relaxed constraints. After that, the coefficients of the polynomial are estimated from the projection vectors to obtain the RAV. Finally, the trajectory matrix is re-scaled using the estimated rotational angle, and accurate 3D geometry is reconstructed. The two major steps, i.e., the cross-range scaling and the factorization, are performed repeatedly to achieve precise 3D geometry reconstruction. Simulation results have proved the effectiveness and robustness of the proposed method.

  18. Sodium inversion recovery MRI of the knee joint in vivo at 7T

    NASA Astrophysics Data System (ADS)

    Madelin, Guillaume; Lee, Jae-Seung; Inati, Souheil; Jerschow, Alexej; Regatte, Ravinder R.

    2010-11-01

    The loss of proteoglycans (PG) in the articular cartilage is an early signature of osteoarthritis (OA). The ensuing changes in the fixed charge density in the cartilage can be directly linked to sodium concentration via charge balance. Sodium ions in the knee joint appear in two pools: in the synovial fluids or joint effusion where the ions are in free motion and bound within the cartilage tissue where the Na+ ions have a restricted motion. The ions in these two compartments have therefore different T1 and T2 relaxation times. The purpose of this study is to demonstrate the feasibility of a fluid-suppressed 3D ultrashort TE radial sodium sequence by implementing an inversion recovery (IR) preparation of the magnetization at 7T. This method could allow a more accurate and more sensitive quantification of loss of PG in patients with OA. It is shown that adiabatic pulses offer significantly improved performance in terms of robustness to B1 and B0 inhomogeneities when compared to the hard pulse sequence. Power deposition considerations further pose a limit to the RF inversion power, and we demonstrate in simulations and experiments how a practical compromise can be struck between clean suppression of fluid signals and power deposition levels. Two IR sequences with different types of inversion pulses (a rectangular pulse and an adiabatic pulse) were tested on a liquid phantom, ex vivo on a human knee cadaver and then in vivo on five healthy volunteers, with a (Nyquist) resolution of ∼3.6 mm and a signal-to-noise ratio of ∼30 in cartilage without IR and ∼20 with IR. Due to specific absorption rate limitations, the total acquisition time was ∼17 min for the 3D radial sequence without inversion or with the rectangular IR, and 24:30 min for the adiabatic IR sequence. It is shown that the adiabatic IR sequence generates a more uniform fluid suppression over the whole sample than the rectangular IR sequence.

  19. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial (uni-compartmental) metal... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated...

  20. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial (uni-compartmental) metal... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated...

  1. Longevity of duct tape in residential air distribution systems: 1-D, 2-D, and 3-D joints

    SciTech Connect

    Abushakra, Bass

    2002-05-30

    The aging tests conducted so far showed that duct tape tends to degrade in its performance as the joint it is applied to requires a geometrical description of a higher number of space dimensions (1-D, 2-D, 3-D). One-dimensional joints are the easiest to seal with duct tape, and thus the least to experience failure. Two-dimensional joints, such as the flexible duct core-to-collar joints tested in this study, are less likely to fail than three-dimensional collar-to-plenum joints, as the shrinkage could have a positive effect in tightening the joint. Three-dimensional joints are the toughest to seal and the most likely to experience failure. The 2-D flexible duct core-to-collar joints passed the six-month period of the aging test in terms of leakage, but with the exception of the foil-butyl tape, showed degradation in terms hardening, brittleness, partial peeling, shrinkage, wrinkling, delamination of the tape layers, flaking, cracking, bubbling, oozing and discoloration. The baking test results showed that the failure in the duct tape joints could be attributed to the type of combination of the duct tape and the material it is applied to, as the duct tape behaves differently with different substrates. Overall, the foil-butyl tape (Tape 4) had the best results, while the film tape (Tape 3) showed the most deterioration. The conventional duct tapes tested (Tape 1 and Tape 2) were between these two extremes, with Tape 2 performing better than Tape 1. Lastly, we found that plastic straps became discolored and brittle during the tests, and a couple of straps broke completely. Therefore, we recommend that clamping the duct-taped flexible core-to-collar joints should be done with metallic adjustable straps.

  2. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces

    PubMed Central

    Gerus, Pauline; Sartori, Massimo; Besier, Thor F.; Fregly, Benjamin J.; Delp, Scott L.; Banks, Scott A.; Pandy, Marcus G.; D’Lima, Darryl D.; Lloyd, David G.

    2013-01-01

    Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. PMID:24074941

  3. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces.

    PubMed

    Gerus, Pauline; Sartori, Massimo; Besier, Thor F; Fregly, Benjamin J; Delp, Scott L; Banks, Scott A; Pandy, Marcus G; D'Lima, Darryl D; Lloyd, David G

    2013-11-15

    Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model.

  4. Three dimensional measurement of minimum joint space width in the knee from stereo radiographs using statistical shape models

    PubMed Central

    van IJsseldijk, E. A.; Valstar, E. R.; Stoel, B. C.; Nelissen, R. G. H. H.; Baka, N.; van’t Klooster, R.

    2016-01-01

    Objectives An important measure for the diagnosis and monitoring of knee osteoarthritis is the minimum joint space width (mJSW). This requires accurate alignment of the x-ray beam with the tibial plateau, which may not be accomplished in practice. We investigate the feasibility of a new mJSW measurement method from stereo radiographs using 3D statistical shape models (SSM) and evaluate its sensitivity to changes in the mJSW and its robustness to variations in patient positioning and bone geometry. Materials and Methods A validation study was performed using five cadaver specimens. The actual mJSW was varied and images were acquired with variation in the cadaver positioning. For comparison purposes, the mJSW was also assessed from plain radiographs. To study the influence of SSM model accuracy, the 3D mJSW measurement was repeated with models from the actual bones, obtained from CT scans. Results The SSM-based measurement method was more robust (consistent output for a wide range of input data/consistent output under varying measurement circumstances) than the conventional 2D method, showing that the 3D reconstruction indeed reduces the influence of patient positioning. However, the SSM-based method showed comparable sensitivity to changes in the mJSW with respect to the conventional method. The CT-based measurement was more accurate than the SSM-based measurement (smallest detectable differences 0.55 mm versus 0. 82 mm, respectively). Conclusion The proposed measurement method is not a substitute for the conventional 2D measurement due to limitations in the SSM model accuracy. However, further improvement of the model accuracy and optimisation technique can be obtained. Combined with the promising options for applications using quantitative information on bone morphology, SSM based 3D reconstructions of natural knees are attractive for further development. Cite this article: E. A. van IJsseldijk, E. R. Valstar, B. C. Stoel, R. G. H. H. Nelissen, N. Baka, R. van

  5. Effect of Joint Scale and Processing on the Fracture of Sn-3Ag-0.5Cu Solder Joints: Application to Micro-bumps in 3D Packages

    NASA Astrophysics Data System (ADS)

    Talebanpour, B.; Huang, Z.; Chen, Z.; Dutta, I.

    2016-01-01

    In 3-dimensional (3D) packages, a stack of dies is vertically connected to each other using through-silicon vias and very thin solder micro-bumps. The thinness of the micro-bumps results in joints with a very high volumetric proportion of intermetallic compounds (IMCs), rendering them much more brittle compared to conventional joints. Because of this, the reliability of micro-bumps, and the dependence thereof on the proportion of IMC in the joint, is of substantial concern. In this paper, the growth kinetics of IMCs in thin Sn-3Ag-0.5Cu joints attached to Cu substrates were analyzed, and empirical kinetic laws for the growth of Cu6Sn5 and Cu3Sn in thin joints were obtained. Modified compact mixed mode fracture mechanics samples, with adhesive solder joints between massive Cu substrates, having similar thickness and IMC content as actual micro-bumps, were produced. The effects of IMC proportion and strain rate on fracture toughness and mechanisms were investigated. It was found that the fracture toughness G C decreased with decreasing joint thickness ( h Joint). In addition, the fracture toughness decreased with increasing strain rate. Aging also promoted alternation of the crack path between the two joint-substrate interfaces, possibly proffering a mechanism to enhance fracture toughness.

  6. Correlating PMC-MMC Bonded Joint 3D FEA with Test

    NASA Technical Reports Server (NTRS)

    Jacobson, Mindy; Rodini, Benjamin; Chen, Wayne C.; Flom, Yury A.; Posey, Alan J.

    2005-01-01

    A viewgraph presentation on the correlation of Polymer Matrix Composites (PMC) and Metal Matrix Composites (MMC) bonded joints using three dimensional finite element analyses with materials tests is shown.

  7. Correlation among Joint Motions Allows Classification of Parkinsonian versus Normal 3D Reaching

    PubMed Central

    Chan, Jacky; Leung, Howard; Poizner, Howard

    2009-01-01

    In this paper, an objective assessment for determining whether a person has Parkinson disease is proposed. This is achieved by analyzing the correlation between joint movements, since Parkinsonian patients often have trouble coordinating different joints in a movement. Thus, the auto-correlation coefficient of single joint movements and the cross-correlation between movements in a pair of joints (hand, wrist, elbow and shoulder) were studied. These features were used to train and provide classification of subjects as having or not having Parkinson's disease using the Least Square Support Vector Machine. Experimental results showed that using either auto-correlation or cross-correlation features for classification provided over 91% correct classification. Using both features together provided better performance (96.0%) than using either feature alone. In addition, the performance of LS-SVM is better than that of Self Organizing Map (SOM) and k-nearest neighbor (KNN) in this case. PMID:19497826

  8. Biomechanical comparison of frontal plane knee joint moment arms during normal and Tai Chi walking.

    PubMed

    Jagodinsky, Adam; Fox, John; Decoux, Brandi; Weimar, Wendi; Liu, Wei

    2015-09-01

    [Purpose] Medial knee osteoarthritis, a degenerative joint disease, affects adults. The external knee adduction moment, a surrogate knee-loading measure, has clinical implications for knee osteoarthritis patients. Tai Chi is a promising intervention for pain alleviation in knee osteoarthritis; however, the characteristics of external knee adduction moment during Tai Chi have not been established. [Subjects and Methods] During normal and Tai Chi walking, a gait analysis was performed to compare the external knee adduction moment moment-arm characteristics and paired t-tests to compare moment-arm magnitudes. [Results] A significant difference was observed in the average lateral direction of moment-arm magnitude during Tai Chi walking (-0.0239 ± 0.011 m) compared to that during normal walking (-0.0057 ± 0.004 m). No significant difference was found between conditions in average medial direction of moment-arm magnitude (normal walking: 0.0143 ± 0.010 m; Tai Chi walking: 0.0098 ± 0.014 m). [Conclusion] Tai Chi walking produced a larger peak lateral moment-arm value than normal walking during the stance phase, whereas Tai Chi walking and normal walking peak medial moment-arm values were similar, suggesting that medial knee joint loading may be avoided during Tai Chi walking.

  9. Biomechanical comparison of frontal plane knee joint moment arms during normal and Tai Chi walking

    PubMed Central

    Jagodinsky, Adam; Fox, John; Decoux, Brandi; Weimar, Wendi; Liu, Wei

    2015-01-01

    [Purpose] Medial knee osteoarthritis, a degenerative joint disease, affects adults. The external knee adduction moment, a surrogate knee-loading measure, has clinical implications for knee osteoarthritis patients. Tai Chi is a promising intervention for pain alleviation in knee osteoarthritis; however, the characteristics of external knee adduction moment during Tai Chi have not been established. [Subjects and Methods] During normal and Tai Chi walking, a gait analysis was performed to compare the external knee adduction moment moment-arm characteristics and paired t-tests to compare moment-arm magnitudes. [Results] A significant difference was observed in the average lateral direction of moment-arm magnitude during Tai Chi walking (−0.0239 ± 0.011 m) compared to that during normal walking (−0.0057 ± 0.004 m). No significant difference was found between conditions in average medial direction of moment-arm magnitude (normal walking: 0.0143 ± 0.010 m; Tai Chi walking: 0.0098 ± 0.014 m). [Conclusion] Tai Chi walking produced a larger peak lateral moment-arm value than normal walking during the stance phase, whereas Tai Chi walking and normal walking peak medial moment-arm values were similar, suggesting that medial knee joint loading may be avoided during Tai Chi walking. PMID:26504334

  10. Large subarticular cysts (geodes) adjacent to the knee-joint in rheumatoid arthritis.

    PubMed

    Carter, A R; Liyanage, S P

    1975-10-01

    Two patients with rheumatoid arthritis are described, who developed very large bone cysts or geodes adjacent to the knee-joint. The existence of cysts adjacent to joints involved by rheumatoid arthritis is well recognised, but the occurrence of very large cysts is unusual and may present diagnostic difficulties. Possible aetiological factors are discussed.

  11. Septic arthritis of a native knee joint due to Corynebacterium striatum.

    PubMed

    Westblade, Lars F; Shams, Farah; Duong, Scott; Tariq, Oosman; Bulbin, Alan; Klirsfeld, Dava; Zhen, Wei; Sakaria, Smita; Ford, Bradley A; Burnham, Carey-Ann D; Ginocchio, Christine C

    2014-05-01

    We report a case of septic arthritis of a native knee joint due to Corynebacterium striatum, a rare and unusual cause of septic arthritis of native joints. The isolate was identified by a combination of phenotypic, mass spectrometric, and nucleic acid-based assays and exhibited high-level resistance to most antimicrobials.

  12. 3-D Analysis of Flanged Joints Through Various Preload Methods Using ANSYS

    NASA Astrophysics Data System (ADS)

    Murugan, Jeyaraj Paul; Kurian, Thomas; Jayaprakash, Janardhan; Sreedharapanickar, Somanath

    2015-10-01

    Flanged joints are being employed in aerospace solid rocket motor hardware for the integration of various systems or subsystems. Hence, the design of flanged joints is very important in ensuring the integrity of motor while functioning. As these joints are subjected to higher loads due to internal pressure acting inside the motor chamber, an appropriate preload is required to be applied in this joint before subjecting it to the external load. Preload, also known as clamp load, is applied on the fastener and helps to hold the mating flanges together. Generally preload is simulated as a thermal load and the exact preload is obtained through number of iterations. Infact, more iterations are required when considering the material nonlinearity of the bolt. This way of simulation will take more computational time for generating the required preload. Now a days most commercial software packages use pretension elements for simulating the preload. This element does not require iterations for inducing the preload and it can be solved with single iteration. This approach takes less computational time and thus one can study the characteristics of the joint easily by varying the preload. When the structure contains more number of joints with different sizes of fasteners, pretension elements can be used compared to thermal load approach for simulating each size of fastener. This paper covers the details of analyses carried out simulating the preload through various options viz., preload through thermal, initial state command and pretension element etc. using ANSYS finite element package.

  13. Design and evaluation of a new type of knee orthosis to align the mediolateral angle of the knee joint with osteoarthritis.

    PubMed

    Esrafilian, Amir; Karimi, Mohammad Taghi; Eshraghi, Arezoo

    2012-01-01

    Background. Osteoarthritis (OA) is a disease which influences the performance of the knee joint. Moreover, the force and moments applied on the joint increase in contrast to normal subjects. Various types of knee orthoses have been designed to solve the mentioned problems. However, there are other problems in terms of distal migration during walking and the alignment of the orthosis which cannot be changed following the use of brace. Therefore, the main aim of the research was to design an orthosis to solve the aforementioned problems. Method. A new type of knee orthosis was designed with a modular structure. Two patients with knee OA participated in this research project. The force applied on the foot, moment transmitted through the knee joint, and spatiotemporal gait parameters were measured by use of a motion analysis system. Results. The results of the research showed that the adduction moment applied on the knee joint decreased while subjects walked with the new knee orthosis (P-value < 0.05). Conclusion. The new design of the knee brace can be used as an effective treatment to decrease the loads applied on the knee joint and to improve the alignment whilst walking.

  14. Failed Radiation Synovectomy in Diseased Knee Joint with Missed Tuberculous Synovitis

    PubMed Central

    Sood, Ashwani; Sharma, Aman; Chouhan, Devendra Kumar; Gupta, Kirti; Parghane, Rahul; Shukla, Jaya; Mittal, Bhagwant Rai

    2016-01-01

    The authors in this case report highlight the poor outcome of radiation synovectomy (RSV) for repeated knee joint effusion in a patient with histopathologically proven nonspecific arthritis. There was partial response initially following RSV but later follow-up showed recurrence in joint effusion with limited and painful mobility of the knee joint. Subsequent surgical synovectomy and histopathological examination showed it to be tubercular in origin. Thus in a country endemic for tuberculosis, an alternative infective etiology should also be kept in mind before subjecting the patient to RSV.

  15. Failed Radiation Synovectomy in Diseased Knee Joint with Missed Tuberculous Synovitis.

    PubMed

    Sood, Ashwani; Sharma, Aman; Chouhan, Devendra Kumar; Gupta, Kirti; Parghane, Rahul; Shukla, Jaya; Mittal, Bhagwant Rai

    2016-09-01

    The authors in this case report highlight the poor outcome of radiation synovectomy (RSV) for repeated knee joint effusion in a patient with histopathologically proven nonspecific arthritis. There was partial response initially following RSV but later follow-up showed recurrence in joint effusion with limited and painful mobility of the knee joint. Subsequent surgical synovectomy and histopathological examination showed it to be tubercular in origin. Thus in a country endemic for tuberculosis, an alternative infective etiology should also be kept in mind before subjecting the patient to RSV. PMID:27651744

  16. Failed Radiation Synovectomy in Diseased Knee Joint with Missed Tuberculous Synovitis.

    PubMed

    Sood, Ashwani; Sharma, Aman; Chouhan, Devendra Kumar; Gupta, Kirti; Parghane, Rahul; Shukla, Jaya; Mittal, Bhagwant Rai

    2016-09-01

    The authors in this case report highlight the poor outcome of radiation synovectomy (RSV) for repeated knee joint effusion in a patient with histopathologically proven nonspecific arthritis. There was partial response initially following RSV but later follow-up showed recurrence in joint effusion with limited and painful mobility of the knee joint. Subsequent surgical synovectomy and histopathological examination showed it to be tubercular in origin. Thus in a country endemic for tuberculosis, an alternative infective etiology should also be kept in mind before subjecting the patient to RSV.

  17. Failed Radiation Synovectomy in Diseased Knee Joint with Missed Tuberculous Synovitis

    PubMed Central

    Sood, Ashwani; Sharma, Aman; Chouhan, Devendra Kumar; Gupta, Kirti; Parghane, Rahul; Shukla, Jaya; Mittal, Bhagwant Rai

    2016-01-01

    The authors in this case report highlight the poor outcome of radiation synovectomy (RSV) for repeated knee joint effusion in a patient with histopathologically proven nonspecific arthritis. There was partial response initially following RSV but later follow-up showed recurrence in joint effusion with limited and painful mobility of the knee joint. Subsequent surgical synovectomy and histopathological examination showed it to be tubercular in origin. Thus in a country endemic for tuberculosis, an alternative infective etiology should also be kept in mind before subjecting the patient to RSV. PMID:27651744

  18. The effect of CT dose on glenohumeral joint congruency measurements using 3D reconstructed patient-specific bone models

    NASA Astrophysics Data System (ADS)

    Lalone, Emily A.; Fox, Anne-Marie V.; Kedgley, Angela E.; Jenkyn, Thomas R.; King, Graham J. W.; Athwal, George S.; Johnson, James A.; Peters, Terry M.

    2011-10-01

    The study of joint congruency at the glenohumeral joint of the shoulder using computed tomography (CT) and three-dimensional (3D) reconstructions of joint surfaces is an area of significant clinical interest. However, ionizing radiation delivered to patients during CT examinations is much higher than other types of radiological imaging. The shoulder represents a significant challenge for this modality as it is adjacent to the thyroid gland and breast tissue. The objective of this study was to determine the optimal CT scanning techniques that would minimize radiation dose while accurately quantifying joint congruency of the shoulder. The results suggest that only one-tenth of the standard applied total current (mA) and a pitch ratio of 1.375:1 was necessary to produce joint congruency values consistent with that of the higher dose scans. Using the CT scanning techniques examined in this study, the effective dose applied to the shoulder to quantify joint congruency was reduced by 88.9% compared to standard clinical CT imaging techniques.

  19. [Partial replacement of the knee joint with patient-specific instruments and implants (ConforMIS iUni, iDuo)].

    PubMed

    Beckmann, J; Steinert, A; Zilkens, C; Zeh, A; Schnurr, C; Schmitt-Sody, M; Gebauer, M

    2016-04-01

    Knee arthroplasty is a successful standard procedure in orthopedic surgery; however, approximately 20 % of patients are dissatisfied with the clinical results as they suffer pain and can no longer achieve the presurgery level of activity. According to the literature the reasons are inexact fitting of the prosthesis or too few anatomically formed implants resulting in less physiological kinematics of the knee joint. Reducing the number of dissatisfied patients and the corresponding number of revisions is an important goal considering the increasing need for artificial joints. In this context, patient-specific knee implants are an obvious alternative to conventional implants. For the first time implants are now matched to the individual bone and not vice versa to achieve the best possible individual situation and geometry and more structures (e.g. ligaments and bone) are preserved or only those structures are replaced which were actually destroyed by arthrosis. According to the authors view, this represents an optimal and pioneering addition to conventional implants. Patient-specific implants and the instruments needed for correct alignment and fitting can be manufactured by virtual 3D reconstruction and 3D printing based on computed tomography (CT) scans. The portfolio covers medial as well as lateral unicondylar implants, medial as well as lateral bicompartmental implants (femorotibial and patellofemoral compartments) and cruciate ligament-preserving as well as cruciate ligament-substituting total knee replacements; however, it must be explicitly emphasized that the literature is sparse and no long-term data are available. PMID:26984107

  20. Effect studies of Uyghur sand therapy on the hemodynamics of the knee-joint arteries.

    PubMed

    Fu, Rongchang; Mahemut, Dilinaer; Tiyipujiang, Rexiati; Aihemaiti, Kuwahan; Ainiwaierjiang, Nuerya

    2014-01-01

    This paper studies the effect of Uyghur sand therapy on dynamics of arterial flow of knee joints via experiments and numerical simulations. Experiments have been carried out on 30 volunteers, with their diameter and flow rate of arteries of knee joints measured before and after Uyghur sand therapy. It has been found that Uyghur sand therapy will increase the inner diameter of knee arteries and speed up the blood flow. Experimental results show that Uyghur sand therapy can help relieve obstacles in local blood flow. By choosing one volunteer for CT scanning, three-dimensional reconstruction of knee-joint arteries via MIMICS software is achieved. Calculation model is the established with numerical calculations performed by ANSYS software. According to the calculations, the blood flow of the knee arteries speeds up and the uniform distribution of velocity enlarges after Uyghur sand therapy, which further confirms the experimental results. Besides, the research also suggests that Uyghur sand therapy has stronger effect on blood flow of knee-joint arteries than the inner diameter.

  1. Joint synchronization and high capacity data hiding for 3D meshes

    NASA Astrophysics Data System (ADS)

    Itier, Vincent; Puech, William; Gesquière, Gilles; Pedeboy, Jean-Pierre

    2015-03-01

    Three-dimensional (3-D) meshes are already profusely used in lot of domains. In this paper, we propose a new high capacity data hiding scheme for vertex cloud. Our approach is based on very small displacements of vertices, that produce very low distortion of the mesh. Moreover this method can embed three bits per vertex relying only on the geometry of the mesh. As an application, we show how we embed a large binary logo for copyright purpose.

  2. Displacement of the medial meniscus within the passive motion characteristics of the human knee joint: an RSA study in human cadaver knees.

    PubMed

    Tienen, T G; Buma, P; Scholten, J G F; van Kampen, A; Veth, R P H; Verdonschot, N

    2005-05-01

    The objective of this study was to validate an in vitro human cadaver knee-joint model for the evaluation of the meniscal movement during knee-joint flexion. The question was whether our model showed comparable meniscal displacements to those found in earlier meniscal movement studies in vivo. Furthermore, we determined the influence of tibial torque on the meniscal displacement during knee-joint flexion. Three tantalum beads were inserted in the medial meniscus of six human-cadaver joints. The knee joints were placed and loaded in a loading apparatus, and the movements of the beads were determined by means of RSA during knee-joint flexion and extension with and without internal tibial (IT) and external tibial (ET) torque. During flexion without tibial torque, all menisci moved in posterior and lateral direction. The anterior horn showed significantly greater excursions than the posterior horn in both posterior and lateral direction. Internal tibial torque caused an anterior displacement of the pathway on the tibial plateau. External tibial torque caused a posterior displacement of the pathway. External tibial torque restricted the meniscal displacement during the first 30 degrees of knee-joint flexion. The displacements of the meniscus in this experiment were similar to the displacements described in the in vivo MRI studies. Furthermore, the application of tibial torque confirmed the relative immobility of the posterior horn of the meniscus. During external tibial torque, the posterior displacement of the pathway on the tibial plateau during the first 30 degrees of flexion might be restricted by the attached knee-joint capsule or the femoral condyle. This model revealed representative meniscal displacements during simple knee-joint flexion and also during the outer limits of passive knee-joint motion.

  3. Patterns of compensation of functional deficits of the knee joint in patients with juvenile idiopathic arthritis

    PubMed Central

    Księżopolska-Orłowska, Krystyna

    2015-01-01

    Objectives Juvenile idiopathic arthritis (JIA) is a group of pathological syndromes of unknown aetiology, observed at the developmental age. Their common feature is sustained chronic arthritis with flares and remissions. Clinical signs and symptoms include joint pain, periarticular tissue oedema or articular exudate, frequently associated with hypertrophy of the synovial membrane. The intra- and extra-articular structural damage impairs the motion range and smoothness. The disease process may involve any joint. The knee joint is the most frequently affected in oligo- and polyarthritis. The aim of the study was to determine a direct correlation between disorders of knee joint function and the change in the range of motion of the ankle and hip joints of both lower extremities, and the so-called indirect impact of these changes on patients’ posture. Material and methods The study included 36 JIA patients and 56 healthy controls aged 8–16 years. The evaluation was based on physical examination. Results The results showed differences in the values of quality and range of motion between patients and controls. In the patient group pes planovalgus was more frequently associated with knee joint dysfunction along with the inherent restriction of dorsal flexion of the foot. Shortening of the iliotibial band, increased outward rotation of the right lower extremity with enlarged joint contour and augmented inward rotation of the contralateral healthy extremity all proved significant. Changes in motion range in the joints below and over the knee were associated with alterations of antero-posterior spine curvatures and vertebral rotation along the long spinal axis. Based on the results, the mechanism of the compensation is outlined. Conclusions The observed differences in the range and quality of motion in the ankle, hip and spinal joints between patients and healthy children provide evidence that dysfunction of the knee joint affects the function of the other above

  4. The Influence of Task Complexity on Knee Joint Kinetics Following ACL Reconstruction

    PubMed Central

    Schroeder, Megan J.; Krishnan, Chandramouli; Dhaher, Yasin Y.

    2015-01-01

    Background Previous research indicates that subjects with anterior cruciate ligament reconstruction exhibit abnormal knee joint movement patterns during functional activities like walking. While the sagittal plane mechanics have been studied extensively, less is known about the secondary planes, specifically with regard to more demanding tasks. This study explored the influence of task complexity on functional joint mechanics in the context of graft-specific surgeries. Methods In 25 participants (10 hamstring tendon graft, 6 patellar tendon graft, 9 matched controls), three-dimensional joint torques were calculated using a standard inverse dynamics approach during level walking and stair descent. The stair descent task was separated into two functionally different sub-tasks—step-to-floor and step-to-step. The differences in external knee moment profiles were compared between groups; paired differences between the reconstructed and non-reconstructed knees were also assessed. Findings The reconstructed knees, irrespective of graft type, typically exhibited significantly lower peak knee flexion moments compared to control knees during stair descent, with the differences more pronounced in the step-to-step task. Frontal plane adduction torque deficits were graft-specific and limited to the hamstring tendon knees during the step-to-step task. Internal rotation torque deficits were also primarily limited to the hamstring tendon graft group during stair descent. Collectively, these results suggest that task complexity was a primary driver of differences in joint mechanics between anterior cruciate ligament reconstructed individuals and controls, and such differences were more pronounced in individuals with hamstring tendon grafts. Interpretation The mechanical environment experienced in the cartilage during repetitive, cyclical tasks such as walking and other activities of daily living has been argued to contribute to the development of degenerative changes to the joint

  5. Three-dimensional knee joint contact forces during walking in unilateral transtibial amputees.

    PubMed

    Silverman, Anne K; Neptune, Richard R

    2014-08-22

    Individuals with unilateral transtibial amputations have greater prevalence of osteoarthritis in the intact knee joint relative to the residual leg and non-amputees, but the cause of this greater prevalence is unclear. The purpose of this study was to compare knee joint contact forces and the muscles contributing to these forces between amputees and non-amputees during walking using forward dynamics simulations. We predicted that the intact knee contact forces would be higher than those of the residual leg and non-amputees. In the axial and mediolateral directions, the intact and non-amputee legs had greater peak tibio-femoral contact forces and impulses relative to the residual leg. The peak axial contact force was greater in the intact leg relative to the non-amputee leg, but the stance phase impulse was greater in the non-amputee leg. The vasti and hamstrings muscles in early stance and gastrocnemius in late stance were the largest contributors to the joint contact forces in the non-amputee and intact legs. Through dynamic coupling, the soleus and gluteus medius also had large contributions, even though they do not span the knee joint. In the residual leg, the prosthesis had large contributions to the joint forces, similar to the soleus in the intact and non-amputee legs. These results identify the muscles that contribute to knee joint contact forces during transtibial amputee walking and suggest that the peak knee contact forces may be more important than the knee contact impulses in explaining the high prevalence of intact leg osteoarthritis.

  6. [A novel knee endoprosthesis with a physiological joint shape. Part 1: Biomechanical basics and tribological studies].

    PubMed

    Frosch, K-H; Floerkemeier, T; Abicht, C; Adam, P; Dathe, H; Fanghänel, J; Stürmer, K M; Kubein-Meesenburg, D; Nägerl, H

    2009-02-01

    The natural tibiofemoral joint (TFJ) functions according to a roll-glide mechanism. In the stance phase (0-20 degrees flexion), the femur rolls backwards over the tibia plateau, while further flexion causes increased gliding. This kinematics is based on the principle of a quadruple joint. The four morphological axes of rotation are the midpoints of the curvatures of the medial and lateral femoral condyles and the medial and lateral tibia plateau. In addition, the medial and lateral compartments are shifted a few millimetres in a sagittal direction, the medial tibia plateau being concave and the lateral plateau convex. In most knee arthroplasties, these factors are not taken into account; instead they are equipped with symmetrical medial and lateral joint surfaces. Thereby, the midpoints of the curvatures of the sagittal contours of the lateral and medial joint surfaces, on the femoral as well as on the tibial sides, create a common axis of rotation which does not allow a physiological roll-glide mechanism. The goal of this study was therefore to report on the biomechanical basis of the natural knee and to describe the development of a novel knee endoprosthesis based on a mathematical model. The design of the structurally new knee joint endoprosthesis has, on the lateral side, a convex shape of the tibial joint surface in a sagittal cross section. Furthermore, from a mathematical point of view, this knee endoprosthesis possesses essential kinematic and static properties similar to those of a physiological TFJ. Within the framework of the authorization tests, the endoprosthesis was examined according to ISO/WC 14243 in a knee simulator. The abrasion rates were, thereby, lower than or at least as good as those for conventional endoprostheses. The presented data demonstrate a novel concept in knee arthroplasty, which still has to be clinically confirmed by long term results.

  7. The use of focal knee joint cryotherapy to improve functional outcomes after total knee arthroplasty: review article.

    PubMed

    Ewell, Melvin; Griffin, Christopher; Hull, Jason

    2014-08-01

    The purpose of this study was to review and synthesize available evidence on the effect of focal knee joint cryotherapy on quadriceps arthrogenic muscle inhibition and to discuss the implications of the findings regarding the use of this modality for patients after a total knee arthroplasty. An electronic literature search that targeted peer reviewed journals was completed by using the PubMed, CINAHL, ScienceDirect, and OvidSP databases. An article was included when it was determined that the article was relevant to the topic of focal knee joint cryotherapy and its effect on quadriceps muscle function. There were 6 studies that met the inclusion criteria. Of the reviewed studies, effect sizes for quadriceps activation ranged from very small to large. Five of the 6 studies observed medium to large effects. Effect sizes for quadriceps torque and force production ranged from no effect to a large effect. Two of the 5 studies with outcome measurements related to quadriceps torque or force production observed medium and large effects. Analysis of this evidence suggests that focal joint cooling of the knee shows the potential to improve quadriceps activation as well as quadriceps torque and force production in patients with arthrogenic muscle inhibition. Arthrogenic muscle inhibition of the quadriceps is an impairment commonly observed in patients after a total knee arthroplasty. Analysis of the evidence uncovered in this review suggests that this patient population may be positively impacted by the use of this modality to improve quadriceps activation as well as quadriceps torque and force production.

  8. Resultant knee joint moments for lateral movement tasks on sliding and non-sliding sport surfaces.

    PubMed

    Nigg, Benno M; Stefanyshyn, Darren J; Rozitis, Antra I; Mundermann, Annegret

    2009-03-01

    The aim of this study was to compare ankle and knee joint moments observed when playing on sport surfaces that slide slightly relative to the ground with the moments observed when playing on conventional sport surfaces. Three-dimensional resultant internal joint moments and kinematic characteristics of the lower extremity were quantified for 21 university basketball players when performing v-cut and side-shuffle tasks on three types of sliding surface (interlocking tiles) and on two types of conventional surface (maple wood and rolled vinyl). Translational and rotational friction between the five test surfaces and a test shoe were also quantified. The five sport surfaces moved horizontally between 0.2 and 1.6 mm during the landing phase of the two tasks. The medio-lateral ground reaction forces were lowest for the surfaces with the highest horizontal movement. Resultant ankle joint moments were lower and resultant knee moments were higher on the sliding surfaces than the conventional surfaces. Sport surfaces that allow a few millimetres of horizontal movement during ground contact may reduce joint loading at the ankle joint, but increase joint loading at the knee joint, when compared with conventional sport surfaces, and thus may influence the prevalence of knee injuries.

  9. Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Kolappan Geetha, Ganesh; Roy Mahapatra, D.; Srinivasan, Gopalakrishnan

    2012-04-01

    Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

  10. Remobilization does not restore immobilization-induced adhesion of capsule and restricted joint motion in rat knee joints.

    PubMed

    Ando, Akira; Suda, Hideaki; Hagiwara, Yoshihiro; Onoda, Yoshito; Chimoto, Eiichi; Itoi, Eiji

    2012-01-01

    Joint immobilization, which is used in orthopaedic treatments and observed in bedridden people, usually causes restricted joint motion. Decreased joint motion diminishes activities of daily living and increases burden of nursing-care. The purpose of this study was to clarify the reversibility of immobilization-induced capsular changes and restricted joint motion in rat knee joints. The unilateral knee joints of adult male rats were immobilized with an internal fixator for 1, 2, 4, 8, and 16 weeks as a model of immobilization after surgery or disuse of the joint. After the fixation devices were removed, the rats were allowed to move freely for 16 weeks. Sham-operated rats were used as controls. Sagittal sections at medial midcondylar regions were made and assessed with histological, histomorphometric, and immunohistochemical methods. Joint motion was measured using a custom-made device under x-ray control after removal of the periarticular muscles. In the 1/16-week and 2/16-week immobilization-remobilization (Im-Rm) groups, cord-like structures connecting the superior and inferior portions of the posterior capsule (partial adhesion) were observed without restricted joint motion. In the 4/16-, 8/16-, and 16/16-week Im-Rm groups, global adhesion of the posterior capsule and restricted joint motion were observed. The restricted joint motion was not completely restored after incision of the posterior capsule. These data indicate that immobilization alone causes irreversible capsular changes and arthrogenic restricted joint motion. Besides the joint capsule, other arthrogenic factors such as ligaments might influence the restricted joint motion. Prolonged immobilization over 4 weeks should be avoided to prevent irreversible joint contracture.

  11. Joint moment contributions to swing knee extension acceleration during gait in children with spastic hemiplegic cerebral palsy.

    PubMed

    Goldberg, Evan J; Requejo, Philip S; Fowler, Eileen G

    2010-03-22

    Inadequate peak knee extension during the swing phase of gait is a major deficit in individuals with spastic cerebral palsy (CP). The biomechanical mechanisms responsible for knee extension have not been thoroughly examined in CP. The purpose of this study was to assess the contributions of joint moments and gravity to knee extension acceleration during swing in children with spastic hemiplegic CP. Six children with spastic hemiplegic CP were recruited (age=13.4+/-4.8 years). Gait data were collected using an eight-camera system. Induced acceleration analysis was performed for each limb during swing. Average joint moment and gravity contributions to swing knee extension acceleration were calculated. Total swing and stance joint moment contributions were compared between the hemiplegic and non-hemiplegic limbs using paired t-tests (p<0.05). Swing limb joint moment contributions from the hemiplegic limb decelerated swing knee extension significantly more than those of the non-hemiplegic limb and resulted in significantly reduced knee extension acceleration. Total stance limb joint moment contributions were not statistically different. Swing limb joint moment contributions that decelerated knee extension appeared to be the primary cause of inadequate knee extension acceleration during swing. Stance limb muscle strength did not appear to be the limiting factor in achieving adequate knee extension in children with CP. Recent research has shown that the ability to extend the knee during swing is dependent on the selective voluntary motor control of the limb. Data from individual participants support this concept.

  12. A comparison of thermography, radioisotope scanning and clinical assessment of the knee joints in haemophilia.

    PubMed

    Forbes, C D; James, W; Prentice, C R; Greig, W R

    1975-01-01

    Thermography, radioactive scanning and clinical assessment of the knee joints of a series of patients with haemophilia or Christmas disease have been performed. A positive correlation was found between the abnormalities of the thermograms, radioactive scans and the clinical signs in acute haemarthrosis, but not in chronic haemophilic joint disease nor in patients without clinical joint disease. No correlation between the thermograms, radioactive scans and the number of previous joint bleeds was shown. Thermography and radionuclide scanning provide rapid means of quantifying changes within the haemophilic joint and may be useful in assessing treatment of haemophilic haemarthrosis.

  13. Custom Anatomical 3D Spacer for Temporomandibular Joint Resection and Reconstruction.

    PubMed

    Green, John Marshall; Lawson, Sarah T; Liacouras, Peter C; Wise, Edward M; Gentile, Michael A; Grant, Gerald Thomas

    2016-03-01

    Two cases are presented using a two-stage approach and a custom antibiotic spacer placement. Temporomandibular reconstruction can be very demanding and accomplished with a variety of methods in preparation of a total joint and ramus reconstruction with total joint prostheses (TMJ Concepts, Ventura, CA). Three-dimensional reconstructions from diagnostic computed tomography were used to establish a virtually planned resection which included the entire condyle-ramus complex. From these data, digital designs were used to manufacture molds to facilitate intraoperative fabrication of precise custom anatomic spacers from rapidly setting antibiotic-impregnated polymethyl methacrylate. Molds were manufactured using vat polymerization (stereolithography) with a photopolymer in the first case and powder bed fusion (electron beam melting) with Ti6AL4V for the second. Surgical methodology and the use of molds for intraoperative spacer fabrication for each case are discussed. PMID:26889353

  14. Comparison of PD BLADE with fat saturation (FS), PD FS and T2 3D DESS with water excitation (WE) in detecting articular knee cartilage defects.

    PubMed

    Lavdas, Eleftherios; Topalzikis, Theofilos; Mavroidis, Panayiotis; Kyriakis, Ioannis; Roka, Violeta; Kostopoulos, Spiros; Glotsos, Dimitrios; Zilidis, Christos; Stathakis, Sotiris; Tsagkalis, Antonios; Papanikolaou, Nikos; Batsikas, Georgios; Arvanitis, Dimitrios L; Vassiou, Katerina

    2013-10-01

    The purpose of this study, is to compare the sequences: 1) proton density (PD) BLADE (BLADE is a PROPELLER-equivalent implementation of the Siemens Medical System) with fat saturation (FS) coronal (COR), 2) PD FS COR, 3) multi-planar reconstruction (MPR) with 3mm slice thickness and 4) multi-planar reconstruction (MPR) with 1.5mm slice thickness, both from the T2 3D-double-echo steady state (DESS) with water excitation (WE) sagittal (SAG), regarding their abilities to identify changes in the femorotibial condyle cartilage in knee MRI examinations. Thirty three consecutive patients with osteoarthritis (18 females, 15 males; mean age 56years, range 37-71years), who had been routinely scanned for knee examination using the previously mentioned image acquisition techniques, participated in the study. A quantitative analysis was performed based on the relative contrast (ReCON) measurements, which were taken both on normal tissues as well as on pathologies. Additionally, a qualitative analysis was performed by two radiologists. Motion and pulsatile flow artifacts were evaluated. The PD BLADE FS COR sequence produced images of higher contrast between Menisci and Cartilage, Fluid and Cartilage, Pathologies and Cartilage as well as of the Conspicuousness Superficial Cartilage and it was found to be superior to the other sequences (p<0.001). The sequences T2 3D DESS 1.5mm and T2 3D DESS 3mm were significantly superior to the PD BLADE FS COR and the PD FS COR sequences in the visualization of Bone and Cartilage and the Conspicuousness Deep Surface Cartilage. This pattern of results is also confirmed by the quantitative analysis. PD FS BLADE sequences are ideal for the depiction of the cartilage pathologies compared to the conventional PD FS and T2 3D DESS sequences.

  15. Controlled trial of synovectomy of knee and metacarpophalangeal joints in rheumatoid arthritis.

    PubMed

    1975-10-01

    In a multicentre study patients with rheumatoid arthritis judged by prevailing criteria to be suitable for synovectomy of the knee or metacarpophalangeal (MCP) joints were randomly allocated to one of two groups. One group had the operation, the other was observed without operation from a notional corresponding date. 3 years later the outcome of synovectomy was compared with that of observation without synovectomy. Synovectomy of the knee was followed by significantly less pain and tenderness, smaller effusions, and smaller and less frequent erosions and geodes. By contrast, MCP joints were no better clinically or radiographically than those treated conservatively. The results have been compared with those of two other controlled trials, one concerned with the knee and MCP joints, the other only with MCP joints. In the present trial results were more favourable in the knee but comparable in the MCP joints with those reported in the first of these two trials but less favourable in the MCP joints than those observed in the second.

  16. The effect of angle and moment of the hip and knee joint on iliotibial band hardness.

    PubMed

    Tateuchi, Hiroshige; Shiratori, Sakiko; Ichihashi, Noriaki

    2015-02-01

    Although several studies have described kinematic deviations such as excessive hip adduction in patients with iliotibial band (ITB) syndrome, the factors contributing to increased ITB hardness remains undetermined, owing to lack of direct in vivo measurement. The purpose of this study was to clarify the factors contributing to an increase in ITB hardness by comparing the ITB hardness between the conditions in which the angle, moment, and muscle activity of the hip and knee joint are changed. Sixteen healthy individuals performed the one-leg standing under five conditions in which the pelvic and trunk inclination were changed in the frontal plane. The shear elastic modulus in the ITB was measured as an indicator of the ITB hardness using shear wave elastography. The three-dimensional joint angle and external joint moment in the hip and knee joints, and muscle activities of the gluteus maximus, gluteus medius, tensor fasciae latae, and vastus lateralis, which anatomically connect to the ITB, were also measured. ITB hardness was significantly increased in the posture with pelvic and trunk inclination toward the contralateral side of the standing leg compared with that in all other conditions (increase of approximately 32% compared with that during normal one-leg standing). This posture increased both the hip adduction angle and external adduction moment at the hip and knee joint, although muscle activities were not increased. Our findings suggest that coexistence of an increased adduction moment at the hip and knee joints with an excessive hip adduction angle lead to an increase in ITB hardness.

  17. Isokinetic evaluation of knee joint flexor and extensor muscles after tibial eminence fractures.

    PubMed

    Melzer, Piotr; Głowacki, Maciej; Głowacki, Jakub; Misterska, Ewa

    2014-01-01

    The aim of the study was to evaluate the knee joint function in adolescent patients following operative treatment - fixation via arthroscopic or open surgery (arthrotomy), due to tibial eminence fractures. 28 patients, aged from 7 to 16 years, treated operatively between 1994-2009 in four orthopeadic centres underwent evaluation. Evaluation was performed 12-180 months following surgery. Patients were divided into two groups depending on the operative treatment received. Group A consisted of 14 patients who underwent arthroscopic reduction and stabilization. Group B consisted of 14 patients who were treated by open reduction (artrothomy) and stabilization. The results of clinical and radiological examinations and isokinetic tests used in the evaluation declared that operative treatment due to tibial eminence fracture, regardless of surgical method used, does not significantly disrupt knee joint function resulting in a slight weakening of knee joint extensor muscle strength.

  18. Effect of patient positions on measurement errors of the knee-joint space on radiographs

    NASA Astrophysics Data System (ADS)

    Gilewska, Grazyna

    2001-08-01

    Osteoarthritis (OA) is one of the most important health problems these days. It is one of the most frequent causes of pain and disability of middle-aged and old people. Nowadays the radiograph is the most economic and available tool to evaluate changes in OA. Error of performance of radiographs of knee joint is the basic problem of their evaluation for clinical research. The purpose of evaluation of such radiographs in my study was measuring the knee-joint space on several radiographs performed at defined intervals. Attempt at evaluating errors caused by a radiologist of a patient was presented in this study. These errors resulted mainly from either incorrect conditions of performance or from a patient's fault. Once we have information about size of the errors, we will be able to assess which of these elements have the greatest influence on accuracy and repeatability of measurements of knee-joint space. And consequently we will be able to minimize their sources.

  19. The Effects of Common Footwear on Joint Loading in Osteoarthritis of the Knee

    PubMed Central

    Shakoor, Najia; Sengupta, Mondira; Foucher, Kharma C.; Wimmer, Markus A.; Fogg, Louis F.; Block, Joel A.

    2010-01-01

    Objective Elevated joint loads during walking have been associated with the severity and progression of osteoarthritis (OA) of the knee. Footwear may have the potential to alter these loads. This study compared the effects of several common shoe types on knee loading in subjects with OA of the knee. Methods 31 subjects (10 men, 21 women) with radiographic and symptomatic knee OA underwent gait analyses using an optoelectronic camera system and multi-component force plate. In each case, gait was evaluated barefoot and while wearing 4 different shoes: 1) clogs (Dansko®), 2) stability shoes (Brooks Addiction®), 3) flat walking shoes (Puma H Street®), and 4) flip-flops. Peak knee loads were compared between the different footwear conditions. Results Overall, the clogs and stability shoes, resulted in a significantly higher peak knee adduction moment (3.1±0.7 and 3.0±0.7 %BW*ht, respectively, ~15% higher, p<0.05)) compared with that of flat walking shoes (2.8±0.7%BW*ht), flip-flops (2.7±0.8%BW*ht) and barefoot walking (2.7±0.7%BW*ht). There were no statistically significant differences in knee loads with the flat walking shoes and flip-flops compared to barefoot walking. Conclusions These data confirm that footwear may have significant effects on knee loads during walking in subjects with OA of the knee. Flexibility and heel height may be important differentiating characteristics of shoes which affect knee loads. In light of the strong relationship between knee loading and OA, the design and biomechanical effects of modern footwear should be more closely evaluated in terms of their effects on the disease. PMID:20191571

  20. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device.

    PubMed

    Zavieh, Minoo Khalkhali; Amirshakeri, Bahram; Rezasoltani, Asghar; Talebi, Ghadam Ali; Kalantari, Khosro Khademi; Nedaey, Vahab; Baghban, Alireza Akbarzadeh

    2016-08-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint. PMID:27630421

  1. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device.

    PubMed

    Zavieh, Minoo Khalkhali; Amirshakeri, Bahram; Rezasoltani, Asghar; Talebi, Ghadam Ali; Kalantari, Khosro Khademi; Nedaey, Vahab; Baghban, Alireza Akbarzadeh

    2016-08-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint.

  2. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device

    PubMed Central

    Zavieh,, Minoo Khalkhali; Amirshakeri,, Bahram; Rezasoltani,, Asghar; Talebi,, Ghadam Ali; Kalantari,, Khosro Khademi; Nedaey,, Vahab; Baghban,, Alireza Akbarzadeh

    2016-01-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint.

  3. Open knee joint injuries--an evidence-based approach to management.

    PubMed

    Konda, Sanjit R; Davidovitch, Roy I; Egol, Kenneth A

    2014-01-01

    Open knee joint injuries are potentially devastating injuries if not properly diagnosed and treated. Current diagnostic techniques, such as the saline load test (SLT), are based on outdated literature. Diagnosis of traumatic arthrotomies via the presence of intra-articular air on computed tomography (CT) scan has recently been shown to be 100% sensitive and specific to detect these injuries. Additionally, open knee joint injuries have a high rate of associated periarticular fractures (51%). The workhorse open surgical approach to the knee is the medial parapatellar approach; however, arthroscopic irrigation and debridement (I&D) should be considered in the setting of small puncture wounds (e.g., gunshot wounds). Antibiotic therapy following I&D of an open knee joint injury includes 24 to 48 hours of intravenous antibiotics. Oral antibiotic therapy can be administered afterwards for 3 to 5 days if the original injury was grossly contaminated. Ultimately, a unified management algorithm for open knee joint injuries based on current literature should be followed to ensure appropriate diagnosis and treatment of this potentially devastating injury.

  4. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device

    PubMed Central

    Zavieh,, Minoo Khalkhali; Amirshakeri,, Bahram; Rezasoltani,, Asghar; Talebi,, Ghadam Ali; Kalantari,, Khosro Khademi; Nedaey,, Vahab; Baghban,, Alireza Akbarzadeh

    2016-01-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint. PMID:27630421

  5. Role of gastrocnemius activation in knee joint biomechanics: gastrocnemius acts as an ACL antagonist.

    PubMed

    Adouni, M; Shirazi-Adl, A; Marouane, H

    2016-01-01

    Gastrocnemius is a premier muscle crossing the knee, but its role in knee biomechanics and on the anterior cruciate ligament (ACL) remains less clear when compared to hamstrings and quadriceps. The effect of changes in gastrocnemius force at late stance when it peaks on the knee joint response and ACL force was initially investigated using a lower extremity musculoskeletal model driven by gait kinematics-kinetics. The tibiofemoral joint under isolated isometric contraction of gastrocnemius was subsequently analyzed at different force levels and flexion angles (0°-90°). Changes in gastrocnemius force at late stance markedly influenced hamstrings forces. Gastrocnemius acted as ACL antagonist by substantially increasing its force. Simulations under isolated contraction of gastrocnemius confirmed this role at all flexion angles, in particular, at extreme knee flexion angles (0° and 90°). Constraint on varus/valgus rotations substantially decreased this effect. Although hamstrings and gastrocnemius are both knee joint flexors, they play opposite roles in respectively protecting or loading ACL. Although the quadriceps is also recognized as antagonist of ACL, at larger joint flexion and in contrast to quadriceps, activity in gastrocnemius substantially increased ACL forces (anteromedial bundle). The fact that gastrocnemius is an antagonist of ACL should help in effective prevention and management of ACL injuries.

  6. Joint Alignment of Underwater and Above-The Photogrammetric 3d Models by Independent Models Adjustment

    NASA Astrophysics Data System (ADS)

    Menna, F.; Nocerino, E.; Troisi, S.; Remondino, F.

    2015-04-01

    The surveying and 3D modelling of objects that extend both below and above the water level, such as ships, harbour structures, offshore platforms, are still an open issue. Commonly, a combined and simultaneous survey is the adopted solution, with acoustic/optical sensors respectively in underwater and in air (most common) or optical/optical sensors both below and above the water level. In both cases, the system must be calibrated and a ship is to be used and properly equipped with also a navigation system for the alignment of sequential 3D point clouds. Such a system is usually highly expensive and has been proved to work with still structures. On the other hand for free floating objects it does not provide a very practical solution. In this contribution, a flexible, low-cost alternative for surveying floating objects is presented. The method is essentially based on photogrammetry, employed for surveying and modelling both the emerged and submerged parts of the object. Special targets, named Orientation Devices, are specifically designed and adopted for the successive alignment of the two photogrammetric models (underwater and in air). A typical scenario where the proposed procedure can be particularly suitable and effective is the case of a ship after an accident whose damaged part is underwater and necessitate to be measured (Figure 1). The details of the mathematical procedure are provided in the paper, together with a critical explanation of the results obtained from the adoption of the method for the survey of a small pleasure boat in floating condition.

  7. Knee joint proprioception in normal volunteers and patients with anterior cruciate ligament tears, taking special account of the effect of a knee bandage.

    PubMed

    Jerosch, J; Prymka, M

    1996-01-01

    Proprioception of the knee joint was tested in 30 healthy volunteers with clinically inconspicuous knee joints. To examine proprioception, an angle reproduction test was performed. We could not document any differences between the left and the right knee joint or between men and women. At the mid-range, proprioception was worse compared with the end range of motion. In addition, 25 patients with an isolated rupture of the anterior cruciate ligament were evaluated, 14 before and 11 after operative anterior cruciate ligament (ACL) reconstruction. Preoperatively, there was a significant deterioration of proprioception compared with the control group. We were able to show a positive influence of a knee bandage on the proprioception of the injured knee. Patients after ACL reconstruction showed no significantly better proprioception compared with the preoperative group.

  8. Processing of nociceptive mechanical and thermal information in central amygdala neurons with knee-joint input.

    PubMed

    Neugebauer, Volker; Li, Weidong

    2002-01-01

    Pain has a strong emotional dimension, and the amygdala plays a key role in emotionality. The processing of nociceptive mechanical and thermal information was studied in individual neurons of the central nucleus of the amygdala, the target of the spino-parabrachio-amygdaloid pain pathway and a major output nucleus of the amygdala. This study is the first to characterize nociceptive amygdala neurons with input from deep tissue, particularly the knee joint. In 46 anesthetized rats, extracellular single-unit recordings were made from 119 central amygdala neurons that were activated orthodromically by electrical stimulation in the lateral pontine parabrachial area and were tested for receptive fields in the knee joints. Responses to brief mechanical stimulation of joints, muscles, and skin and to cutaneous thermal stimuli were recorded. Receptive-field sizes and thresholds were mapped and stimulus-response functions constructed. Neurons in the central nucleus of the amygdala with excitatory input from the knee joint (n = 62) typically had large symmetrical receptive fields in both hindlimbs or in all four extremities and responded exclusively or preferentially to noxious mechanical stimulation of deep tissue (n = 58). Noxious mechanical stimulation of the skin excited 30 of these neurons; noxious heat activated 21 neurons. Stimulus-response data were best fitted by a sigmoid nonlinear regression model rather than by a monotonically increasing linear function. Another 15 neurons were inhibited by noxious mechanical stimulation of the knee joint and other deep tissue. Fifteen neurons had no receptive field in the knee but responded to noxious stimulation of other body areas; 27 nonresponsive neurons were not activated by natural somesthetic stimulation. Our data suggest that excitation is the predominant effect of brief painful stimulation of somatic tissue on the population of central amygdala neurons with knee joint input. Their large symmetrical receptive fields and

  9. Knee joint passive stiffness and moment in sagittal and frontal planes markedly increase with compression.

    PubMed

    Marouane, H; Shirazi-Adl, A; Adouni, M

    2015-01-01

    Knee joints are subject to large compression forces in daily activities. Due to artefact moments and instability under large compression loads, biomechanical studies impose additional constraints to circumvent the compression position-dependency in response. To quantify the effect of compression on passive knee moment resistance and stiffness, two validated finite element models of the tibiofemoral (TF) joint, one refined with depth-dependent fibril-reinforced cartilage and the other less refined with homogeneous isotropic cartilage, are used. The unconstrained TF joint response in sagittal and frontal planes is investigated at different flexion angles (0°, 15°, 30° and 45°) up to 1800 N compression preloads. The compression is applied at a novel joint mechanical balance point (MBP) identified as a point at which the compression does not cause any coupled rotations in sagittal and frontal planes. The MBP of the unconstrained joint is located at the lateral plateau in small compressions and shifts medially towards the inter-compartmental area at larger compression forces. The compression force substantially increases the joint moment-bearing capacities and instantaneous angular rigidities in both frontal and sagittal planes. The varus-valgus laxities diminish with compression preloads despite concomitant substantial reductions in collateral ligament forces. While the angular rigidity would enhance the joint stability, the augmented passive moment resistance under compression preloads plays a role in supporting external moments and should as such be considered in the knee joint musculoskeletal models.

  10. Registration of 2D to 3D joint images using phase-based mutual information

    NASA Astrophysics Data System (ADS)

    Dalvi, Rupin; Abugharbieh, Rafeef; Pickering, Mark; Scarvell, Jennie; Smith, Paul

    2007-03-01

    Registration of two dimensional to three dimensional orthopaedic medical image data has important applications particularly in the area of image guided surgery and sports medicine. Fluoroscopy to computer tomography (CT) registration is an important case, wherein digitally reconstructed radiographs derived from the CT data are registered to the fluoroscopy data. Traditional registration metrics such as intensity-based mutual information (MI) typically work well but often suffer from gross misregistration errors when the image to be registered contains a partial view of the anatomy visible in the target image. Phase-based MI provides a robust alternative similarity measure which, in addition to possessing the general robustness and noise immunity that MI provides, also employs local phase information in the registration process which makes it less susceptible to the aforementioned errors. In this paper, we propose using the complex wavelet transform for computing image phase information and incorporating that into a phase-based MI measure for image registration. Tests on a CT volume and 6 fluoroscopy images of the knee are presented. The femur and the tibia in the CT volume were individually registered to the fluoroscopy images using intensity-based MI, gradient-based MI and phase-based MI. Errors in the coordinates of fiducials present in the bone structures were used to assess the accuracy of the different registration schemes. Quantitative results demonstrate that the performance of intensity-based MI was the worst. Gradient-based MI performed slightly better, while phase-based MI results were the best consistently producing the lowest errors.

  11. EFFECTS OF A MOVEMENT TRAINING PROGRAM ON HIP AND KNEE JOINT FRONTAL PLANE RUNNING MECHANICS

    PubMed Central

    Wouters, Isaac; Almonroeder, Thomas; DeJarlais, Bryan; Laack, Andrew; Kernozek, Thomas W.

    2012-01-01

    Background/Purpose: Frontal plane running mechanics may contribute to the etiology or exacerbation of common running related injuries. Hip strengthening alone may not change frontal plane hip and knee joint running mechanics. The purpose of the current study was to evaluate whether a training program including visual, verbal, and tactile feedback affects hip and knee joint frontal plane running mechanics among females with evidence of altered weight bearing kinematics. Methods: The knee frontal plane projection angle of 69 apparently healthy females was determined during a single leg squat. The twenty females from this larger sample who exhibited the most acute frontal plane projection angle (medial knee position) during this activity were chosen to participate in this study (age = 20 ± 1.6 years, height = 167.9 ± 6.0 cm, mass = 63.2 ± 8.3 kg, Tegner Activity Rating mode = 7.0). Participants engaged in a 4‐week movement training program using guided practice during weight bearing exercises with visual, verbal, and tactile feedback regarding lower extremity alignment. Paired t‐tests were used to compare frontal plane knee and hip joint angles and moments before and after the training program. Results: After training, internal hip and knee abduction moments during running decreased by 23% (P=0.007) and 29% (P=0.033) respectively. Knee adduction and abduction excursion decreased by 2.1° (P = 0.050) and 2.7° (P=0.008) respectively, suggesting that less frontal plane movement of the knee occurred during running after training. Peak knee abduction angle decreased 1.8° after training (P=0.051) although this was not statistically significant. Contralateral peak pelvic drop, pelvic drop excursion, peak hip adduction angle, hip adduction excursion, and peak knee adduction angle were unchanged following training. Conclusions: A four week movement training program may reduce frontal plane hip and knee joint mechanics thought to contribute to the etiology and

  12. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  13. 21 CFR 888.3560 - Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis. 888.3560 Section 888.3560 Food and Drugs FOOD AND DRUG... Devices § 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained...

  14. 21 CFR 888.3560 - Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis. 888.3560 Section 888.3560 Food and Drugs FOOD AND DRUG... Devices § 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained...

  15. 21 CFR 888.3560 - Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis. 888.3560 Section 888.3560 Food and Drugs FOOD AND DRUG... Devices § 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained...

  16. 21 CFR 888.3560 - Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis. 888.3560 Section 888.3560 Food and Drugs FOOD AND DRUG... Devices § 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained...

  17. 21 CFR 888.3560 - Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis. 888.3560 Section 888.3560 Food and Drugs FOOD AND DRUG... Devices § 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained...

  18. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  19. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... Devices § 888.3535 Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer...

  20. [The lateral splitting of the knee joint capsule for treatment of chondropathia patellae (author's transl)].

    PubMed

    Dobler, R

    1977-06-26

    This is a report on the results of the lateral splitting of the knee-joint capsule for treatment of chondropathia patellae. The operative procedure is described. Pains relative to the patella syndrome, chondropathia patellae, forms of dysplasia of the patella and lateral dislocation of the patella are regarded as indications. 50 knee-joints were post-examined. 26% were without complaints, 54% showed improvement, 10% no change, 10% deteriorated. These results are comparable to those of other, more intensive surgery. Representing a comparatively minor operation, the lateral splitting of the capsule is therefore particularly recommended for young patients.

  1. Arthroscopic-assisted Arthrodesis of the Knee Joint With the Ilizarov Technique: A Case Report and Literature Review.

    PubMed

    Waszczykowski, Michal; Niedzielski, Kryspin; Radek, Maciej; Fabis, Jaroslaw

    2016-01-01

    Arthrodesis of the knee joint is a mainly a salvage surgical procedure performed in cases of infected total knee arthroplasty, tumor, failed knee arthroplasty or posttraumatic complication.The authors report the case of 18-year-old male with posttraumatic complication of left knee because of motorbike accident 1 year before. He was treated immediately after the injury in the local Department of Orthopaedics and Traumatology. The examination in the day of admission to our department revealed deformation of the left knee, massive scar tissue adhesions to the proximal tibial bone and multidirectional instability of the knee. The plain radiographs showed complete lack of lateral compartment of the knee joint and patella. The patient complained of severe instability and pain of the knee and a consecutive loss of supporting function of his left limb. The authors decided to perform an arthroscopic-assisted fusion of the knee with Ilizarov external fixator because of massive scar tissue in the knee region and the prior knee infection.In the final follow-up after 54 months a complete bone fusion, good functional and clinical outcome were obtained.This case provides a significant contribution to the development and application of low-invasive techniques in large and extensive surgical procedures in orthopedics and traumatology. Moreover, in this case fixation of knee joint was crucial for providing good conditions for the regeneration of damaged peroneal nerve. PMID:26817899

  2. Arthroscopic-assisted Arthrodesis of the Knee Joint With the Ilizarov Technique: A Case Report and Literature Review.

    PubMed

    Waszczykowski, Michal; Niedzielski, Kryspin; Radek, Maciej; Fabis, Jaroslaw

    2016-01-01

    Arthrodesis of the knee joint is a mainly a salvage surgical procedure performed in cases of infected total knee arthroplasty, tumor, failed knee arthroplasty or posttraumatic complication.The authors report the case of 18-year-old male with posttraumatic complication of left knee because of motorbike accident 1 year before. He was treated immediately after the injury in the local Department of Orthopaedics and Traumatology. The examination in the day of admission to our department revealed deformation of the left knee, massive scar tissue adhesions to the proximal tibial bone and multidirectional instability of the knee. The plain radiographs showed complete lack of lateral compartment of the knee joint and patella. The patient complained of severe instability and pain of the knee and a consecutive loss of supporting function of his left limb. The authors decided to perform an arthroscopic-assisted fusion of the knee with Ilizarov external fixator because of massive scar tissue in the knee region and the prior knee infection.In the final follow-up after 54 months a complete bone fusion, good functional and clinical outcome were obtained.This case provides a significant contribution to the development and application of low-invasive techniques in large and extensive surgical procedures in orthopedics and traumatology. Moreover, in this case fixation of knee joint was crucial for providing good conditions for the regeneration of damaged peroneal nerve.

  3. The influence of footwear on knee joint loading during walking--in vivo load measurements with instrumented knee implants.

    PubMed

    Kutzner, Ines; Stephan, Daniel; Dymke, Jörn; Bender, Alwina; Graichen, Friedmar; Bergmann, Georg

    2013-02-22

    Since footwear is commonly used every day, its influence on knee joint loading and thereby on the development and progression of osteoarthritis may be crucial. So far the influence of footwear has been examined only indirectly. The aim of this study was to directly measure the effect of footwear on tibiofemoral contact loads during walking. Instrumented knee implants with telemetric data transmission were used to measure the tibiofemoral contact forces and moments in six subjects. The loads during walking with four different shoes (basic running shoes, advanced running shoes, classical dress shoes and shoes with a soft rounded sole in the sagittal plane (MBT)) were compared to those during barefoot walking. Peak values of all six load components were analyzed. In general, footwear tended to increase knee joint loading slightly, with the dress shoe being the most unfavorable type of footwear. At the early stance phase all load components were increased by all shoe types. The resultant force rose by 2-5%, the internal adduction moment by 7-12% and the forces on the medial compartment by 3-5%. Significant reductions of the resultant force were solely observed for the advanced running shoe (-6%) and the MBT (-9%) shoe at late stance. Also the medial compartment force was slightly yet non-significantly reduced by 2-5% with the two shoes. It is questionable whether such small load changes have an influence on the progression of gonarthrosis. Future research is necessary to examine which factors regarding the shoe design, such as heel height, arch support or flexibility are most decisive for a reduction of knee joint loading.

  4. Automating measurement of subtle changes in articular cartilage from MRI of the knee by combining 3D image registration and segmentation

    NASA Astrophysics Data System (ADS)

    Lynch, John A.; Zaim, Souhil; Zhao, Jenny; Peterfy, Charles G.; Genant, Harry K.

    2001-07-01

    In osteoarthritis, articular cartilage loses integrity and becomes thinned. This usually occurs at sites which bear weight during normal use. Measurement of such loss from MRI scans, requires precise and reproducible techniques, which can overcome the difficulties of patient repositioning within the scanner. In this study, we combine a previously described technique for segmentation of cartilage from MRI of the knee, with a technique for 3D image registration that matches localized regions of interest at followup and baseline. Two patients, who had recently undergone meniscal surgery, and developed lesions during the 12 month followup period were examined. Image registration matched regions of interest (ROI) between baseline and followup, and changes within the cartilage lesions were estimate to be about a 16% reduction in cartilage volume within each ROI. This was more than 5 times the reproducibility of the measurement, but only represented a change of between 1 and 2% in total femoral cartilage volume. Changes in total cartilage volume may be insensitive for quantifying changes in cartilage morphology. A combined used of automated image segmentation, with 3D image registration could be a useful tool for the precise and sensitive measurement of localized changes in cartilage from MRI of the knee.

  5. 3D visualization of the lumbar facet joint after degeneration using propagation phase contrast micro-tomography

    PubMed Central

    Cao, Yong; Zhang, Yi; Yin, Xianzheng; Lu, Hongbin; Hu, Jianzhong; Duan, Chunyue

    2016-01-01

    Lumbar facet joint (LFJ) degeneration is believed to be an important cause of low back pain (LBP). Identifying the morphological changes of the LFJ in the degeneration process at a high-resolution level could be meaningful for our better understanding of the possible mechanisms underlying this process. In the present study, we determined the 3D morphology of the LFJ using propagation phase contrast micro-tomography (PPCT) in rats to assess the subtle changes that occur during the degeneration process. PPCT provides vivid 3D images of micromorphological changes in the LFJ during its degeneration process, and the changes in the subchondral bone occurred earlier than in the cartilage during the early stage of degeneration of the LFJ. The delineation of this alteration was similar to that with the histological method. Our findings demonstrated that PPCT could serve as a valuable tool for 3D visualization of the morphology of the LFJ by providing comprehensive information about the cartilage and the underlying subchondral bone and their changes during degeneration processes. It might also have great potential for providing effective diagnostic tools to track changes in the cartilage and to evaluate the effects of therapeutic interventions for LFJ degeneration in preclinical studies. PMID:26907889

  6. Weightlifting performance is related to kinematic and kinetic patterns of the hip and knee joints.

    PubMed

    Kipp, Kristof; Redden, Josh; Sabick, Michelle B; Harris, Chad

    2012-07-01

    The purpose of this study was to investigate the correlations between biomechanical outcome measures and weightlifting performance. Joint kinematics and kinetics of the hip, knee, and ankle were calculated while 10 subjects performed a clean at 85% of 1 repetition maximum (1RM). Kinematic and kinetic time-series patterns were extracted with principal components analysis. Discrete scores for each time-series pattern were calculated and used to determine how each pattern was related to body mass-normalized 1RM. Two hip kinematic and 2 knee kinetic patterns were significantly correlated with relative 1RM. The kinematic patterns captured hip and trunk motions during the first pull and hip joint motion during the movement transition between the first and second pulls. The first kinetic pattern captured a peak in the knee extension moment during the second pull. The second kinetic pattern captured a spatiotemporal shift in the timing and amplitude of the peak knee extension moment. The kinematic results suggest that greater lift mass was associated with steady trunk position during the first pull and less hip extension motion during the second-knee bend transition. Further, the kinetic results suggest that greater lift mass was associated with a smaller knee extensor moments during the first pull, but greater knee extension moments during the second pull, and an earlier temporal transition between knee flexion-extension moments at the beginning of the second pull. Collectively, these results highlight the importance of controlled trunk and hip motions during the first pull and rapid employment of the knee extensor muscles during the second pull in relation to weightlifting performance.

  7. Effects of Specialized Footwear on Joint Loads in Osteoarthritis of the Knee

    PubMed Central

    Shakoor, Najia; Lidtke, Roy H.; Sengupta, Mondira; Fogg, Louis F.; Block, Joel A.

    2013-01-01

    Objective Elevated dynamic joint loads have been associated with the severity and progression of osteoarthritis (OA) of the knee. This study compared the effects of a specialized shoe (the mobility shoe) designed to lower dynamic loads at the knee with self-chosen conventional walking shoes and with a commercially available walking shoe as a control. Methods Subjects with knee OA were evaluated in 2 groups. Group A (n = 28) underwent gait analyses with both their self-chosen walking shoes and the mobility shoes. Group B (n = 20) underwent gait analyses with a control shoe and the mobility shoe. Frontal plane knee loads were compared between the different footwear conditions. Results Group A demonstrated an 8% reduction in the peak external knee adduction moment with the mobility shoe compared with self-chosen walking shoes (mean ± SD 49 ± 0.80 versus 2.71 ± 0.84 %BW × H; P < 0.05). Group B demonstrated a 12% reduction in the peak external knee adduction moment with the mobility shoe compared with the control shoe (mean ± SD 2.66 ± 0.69 versus 3.07 ± 0.75 %BW × H; P < 0.05). Conclusion Specialized footwear can effectively reduce joint loads in subjects with knee OA, compared with self-chosen shoes and control walking shoes. Footwear may represent a therapeutic target for the treatment of knee OA. The types of shoes worn by subjects with knee OA should be evaluated more closely in terms of their effects on the disease. PMID:18759313

  8. Evaluation of 3D-CPA, HR-HPV, and TCT joint detection on cervical disease screening

    PubMed Central

    Liang, Hui; Fu, Min; Zhou, Jian; Song, Lei

    2016-01-01

    The application value of three-dimensional color power angiography (3D-CPA), high-risk human papillomavirus (HR-HPV), ThinPrep cytology test (TCT) joint detection on cervical disease screening was investigated. In total, 1,900 patients that were examined in Gynecological and Cervix Clinic of Maternal and Child Care Service Center of Xuzhou from June 2012 to March 2015 were enrolled in the present study. After admission, the patients underwent TCT, HR-HPV and 3D-CPA examinations, and vascular morphology and typing, vascularization index (VI) were recorded. Colposcopic biopsy was performed in patients with a positive outcome of any of the three indices. Pathological diagnosis was taken as the golden standard to assess the sensitivity, specificity, diagnostic rate, and Youden index of the three methods being used independently or jointly. Of the 1,900 patients, 276 cases (14.53%) were HR-HPV-positive, 214 cases (11.26%) were VI-positive and 164 cases (8.63%) were TCT-positive. A total of 418 cases were confirmed with a positive outcome of any of the three indices and a cervical biopsy was obtained. Of the 418 cases, 162 cases (38.75%) were diagnosed with chronic cervicitis, 146 cases with low-level cervical intraepithelial neoplasia (CIN) (34.93%), 104 cases (24.88%) with high level CIN, 6 cases (1.44%) with cervical cancer. Histology more than low level CIN was defined as positive: i) screening results when the three methods were used independently: HPV was confirmed with the highest sensitivity (90.63%), VI with the highest specificity (83.95%), and HPV with the highest diagnostic accuracy (83.73%); ii) screening results under HPV+TCT and HPV+TCT+VI: HPV+TCT+VI was confirmed with the highest sensitivity and specificity: sensitivity (94.53%), specificity (81.48%), diagnosis coincidence rate (89.47%) and the highest Youden index of 0.760; and iii) vascular morphology and grading were significantly different in the early stage cervical carcinoma, high level CIM, and

  9. Joint 3D inversion of gravity and magnetic data with geological constraints - an alternative approach

    NASA Astrophysics Data System (ADS)

    Prutkin, Ilya; Vajda, Peter; Jentzsch, Gerhard

    2016-04-01

    Quite a popular approach now by interpretation of gravity data is a linear one - an attempt is made to find a density distribution d(x,y,z) below the Earth's surface. This approach has clear disadvantages. First, we face the problem of dimensionality: one looks for 3D function based on 2D data set (measurements on the Earth's surface), the degree of non-uniqueness is extremely high, and no regularization can save the situation. The number of unknowns is many times higher than the number of observations; otherwise, we obtain a very rough model of the lower half-space. Second, the linear approach is not reasonable from the geological point of view. It implies that density varies from one point to another. Usually, we assume big volumes with nearly homogeneous density - layers, blocks, intrusions. It looks more understandable, to search for geometry of density interfaces: 3D topography of contact surfaces and shapes of restricted bodies (intrusions). Third, in the framework of the linear approach even for a synthetic field of two separate objects we obtain clouds of points with slightly increased density. It is hardly ever possible, to isolate objects, particularly when one of them is located above another one. We suggest an alternative approach for the linear one. Our approach has been successfully applied for several case histories including a local gravity anomaly Kolarovo and a bigger area of the Thuringian Basin, where both gravity and magnetic data are inverted. First, we separate sources into deep, intermediate and shallow ones, using subsequent upward and downward continuation. All components are inverted separately. We address a problem which we name the problem of low frequencies: deep objects generate long wavelengths, but the converse implication is not necessarily true. For instance, the effect of the basin structure contributes substantially into low frequencies, though it is caused by shallow sources. However, our numerical experiments with intermediate

  10. Injury tolerance and moment response of the knee joint to combined valgus bending and shear loading.

    PubMed

    Bose, Dipan; Bhalla, Kavi S; Untaroiu, Costin D; Ivarsson, B Johan; Crandall, Jeff R; Hurwitz, Shepard

    2008-06-01

    Valgus bending and shearing of the knee have been identified as primary mechanisms of injuries in a lateral loading environment applicable to pedestrian-car collisions. Previous studies have reported on the structural response of the knee joint to pure valgus bending and lateral shearing, as well as the estimated injury thresholds for the knee bending angle and shear displacement based on experimental tests. However, epidemiological studies indicate that most knee injuries are due to the combined effects of bending and shear loading. Therefore, characterization of knee stiffness for combined loading and the associated injury tolerances is necessary for developing vehicle countermeasures to mitigate pedestrian injuries. Isolated knee joint specimens (n=40) from postmortem human subjects were tested in valgus bending at a loading rate representative of a pedestrian-car impact. The effect of lateral shear force combined with the bending moment on the stiffness response and the injury tolerances of the knee was concurrently evaluated. In addition to the knee moment-angle response, the bending angle and shear displacement corresponding to the first instance of primary ligament failure were determined in each test. The failure displacements were subsequently used to estimate an injury threshold function based on a simplified analytical model of the knee. The validity of the determined injury threshold function was subsequently verified using a finite element model. Post-test necropsy of the knees indicated medial collateral ligament injury consistent with the clinical injuries observed in pedestrian victims. The moment-angle response in valgus bending was determined at quasistatic and dynamic loading rates and compared to previously published test data. The peak bending moment values scaled to an average adult male showed no significant change with variation in the superimposed shear load. An injury threshold function for the knee in terms of bending angle and shear

  11. The Waist Width of Skis Influences the Kinematics of the Knee Joint in Alpine Skiing

    PubMed Central

    Zorko, Martin; Nemec, Bojan; Babič, Jan; Lešnik, Blaz; Supej, Matej

    2015-01-01

    Recently alpine skis with a wider waist width, which medially shifts the contact between the ski edge and the snow while turning, have appeared on the market. The aim of this study was to determine the knee joint kinematics during turning while using skis of different waist widths (65mm, 88mm, 110mm). Six highly skilled skiers performed ten turns on a predefined course (similar to a giant slalom course). The relation of femur and tibia in the sagital, frontal and coronal planes was captured by using an inertial motion capture suit, and Global Navigation Satellite System was used to determine the skiers’ trajectories. With respect of the outer ski the knee joint flexion, internal rotation and abduction significantly decreased with the increase of the ski waist width for the greatest part of the ski turn. The greatest abduction with the narrow ski and the greatest external rotation (lowest internal rotation) with the wide ski are probably the reflection of two different strategies of coping the biomechanical requirements in the ski turn. These changes in knee kinematics were most probably due to an active adaptation of the skier to the changed biomechanical conditions using wider skis. The results indicated that using skis with large waist widths on hard, frozen surfaces could bring the knee joint unfavorably closer to the end of the range of motion in transversal and frontal planes as well as potentially increasing the risk of degenerative knee injuries. Key points The change in the skis’ waist width caused a change in the knee joint movement strategies, which had a tendency to adapt the skier to different biomechanical conditions. The use of wider skis or, in particular, skis with a large waist width, on a hard or frozen surface, could unfavourably bring the knee joint closer to the end of range of motion in transversal and frontal planes as well as may potentially increase the risk of degenerative knee injuries. The overall results of the abduction and

  12. The Waist Width of Skis Influences the Kinematics of the Knee Joint in Alpine Skiing.

    PubMed

    Zorko, Martin; Nemec, Bojan; Babič, Jan; Lešnik, Blaz; Supej, Matej

    2015-09-01

    Recently alpine skis with a wider waist width, which medially shifts the contact between the ski edge and the snow while turning, have appeared on the market. The aim of this study was to determine the knee joint kinematics during turning while using skis of different waist widths (65mm, 88mm, 110mm). Six highly skilled skiers performed ten turns on a predefined course (similar to a giant slalom course). The relation of femur and tibia in the sagital, frontal and coronal planes was captured by using an inertial motion capture suit, and Global Navigation Satellite System was used to determine the skiers' trajectories. With respect of the outer ski the knee joint flexion, internal rotation and abduction significantly decreased with the increase of the ski waist width for the greatest part of the ski turn. The greatest abduction with the narrow ski and the greatest external rotation (lowest internal rotation) with the wide ski are probably the reflection of two different strategies of coping the biomechanical requirements in the ski turn. These changes in knee kinematics were most probably due to an active adaptation of the skier to the changed biomechanical conditions using wider skis. The results indicated that using skis with large waist widths on hard, frozen surfaces could bring the knee joint unfavorably closer to the end of the range of motion in transversal and frontal planes as well as potentially increasing the risk of degenerative knee injuries. Key pointsThe change in the skis' waist width caused a change in the knee joint movement strategies, which had a tendency to adapt the skier to different biomechanical conditions.The use of wider skis or, in particular, skis with a large waist width, on a hard or frozen surface, could unfavourably bring the knee joint closer to the end of range of motion in transversal and frontal planes as well as may potentially increase the risk of degenerative knee injuries.The overall results of the abduction and internal

  13. The impact of joint line restoration on functional results after hinged knee prosthesis

    PubMed Central

    Yilmaz, Serdar; Cankaya, Deniz; Deveci, Alper; Firat, Ahmet; Ozkurt, Bulent; Bozkurt, Murat

    2016-01-01

    Background: Hinged knee prosthesis is an effective treatment method as a salvage procedure in marked ligamentous insufficiency and severe bone defects. Joint line determination and restoration are difficult due to large bone defects and distorted anatomy. We evaluated the impact of joint line alteration on the outcome in rotating hinge knee arthroplasty (RHKA). Materials and Methods: 35 patients who had rotating hinged knee prosthesis applied between 2008 and 2013 were evaluated in this retrospective study. The patients were studied radiologically and clinically. Five patients were lost to followup and two patients died, leaving a total of 28 (7 male, 21 female) patients for final evaluation. The average age of the patients was 66.19 ± 8.35 years (range 52–83 years). The patients were evaluated clinically with Knee Society knee and functional score and patellar score. The joint line positions were evaluated radiographically with femoral epicondylar ratio method. The outcomes were also evaluated according to age, body weight and gender. Student's t-test, independent t-test, and the Wilcoxon signed rank test were used in the statistical analysis. Results: The mean Knee Society knee and functional score significantly improved from preoperative 19.52 ± 11.77 and 12.5 ± 15.66 respectively to 72.46 ± 14.01 and 70.36 ± 9.22 respectively postoperatively (P < 0.001). The mean range of motion of the knee improved from 55.95° ± 25.08° preoperatively to 92.14° ± 13.47° postoperatively (P < 0.001). Joint line position was restored in 20 patients (71.4%). Joint line alteration did not affect Knee Society Scores (KSSs) in contrast to patellar scores. Additionally, KSS was better in the patients with body mass index ≤30 at followup (P = 0.022 and P = 0.045). Conclusion: RHKA is an effective salvage procedure for serious instability and large bone defects. Restoration of the joint line improves the patellar score although it had no effect on the clinical outcome

  14. Knee joint loading during lineman-specific movements in American football players.

    PubMed

    Lambach, Rebecca L; Young, Jay W; Flanigan, David C; Siston, Robert A; Chaudhari, Ajit M

    2015-06-01

    Linemen are at high risk for knee cartilage injuries and osteoarthritis. High-intensity movements from squatting positions (eg, 3-point stance) may produce high joint loads, increasing the risk for cartilage damage. We hypothesized that knee moments and joint reaction forces during lineman-specific activities would be greater than during walking or jogging. Data were collected using standard motion analysis techniques. Fifteen NCAA linemen (mean ± SD: height = 1.86 ± 0.07 m, mass = 121.45 ± 12.78 kg) walked, jogged, and performed 3 unloaded lineman-specific blocking movements from a 3-point stance. External 3-dimensional knee moments and joint reaction forces were calculated using inverse dynamics equations. MANOVA with subsequent univariate ANOVA and post hoc Tukey comparisons were used to determine differences in peak kinetic variables and the flexion angles at which they occurred. All peak moments and joint reaction forces were significantly higher during jogging than during all blocking drills (all P < .001). Peak moments occurred at average knee flexion angles > 70° during blocking versus < 44° in walking or jogging. The magnitude of moments and joint reaction forces when initiating movement from a 3-point stance do not appear to increase risk for cartilage damage, but the high flexion angles at which they occur may increase risk on the posterior femoral condyles. PMID:25536366

  15. Knee joint loading during lineman-specific movements in American football players.

    PubMed

    Lambach, Rebecca L; Young, Jay W; Flanigan, David C; Siston, Robert A; Chaudhari, Ajit M

    2015-06-01

    Linemen are at high risk for knee cartilage injuries and osteoarthritis. High-intensity movements from squatting positions (eg, 3-point stance) may produce high joint loads, increasing the risk for cartilage damage. We hypothesized that knee moments and joint reaction forces during lineman-specific activities would be greater than during walking or jogging. Data were collected using standard motion analysis techniques. Fifteen NCAA linemen (mean ± SD: height = 1.86 ± 0.07 m, mass = 121.45 ± 12.78 kg) walked, jogged, and performed 3 unloaded lineman-specific blocking movements from a 3-point stance. External 3-dimensional knee moments and joint reaction forces were calculated using inverse dynamics equations. MANOVA with subsequent univariate ANOVA and post hoc Tukey comparisons were used to determine differences in peak kinetic variables and the flexion angles at which they occurred. All peak moments and joint reaction forces were significantly higher during jogging than during all blocking drills (all P < .001). Peak moments occurred at average knee flexion angles > 70° during blocking versus < 44° in walking or jogging. The magnitude of moments and joint reaction forces when initiating movement from a 3-point stance do not appear to increase risk for cartilage damage, but the high flexion angles at which they occur may increase risk on the posterior femoral condyles.

  16. Therapeutic effects of segmental resection and decompression combined with joint prosthesis on continuous knee osteoarthritis

    PubMed Central

    Xue, Junlai; Wang, Changhong; Liu, Peng; Xie, Xiangchun; Qi, Shan

    2014-01-01

    Objective: To observe the therapeutic effects of segmental resection and decompression combined with joint prosthesis on continuous knee osteoarthritis (OA). Methods: A total of 130 patients with knee OA were selected and randomly divided into an observation group and a control group (n=65). The control group was treated by segmental resection in combination with joint prosthesis, and the observation group was treated by segmental resection and decompression combined with joint prosthesis. They were followed-up for three months. Results: All patients underwent successful surgeries during which no severe complications occurred. During the follow-up period, the overall effective rates of the observation group and the control group were 93.8% and 78.5% respectively, which were not statistically significantly different (p < 0.05). The observation group was significantly less prone to patellar instability, infection and deep vein thrombosis compared with the control group (P < 0.05). On the same day after surgery, the knee joint scores and functional scores of the two groups were similar, which evidently increased three months later, with significant intra-group and inter-group differences (p < 0.05). Conclusion: Combining segmental resection and decompression with joint prosthesis gave rise to satisfactory short-term prognosis by effectively improving the flexion and extension of injured knee and by decreasing complications, thus being worthy of promotion in clinical practice. PMID:25674115

  17. The effectiveness of ridetherapy in children with benign joint hypermobility syndrome during articulatory changes in the knee joint.

    PubMed

    Mosulishvili, T; Loria, M

    2013-02-01

    Taking into account the biomechanical peculiarities of ridetherapy, the specific methodology of ridetherapy developed by us is given in this paper, also the data of treatment have been studied in the dynamics. Based on the results obtained the reliable advantage of ridetherapy method is determined as compared with therapeutic exercises. It has been established that in children with benign joint hypermobility syndrome during articulatory changes in the knee the use of ridetherapy provides an increase in muscle strength, to a certain degree their hypertrophy, the development of joint-muscular perception, the increase of proprioreception, the minimizing of excessive joint movement, the antinociceptive effect and the avoidance of secondary developed complications.

  18. The effectiveness of ridetherapy in children with benign joint hypermobility syndrome during articulatory changes in the knee joint.

    PubMed

    Mosulishvili, T; Loria, M

    2013-02-01

    Taking into account the biomechanical peculiarities of ridetherapy, the specific methodology of ridetherapy developed by us is given in this paper, also the data of treatment have been studied in the dynamics. Based on the results obtained the reliable advantage of ridetherapy method is determined as compared with therapeutic exercises. It has been established that in children with benign joint hypermobility syndrome during articulatory changes in the knee the use of ridetherapy provides an increase in muscle strength, to a certain degree their hypertrophy, the development of joint-muscular perception, the increase of proprioreception, the minimizing of excessive joint movement, the antinociceptive effect and the avoidance of secondary developed complications. PMID:23482367

  19. The association between antagonist hamstring coactivation and episodes of knee joint shifting and buckling

    PubMed Central

    Segal, N.A.; Nevitt, M.C.; Welborn, R.D.; Nguyen, U.-S.D.T.; Niu, J.; Lewis, C.E.; Felson, D.T.; Frey-Law, L.

    2016-01-01

    SUMMARY Objective Hamstring coactivation during quadriceps activation is necessary to counteract the quadriceps pull on the tibia, but coactivation can be elevated with symptomatic knee osteoarthritis (OA). To guide rehabilitation to attenuate risk for mobility limitations and falls, this study evaluated whether higher antagonistic open kinetic chain hamstring coactivation is associated with knee joint buckling (sudden loss of support) and shifting (a sensation that the knee might give way). Design At baseline, median hamstring coactivation was assessed during maximal isokinetic knee extensor strength testing and at baseline and 24-month follow-up, knee buckling and shifting was self-reported. Associations between tertiles of co-activation and knee (1) buckling, (2) shifting and (3) either buckling or shifting were assessed using logistic regression, adjusted for age, sex, knee OA and pain. Results 1826 participants (1089 women) were included. Mean ± SD age was 61.7 ± 7.7 years, BMI was 30.3 ± 5.5 kg/m2 and 38.2% of knees had OA. There were no consistent statistically significant associations between hamstring coactivation and ipsilateral prevalent or incident buckling or the combination of buckling and shifting. The odds ratios for incident shifting in the highest in comparison with the lowest tertile of coactivation had similar magnitudes in the combined and medial hamstrings, but only reached statistical significance for lateral hamstring coactivation, OR(95%CI) 1.53 (0.99, 2.36). Conclusions Hamstring coactivation during an open kinetic chain quadriceps exercise was not consistently associated with prevalent or incident self-reported knee buckling or shifting in older adults with or at risk for knee OA. PMID:25765501

  20. Functional assessments of the knee joint biomechanics by using pendulum test in adults with Down syndrome.

    PubMed

    Casabona, Antonino; Valle, Maria Stella; Pisasale, Mariangela; Pantò, Maria Rosita; Cioni, Matteo

    2012-12-01

    In this study, we assessed kinematics and viscoelastic features of knee joint in adults with Down syndrome (DS) by means of the Wartenberg pendulum test. This test allows the measuring of the kinematics of the knee joint during passive pendular motion of leg under the influence of gravity. In addition, by a combination of kinematic and anthropometric data, pendulum test provides estimates of joint viscoelastic properties by computing damping and stiffness coefficients. To monitor the occurrences of muscle activation, the surface electromyogram (EMG) of muscle rectus femoris was recorded. The experimental protocol was performed in a group of 10 adults with DS compared with 10 control adults without DS. Joint motion amplitude, velocity, and acceleration of the leg during the first knee flexion significantly decreased in persons with DS with respect to those without DS. This behavior was associated with the activation of rectus femoris in subjects with DS that resulted in increasing of joint resistance shortly after the onset of the first leg flexion. The EMG bursts mostly occurred between 50 and 150 ms from the leg flexion onset. During the remaining cycles of pendular motion, persons with DS exhibited passive leg oscillations with low tonic EMG activity and reduced damping coefficient compared with control subjects. These results suggest that adults with DS might perform preprogrammed contractions to increase joint resistance and compensate for inherent joint instability occurring for quick and unpredictable perturbations. The reduction of damping coefficients observed during passive oscillations could be a predictor of muscle hypotonia.

  1. Effect of Sri Lankan traditional medicine and Ayurveda on Sandhigata Vata (osteoarthritis of knee joint).

    PubMed

    Perera, Pathirage Kamal; Perera, Manaram; Kumarasinghe, Nishantha

    2014-01-01

    Reported case was a 63-year-old female with end-stage osteoarthritis (OA) (Sandhigata Vata) of the left knee joint accompanied by exostoses. Radiology (X-ray) report confirmed it as a Kellgren-Lawrence grade III or less with exostoses. At the beginning, the Knee Society Rating System scores of pain, movement and stability were poor, and function score was fair. Srilankan traditional and Ayurveda medicine treatment was given in three regimens for 70 days. After 70 days, external treatment of oleation and 2 capsules of Shallaki (Boswellia serrata Triana and Planch) and two tablets of Jeewya (comprised of Emblica officinalis Gaertn., Tinospora cordifolia [Willd.] Millers. and Terminalia chebula Retz.), twice daily were continued over 5 months. Visual analogue scale for pain, knee scores in the Knee Society online rating system and a Ayurveda clinical assessment criteria was used to evaluate the effects of treatments in weekly basis. After treatment for 70 days, the Knee Society Rating System scores of pain, movement and stability were also improved up to good level and function score was improved up to excellent level. During the follow-up period, joint symptoms and signs and the knee scores were unchanged. In conclusion, this OA patient's quality of life was improved by the combined treatment of Sri Lankan traditional medicine and Ayurveda. PMID:26195904

  2. The Effects of a Lateral Wedge Insole on Knee and Ankle Joints During Slope Walking.

    PubMed

    Uto, Yuki; Maeda, Tetsuo; Kiyama, Ryoji; Kawada, Masayuki; Tokunaga, Ken; Ohwatashi, Akihiko; Fukudome, Kiyohiro; Ohshige, Tadasu; Yoshimoto, Yoichi; Yone, Kazunori

    2015-12-01

    The purpose of this study was to determine whether a lateral wedge insole reduces the external knee adduction moment during slope walking. Twenty young, healthy subjects participated in this study. Subjects walked up and down a slope using 2 different insoles: a control flat insole and a 7° lateral wedge insole. A three-dimensional motion analysis system and force plate were used to examine the knee adduction moment, the ankle valgus moment, and the moment arm of the ground reaction force to the knee joint center in the frontal plane. The lateral wedge insole significantly decreased the moment arm of the ground reaction force, resulting in a reduction of the knee adduction moment during slope walking, similar to level walking. The reduction ratio of knee adduction moment by the lateral wedge insole during the early stance of up-slope walking was larger than that of level walking. Conversely, the lateral wedge insole increased the ankle valgus moment during slope walking, especially during the early stance phase of up-slope walking. Clinicians should examine the utilization of a lateral wedge insole for knee osteoarthritis patients who perform inclined walking during daily activity, in consideration of the load on the ankle joint. PMID:26252560

  3. Knee joint kinematics during walking influences the spatial cartilage thickness distribution in the knee.

    PubMed

    Koo, Seungbum; Rylander, Jonathan H; Andriacchi, Thomas P

    2011-04-29

    The regional adaptation of knee cartilage morphology to the kinematics of walking has been suggested as an important factor in the evaluation of the consequences of alteration in normal gait leading to osteoarthritis. The purpose of this study was to investigate the association of spatial cartilage thickness distributions of the femur and tibia in the knee to the knee kinematics during walking. Gait data and knee MR images were obtained from 17 healthy volunteers (age 33.2 ± 9.8 years). Cartilage thickness maps were created for the femoral and tibial cartilage. Locations of thickest cartilage in the medial and lateral compartments in the femur and tibia were identified using a numerical method. The flexion-extension (FE) angle associated with the cartilage contact regions on the femur, and the anterior-posterior (AP) translation and internal-external (IE) rotation associated with the cartilage contact regions on the tibia at the heel strike of walking were tested for correlation with the locations of thickest cartilage. The locations of the thickest cartilage had relatively large variation (SD, 8.9°) and was significantly associated with the FE angle at heel strike only in the medial femoral condyle (R(2)=0.41, p<0.01). The natural knee kinematics and contact surface shapes seem to affect the functional adaptation of knee articular cartilage morphology. The sensitivity of cartilage morphology to kinematics at the knee during walking suggests that regional cartilage thickness variations are influenced by both loading and the number of loading cycles. Thus walking is an important consideration in the analysis of the morphological variations of articular cartilage, since it is the dominant cyclic activity of daily living. The sensitivity of cartilage morphology to gait kinematics is also important in understanding the etiology and pathomechanics of osteoarthritis.

  4. Iranian Joint Registry (Iranian National Hip and Knee Arthroplasty Registry)

    PubMed Central

    Aslani, Hamidreza; Nourbakhsh, Seyed Taghi; Lahiji, Farivar A.; Heydarian, Keykavoos; Jabalameli, Mahmood; Ghazavi, Mohammad Taghi; Tahmasebi, Mohammad Naghi; Fayyaz, Mahmoud Reza; Sazegari, Mohammad Ali; Mohaddes, Maziar; Rajabpour, Mojtaba; Emami, Mohammad; Jazayeri, Seyyed Mohammad; Madadi, Firooz; Farahini, Hossein; Mirzatoloee, Fardin; Gharahdaghi, Mohammad; Ebrahimzadeh, Mohammad Hossein; Ebrahimian, Mohammadreza; Mirvakili, Hossein; Bashti, Kaveh; Almasizadeh, Mohtasham; Abolghasemian, Mansour; Taheriazam, Afshin; Motififard, Mehdi; Yazdi, Hamidreza; Mobarakeh, Mahmood Karimi; Shayestehazar, Masoud; Moghtadae, Mehdi; Siavashi, Babak; Sajjadi, Mohammadreza M.; Rasi, Alireza Manafi; Chabok, Seyyed Kazem; Zafarani, Zohreh; Salehi, Shahin; Ahmadi, Monireh; Mohammadi, Amin; Shahsavand, Mohammad Ebrahim

    2016-01-01

    Periodic evaluation and monitoring the health and economic outcome of joint replacement surgery is a common and popular process under the territory of joint registries in many countries. In this article we introduce the methodology used for the foundation of the National Iranian Joint Registry (IJR) with a joint collaboration of the Social Security Organization (SSO) and academic research departments considering the requirements of the Iran’s Ministry of Health and Education. PMID:27200403

  5. Low-level finite state control of knee joint in paraplegic standing.

    PubMed

    Mulder, A J; Veltink, P H; Boom, H B; Zilvold, G

    1992-01-01

    Low-level finite state (locked-unlocked) control is compared with open-loop stimulation of the knee extensor muscles in functional electrical stimulation (FES) induced paraplegic standing. The parameters were: duration of standing, relative torque loss in knee extensor muscles, knee angle stability, average stimulus output and average arm effort during standing. To investigate the impact of external mechanical conditions on controller performance, experiments were performed both under the condition of a freely moving ankle joint and of a mechanically stabilized ankle joint. Finite state control resulted in a 2.5 to 12 times increase of standing duration or in a 1.5 to 5 times decrease of relative torque loss in comparison with open-loop stimulation. Finite state control induced a limit cycle oscillation in the knee joint. Average maximum knee flexion was 6.2 degrees without ankle bracing, and half that value with ankle bracing. Average arm support was 13.9 and 7.5% of the body weight without and with ankle bracing respectively.

  6. A comparison between dynamic implicit and explicit finite element simulations of the native knee joint.

    PubMed

    Naghibi Beidokhti, Hamid; Janssen, Dennis; Khoshgoftar, Mehdi; Sprengers, Andre; Perdahcioglu, Emin Semih; Van den Boogaard, Ton; Verdonschot, Nico

    2016-10-01

    The finite element (FE) method has been widely used to investigate knee biomechanics. Time integration algorithms for dynamic problems in finite element analysis can be classified as either implicit or explicit. Although previously both static/dynamic implicit and dynamic explicit method have been used, a comparative study on the outcomes of both methods is of high interest for the knee modeling community. The aim of this study is to compare static, dynamic implicit and dynamic explicit solutions in analyses of the knee joint to assess the prediction of dynamic effects, potential convergence problems, the accuracy and stability of the calculations, the difference in computational time, and the influence of mass-scaling in the explicit formulation. The heel-strike phase of fast, normal and slow gait was simulated for two different body masses in a model of the native knee. Our results indicate that ignoring the dynamic effect can alter joint motion. Explicit analyses are suitable to simulate dynamic loading of the knee joint in high-speed simulations, as this method offers a substantial reduction of the computational time with a similar prediction of cartilage stresses and meniscus strains. Although mass-scaling can provide even more gain in computational time, it is not recommended for high-speed activities, in which inertial forces play a significant role. PMID:27349493

  7. Design of a Model of Knee Joint for Educational Purposes

    ERIC Educational Resources Information Center

    Jastaniah, Saddig; Alganmi, Ohud

    2016-01-01

    Uses of models play an important role by simulating the bone, obviating the need to experiment on humans or animals. The aim of the present study was to access local materials as gypsum and wax is to be tested for performing a knee model matching bone in the density also to explore how students can come to understand function through a model-based…

  8. Dynamic loading of the knee and hip joint and compensatory strategies in children and adolescents with varus malalignment.

    PubMed

    Stief, Felix; Böhm, Harald; Schwirtz, Ansgar; Dussa, Chakravarthy Ugandhar; Döderlein, Leonhard

    2011-03-01

    Three-dimensional gait analysis is a diagnostic tool that can be used to gain a better understanding of the relationship between joint loading and the onset or progression of articular cartilage degeneration in subjects with varus malalignment. The purpose of the present study was to investigate knee and hip joint angles and moments in children and adolescents with pathological varus alignment of the knee without signs of knee osteoarthritis (OA). Moreover, we wanted to know if compensatory mechanisms are present in this young patient group. Fourteen, otherwise healthy patients with varus malalignment of the knee and 15 healthy control subjects were analysed. Patients showed a reduced knee extension and a significantly lower maximum knee extension moment in terminal stance compared to controls. The maximum knee adduction moment in mid and terminal stance and the maximum hip abduction moment in loading response were significantly higher in the patient group. In the transverse plane, abnormally increased knee internal rotation and hip external rotation moments were present in patients with varus malalignment. These findings imply that varus malalignment is not an isolated problem in the frontal plane. In contrast to adult patients with established medial knee OA, the young patients assessed in the present study did not show typical compensatory mechanisms such as increased foot progression angle or reduced walking speed. This suggests that children and adolescents with varus malalignment of the knee probably do not need to alter their spatio-temporal gait parameters in order to decrease knee joint loading.

  9. Tissue stiffness induced by prolonged immobilization of the rat knee joint and relevance of AGEs (pentosidine).

    PubMed

    Lee, Sachiko; Sakurai, Takashi; Ohsako, Masafumi; Saura, Ryuichi; Hatta, Hideo; Atomi, Yoriko

    2010-12-01

    Joints, connective tissues consisting of extracellular matrix (ECM) with few blood vessels, transfer tension to the skeleton in response to environmental demand. Therefore, joint immobilization decreases active and passive mechanical stress, resulting in increased joint stiffness and tissue degeneration; however, the cause of joint stiffness is obscure. Using a rat knee immobilization model, we examined the relationship between range of motion (ROM) and cell numbers and ECM cross-links by accumulation of advanced glycation end products, pentosidine, in the posterior joint capsule of immobilized joints during 16 weeks of immobilization. The left knee joint was immobilized by internal fixation and compared with the non-immobilized right leg. As early as 2 weeks of immobilization, joint ROM and torque significantly decreased and in parallel, disordered alignment of collagen fiber bundles significantly increased, compared with non-immobilized joints. Those changes continued until 16 weeks of immobilization. Significant increases in pentosidine-positive areas after 8 weeks and significantly decreased cell numbers after 16 weeks of immobilization were also observed compared to the contralateral side. A significant negative correlation between tissue stiffness measured by restriction of ROM and accumulation of pentosidine was observed. This study is the first to show that immobilization of knee joints induces articular contracture associated with sequential changes of ECM alignment, influencing ROM and later pentosidine accumulation and decreased cell numbers during the 16-week immobilization period. Pentosidine appears to be an indicator toward a chronic tissue stiffness leading to decreased cell number rather than a cause of ROM restriction induced by joint immobilization.

  10. Practical approach to subject-specific estimation of knee joint contact force

    PubMed Central

    Knarr, Brian A.; Higginson, Jill S.

    2015-01-01

    Compressive forces experienced at the knee can significantly contribute to cartilage degeneration. Musculoskeletal models enable predictions of the internal forces experienced at the knee, but validation is often not possible, as experimental data detailing loading at the knee joint is limited. Recently available data reporting compressive knee force through direct measurement using instrumented total knee replacements offer a unique opportunity to evaluate the accuracy of models. Previous studies have highlighted the importance of subject-specificity in increasing the accuracy of model predictions; however, these techniques may be unrealistic outside of a research setting. Therefore, the goal of our work was to identify a practical approach for accurate prediction of tibiofemoral knee contact force (KCF). Four methods for prediction of knee contact force were compared: (1) standard static optimization, (2) uniform muscle coordination weighting, (3) subject-specific muscle coordination weighting and (4) subject-specific strength adjustments. Walking trials for three subjects with instrumented knee replacements were used to evaluate the accuracy of model predictions. Predictions utilizing subject-specific muscle coordination weighting yielded the best agreement with experimental data, however this method required in vivo data for weighting factor calibration. Including subject-specific strength adjustments improved models’ predictions compared to standard static optimization, with errors in peak KCF less than 0.5 body weight for all subjects. Overall, combining clinical assessments of muscle strength with standard tools available in the OpenSim software package, such as inverse kinematics and static optimization, appears to be a practical method for predicting joint contact force that can be implemented for many applications. PMID:25952546

  11. Practical approach to subject-specific estimation of knee joint contact force.

    PubMed

    Knarr, Brian A; Higginson, Jill S

    2015-08-20

    Compressive forces experienced at the knee can significantly contribute to cartilage degeneration. Musculoskeletal models enable predictions of the internal forces experienced at the knee, but validation is often not possible, as experimental data detailing loading at the knee joint is limited. Recently available data reporting compressive knee force through direct measurement using instrumented total knee replacements offer a unique opportunity to evaluate the accuracy of models. Previous studies have highlighted the importance of subject-specificity in increasing the accuracy of model predictions; however, these techniques may be unrealistic outside of a research setting. Therefore, the goal of our work was to identify a practical approach for accurate prediction of tibiofemoral knee contact force (KCF). Four methods for prediction of knee contact force were compared: (1) standard static optimization, (2) uniform muscle coordination weighting, (3) subject-specific muscle coordination weighting and (4) subject-specific strength adjustments. Walking trials for three subjects with instrumented knee replacements were used to evaluate the accuracy of model predictions. Predictions utilizing subject-specific muscle coordination weighting yielded the best agreement with experimental data; however this method required in vivo data for weighting factor calibration. Including subject-specific strength adjustments improved models' predictions compared to standard static optimization, with errors in peak KCF less than 0.5 body weight for all subjects. Overall, combining clinical assessments of muscle strength with standard tools available in the OpenSim software package, such as inverse kinematics and static optimization, appears to be a practical method for predicting joint contact force that can be implemented for many applications.

  12. Knee Injuries and Disorders

    MedlinePlus

    Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty ...

  13. Defining the knee joint flexion-extension axis for purposes of quantitative gait analysis: an evaluation of methods.

    PubMed

    Schache, Anthony G; Baker, Richard; Lamoreux, Larry W

    2006-08-01

    Minimising measurement variability associated with hip axial rotation and avoiding knee joint angle cross-talk are two fundamental objectives of any method used to define the knee joint flexion-extension axis for purposes of quantitative gait analysis. The aim of this experiment was to compare three different methods of defining this axis: the knee alignment device (KAD) method, a method based on the transepicondylar axis (TEA) and an alternative numerical method (Dynamic). The former two methods are common approaches that have been applied clinically in many quantitative gait analysis laboratories; the latter is an optimisation procedure. A cohort of 20 subjects performed three different functional tasks (normal gait; squat; non-weight bearing knee flexion) on repeated occasions. Three-dimensional hip and knee angles were computed using the three alternative methods of defining the knee joint flexion-extension axis. The repeatability of hip axial rotation measurements during normal gait was found to be significantly better for the Dynamic method (p<0.01). Furthermore, both the variance in the knee varus-valgus kinematic profile and the degree of knee joint angle cross-talk were smallest for the Dynamic method across all functional tasks. The Dynamic method therefore provided superior results in comparison to the KAD and TEA-based methods and thus represents an attractive solution for orientating the knee joint flexion-extension axis for purposes of quantitative gait analysis.

  14. Partitioning of knee joint internal forces in gait is dictated by the knee adduction angle and not by the knee adduction moment.

    PubMed

    Adouni, M; Shirazi-Adl, A

    2014-05-01

    Medial knee osteoarthritis is a debilitating disease. Surgical and conservative interventions are performed to manage its progression via reduction of load on the medial compartment or equivalently its surrogate measure, the external adduction moment. However, some studies have questioned a correlation between the medial load and adduction moment. Using a musculoskeletal model of the lower extremity driven by kinematics-kinetics of asymptomatic subjects at gait midstance, we aim here to quantify the relative effects of changes in the knee adduction angle versus changes in the adduction moment on the joint response and medial/lateral load partitioning. The reference adduction rotation of 1.6° is altered by ±1.5° to 3.1° and 0.1° or the knee reference adduction moment of 17Nm is varied by ±50% to 25.5Nm and 8.5Nm. Quadriceps, hamstrings and tibiofemoral contact forces substantially increased as adduction angle dropped and diminished as it increased. The medial/lateral ratio of contact forces slightly altered by changes in the adduction moment but a larger adduction rotation hugely increased this ratio from 8.8 to a 90 while in contrast a smaller adduction rotation yielded a more uniform distribution. If the aim in an intervention is to diminish the medial contact force and medial/lateral load ratio, a drop of 1.5° in adduction angle is much more effective (causing respectively 12% and 80% decreases) than a reduction of 50% in the adduction moment (causing respectively 4% and 13% decreases). Substantial role of changes in adduction angle is due to the associated alterations in joint nonlinear passive resistance. These findings explain the poor correlation between knee adduction moment and tibiofemoral compartment loading during gait suggesting that the internal load partitioning is dictated by the joint adduction angle.

  15. Estimating the Mechanical Behavior of the Knee Joint During Crouch Gait: Implications for Real-Time Motor Control of Robotic Knee Orthoses.

    PubMed

    Lerner, Zachary F; Damiano, Diane L; Bulea, Thomas C

    2016-06-01

    Individuals with cerebral palsy frequently exhibit crouch gait, a pathological walking pattern characterized by excessive knee flexion. Knowledge of the knee joint moment during crouch gait is necessary for the design and control of assistive devices used for treatment. Our goal was to 1) develop statistical models to estimate knee joint moment extrema and dynamic stiffness during crouch gait, and 2) use the models to estimate the instantaneous joint moment during weight-acceptance. We retrospectively computed knee moments from 10 children with crouch gait and used stepwise linear regression to develop statistical models describing the knee moment features. The models explained at least 90% of the response value variability: peak moment in early (99%) and late (90%) stance, and dynamic stiffness of weight-acceptance flexion (94%) and extension (98%). We estimated knee extensor moment profiles from the predicted dynamic stiffness and instantaneous knee angle. This approach captured the timing and shape of the computed moment (root-mean-squared error: 2.64 Nm); including the predicted early-stance peak moment as a correction factor improved model performance (root-mean-squared error: 1.37 Nm). Our strategy provides a practical, accurate method to estimate the knee moment during crouch gait, and could be used for real-time, adaptive control of robotic orthoses.

  16. A parallel framework for the FE-based simulation of knee joint motion.

    PubMed

    Wawro, Martin; Fathi-Torbaghan, Madjid

    2004-08-01

    We present an object-oriented framework for the finite-element (FE)-based simulation of the human knee joint motion. The FE model of the knee joint is acquired from the patients in vivo by using magnetic resonance imaging. The MRI images are converted into a three-dimensional model and finally an all-hexahedral mesh for the FE analysis is generated. The simulation environment uses nonlinear finite-element analysis (FEA) and is capable of handling contact of the model to handle the complex rolling/sliding motion of the knee joint. The software strictly follows object-oriented concepts of software engineering in order to guarantee maximum extensibility and maintainability. The final goal of this work-in-progress is the creation of a computer-based biomechanical model of the knee joint which can be used in a variety of applications, ranging from prosthesis design and treatment planning (e.g., optimal reconstruction of ruptured ligaments) over surgical simulation to impact computations in crashworthiness simulations.

  17. What role do periodontal pathogens play in osteoarthritis and periprosthetic joint infections of the knee?

    PubMed

    Ehrlich, Garth D; Hu, Fen Z; Sotereanos, Nicholas; Sewicke, Jeffrey; Parvizi, Javad; Nara, Peter L; Arciola, Carla Renata

    2014-01-01

    Through the use of polymerase chain reaction (PCR)-electron spray ionization (ESI)-time of flight (TOF)-mass spectrometry (MS), we identified multiple periodontal pathogens within joint tissues of individuals undergoing replacement arthroplasties of the knee. The most prevalent of the periodontal pathogens were Treponema denticola and Enterococcus faecalis, the latter of which is commonly associated with apical periodontitis. These findings were unique to periprosthetic joint infections (PJI) of the knee and were never observed for PJIs of other lower extremity joints (hip and ankle) or upper extremity joints (shoulder and elbow). These data were confirmed by multiple independent methodologies including fluorescent in situ hybridization (FISH) which showed the bacteria deeply penetrated inside the diseased tissues, and 454-based deep 16S rDNA sequencing. The site-specificity, the tissue investment, and the identical findings by multiple nucleic-acid-based techniques strongly suggests the presence of infecting bacteria within these diseased anatomic sites. Subsequently, as part of a control program using PCR-ESI-TOF-MS, we again detected these same periodontal pathogens in aspirates from patients with osteoarthritis who were undergoing primary arthroplasty of the knee and thus who had no history of orthopedic implants. This latter finding raises the question of whether hematogenic spread of periodontal pathogens to the knee play a primary or secondary-exacerbatory role in osteoarthritis. PMID:24921460

  18. Balance lower limb loads and 3D spine modifications after total hip joint replacement: effects of leg length discrepancy correction.

    PubMed

    D'Amico, Moreno; Ciarrocca, Francesca; Liscio, Grazia; Serafini, Paolo; Tommasini, Maura; Vallasciani, Massimo

    2006-01-01

    Following total hip joint replacement (THJR), the durability of a prosthesis is limited by: wearing of frictional surfaces and loosening and migration of the prosthesis-cement-bone system. Literature review witnesses biomechanical studies focused mainly/only on hip functional state while none of them approached leg length discrepancy (LLD), posture unbalancing or spine related problems after THJR. Conversely, these latter could be critical elements for surgery and rehabilitation success, given the possible induction of asymmetric loading patterns. This study presents the results obtained by using a recently proposed methodology, to measure 3D subject posture balance and spine morphology and to evaluate its usefulness in individual therapy tuning/follow up. 3D subject's posture has been measured by means of 3D opto-electronic device, force platform and baropodography. 90 subjects after THJR have been included in this study. The subjects have been evaluated in two different epochs: 3 weeks after surgical intervention and after 3 months. 77/90 patients presented a LLD, pelvic obliquity and posture unbalancing. More than 90% of this group showed an overall postural re-balancing induced by the use of simple underfoot wedge. 70/77 patients needed wedge under the healthy side showing the surgical intervention produced a leg lengthening. 60/90 (52 LLD) patients underwent up to now to control and patients who wore the suggested wedge (63.4%) presented an improvement over all the considered quantitative parameters. Patients who wore a shorter than suggested wedge (23.1%), or that did not wear the suggested wedge (13.5%) presented a moderate or significant worsening of their postural balancing respectively.

  19. Isokinetic knee joint evaluation in track and field events.

    PubMed

    Deli, Chariklia K; Paschalis, Vassilis; Theodorou, Anastasios A; Nikolaidis, Michalis G; Jamurtas, Athanasios Z; Koutedakis, Yiannis

    2011-09-01

    The purpose of this study was to evaluate maximal torque of the knee flexors and extensors, flexor/extensor ratios, and maximal torque differences between the 2 lower extremities in young track and field athletes. Forty male track and field athletes 13-17 years old and 20 male nonathletes of the same age participated in the study. Athletes were divided into 4 groups according to their age and event (12 runners and 10 jumpers 13-15 years old, 12 runners and 6 jumpers 16-17 years old) and nonathletes into 2 groups of the same age. Maximal torque evaluation of knee flexors and extensors was performed on an isokinetic dynamometer at 60°·s(-1). At the age of 16-17 years, jumpers exhibited higher strength values at extension than did runners and nonathletes, whereas at the age of 13-15 years, no significant differences were found between events. Younger athletes were weaker than older athletes at flexion. Runners and jumpers were stronger than nonathletes in all relative peak torque parameters. Nonathletes exhibited a higher flexor/extensor ratio compared with runners and jumpers. Strength imbalance in athletes was found between the 2 lower extremities in knee flexors and extensors and also at flexor/extensor ratio of the same extremity. Young track and field athletes exhibit strength imbalances that could reduce their athletic performance, and specific strength training for the weak extremity may be needed.

  20. Videoradiographic analysis of the range of motion in unilateral experimental knee joint arthritis in rats

    PubMed Central

    2011-01-01

    Introduction The translational and predictive value of animal models highly depends on the validity of respective readout parameters. In arthritis research, there has been a shift from sole threshold testing for pain-related behavior, as well as from swelling and histology assessment for inflammation, toward an analysis of joint function as indicated, for instance, by an increasing number of studies on gait abnormalities. Clinically, the range of motion (ROM) of the affected joint plays a major role in diagnosis and the assessment of treatment benefits. This parameter, however, is only insufficiently detected by currently used analytic systems in animals. Methods Here we used high-resolution videoradiographic analysis to assess ROM in experimental knee joint arthritis in rats. This parameter is described during the 21-day course of antigen-induced arthritis in rats. Furthermore, the therapeutic effects of antinociceptive (morphine) and anti-inflammatory (dexamethasone) treatment on ROM are documented. To obtain additional information on the implications of ROM in animal models, correlations were performed to measure pain-related behavior and inflammation. Results The study animals showed a significant reduction in ROM of the inflamed knee joint in the acute phase of arthritis. This was accompanied by an increase in knee joint movement on the contralateral side, indicating a compensational mechanism. Both morphine and dexamethasone treatment increased and thus normalized ROM. Changes in ROM were further stage-dependently correlated with weight bearing and joint swelling, that is, with both pain-related behavior and signs of inflammation. Conclusions The dynamic ROM observed in freely moving rats in our model of knee joint arthritis might serve as a parameter for global disease activity and might thus represent a promising readout parameter for preclinical assessment regarding the overall efficacy not only of antiarthritic but also of antinociceptive compounds. PMID

  1. Knee Joint Loading during Gait in Healthy Controls and Individuals with Knee Osteoarthritis

    PubMed Central

    Kumar, Deepak; Manal, Kurt T.; Rudolph, Katherine S.

    2013-01-01

    Objective People with knee osteoarthritis (OA) are thought to walk with high loads at the knee which are yet to be quantfied using modeling techniques that account for subject specific EMG patterns, kinematics and kinetics. The objective was to estimate medial and lateral loading for people with knee OA and controls using an approach that is sensitive to subject specific muscle activation patterns. Methods 16 OA and 12 control (C) subjects walked while kinematic, kinetic and EMG data were collected. Muscle forces were calculated using an EMG-Driven model and loading was calculated by balancing the external moments with internal muscle and contact forces Results OA subjects walked slower and had greater laxity, static and dynamic varus alignment, less flexion and greater knee adduction moment (KAM). Loading (normalized to body weight) was no different between the groups but OA subjects had greater absolute medial load than controls and maintained a greater %total load on the medial compartment. These patterns were associated with body mass, sagittal and frontal plane moments, static alignment and close to signficance for dynamic alignment. Lateral compartment unloading during mid-late stance was observed in 50% of OA subjects. Conclusions Loading for control subjects was similar to data from instrumented prostheses. Knee OA subjects had high medial contact loads in early stance and half of the OA cohort demonstared lateral compartment lift-off. Results suggest that interventions aimed at reducing body weight and dynamic malalignment might be effective in reducing medial compartment loading and establishing normal medio-lateral load sharing patterns. PMID:23182814

  2. First Case of Lyme Arthritis Involving a Prosthetic Knee Joint.

    PubMed

    Wright, William F; Oliverio, James A

    2016-04-01

    Borrelia burgdorferi sensu stricto is the most common tick-borne illness in the United States. Arthritis is usually a mani-festation of late dis-ease but has not been associated with cases of periprosthetic joint infections. We report on a patient who was first diagnosed with periprosthetic joint infection and subsequently Lyme arthritis. PMID:27419168

  3. The effect of action observation training on knee joint function and gait ability in total knee replacement patients

    PubMed Central

    Park, Seong Doo; Song, Hyun Seung; Kim, Jin Young

    2014-01-01

    The purpose of this study is to investigate that effect of action observation training (AOT) on knee joint function and balance in total knee replacement (TKR) patients. The subjects consisted of eighteen post-TKR patients. All participants underwent conventional physical therapy. In addition, patients in the AOT group (n= 9) were asked to observe video clips showing daily actions and to imitate them afterward. Patients in the control group (n= 9) were asked to execute the same actions as patients in the AOT group. Outcome measures Western Ontario and Mc-Master Universities Osteoarthritis Index (WOMAC) included pain, stiffness, function and Timed Up and Go (TUG) test. After intervention, patients in the AOT group score better than patients in the control group. After TUG test, patients in the AOT group and control group were no significant difference between two groups. In addition to conventional physical therapy, AOT is effective in the rehabilitation of post-TKR patients. Action observation training is considered conducive to improving knee functions and ameliorating pain and stiffness, of patients who underwent TKR. PMID:25061596

  4. Chronic septic arthritis and osteomyelitis in a prosthetic knee joint due to Clostridium difficile.

    PubMed

    Pron, B; Merckx, J; Touzet, P; Ferroni, A; Poyart, C; Berche, P; Gaillard, J L

    1995-07-01

    A case of chronic septic arthritis and osteomyelitis in a prosthetic knee joint due to Clostridium difficile is reported. A knee prosthesis was installed in a 16-year-old boy for surgical treatment of an osteosarcoma of the femur. Later, the patient suffered a traumatic closed fracture of his patella, and a sterile fluid was aspirated. One month later, the joint displayed inflammation. Culture of the articular fluid yielded a nontoxigenic Clostridium difficile strain. Despite several attempts using conservative medical treatment with penicillins and ornidazole, Clostridium difficile strains with the same antibiotic susceptibility pattern were repeatedly isolated from the joint over an eight-month period. The foreign material was then ablated, and finally, the patient's leg was amputated one year after Clostridium difficile was first isolated. The possible sources of contamination in our case and other reported cases of extraintestinal infection due to Clostridium difficile are discussed.

  5. Loading of the knee joint during activities of daily living measured in vivo in five subjects.

    PubMed

    Kutzner, I; Heinlein, B; Graichen, F; Bender, A; Rohlmann, A; Halder, A; Beier, A; Bergmann, G

    2010-08-10

    Detailed knowledge about loading of the knee joint is essential for preclinical testing of implants, validation of musculoskeletal models and biomechanical understanding of the knee joint. The contact forces and moments acting on the tibial component were therefore measured in 5 subjects in vivo by an instrumented knee implant during various activities of daily living. Average peak resultant forces, in percent of body weight, were highest during stair descending (346% BW), followed by stair ascending (316% BW), level walking (261% BW), one legged stance (259% BW), knee bending (253% BW), standing up (246% BW), sitting down (225% BW) and two legged stance (107% BW). Peak shear forces were about 10-20 times smaller than the axial force. Resultant forces acted almost vertically on the tibial plateau even during high flexion. Highest moments acted in the frontal plane with a typical peak to peak range -2.91% BWm (adduction moment) to 1.61% BWm (abduction moment) throughout all activities. Peak flexion/extension moments ranged between -0.44% BWm (extension moment) and 3.16% BWm (flexion moment). Peak external/internal torques lay between -1.1% BWm (internal torque) and 0.53% BWm (external torque). The knee joint is highly loaded during daily life. In general, resultant contact forces during dynamic activities were lower than the ones predicted by many mathematical models, but lay in a similar range as measured in vivo by others. Some of the observed load components were much higher than those currently applied when testing knee implants.

  6. A viscoelastic poromechanical model of the knee joint in large compression.

    PubMed

    Kazemi, M; Li, L P

    2014-08-01

    The elastic response of the knee joint in various loading and pathological conditions has been investigated using anatomically accurate geometry. However, it is still challenging to predict the poromechanical response of the knee in realistic loading conditions. In the present study, a viscoelastic, poromechanical model of the knee joint was developed for soft tissues undergoing large deformation. Cartilages and menisci were modeled as fibril-reinforced porous materials and ligaments were considered as fibril-reinforced hyperelastic solids. Quasi-linear viscoelasticty was formulated for the collagen network of these tissues and nearly incompressible Neo-Hookean hyperelasticity was used for the non-fibrillar matrix. The constitutive model was coded with a user defined FORTRAN subroutine, in order to use ABAQUS for the finite element analysis. Creep and stress relaxation were investigated with large compression of the knee in full extension. The contact pressure distributions were found similar in creep and stress relaxation. However, the load transfer in the joint was completely different in these two loading scenarios. During creep, the contact pressure between cartilages decreased but the pressure between cartilage and meniscus increased with time. This led to a gradual transfer of some loading from the central part of cartilages to menisci. During stress relaxation, however, both contact pressures decreased monotonically. PMID:24933338

  7. Raman spectroscopy of dried synovial fluid droplets as a rapid diagnostic for knee joint damage

    NASA Astrophysics Data System (ADS)

    Esmonde-White, Karen A.; Mandair, Gurjit S.; Raaii, Farhang; Roessler, Blake J.; Morris, Michael D.

    2008-02-01

    Human synovial fluid droplets were investigated using drop deposition in combination with Raman spectroscopy. Following informed consent, synovial fluid was obtained from forty human patients with various severities of knee pain and/or osteoarthritis at the time of knee arthroscopy or total joint replacement. Synovial fluid was aspirated from the knee joint of each patient and stored at -80°C until examination by near-infrared Raman spectroscopy. Synovial fluid aspirates from the knee joint of each patient were deposited onto a clean fused silica microscope slide and the droplet dried under ambient laboratory conditions. Each droplet was illuminated by a line-focused or a ring-focused 785 nm laser. As the droplet dries, biofluid components segregated based on solubility differences and a deposit that is spatially heterogeneous was made. Spectra taken from the droplet edges and center were dominated by protein bands and showed the presence of at least two protein moieties in the droplet. Band area and band height ratios (1410 cm -1/1450 cm -1) showed the greatest change between specimens from patients with mild/early osteoarthritis compared to those with severe/late stage osteoarthritis. The greatest differences were found in the center of the droplet, which contains more soluble protein components than the edges.

  8. The effect of angle and moment of the hip and knee joint on iliotibial band hardness.

    PubMed

    Tateuchi, Hiroshige; Shiratori, Sakiko; Ichihashi, Noriaki

    2015-02-01

    Although several studies have described kinematic deviations such as excessive hip adduction in patients with iliotibial band (ITB) syndrome, the factors contributing to increased ITB hardness remains undetermined, owing to lack of direct in vivo measurement. The purpose of this study was to clarify the factors contributing to an increase in ITB hardness by comparing the ITB hardness between the conditions in which the angle, moment, and muscle activity of the hip and knee joint are changed. Sixteen healthy individuals performed the one-leg standing under five conditions in which the pelvic and trunk inclination were changed in the frontal plane. The shear elastic modulus in the ITB was measured as an indicator of the ITB hardness using shear wave elastography. The three-dimensional joint angle and external joint moment in the hip and knee joints, and muscle activities of the gluteus maximus, gluteus medius, tensor fasciae latae, and vastus lateralis, which anatomically connect to the ITB, were also measured. ITB hardness was significantly increased in the posture with pelvic and trunk inclination toward the contralateral side of the standing leg compared with that in all other conditions (increase of approximately 32% compared with that during normal one-leg standing). This posture increased both the hip adduction angle and external adduction moment at the hip and knee joint, although muscle activities were not increased. Our findings suggest that coexistence of an increased adduction moment at the hip and knee joints with an excessive hip adduction angle lead to an increase in ITB hardness. PMID:25542398

  9. [Proposal for an auxiliary tool designed to reduce retake rates for lateral radiography of the knee joint].

    PubMed

    Yasuda, Yu; Sato, Hisaya; Ohsawa, Miwa; Takahashi, Kanji; Noda, Chikara; Sai, Syogo; Sukezaki, Fumio; Nakazawa, Yasuo

    2013-10-01

    The reproducibility of lateral radiography of the knee joint in the lateral position is low because patient positioning can be easily affected by passive rotation of the knee joint. We calculated the correction angle of the femoral external rotation and the lower leg elevation and developed our own auxiliary tool for obtaining a lateral view image. We were able to obtain, in a single attempt, an image with misalignment of the condyle limited to less than 7 mm. Our tool also contributed to the reduction of the re-imaging rate, suggesting its usefulness in contributing to a lower re-imaging rate for lateral radiography of the knee joint.

  10. The effect of knee joint angle on plantar flexor power in young and old men.

    PubMed

    Dalton, Brian H; Allen, Matti D; Power, Geoffrey A; Vandervoort, Anthony A; Rice, Charles L

    2014-04-01

    Human adult aging is associated with a loss of strength, contractile velocity and hence, power. The principal plantar flexors, consisting of the bi-articular gastrocnemeii and the mono-articular soleus, appear to be affected differently by the aging process. However, the age-related effect of knee joint angle on the torque-angular velocity relationship and power production of this functionally important muscle group is unknown. The purpose was to determine whether flexing the knee, thereby reducing the gastrocnemius contribution to plantar flexion, would exacerbate the age-related decrements in plantar flexion power, or shift the torque-angular velocity relationship differently in older compared with young men. Neuromuscular properties were recorded from 10 young (~25 y) and 10 old (~78 y) men with the knee extended (170°) and flexed (90°), in a randomized order. Participants performed maximal voluntary isometric contractions (MVCs), followed by maximal velocity-dependent shortening contractions at pre-set loads, ranging from 15 to 75% MVC. The young men were ~20-25% stronger, ~12% faster and ~30% more powerful than the old for both knee angles (P<0.05). In both age groups, isometric MVC torque was ~17% greater in the extended than flexed knee position, with no differences in voluntary activation (>95%). The young men produced 7-12% faster angular velocities in the extended knee position for loads ≤30% MVC, but no differences at higher loads; whereas there were no detectable differences in angular velocity between knee positions in the old across all relative loads. For both knee angles, young men produced peak power at 43.3±9.0% MVC, whereas the old men produced peak power at 54.8±7.9% MVC. These data indicate that the young, who have faster contracting muscles compared with the old, can rely more on velocity than torque for generating maximal power.

  11. A Combined Experimental and Computational Approach to Subject-Specific Analysis of Knee Joint Laxity.

    PubMed

    Harris, Michael D; Cyr, Adam J; Ali, Azhar A; Fitzpatrick, Clare K; Rullkoetter, Paul J; Maletsky, Lorin P; Shelburne, Kevin B

    2016-08-01

    Modeling complex knee biomechanics is a continual challenge, which has resulted in many models of varying levels of quality, complexity, and validation. Beyond modeling healthy knees, accurately mimicking pathologic knee mechanics, such as after cruciate rupture or meniscectomy, is difficult. Experimental tests of knee laxity can provide important information about ligament engagement and overall contributions to knee stability for development of subject-specific models to accurately simulate knee motion and loading. Our objective was to provide combined experimental tests and finite-element (FE) models of natural knee laxity that are subject-specific, have one-to-one experiment to model calibration, simulate ligament engagement in agreement with literature, and are adaptable for a variety of biomechanical investigations (e.g., cartilage contact, ligament strain, in vivo kinematics). Calibration involved perturbing ligament stiffness, initial ligament strain, and attachment location until model-predicted kinematics and ligament engagement matched experimental reports. Errors between model-predicted and experimental kinematics averaged <2 deg during varus-valgus (VV) rotations, <6 deg during internal-external (IE) rotations, and <3 mm of translation during anterior-posterior (AP) displacements. Engagement of the individual ligaments agreed with literature descriptions. These results demonstrate the ability of our constraint models to be customized for multiple individuals and simultaneously call attention to the need to verify that ligament engagement is in good general agreement with literature. To facilitate further investigations of subject-specific or population based knee joint biomechanics, data collected during the experimental and modeling phases of this study are available for download by the research community. PMID:27306137

  12. A Combined Experimental and Computational Approach to Subject-Specific Analysis of Knee Joint Laxity.

    PubMed

    Harris, Michael D; Cyr, Adam J; Ali, Azhar A; Fitzpatrick, Clare K; Rullkoetter, Paul J; Maletsky, Lorin P; Shelburne, Kevin B

    2016-08-01

    Modeling complex knee biomechanics is a continual challenge, which has resulted in many models of varying levels of quality, complexity, and validation. Beyond modeling healthy knees, accurately mimicking pathologic knee mechanics, such as after cruciate rupture or meniscectomy, is difficult. Experimental tests of knee laxity can provide important information about ligament engagement and overall contributions to knee stability for development of subject-specific models to accurately simulate knee motion and loading. Our objective was to provide combined experimental tests and finite-element (FE) models of natural knee laxity that are subject-specific, have one-to-one experiment to model calibration, simulate ligament engagement in agreement with literature, and are adaptable for a variety of biomechanical investigations (e.g., cartilage contact, ligament strain, in vivo kinematics). Calibration involved perturbing ligament stiffness, initial ligament strain, and attachment location until model-predicted kinematics and ligament engagement matched experimental reports. Errors between model-predicted and experimental kinematics averaged <2 deg during varus-valgus (VV) rotations, <6 deg during internal-external (IE) rotations, and <3 mm of translation during anterior-posterior (AP) displacements. Engagement of the individual ligaments agreed with literature descriptions. These results demonstrate the ability of our constraint models to be customized for multiple individuals and simultaneously call attention to the need to verify that ligament engagement is in good general agreement with literature. To facilitate further investigations of subject-specific or population based knee joint biomechanics, data collected during the experimental and modeling phases of this study are available for download by the research community.

  13. Modelling and Simulation of the Knee Joint with a Depth Sensor Camera for Prosthetics and Movement Rehabilitation

    NASA Astrophysics Data System (ADS)

    Risto, S.; Kallergi, M.

    2015-09-01

    The purpose of this project was to model and simulate the knee joint. A computer model of the knee joint was first created, which was controlled by Microsoft's Kinect for Windows. Kinect created a depth map of the knee and lower leg motion independent of lighting conditions through an infrared sensor. A combination of open source software such as Blender, Python, Kinect SDK and NI_Mate were implemented for the creation and control of the simulated knee based on movements of a live physical model. A physical size model of the knee and lower leg was also created, the movement of which was controlled remotely by the computer model and Kinect. The real time communication of the model and the robotic knee was achieved through programming in Python and Arduino language. The result of this study showed that Kinect in the modelling of human kinematics and can play a significant role in the development of prosthetics and other assistive technologies.

  14. Prediction of medial and lateral contact force of the knee joint during normal and turning gait after total knee replacement.

    PubMed

    Purevsuren, Tserenchimed; Dorj, Ariunzaya; Kim, Kyungsoo; Kim, Yoon Hyuk

    2016-04-01

    The computational modeling approach has commonly been used to predict knee joint contact forces, muscle forces, and ligament loads during activities of daily living. Knowledge of these forces has several potential applications, for example, within design of equipment to protect the knee joint from injury and to plan adequate rehabilitation protocols, although clinical applications of computational models are still evolving and one of the limiting factors is model validation. The objective of this study was to extend previous modeling technique and to improve the validity of the model prediction using publicly available data set of the fifth "Grand Challenge Competition to Predict In Vivo Knee Loads." A two-stage modeling approach, which combines conventional inverse dynamic analysis (the first stage) with a multi-body subject-specific lower limb model (the second stage), was used to calculate medial and lateral compartment contact forces. The validation was performed by direct comparison of model predictions and experimental measurement of medial and lateral compartment contact forces during normal and turning gait. The model predictions of both medial and lateral contact forces showed strong correlations with experimental measurements in normal gait (r = 0.75 and 0.71) and in turning gait trials (r = 0.86 and 0.72), even though the current technique over-estimated medial compartment contact forces in swing phase. The correlation coefficient, Sprague and Geers metrics, and root mean squared error indicated that the lateral contact forces were predicted better than medial contact forces in comparison with the experimental measurements during both normal and turning gait trials. PMID:26908641

  15. Differences in injury pattern and prevalence of cartilage lesions in knee and ankle joints: a retrospective cohort study.

    PubMed

    Aurich, Matthias; Hofmann, Gunther O; Rolauffs, Bernd; Gras, Florian

    2014-10-27

    Osteoarthritis (OA) is more common in the knee compared to the ankle joint. This can not be explained exclusively by anatomical and biomechanical differences. The aim of this study is to analyze and compare the injury pattern (clinically) and the cartilage lesions (arthroscopically) of knee and ankle joints in a cohort of patients from the same catchment area. A retrospective study of the clinical data of 3122 patients (2139 outpatients and 983 inpatients) was performed, who were treated due to an injury of the knee and ankle joint. Statistical analysis was performed using SigmaStat 3.0 (SPSS Inc, Chicago, USA). There is a higher prevalence of injuries in the ankle as compared to the knee joint in this population from the same catchment area. In contrast, high-grade cartilage lesions are more prevalent in the knee, whereas low grade cartilage lesions are equally distributed between knee and ankle. From this data it can be concluded that the frequency of injuries and the injury pattern of knee versus ankle joints do not correlate with the severity of cartilage lesions and may therefore have no direct influence on the differential incidence of OA in those two joints.

  16. Dissecting the contribution of knee joint NGF to spinal nociceptive sensitization in a model of OA pain in the rat

    PubMed Central

    Sagar, D.R.; Nwosu, L.; Walsh, D.A.; Chapman, V.

    2015-01-01

    Summary Objective Although analgesic approaches targeting nerve growth factor (NGF) for the treatment of osteoarthritis (OA) pain remain of clinical interest, neurophysiological mechanisms by which NGF contribute to OA pain remain unclear. We investigated the impact of local elevation of knee joint NGF on knee joint, vs remote (hindpaw), evoked responses of spinal neurones in a rodent model of OA pain. Design In vivo spinal electrophysiology was carried out in anaesthetised rats with established pain behaviour and joint pathology following intra-articular injection of monosodium iodoacetate (MIA), vs injection of saline. Neuronal responses to knee joint extension and flexion, mechanical punctate stimulation of the peripheral receptive fields over the knee and at a remote site (ipsilateral hind paw) were studied before, and following, intra-articular injection of NGF (10 μg/50 μl) or saline. Results MIA-injected rats exhibited significant local (knee joint) and remote (lowered hindpaw withdrawal thresholds) changes in pain behaviour, and joint pathology. Intra-articular injection of NGF significantly (P < 0.05) increased knee extension-evoked firing of spinal neurones and the size of the peripheral receptive fields of spinal neurones (100% increase) over the knee joint in MIA rats, compared to controls. Intra-articular NGF injection did not significantly alter responses of spinal neurones following noxious stimulation of the ipsilateral hind paw in MIA-injected rats. Conclusion The facilitatory effects of intra-articular injection of NGF on spinal neurones receiving input from the knee joint provide a mechanistic basis for NGF mediated augmentation of OA knee pain, however additional mechanisms may contribute to the spread of pain to remote sites. PMID:25623624

  17. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallares, V.; Ranero, C. R.

    2012-12-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  18. TOMO3D: 3-D joint refraction and reflection traveltime tomography parallel code for active-source seismic data—synthetic test

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallarès, V.; Miniussi, A.; Ranero, C. R.

    2015-10-01

    We present a new 3-D traveltime tomography code (TOMO3D) for the modelling of active-source seismic data that uses the arrival times of both refracted and reflected seismic phases to derive the velocity distribution and the geometry of reflecting boundaries in the subsurface. This code is based on its popular 2-D version TOMO2D from which it inherited the methods to solve the forward and inverse problems. The traveltime calculations are done using a hybrid ray-tracing technique combining the graph and bending methods. The LSQR algorithm is used to perform the iterative regularized inversion to improve the initial velocity and depth models. In order to cope with an increased computational demand due to the incorporation of the third dimension, the forward problem solver, which takes most of the run time (˜90 per cent in the test presented here), has been parallelized with a combination of multi-processing and message passing interface standards. This parallelization distributes the ray-tracing and traveltime calculations among available computational resources. The code's performance is illustrated with a realistic synthetic example, including a checkerboard anomaly and two reflectors, which simulates the geometry of a subduction zone. The code is designed to invert for a single reflector at a time. A data-driven layer-stripping strategy is proposed for cases involving multiple reflectors, and it is tested for the successive inversion of the two reflectors. Layers are bound by consecutive reflectors, and an initial velocity model for each inversion step incorporates the results from previous steps. This strategy poses simpler inversion problems at each step, allowing the recovery of strong velocity discontinuities that would otherwise be smoothened.

  19. Early diagnosis and treatment of trauma in knee joints accompanied with popliteal vascular injury

    PubMed Central

    Xu, Yun-Qin; Li, Qiang; Shen, Tu-Gang; Su, Pei-Hua; Zhu, Ya-Zhong

    2015-01-01

    Objective: The objective of the present study was to investigate the early diagnosis and treatment of trauma in the knee joints accompanied with popliteal vascular injury. Methods: Fifteen cases of patients with trauma in knee joints accompanied with popliteal vascular injury. These patients included 8 males and 6 females between the ages of 27 and 62, the average age being 39.2. Data of clinical symptoms and signs; blood oxygen saturation, color Doppler examination; vascular intervention by DSA angiography; and surgical operations were analyzed to clearly identify their role in early diagnosis and treatment. Results: In the patient group for this study there were: 1 death case; 4 stage I amputation cases; 4 stage II amputation cases due to failure to salvage limbs; and 6 cases with patients who had successful limb salvage. The six cases of limb survival patients were followed up for 12 to 60 months, with an average follow up time of 28.3 months. The excellent rate of joint function of these patients with successful limb salvage was 83.3%. Conclusions: For patients with injured limbs, unclear dorsalis pedis artery palpation, decreased skin temperature, and decreased oxygen saturation of the toes, clinical manifestations combined with proper auxiliary inspection (such as color Doppler and blood vessel angiography of interventional DSA) enabled early diagnose of peripheral trauma in the knee joint accompanied with popliteal vascular injury. PMID:26309604

  20. Effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction

    PubMed Central

    Shim, Jae-Kwang; Choi, Ho-Suk; Shin, Jun-Ho

    2015-01-01

    [Purpose] This study examined the effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 16 adults who underwent arthroscopic anterior cruciate reconstruction and neuromuscular training. The Lysholm scale was used to assess functional disorders on the affected knee joint. A KT-2000 arthrometer was used to measure anterior displacement of the tibia against the femur. Surface electromyography was used to detect the muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus before and after neuromuscular training. [Results] There was significant relaxation in tibial anterior displacement of the affected and sound sides in the supine position before neuromuscular training. Furthermore, the difference in the tibial anterior displacement of the affected knee joints in the standing position was reduced after neuromuscular training. Moreover, the variation of the muscle activation evoked higher muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus. [Conclusion] Neuromuscular training may improve functional joint stability in patients with orthopedic musculoskeletal injuries in the postoperative period. PMID:26834316

  1. Effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction.

    PubMed

    Shim, Jae-Kwang; Choi, Ho-Suk; Shin, Jun-Ho

    2015-12-01

    [Purpose] This study examined the effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 16 adults who underwent arthroscopic anterior cruciate reconstruction and neuromuscular training. The Lysholm scale was used to assess functional disorders on the affected knee joint. A KT-2000 arthrometer was used to measure anterior displacement of the tibia against the femur. Surface electromyography was used to detect the muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus before and after neuromuscular training. [Results] There was significant relaxation in tibial anterior displacement of the affected and sound sides in the supine position before neuromuscular training. Furthermore, the difference in the tibial anterior displacement of the affected knee joints in the standing position was reduced after neuromuscular training. Moreover, the variation of the muscle activation evoked higher muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus. [Conclusion] Neuromuscular training may improve functional joint stability in patients with orthopedic musculoskeletal injuries in the postoperative period.

  2. A two-dimensional dynamic anatomical model of the human knee joint.

    PubMed

    Abdel-Rahman, E; Hefzy, M S

    1993-11-01

    The objective of this study is to develop a two-dimensional dynamic model of the knee joint to simulate its response under sudden impact. The knee joint is modeled as two rigid bodies, representing a fixed femur and a moving tibia, connected by 10 nonlinear springs representing the different fibers of the anterior and posterior cruciate ligaments, the medial and lateral collateral ligaments, and the posterior part of the capsule. In the analysis, the joint profiles were represented by polynomials. Model equations include three nonlinear differential equations of motion and three nonlinear algebraic equations representing the geometric constraints. A single point contact was assumed to exist at all times. Numerical solutions were obtained by applying Newmark constant-average-acceleration scheme of differential approximation to transform the motion equations into a set of nonlinear simultaneous algebraic equations. The equations reduced thus to six nonlinear algebraic equations in six unknowns. The Newton-Raphson iteration technique was then used to obtain the solution. Knee response was determined under sudden rectangular pulsing posterior forces applied to the tibia and having different amplitudes and durations. The results indicate that increasing pulse amplitude and/or duration produced a decrease in the magnitude of the tibio-femoral contact force, indicating thus a reduction in the joint stiffness.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Design, calibration and validation of a novel 3D printed instrumented spatial linkage that measures changes in the rotational axes of the tibiofemoral joint.

    PubMed

    Bonny, Daniel P; Hull, M L; Howell, S M

    2014-01-01

    An accurate axis-finding technique is required to measure any changes from normal caused by total knee arthroplasty in the flexion-extension (F-E) and longitudinal rotation (LR) axes of the tibiofemoral joint. In a previous paper, we computationally determined how best to design and use an instrumented spatial linkage (ISL) to locate the F-E and LR axes such that rotational and translational errors were minimized. However, the ISL was not built and consequently was not calibrated; thus the errors in locating these axes were not quantified on an actual ISL. Moreover, previous methods to calibrate an ISL used calibration devices with accuracies that were either undocumented or insufficient for the device to serve as a gold-standard. Accordingly, the objectives were to (1) construct an ISL using the previously established guidelines,(2) calibrate the ISL using an improved method, and (3) quantify the error in measuring changes in the F-E and LR axes. A 3D printed ISL was constructed and calibrated using a coordinate measuring machine, which served as a gold standard. Validation was performed using a fixture that represented the tibiofemoral joint with an adjustable F-E axis and the errors in measuring changes to the positions and orientations of the F-E and LR axes were quantified. The resulting root mean squared errors (RMSEs) of the calibration residuals using the new calibration method were 0.24, 0.33, and 0.15 mm for the anterior-posterior, medial-lateral, and proximal-distal positions, respectively, and 0.11, 0.10, and 0.09 deg for varus-valgus, flexion-extension, and internal-external orientations, respectively. All RMSEs were below 0.29% of the respective full-scale range. When measuring changes to the F-E or LR axes, each orientation error was below 0.5 deg; when measuring changes in the F-E axis, each position error was below 1.0 mm. The largest position RMSE was when measuring a medial-lateral change in the LR axis (1.2 mm). Despite the large size

  4. Design, calibration and validation of a novel 3D printed instrumented spatial linkage that measures changes in the rotational axes of the tibiofemoral joint.

    PubMed

    Bonny, Daniel P; Hull, M L; Howell, S M

    2014-01-01

    An accurate axis-finding technique is required to measure any changes from normal caused by total knee arthroplasty in the flexion-extension (F-E) and longitudinal rotation (LR) axes of the tibiofemoral joint. In a previous paper, we computationally determined how best to design and use an instrumented spatial linkage (ISL) to locate the F-E and LR axes such that rotational and translational errors were minimized. However, the ISL was not built and consequently was not calibrated; thus the errors in locating these axes were not quantified on an actual ISL. Moreover, previous methods to calibrate an ISL used calibration devices with accuracies that were either undocumented or insufficient for the device to serve as a gold-standard. Accordingly, the objectives were to (1) construct an ISL using the previously established guidelines,(2) calibrate the ISL using an improved method, and (3) quantify the error in measuring changes in the F-E and LR axes. A 3D printed ISL was constructed and calibrated using a coordinate measuring machine, which served as a gold standard. Validation was performed using a fixture that represented the tibiofemoral joint with an adjustable F-E axis and the errors in measuring changes to the positions and orientations of the F-E and LR axes were quantified. The resulting root mean squared errors (RMSEs) of the calibration residuals using the new calibration method were 0.24, 0.33, and 0.15 mm for the anterior-posterior, medial-lateral, and proximal-distal positions, respectively, and 0.11, 0.10, and 0.09 deg for varus-valgus, flexion-extension, and internal-external orientations, respectively. All RMSEs were below 0.29% of the respective full-scale range. When measuring changes to the F-E or LR axes, each orientation error was below 0.5 deg; when measuring changes in the F-E axis, each position error was below 1.0 mm. The largest position RMSE was when measuring a medial-lateral change in the LR axis (1.2 mm). Despite the large size

  5. Reduced knee joint moment in ACL deficient patients at a cost of dynamic stability during landing.

    PubMed

    Oberländer, Kai Daniel; Brüggemann, Gert-Peter; Höher, Jürgen; Karamanidis, Kiros

    2012-05-11

    The current study aimed to examine the effect of anterior cruciate ligament deficiency (ACLd) on joint kinetics and dynamic stability control after a single leg hop test (SLHT). Twelve unilateral ACLd patients and a control subject group (n=13) performed a SLHT over a given distance with both legs. The calculation of joint kinetics was done by means of a soft-tissue artifact optimized rigid full-body model. Margin of stability (MoS) was quantified by the difference between the base of support and the extrapolated center of mass. During landing, the ACLd leg showed lower external knee flexion moments but demonstrated higher moments at the ankle and hip compared to controls (p<0.05). The main reason for the joint moment redistribution in the ACLd leg was a more anterior position of the ground reaction force (GRF) vector, which affected the moment arms of the GRF acting about the joints (p<0.05). For the ACLd leg, trunk angle was more flexed over the entire landing phase compared to controls (p<0.05) and we found a significant correlation between moment arms at the knee joint and trunk angle (r² = 0.48;p<0.01). The consequence of this altered landing strategy in ACLd legs was a more anterior position of the center of mass reducing the MoS (p<0.05). The results illustrate the interaction between trunk angle, joint kinetics and dynamic stability during landing maneuvers and provide evidence of a feedforward adaptive adjustment in ACLd patients (i.e. more flexed trunk angle) aimed at reducing knee joint moments at the cost of dynamic stability control. PMID:22440611

  6. Reduced knee joint moment in ACL deficient patients at a cost of dynamic stability during landing.

    PubMed

    Oberländer, Kai Daniel; Brüggemann, Gert-Peter; Höher, Jürgen; Karamanidis, Kiros

    2012-05-11

    The current study aimed to examine the effect of anterior cruciate ligament deficiency (ACLd) on joint kinetics and dynamic stability control after a single leg hop test (SLHT). Twelve unilateral ACLd patients and a control subject group (n=13) performed a SLHT over a given distance with both legs. The calculation of joint kinetics was done by means of a soft-tissue artifact optimized rigid full-body model. Margin of stability (MoS) was quantified by the difference between the base of support and the extrapolated center of mass. During landing, the ACLd leg showed lower external knee flexion moments but demonstrated higher moments at the ankle and hip compared to controls (p<0.05). The main reason for the joint moment redistribution in the ACLd leg was a more anterior position of the ground reaction force (GRF) vector, which affected the moment arms of the GRF acting about the joints (p<0.05). For the ACLd leg, trunk angle was more flexed over the entire landing phase compared to controls (p<0.05) and we found a significant correlation between moment arms at the knee joint and trunk angle (r² = 0.48;p<0.01). The consequence of this altered landing strategy in ACLd legs was a more anterior position of the center of mass reducing the MoS (p<0.05). The results illustrate the interaction between trunk angle, joint kinetics and dynamic stability during landing maneuvers and provide evidence of a feedforward adaptive adjustment in ACLd patients (i.e. more flexed trunk angle) aimed at reducing knee joint moments at the cost of dynamic stability control.

  7. Sex differences in knee joint laxity change across the female menstrual cycle

    PubMed Central

    SHULTZ, S. J.; SANDER, T. C.; KIRK, S. E.; PERRIN, D. H.

    2007-01-01

    Aim To elucidate the hormonal influences on sex differences in knee joint behavior, normal-menstruating females were compared to males on serum hormone levels and anterior knee joint laxity (displacement at 46N, 89N and 133N) and stiffness (Linear slope of ΔForce/ΔDisplacement for 46–89N and 89–133N) across the female menstrual cycle. Methods Twenty-two females were tested daily across one complete menstrual cycle, and 20 males were tested once per week for 4 weeks. Five days each representing the hormonal milieu for menses, the initial estrogen rise near ovulation, and the early and late luteal phases (total of 20 days) were compared to the average value obtained from males across their 4 test days. Results Sex differences in knee laxity were menstrual cycle dependent, coinciding with significant elevations in estradiol levels. Females had greater laxity than males on day 5 of menses, days 3–5 near ovulation, days 1–4 of the early luteal phase and days 1, 2, 4 and 5 of the late luteal phases. Within females, knee laxity was greater on day 5 near ovulation compared to day 3 of menses, and days 1–3 of the early luteal phase compared to all days of menses and day 1 near ovulation. On average, differences observed between sexes were greater than those within females across their cycle. There were no differences in anterior knee stiffness between sexes or within females across days of the menstrual cycle. Conclusion These results suggest sex hormones may be a primary mediator of the observed sex differences in knee laxity. PMID:16446695

  8. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallarès, V.; Ranero, C. R.

    2012-04-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  9. Modeling and simulating the neuromuscular mechanisms regulating ankle and knee joint stiffness during human locomotion

    PubMed Central

    Maculan, Marco; Pizzolato, Claudio; Reggiani, Monica; Farina, Dario

    2015-01-01

    This work presents an electrophysiologically and dynamically consistent musculoskeletal model to predict stiffness in the human ankle and knee joints as derived from the joints constituent biological tissues (i.e., the spanning musculotendon units). The modeling method we propose uses electromyography (EMG) recordings from 13 muscle groups to drive forward dynamic simulations of the human leg in five healthy subjects during overground walking and running. The EMG-driven musculoskeletal model estimates musculotendon and resulting joint stiffness that is consistent with experimental EMG data as well as with the experimental joint moments. This provides a framework that allows for the first time observing 1) the elastic interplay between the knee and ankle joints, 2) the individual muscle contribution to joint stiffness, and 3) the underlying co-contraction strategies. It provides a theoretical description of how stiffness modulates as a function of muscle activation, fiber contraction, and interacting tendon dynamics. Furthermore, it describes how this differs from currently available stiffness definitions, including quasi-stiffness and short-range stiffness. This work offers a theoretical and computational basis for describing and investigating the neuromuscular mechanisms underlying human locomotion. PMID:26245321

  10. The effect of hip joint muscle exercise on muscle strength and balance in the knee joint after meniscal injury.

    PubMed

    Park, Sun Ja; Kim, Young Mi; Kim, Ha Roo

    2016-04-01

    [Purpose] This study aimed to evaluate the effect of hip muscle strengthening on muscle strength and balance in the knee joint after a meniscal injury. [Subjects and Methods] This randomized control study enrolled 24 patients who had undergone arthroscopic treatment after a meniscal injury and began a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into 2 groups of 12 subjects each: gluteus medius resistance exercise group and control group. This study investigated muscle strength and balance in the knee joint flexor, extensor, and abductor during an 8-week period. [Results] Measurements of knee extensor muscle strength revealed no significant difference between the control group and the experimental group. Measurements of abductor muscle strength, however, identified a significant difference between the 2 groups. The groups did not differ significantly with regard to balance measurements. [Conclusion] The results of this study suggest that this subject should be approached in light of the correlation between the hip abductor and injury to the lower extremities. PMID:27190461

  11. The effect of hip joint muscle exercise on muscle strength and balance in the knee joint after meniscal injury

    PubMed Central

    Park, Sun Ja; Kim, Young Mi; Kim, Ha Roo

    2016-01-01

    [Purpose] This study aimed to evaluate the effect of hip muscle strengthening on muscle strength and balance in the knee joint after a meniscal injury. [Subjects and Methods] This randomized control study enrolled 24 patients who had undergone arthroscopic treatment after a meniscal injury and began a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into 2 groups of 12 subjects each: gluteus medius resistance exercise group and control group. This study investigated muscle strength and balance in the knee joint flexor, extensor, and abductor during an 8-week period. [Results] Measurements of knee extensor muscle strength revealed no significant difference between the control group and the experimental group. Measurements of abductor muscle strength, however, identified a significant difference between the 2 groups. The groups did not differ significantly with regard to balance measurements. [Conclusion] The results of this study suggest that this subject should be approached in light of the correlation between the hip abductor and injury to the lower extremities. PMID:27190461

  12. Using a surrogate contact pair to evaluate polyethylene wear in prosthetic knee joints.

    PubMed

    Sanders, Anthony P; Lockard, Carly A; Weisenburger, Joel N; Haider, Hani; Raeymaekers, Bart

    2016-01-01

    With recent improvements to the properties of ultra-high molecular weight polyethylene (UHMWPE) used in joint replacements, prosthetic knee and hip longevity may extend beyond two decades. However, it is difficult and costly to replicate such a long in vivo lifetime using clinically relevant in vitro wear testing approaches such as walking gait joint simulators. We advance a wear test intermediate in complexity between pin-on-disk and knee joint simulator tests. The test uses a surrogate contact pair, consisting of a surrogate femoral and tibial specimen that replicate the contact mechanics of any full-scale knee condyle contact pair. The method is implemented in a standard multi-directional pin-on-disk wear test machine, and we demonstrate its application via a two-million-cycle wear test of three different UHMWPE formulations. Further, we demonstrate the use of digital photography and image processing to accurately quantify fatigue damage based on the reduced transmission of light through a damage area in a UHMWPE specimen. The surrogate contact pairs replicate the knee condyle contact areas within -3% to +12%. The gravimetric wear test results reflect the dose of crosslinking radiation applied to the UHMWPE: 35 kGy yielded a wear rate of 7.4 mg/Mcycles, 55 kGy yielded 1.0 mg/Mcycles, and 75 kGy (applied to a 0.1% vitamin E stabilized UHMWPE) yielded 1.5 mg/Mcycles. A precursor to spalling fatigue is observed and precisely measured in the radiation-sterilized (35 kGy) and aged UHMWPE specimen. The presented techniques can be used to evaluate the high-cycle fatigue performance of arbitrary knee condyle contact pairs under design-specific contact stresses, using existing wear test machines. This makes the techniques more economical and well-suited to standardized comparative testing.

  13. Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Czaplicki, Adam; Jarocka, Marta; Walawski, Jacek

    2015-01-01

    The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age. PMID:26646385

  14. Knee joint function and the energy cost of level walking in soccer players

    PubMed Central

    Tofts, L. J.; Stanley, C. S.; Barnett, T. G.; Logan, J. G.

    1998-01-01

    OBJECTIVES: To study self reported knee joint problems and the energy costs of level walking in soccer players. METHODS: Seventeen soccer players and twelve control subjects between 18 and 27 years old participated in the study. A questionnaire was used to establish the amount of participation in soccer and the frequency and extent of knee injuries. The physiological cost index (PCI) was used as an index of the energy costs of level walking. RESULTS: Soccer players had a significantly higher PCI than control subjects (p = 0.0001). Control subjects had a mean (SD) PCI of 0.23 (0.06) beats/m and soccer players had a mean PCI of 0.42 (0.12) beats/m. Some 82% of the soccer players experienced knee joint problems, whereas only 25% of the control group had problems. CONCLUSIONS: This study shows that college soccer players have a higher rate of self reported knee problems and higher energy costs of level walking than people who do not play soccer. 




 PMID:9631219

  15. Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction.

    PubMed

    Czaplicki, Adam; Jarocka, Marta; Walawski, Jacek

    2015-01-01

    The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age.

  16. Agreement between weight bearing and non-weight bearing joint position replication tasks at the knee and hip.

    PubMed

    Foch, Eric; Milner, Clare E

    2013-01-01

    Peak joint angles assumed during the stance phase of running may indicate a runner's ability to sense limb position in space. Joint position sense can be assessed through weight bearing and non-weight bearing tasks. The purpose of this investigation was to determine if weight bearing and non-weight bearing knee and hip joint replication tasks elicited similar joint position sense test results. Absolute replication error was measured during sagittal plane knee and frontal plane hip conditions on 23 healthy runners. Three-dimensional kinematics was recorded during running. Intraclass correlation coefficients (ICCs) determined agreement between the two measures of joint position sense. Pearson's correlation coefficients measured the relationship between hip and knee absolute error and peak joint angles during running. Despite similar mean absolute error, ICCs indicated low agreement between weight bearing and non-weight bearing conditions at each joint. The results indicate the tests are not interchangeable. Absolute error for non-weight bearing hip replication was correlated with peak stance hip adduction during running. Weight bearing and non-weight bearing joint position sense tasks within the knee and hip joints measure joint position sense differently. Therefore, a task that is relevant to the activity of interest should be selected to measure joint position sense.

  17. Effects of electrical noise to a knee joint on quiet bipedal stance and treadmill walking.

    PubMed

    Kimura, T; Taki, C; Shiozawa, N; Kouzaki, M

    2013-01-01

    The present study assessed whether an unperceivable, noise-like electrical stimulation of a knee joint enhances the stability of quiet bipedal stance and treadmill walking in young subjects. The results showed that the slow postural sway measures in quiet bipedal stance were significantly reduced by the electrical noise (P<0.05). In the treadmill walking, low frequency component (below 1 Hz) of mediolateral acceleration, measured at the third lumbar vertebra, significantly decreased with the electrical noise (P<0.05), while there were no changes in the anteroposterior and vertical directions. These results indicate that the electrical noise to a knee joint can be applied to enhance postural control in quiet bipedal stance and treadmill walking. PMID:24110917

  18. Extensor-mechanism-reconstruction of the knee joint after traumatic loss of the entire extensor apparatus.

    PubMed

    Raschke, D; Schüttrumpf, J P; Tezval, M; Stürmer, K M; Balcarek, P

    2014-06-01

    Injuries to the extensor apparatus of the knee joint have an incidence of 0.5% to 6%. Although previous studies have described the advantages and disadvantages of operative treatment in cases of patellar tendon rupture, patella fracture or quadriceps tendon lesions, a report on the reconstruction of the extensor apparatus after traumatic loss of the patella, the patellar tendon, the tibial tuberosity and parts of the lateral quadriceps muscle is absent from the literature. We present the case of a young motorcyclist who underwent a reconstruction of the extensor apparatus using autologous tendon grafts. At a 24-month follow-up, the patient has a nearly physiological range of motion of the knee joint and is able to cope well with everyday life.

  19. Effect of malpositioned anterior cruciate ligament replacement on knee joint structures: a biomechanical model.

    PubMed

    Horas, Uwe; Meissner, Stefan A; Kraus, Ralf; Heiss, Christian; Schnettler, Reinhard

    2011-12-01

    Any sort of malpositioning of anterior cruciate ligament (ACL) replacement leads to an overload of single fibers of the ACL replacement. As long as this does not result in a tear of these fibers so that isometry of the ACL replacement is restored, the abnormal forces acting in and on the ACL replacement are transmitted from the ACL replacement to the remainder of the knee joint structures. We assumed that the posterior cruciate ligament (PCL) is notably affected. The present biomechanical model illustrates the relevant force vectors and reveals the extent of the effect of malpositioned ACL replacement on knee joint structures, particularly the PCL. Further investigations are needed to find out if the presumably occurring overload of a malpositioned ACL replacement can be calculated from its position on an individual basis. This may help deduce recommendations for ACL replacement procedures in the future.

  20. Three-dimensional anatomy of the ostrich (Struthio camelus) knee joint.

    PubMed

    Chadwick, Kyle P; Regnault, Sophie; Allen, Vivian; Hutchinson, John R

    2014-01-01

    The three-dimensional anatomy of the ostrich (Struthio camelus) knee (femorotibial, femorofibular, and femoropatellar) joint has scarcely been studied, and could elucidate certain mechanobiological properties of sesamoid bones. The adult ostrich is unique in that it has double patellae, while another similar ratite bird, the emu, has none. Understanding why these patellae form and what purpose they may serve is dually important for future studies on ratites as well as for understanding the mechanobiological characteristics of sesamoid bone development. For this purpose, we present a three-dimensional anatomical study of the ostrich knee joint, detailing osteology, ligaments and menisci, and myology. We have identified seven muscles which connect to the two patellae and compare our findings to past descriptions. These descriptions can be used to further study the biomechanical loading and implications of the double patella in the ostrich. PMID:25551024

  1. Three-dimensional anatomy of the ostrich (Struthio camelus) knee joint

    PubMed Central

    Regnault, Sophie; Allen, Vivian; Hutchinson, John R.

    2014-01-01

    The three-dimensional anatomy of the ostrich (Struthio camelus) knee (femorotibial, femorofibular, and femoropatellar) joint has scarcely been studied, and could elucidate certain mechanobiological properties of sesamoid bones. The adult ostrich is unique in that it has double patellae, while another similar ratite bird, the emu, has none. Understanding why these patellae form and what purpose they may serve is dually important for future studies on ratites as well as for understanding the mechanobiological characteristics of sesamoid bone development. For this purpose, we present a three-dimensional anatomical study of the ostrich knee joint, detailing osteology, ligaments and menisci, and myology. We have identified seven muscles which connect to the two patellae and compare our findings to past descriptions. These descriptions can be used to further study the biomechanical loading and implications of the double patella in the ostrich. PMID:25551024

  2. Biomechanical reasons for the divergent morphology of the knee joint and the distal epiphyseal suture in hominoids.

    PubMed

    Preuschoft, H; Tardieu, C

    1996-01-01

    The obliquity of the femoral diaphysis accounts for the valgus position of the human knee joint and reduces bending moments in the frontal plane. A high angle of obliquity is considered a hallmark of hominid bipedality, but its functional importance has rarely been identified correctly. A biostatic investigation of the knee joint in various realistic positions unveils resultant joint forces which do not deviate greatly from the long axis of the femoral shaft. This is due to the length of the femur and to the shortness of the human foot. The flat epiphyseal suture is more or less perpendicular to these joint forces, and the equal size of the femoral condyles reflects the even distribution of forces between them. In great apes the resultant forces acting in the knee joint vary considerably in dependence on the degree of flexion and rotation of the knee joint. The resultant joint force may be line with the femur shaft or diverge. The epiphyseal surfaces offer facets to all joint forces found in the course of the study. Due to the pronounced varus position of the knee joint, the joint itself and the adjacent part of the femur are under medially concave bending moments, which lead to higher compressive forces at the medial than at the lateral condyle. The enlarged medial condyle allows the distribution of medially displaced joint forces over a relatively large area, and the elliptic cross-section yields high bending resistance in the frontal plane. A human-like angle of obliquity is present in the early australopithecines, the values being mostly within the range of variation of children. The valgus position of the australopithecine knee joint is considered to be a functional, and epigenetic consequence of habitual bipedality. It is particularly pronounced because of the short length of the femur and the great bitrochanteric width. PMID:8953752

  3. Improvement of the size estimation of 3D tracked droplets using digital in-line holography with joint estimation reconstruction

    NASA Astrophysics Data System (ADS)

    Verrier, N.; Grosjean, N.; Dib, E.; Méès, L.; Fournier, C.; Marié, J.-L.

    2016-04-01

    Digital holography is a valuable tool for three-dimensional information extraction. Among existing configurations, the originally proposed set-up (i.e. Gabor, or in-line holography), is reasonably immune to variations in the experimental environment making it a method of choice for studies of fluid dynamics. Nevertheless, standard hologram reconstruction techniques, based on numerical light back-propagation are prone to artifacts such as twin images or aliases that limit both the quality and quantity of information extracted from the acquired holograms. To get round this issue, the hologram reconstruction as a parametric inverse problem has been shown to accurately estimate 3D positions and the size of seeding particles directly from the hologram. To push the bounds of accuracy on size estimation still further, we propose to fully exploit the information redundancy of a hologram video sequence using joint estimation reconstruction. Applying this approach in a bench-top experiment, we show that it led to a relative precision of 0.13% (for a 60 μm diameter droplet) for droplet size estimation, and a tracking precision of {σx}× {σy}× {σz}=0.15× 0.15× 1~\\text{pixels} .

  4. Clinical laboratory parameters in osteoarthritic knee-joint effusions correlated to trace element concentrations.

    PubMed

    Krachler, M; Domej, W

    2001-02-01

    Interactions of clinical laboratory parameters with trace elements in knee-joint effusions might turn out to be potential diagnostic tool, increasing our pathophysiological understanding and knowledge on knee-joint effusions. Thus, the 11 clinical laboratory parameters, total protein, albumin, glucose, lactate dehydrogenase, uric acid, pH, rheumatoid factor, antistreptolysin, C-reactive protein, leukocyte, and erythrocyte counts were determined in 39 osteoarthritic knee-joint effusions and in corresponding sera. Additionally, concentrations of the 17 trace elements barium, beryllium, calcium, cadmium, cesium, copper, lanthanum, lithium, magnesium, molybdenum, lead, rubidium, antimony, tin, strontium, thallium, and zinc in both effusions and corresponding sera were quantified by inductively coupled plasma-mass spectrometry. Concentrations of most laboratory parameters in synovial fluid were within the normal ranges for serum. However, concentrations of total protein and albumin in effusions were distinctly lower than in sera of healthy adults. Results for rheumatoid factor, antistreptolysin, and C-reactive protein in the effusions were below their corresponding threshold values for serum. An indicator for inflammation, the leukocyte count had a median < 6.3 G/L. The erythrocyte count (median: < 0.06 T/L) revealed a very low presence of red blood cells in the effusions. Total protein concentrations and lactate dehydrogenase activity in the effusions correlated positively with effusion copper (r = 0.61 and 0.66) and effusion zinc (r = 0.71 and 0.49). For cesium, a negative correlation in both sera (r = -0.44) and effusions (r = -0.44) with LDH activity could be established. Concentrations of rubidium, strontium, and cesium responded to albumin concentrations in sera and in effusions, establishing an inverse correlation. All other trace elements showed no or only weak associations with the clinical laboratory parameters determined. Although distinct relationships

  5. Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs

    PubMed Central

    Lee, Daehee; Lee, Sangyong; Park, Jungseo

    2015-01-01

    [Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles. PMID:26357447

  6. Design of a knee joint mechanism that adapts to individual physiology.

    PubMed

    Jiun-Yih Kuan; Pasch, Kenneth A; Herr, Hugh M

    2014-01-01

    This paper describes the design of a new knee joint mechanism, called the Adaptive Coupling Joint (ACJ). The new mechanism has an adaptive trajectory of the center of rotations (COR) that automatically matches those of the attached biological joint. The detailed design is presented as well as characterization results of the ACJ. Conventional exoskeleton and assistive devices usually consider limb joints as a one to three degrees of freedom (DOFs) joint synthesized by multiple one-DOF hinge joints in a single plane. However, the biological joints are complex and usually rotate with respect to a changing COR. As a result, the mismatch between limb joint motion and mechanical interface motion can lead to forces that cause undesired ligament and muscle length changes and internal mechanical changes. These undesired changes contribute to discomfort, as well as to the slippage and sluggish interaction between humans and devices. It is shown that the ACJ can transmit planetary torques from either active or passive devices to the limbs without altering the normal biological joint motion. PMID:25570389

  7. Design of a knee joint mechanism that adapts to individual physiology.

    PubMed

    Jiun-Yih Kuan; Pasch, Kenneth A; Herr, Hugh M

    2014-01-01

    This paper describes the design of a new knee joint mechanism, called the Adaptive Coupling Joint (ACJ). The new mechanism has an adaptive trajectory of the center of rotations (COR) that automatically matches those of the attached biological joint. The detailed design is presented as well as characterization results of the ACJ. Conventional exoskeleton and assistive devices usually consider limb joints as a one to three degrees of freedom (DOFs) joint synthesized by multiple one-DOF hinge joints in a single plane. However, the biological joints are complex and usually rotate with respect to a changing COR. As a result, the mismatch between limb joint motion and mechanical interface motion can lead to forces that cause undesired ligament and muscle length changes and internal mechanical changes. These undesired changes contribute to discomfort, as well as to the slippage and sluggish interaction between humans and devices. It is shown that the ACJ can transmit planetary torques from either active or passive devices to the limbs without altering the normal biological joint motion.

  8. Repeatability of gait data using a functional hip joint centre and a mean helical knee axis.

    PubMed

    Besier, Thor F; Sturnieks, Daina L; Alderson, Jacque A; Lloyd, David G

    2003-08-01

    Repeatability of traditional kinematic and kinetic models is affected by the ability to accurately locate anatomical landmarks (ALs) to define joint centres and anatomical coordinate systems. Numerical methods that define joint centres and axes of rotation independent of ALs may also improve the repeatability of kinematic and kinetic data. The purpose of this paper was to compare the repeatability of gait data obtained from two models, one based on ALs (AL model), and the other incorporating a functional method to define hip joint centres and a mean helical axis to define knee joint flexion/extension axes (FUN model). A foot calibration rig was also developed to define the foot segment independent of ALs. The FUN model produced slightly more repeatable hip and knee joint kinematic and kinetic data than the AL model, with the advantage of not having to accurately locate ALs. Repeatability of the models was similar comparing within-tester sessions to between-tester sessions. The FUN model may also produce more repeatable data than the AL model in subject populations where location of ALs is difficult. The foot calibration rig employed in both the AL and FUN model provided an easy alternative to define the foot segment and obtain repeatable data, without accurately locating ALs on the foot.

  9. The effects of joint immobilization on articular cartilage of the knee in previously exercised rats

    PubMed Central

    Maldonado, Diogo Correa; da Silva, Marcelo Cavenaghi Pereira; Neto, Semaan El-Razi; Souza, Mônica Rodrigues; Souza, Romeu Rodrigues

    2013-01-01

    Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 μm, P < 0.05), but not in group EI (mean, 174 ± 2.25), and increased significantly in group E (mean, 289.49 ± 9.15) compared with group C (mean, 239.20 ± 6.25). The same results were obtained for cell density, nuclear size, and collagen density (in all cases, P < 0.05). We concluded that exercise can prevent degenerative changes in femoral articular cartilage caused by immobilization of the knee joint. PMID:23480127

  10. Changes in the activity of trunk and hip extensor muscles during bridge exercises with variations in unilateral knee joint angle

    PubMed Central

    Kim, Juseung; Park, Minchul

    2016-01-01

    [Purpose] This study compared abdominal and hip extensor muscle activity during a bridge exercise with various knee joint angles. [Subjects and Methods] Twenty-two healthy male subjects performed a bridge exercise in which the knee joint angle was altered. While subjects performed the bridge exercise, external oblique, internal oblique, gluteus maximus, and semitendinosus muscle activity was measured using electromyography. [Results] The bilateral external and internal oblique muscle activity was significantly higher at 0° knee flexion compared to 120°, 90°, and 60°. The bilateral gluteus maximus muscle activity was significantly different at 0° of knee flexion compared to 120°, 90°, and 60°. The ipsilateral semitendinosus muscle activity was significantly increased at 90° and 60° of knee flexion compared to 120°, and significantly decreased at 0° knee flexion compared with 120°, 90°, and 60°. The contralateral semitendinosus muscle activity was significantly higher at 60° of knee flexion than at 120°, and significantly higher at 0° of knee flexion than at 120°, 90°, and 60°. [Conclusion] Bridge exercises performed with knee flexion less than 90° may be used to train the ipsilateral semitendinosus. Furthermore, bridge exercise performed with one leg may be used to train abdominal and hip extensor muscles. PMID:27799688

  11. The Influence of Radiographic Severity on the Relationship between Muscle Strength and Joint Loading in Obese Knee Osteoarthritis Patients

    PubMed Central

    Aaboe, Jens; Bliddal, Henning; Alkjaer, Tine; Boesen, Mikael; Henriksen, Marius

    2011-01-01

    Objective. To investigate the relationship between knee muscle strength and the external knee adduction moment during walking in obese knee osteoarthritis patients and whether disease severity influences this relationship. Methods. This cross-sectional study included 136 elderly obese (BMI > 30) adults with predominant medial knee osteoarthritis. Muscle strength, standing radiographic severity as measured by the Kellgren and Lawrence scale, and the peak external knee adduction moment were measured at self-selected walking speed. Results. According to radiographic severity, patients were classified as “less severe” (KL 1-2, N = 73) or “severe” (KL 3-4, N = 63). A significant positive association was demonstrated between the peak knee adduction moment and hamstring muscle strength in the whole cohort (P = .047). However, disease severity did not influence the relationship between muscle strength and dynamic medial knee joint loading. Severe patients had higher peak knee adduction moment and more varus malalignment (P < .001). Conclusion. Higher hamstring muscle strength relates to higher estimates of dynamic knee joint loading in the medial compartment. No such relationship existed for quadriceps muscle strength. Although cross sectional, the results suggest that hamstrings function should receive increased attention in future studies and treatments that aim at halting disease progression. PMID:22046519

  12. Three-dimensional bioprinting of multilayered constructs containing human mesenchymal stromal cells for osteochondral tissue regeneration in the rabbit knee joint.

    PubMed

    Shim, Jin-Hyung; Jang, Ki-Mo; Hahn, Sei Kwang; Park, Ju Young; Jung, Hyuntae; Oh, Kyunghoon; Park, Kyeng Min; Yeom, Junseok; Park, Sun Hwa; Kim, Sung Won; Wang, Joon Ho; Kim, Kimoon; Cho, Dong-Woo

    2016-03-01

    The use of cell-rich hydrogels for three-dimensional (3D) cell culture has shown great potential for a variety of biomedical applications. However, the fabrication of appropriate constructs has been challenging. In this study, we describe a 3D printing process for the preparation of a multilayered 3D construct containing human mesenchymal stromal cells with a hydrogel comprised of atelocollagen and supramolecular hyaluronic acid (HA). This construct showed outstanding regenerative ability for the reconstruction of an osteochondral tissue in the knee joints of rabbits. We found that the use of a mechanically stable, host-guest chemistry-based hydrogel was essential and allowed two different types of extracellular matrix (ECM) hydrogels to be easily printed and stacked into one multilayered construct without requiring the use of potentially harmful chemical reagents or physical stimuli for post-crosslinking. To the best of our knowledge, this is the first study to validate the potential of a 3D printed multilayered construct consisting of two different ECM materials (atelocollagen and HA) for heterogeneous tissue regeneration using an in vivo animal model. We believe that this 3D printing-based platform technology can be effectively exploited for regeneration of various heterogeneous tissues as well as osteochondral tissue.

  13. Interposition of the Posterior Cruciate Ligament into the Medial Compartment of the Knee Joint on Coronal Magnetic Resonance Imaging

    PubMed Central

    Kim, Hyun Su; Park, Ki Jeong; Wang, Joon Ho; Choe, Bong-Keun

    2016-01-01

    Objective The purpose of our study was to evaluate the overall prevalence and clinical significance of interposition of the posterior cruciate ligament (PCL) into the medial compartment of the knee joint in coronal magnetic resonance imaging (MRI). Materials and Methods We retrospectively reviewed 317 consecutive patients referred for knee MRI at our institution between October 2009 and December 2009. Interposition of the PCL into the medial compartment of the knee joint on proton coronal MRI was evaluated dichotomously (i.e., present or absent). We analyzed the interposition according to its prevalence as well as its relationship with right-left sidedness, gender, age, and disease categories (osteoarthritis, anterior cruciate ligament tear, and medial meniscus tear). Results Prevalence of interposition of PCL into the medial compartment of the knee joint was 47.0% (149/317). There was no right (50.0%, 83/166) to left (43.7%, 66/151) or male (50.3%, 87/173) to female (43.1%, 62/144) differences in the prevalence. There was no significant association between the prevalence and age, or the disease categories. Conclusion Interposition of the PCL into the medial compartment of the knee joint is observed in almost half of patients on proton coronal MRI of the knee. Its presence is not associated with any particular factors including knee pathology and may be regarded as a normal MR finding. PMID:26957909

  14. Design and evaluation of a quasi-passive knee exoskeleton for investigation of motor adaptation in lower extremity joints.

    PubMed

    Shamaei, Kamran; Cenciarini, Massimo; Adams, Albert A; Gregorczyk, Karen N; Schiffman, Jeffrey M; Dollar, Aaron M

    2014-06-01

    In this study, we describe the mechanical design and control scheme of a quasi-passive knee exoskeleton intended to investigate the biomechanical behavior of the knee joint during interaction with externally applied impedances. As the human knee behaves much like a linear spring during the stance phase of normal walking gait, the exoskeleton implements a spring across the knee in the weight acceptance (WA) phase of the gait while allowing free motion throughout the rest of the gait cycle, accomplished via an electromechanical clutch. The stiffness of the device is able to be varied by swapping springs, and the timing of engagement/disengagement changed to accommodate different loading profiles. After describing the design and control, we validate the mechanical performance and reliability of the exoskeleton through cyclic testing on a mechanical knee simulator. We then describe a preliminary experiment on three healthy adults to evaluate the functionality of the device on both left and right legs. The kinetic and kinematic analyses of these subjects show that the exoskeleton assistance can partially/fully replace the function of the knee joint and obtain nearly invariant moment and angle profiles for the hip and ankle joints, and the overall knee joint and exoskeleton complex under the applied moments of the exoskeleton versus the control condition, implying that the subjects undergo a considerable amount of motor adaptation in their lower extremities to the exoskeletal impedances, and encouraging more in-depth future experiments with the device.

  15. Accurate joint space quantification in knee osteoarthritis: a digital x-ray tomosynthesis phantom study

    NASA Astrophysics Data System (ADS)

    Sewell, Tanzania S.; Piacsek, Kelly L.; Heckel, Beth A.; Sabol, John M.

    2011-03-01

    The current imaging standard for diagnosis and monitoring of knee osteoarthritis (OA) is projection radiography. However radiographs may be insensitive to markers of early disease such as osteophytes and joint space narrowing (JSN). Relative to standard radiography, digital X-ray tomosynthesis (DTS) may provide improved visualization of the markers of knee OA without the interference of superimposed anatomy. DTS utilizes a series of low-dose projection images over an arc of +/-20 degrees to reconstruct tomographic images parallel to the detector. We propose that DTS can increase accuracy and precision in JSN quantification. The geometric accuracy of DTS was characterized by quantifying joint space width (JSW) as a function of knee flexion and position using physical and anthropomorphic phantoms. Using a commercially available digital X-ray system, projection and DTS images were acquired for a Lucite rod phantom with known gaps at various source-object-distances, and angles of flexion. Gap width, representative of JSW, was measured using a validated algorithm. Over an object-to-detector-distance range of 5-21cm, a 3.0mm gap width was reproducibly measured in the DTS images, independent of magnification. A simulated 0.50mm (+/-0.13) JSN was quantified accurately (95% CI 0.44-0.56mm) in the DTS images. Angling the rods to represent knee flexion, the minimum gap could be precisely determined from the DTS images and was independent of flexion angle. JSN quantification using DTS was insensitive to distance from patient barrier and flexion angle. Potential exists for the optimization of DTS for accurate radiographic quantification of knee OA independent of patient positioning.

  16. Inferiorly based thigh flap for reconstruction of defects around the knee joint

    PubMed Central

    Akhtar, Md. Sohaib; Khan, Arshad Hafeez; Khurram, Mohammed Fahud; Ahmad, Imran

    2014-01-01

    Background: Soft-tissue defects around the knees are common in injured limbs and in the same injury the leg is often involved and the thigh is spared. Furthermore due to pliable and relatively lax skin, we have used inferiorly based thigh flap to reconstruct defects around knee joint. Aims and Objectives: The aim of this study is to evaluate the use of inferiorly based thigh flap to cover soft-tissue defects over the proximal one-third of the leg, patellar region, knee, and lower thigh. Materials and Methods: This study was conducted during the period between October 2011 and February 2013. Inferiorly based anteromedial thigh fasciocutaneous flap was performed on 12 patients and inferiorly based anterolateral thigh fasciocutaneous flap on four patients. The sites of the soft-tissue defects included patellar regions, infrapatellar region, upper one-third of leg, lower thigh, and over the knee joint. Results: Patients were evaluated post-operatively in terms of viability of flap, the matching of the flap with the recipient site, and donor site morbidity. All the flaps survived well except one which developed distal marginal flap loss, one in which wound dehiscence was noticed, and two in which mild venous congestion was observed. Venous congestion in two patients subsided on its own within 3 days. One patient with wound dehiscence achieved complete healing by secondary intention. Patient who developed distal flap loss required debridement and skin grafting. No appreciable donor site morbidity was encountered. Skin colour and texture of the flap matched well with the recipient site. Conclusions: The inferiorly based thigh flap is a reliable flap to cover the defect over proximal one-third of the leg, patellar region, knee, and lower thigh. PMID:25190918

  17. Knee joint strength ratios and effects of hip position in rugby players.

    PubMed

    Deighan, Martine A; Serpell, Benjamin G; Bitcon, Mark J; De Ste Croix, Mark

    2012-07-01

    Measures of knee joint function, although useful in predicting injury, can be misleading because hip position in traditional seated isokinetic tests is dissimilar to when injuries occur. This study aimed to determine the differences between seated and supine peak torques and strength ratios and examine the interaction of position with joint velocity. This was a cross-sectional, repeated measures study. Isokinetic knee extensor and flexor concentric and eccentric peak torque was measured seated and supine (10° hip flexion) at 1.04 and 3.14 rad·s(-1) in 11 Rugby players. Repeated measures analysis of variance and paired t-tests were used to analyze peak torques and strength ratios. Bonferroni post hoc, limits of agreement, and Pearson's correlation were applied. Seated peak torque was typically greater than that for supine for muscle actions and velocities. The values ranged from 109 ± 18 N·m (mean ± σ) for supine hamstring concentric peak torque at 1.04 rad·s(-1) to 330 ± 71 for seated quadriceps eccentric peak torque at 1.04 rad·s(-1). There was a significant position × muscle action interaction; eccentric peak torque was reduced more than concentric in the supine position. Knee joint strength ratios ranged from 0.47 ± 0.06 to 0.86 ± 0.23, with a significant difference in means between supine and seated positions for functional ratio at 3.14 rad·s(-1) observed; for seated it was 0.86 ± 0.23; and for supine, it was 0.68 ± 0.15 (p < 0.05). Limits of agreement for traditional and functional ratios ranged from 1.09 ×/÷ 1.37 to 1.13 ×/÷ 1.51. We conclude that hip angle affects isokinetic peak torques and knee joint strength ratios. Therefore, the hip angle should be nearer 10° when measuring knee joint function because this is more ecologically valid. Using similar protocols, sports practitioners can screen for injury and affect training to minimize injury.

  18. THE EFFECT OF CONSERVATIVELY TREATED ACL INJURY ON KNEE JOINT POSITION Sense

    PubMed Central

    Herrington, Lee

    2016-01-01

    ABSTRACT Background Proprioception is critical for effective movement patterns. However, methods of proprioceptive measurement in previous research have been inconsistent and lacking in reliability statistics making it applications to clinical practice difficult. Researchers have suggested that damage to the anterior cruciate ligament (ACL) can alter proprioceptive ability due to a loss of functioning mechanoreceptors. The majority of patients opt for reconstructive surgery following this injury. However, some patients chose conservative rehabilitation options rather than surgical intervention. Purpose The purpose of this study was to determine the effect of ACL deficiency on knee joint position sense following conservative, non-operative treatment and return to physical activity. A secondary purpose was to report the reliability and measurement error of the technique used to measure joint position sense, (JPS) and comment on the clinical utility of this measurement. Study Design Observational study design using a cross-section of ACL deficient patients and matched uninjured controls. Methods Twenty active conservatively treated ACL deficient patients who had returned to physical activity and twenty active matched controls were included in the study. Knee joint position sense was measured using a seated passive-active reproductive angle technique. The average absolute angle of error score, between 10 °-30 ° of knee flexion was determined. This error score was derived from the difference between the target and repositioning angle. Results The ACL deficient patients had a greater error score (7.9 °±3.6) and hence poorer static proprioception ability that both the contra-lateral leg (2.0 °±1.6; p = 0.0001) and the control group (2.6 °±0.9; p = 0.0001). The standard error of the mean (SEM) of this JPS technique was 0.5 ° and 0.2 ° and the minimum detectable change (MDC) was 1.3 ° and 0.4 ° on asymptomatic and symptomatic subjects

  19. Invariant joint distribution of a stationary random field and its derivatives: Euler characteristic and critical point counts in 2 and 3D

    SciTech Connect

    Pogosyan, Dmitry; Gay, Christophe; Pichon, Christophe

    2009-10-15

    The full moments expansion of the joint probability distribution of an isotropic random field, its gradient, and invariants of the Hessian are presented in 2 and 3D. It allows for explicit expression for the Euler characteristic in ND and computation of extrema counts as functions of the excursion set threshold and the spectral parameter, as illustrated on model examples.

  20. A multi-scale finite element model for investigation of chondrocyte mechanics in normal and medial meniscectomy human knee joint during walking.

    PubMed

    Tanska, Petri; Mononen, Mika E; Korhonen, Rami K

    2015-06-01

    Mechanical signals experienced by chondrocytes (articular cartilage cells) modulate cell synthesis and cartilage health. Multi-scale modeling can be used to study how forces are transferred from joint surfaces through tissues to chondrocytes. Therefore, estimation of chondrocyte behavior during certain physical activities, such as walking, could provide information about how cells respond to normal and abnormal loading in joints. In this study, a 3D multi-scale model was developed for evaluating chondrocyte and surrounding peri- and extracellular matrix responses during gait loading within healthy and medial meniscectomy knee joints. The knee joint geometry was based on MRI, whereas the input used for gait loading was obtained from the literature. Femoral and tibial cartilages were modeled as fibril-reinforced poroviscoelastic materials, whereas menisci were considered as transversely isotropic. Fluid pressures in the chondrocyte and cartilage tissue increased up to 2MPa (an increase of 30%) in the meniscectomy joint compared to the normal, healthy joint. The elevated level of fluid pressure was observed during the entire stance phase of gait. A medial meniscectomy caused substantially larger (up to 60%) changes in maximum principal strains in the chondrocyte compared to those in the peri- or extracellular matrices. Chondrocyte volume or morphology did not change substantially due to a medial meniscectomy. Current findings suggest that during walking chondrocyte deformations are not substantially altered due to a medial meniscectomy, while abnormal joint loading exposes chondrocytes to elevated levels of fluid pressure and maximum principal strains (compared to strains in the peri- or extracellular matrices). These might contribute to cell viability and the onset of osteoarthritis.

  1. Three-dimensional knee joint loading in alpine skiing: a comparison between a carved and a skidded turn.

    PubMed

    Klous, Miriam; Müller, Erich; Schwameder, Hermann

    2012-12-01

    Limited data exists on knee biomechanics in alpine ski turns despite the high rate of injuries associated with this maneuver. The purpose of the current study was to compare knee joint loading between a carved and a skidded ski turn and between the inner and outer leg. Kinetic data were collected using Kistler mobile force plates. Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. Inertial properties of the segments were calculated using an extended version of the Yeadon model. Knee joint forces and moments were calculated using inverse dynamics analysis. The obtained results indicate that knee joint loading in carving is not consistently greater than knee joint loading in skidding. In addition, knee joint loading at the outer leg is not always greater than at the inner leg. Differentiation is required between forces and moments, the direction of the forces and moments, and the phase of the turn that is considered. Even though the authors believe that the analyzed turns are representative, results have to be interpreted with caution due to the small sample size.

  2. Effect of interleukin 17 on proteoglycan degradation in murine knee joints

    PubMed Central

    Dudler, J.; Renggli-Zulliger, N.; Busso, N.; Lotz, M.; So, A.

    2000-01-01

    OBJECTIVE—To evaluate the effect of murine interleukin 17 (IL17) on cartilage catabolism and joint inflammation by direct intra-articular injection of the cytokine into murine knee joints.
METHODS—Knees of normal C57 Bl mice were injected once or repeatedly with recombinant IL17 or IL1β. Inflammation was estimated by technetium-99m pertechnetate (99Tc) uptake and histological scoring of tissue sections. Proteoglycan depletion was evaluated by histological scoring of safranin O stained sections. Effects on proteoglycan synthesis were studied by 35SO4 incorporation.
RESULTS—A single intra-articular injection of IL17 (10 ng/knee) produced effects very similar to those of IL1β (10 ng/knee). No inflammation was detected at six or 24 hours by 99Tc uptake. However, safranin O staining showed depletion of proteoglycan at 48 hours. Repeated injections of IL17 induced joint inflammation and cartilage proteoglycan depletion as shown by histological scoring. Unlike IL1β, proteoglycan depletion induced by IL17 seemed to be the result of increased degradation only, as no suppression of 35SO4 incorporation was seen.
CONCLUSION—These findings confirm, in vivo, the catabolic effects of IL17 on cartilage. IL17 is thus the first T cell cytokine showing a direct catabolic effect on cartilage in addition to stimulatory effects on macrophages and synoviocytes, making it a potentially important cytokine in the pathogenesis of arthritis.

 PMID:10873962

  3. Helical Axis Data Visualization and Analysis of the Knee Joint Articulation.

    PubMed

    Millán Vaquero, Ricardo Manuel; Vais, Alexander; Dean Lynch, Sean; Rzepecki, Jan; Friese, Karl-Ingo; Hurschler, Christof; Wolter, Franz-Erich

    2016-09-01

    We present processing methods and visualization techniques for accurately characterizing and interpreting kinematical data of flexion-extension motion of the knee joint based on helical axes. We make use of the Lie group of rigid body motions and particularly its Lie algebra for a natural representation of motion sequences. This allows to analyze and compute the finite helical axis (FHA) and instantaneous helical axis (IHA) in a unified way without redundant degrees of freedom or singularities. A polynomial fitting based on Legendre polynomials within the Lie algebra is applied to provide a smooth description of a given discrete knee motion sequence which is essential for obtaining stable instantaneous helical axes for further analysis. Moreover, this allows for an efficient overall similarity comparison across several motion sequences in order to differentiate among several cases. Our approach combines a specifically designed patient-specific three-dimensional visualization basing on the processed helical axes information and incorporating computed tomography (CT) scans for an intuitive interpretation of the axes and their geometrical relation with respect to the knee joint anatomy. In addition, in the context of the study of diseases affecting the musculoskeletal articulation, we propose to integrate the above tools into a multiscale framework for exploring related data sets distributed across multiple spatial scales. We demonstrate the utility of our methods, exemplarily processing a collection of motion sequences acquired from experimental data involving several surgery techniques. Our approach enables an accurate analysis, visualization and comparison of knee joint articulation, contributing to the evaluation and diagnosis in medical applications. PMID:27367532

  4. Fingerprint authentication via joint transform correlator and its application in remote access control of a 3D microscopic system

    NASA Astrophysics Data System (ADS)

    He, Wenqi; Lai, Hongji; Wang, Meng; Liu, Zeyi; Yin, Yongkai; Peng, Xiang

    2014-05-01

    We present a fingerprint authentication scheme based on the optical joint transform correlator (JTC) and further describe its application to the remote access control of a Network-based Remote Laboratory (NRL). It is built to share a 3D microscopy system of our realistic laboratory in Shenzhen University with the remote co-researchers in Stuttgart University. In this article, we would like to focus on the involved security issues, mainly on the verification of various remote visitors to our NRL. By making use of the JTC-based optical pattern recognition technique as well as the Personal Identification Number (PIN), we are able to achieve the aim of authentication and access control for any remote visitors. Note that only the authorized remote visitors could be guided to the Virtual Network Computer (VNC), a cross-platform software, which allows the remote visitor to access the desktop applications and visually manipulate the instruments of our NRL through the internet. Specifically to say, when a remote visitor attempts to access to our NRL, a PIN is mandatory required in advance, which is followed by fingerprint capturing and verification. Only if both the PIN and the fingerprint are correct, can one be regarded as an authorized visitor, and then he/she would get the authority to visit our NRL by the VNC. It is also worth noting that the aforementioned "two-step verification" strategy could be further applied to verify the identity levels of various remote visitors, and therefore realize the purpose of diversified visitor management.

  5. Impact of 3-D seismic data on the Nigerian National Petroleum Corporation/Chevron Nigeria Limited joint venture development drilling program

    SciTech Connect

    Quam, S. )

    1993-09-01

    The Nigerian National Petroleum Corporation/Chevron Nigeria Limited joint venture has been acquiring three-dimensional (3-D) seismic data over its concessions since 1984. To date, 1700 km[sup 2] have been recorded and processed at a cumulative cost of US $39 million. During 1991 - 1992, 20 development wells were drilled based directly on new 3-D seismic interpretations. These wells have added 148 million bbl of oil in new recoverable reserves, and to date have added 37,000 bbl/day to the joint venture's production. In addition, the 3-D interpretations have resulted in a sizable inventory of wells for future development drilling. The new 3-D interpretations provided more accurate pictures of fault patterns, fluid contacts, channel trends, stratigraphic continuity, and velocity/amplitude anomalies. In addition, the 3-D data were invaluable in designing low risk, directional well trajectories to tap relatively thin oil legs under large gas caps. Wells often were programmed to hit several objectives at their respective gas/oil contacts, resulting in maximized net oil sand pays and reducing the risk of gas production. In order to do this, directional [open quotes]sharpshooting,[close quotes] accurate depth conversion of the seismic time maps, was critical. By using the 3-D seismic, checkshot, and sonic data to develop a variable velocity space, well-top prognoses within 50 ft at depths of 6,000-10,000 ft were possible, and were key to the success of the program. As the joint venture acreage becomes more mature, development wells will be drilled for smaller numbers of stacked objectives, and sometimes for single sands. Highly accurate 3-D interpretations and depth conversions will become even more critical in order to tap thinner pay zones in a cost-effect manner.

  6. Three-dimensional (3D) microstructural characterization and quantification of reflow porosity in Sn-rich alloy/copper joints by X-ray tomography

    SciTech Connect

    Jiang Ling; Chawla, Nikhilesh; Pacheco, Mario; Noveski, Vladimir

    2011-10-15

    In this paper high resolution X-ray tomography was used to characterize reflow porosity in Sn-3.9Ag-0.7Cu/Cu solder joints. The combination of two segmentation techniques was applied for the three-dimensional (3D) visualization of pores in the joints and the quantification on the characteristics of reflow porosity, including pore size, volume fraction and morphology. The size, morphology and distribution of porosity were visualized in 3D for three different solder joints. Since the results are relatively similar for all three, only the results of one joint are presented. Solder reflow porosity was mostly spherical, segregated along the solder/Cu interface, and had an average pore size of 30 {mu}m in diameter. A few large pores (larger than 100 {mu}m in diameter) were present, some of which had lower sphericity, i.e., they were more irregular. The presence of these large pores may significantly influence the mechanical behavior of solder joints. - Highlights: {yields} Non-destructive 3D characterization and quantification of porosity in Pb-free solders by X-ray tomography {yields} Two new image analysis and reconstruction tools are presented that can be used by the community at large {yields} Pore size, volume fraction, and sphericity, is critical to understanding microstructure and modeling of these systems.

  7. Evaluation of knee joint proprioception and balance of young female volleyball players: a pilot study

    PubMed Central

    Şahin, Neşe; Bianco, Antonino; Patti, Antonino; Paoli, Antonio; Palma, Antonio; Ersöz, Gülfem

    2015-01-01

    [Purpose] The main purpose of our study was the evaluation of the effects of long-term volleyball practice on knee joint proprioception and balance of young female athletes. [Subjects and Methods] An observational case-control study was performed. The study enrolled 19 female volleyball players in the experimental group and 19 sedentary counterparts as controls. A Biodex balance system and dynamometer were used for the evaluations. The paired t-test was used to determine the significance of differences between the performance of athletes and controls. [Results] The knee proprioception analysis showed a significant difference at 60° joint position in active and passive tests. A similar trend, but without significance, was found for the 20° joint position. In the postural stability tests both groups showed similar results with no significant differences between them. [Conclusion] In conclusion, the results indicate a significant influence on joint proprioception is elicited by long-term exposure to a team sport like volleyball. However, the postural stability indexes showed similar trends in both groups, highlighting the analogous ontogenesis of the subjects investigated and the low influence of volleyball practice on postural stability. PMID:25729185

  8. The effect of instability training on knee joint proprioception and core strength.

    PubMed

    Cuğ, Mutlu; Ak, Emre; Ozdemir, Recep Ali; Korkusuz, Feza; Behm, David G

    2012-01-01

    Although there are many studies demonstrating increased trunk activation under unstable conditions, it is not known whether this increased activation would translate into meaningful trunk strength with a prolonged training program. Additionally, while balance-training programs have been shown to improve stability, their effect on specific joint proprioception is not clear. Thus the objective of this study was to examine training adaptations associated with a 10-week instability-training program. Participants were tested pre- and post-training for trunk extension and flexion strength and knee proprioception. Forty-three participants participated in either a 10-week (3 days per week) instability-training program using Swiss balls and body weight as resistance or a control group (n = 17). The trained group increased (p < 0. 05) trunk extension peak torque/body weight (23.6%) and total work output (20.1%) from pre- to post-training while the control group decreased by 6.8% and 6.7% respectively. The exercise group increased their trunk flexion peak torque/body weight ratios by 18.1% while the control group decreased by 0.4%. Knee proprioception (combined right and left joint repositioning) improved 44.7% from pre- to post-training (p = 0.0006) and persisted (21.5%) for 9 months post-training. In addition there was a side interaction with the position sense of the right knee at 9 months showing 32.1% (p = 0.03) less deviation from the reference angle than the right knee during pre-testing. An instability-training program using Swiss balls with body weight as resistance can provide prolonged improvements in joint proprioception and core strength in previously untrained individuals performing this novel training stress which would contribute to general health. Key pointsAlthough traditional free weight resistance exercises have been recommended as most beneficial for improving strength and power in athletes (Behm et al., 2010b), an IT program using Swiss balls and body

  9. New Joints, Same Old Weight: Weight Changes After Total Hip and Knee Arthroplasty.

    PubMed

    Hurwit, Daniel J; Trehan, Samir K; Cross, Michael B

    2016-07-01

    Obesity is a well-known risk factor for postoperative complications following total joint arthroplasty. However, because the operation is often successful, orthopedic surgeons continue to operate on obese individuals, and many surgeons do so under the assumption that patients will lose weight after they are able to walk and exercise without pain. In this article, we review a recent study by Ast et al., who performed a retrospective review, using a single-center institutional registry, to determine (1) whether patients do actually lose weight after total hip and/or total knee arthroplasty, (2) whether there are predictors of postoperative weight change, and (3) whether postoperative weight changes affect patient-reported clinical outcomes. The principle conclusion was that most patients maintained their body mass index (BMI) after total hip and total knee arthroplasty (73 and 69%, respectively). However, patients undergoing total knee arthroplasty, patients who had a higher preoperative BMI, and female patients were more likely to lose weight postoperatively. When examined in the context of the current literature, this study provides valuable information for the preoperative counseling of total joint arthroplasty candidates, especially in the setting of obesity. PMID:27385952

  10. A neural network approach for determining gait modifications to reduce the contact force in knee joint implant.

    PubMed

    Ardestani, Marzieh Mostafavizadeh; Chen, Zhenxian; Wang, Ling; Lian, Qin; Liu, Yaxiong; He, Jiankang; Li, Dichen; Jin, Zhongmin

    2014-10-01

    There is a growing interest in non-surgical gait rehabilitation treatments to reduce the loading in the knee joint. In particular, synergetic kinematic changes required for joint offloading should be determined individually for each subject. Previous studies for gait rehabilitation designs are typically relied on a "trial-and-error" approach, using multi-body dynamic (MBD) analysis. However MBD is fairly time demanding which prevents it to be used iteratively for each subject. This study employed an artificial neural network to develop a cost-effective computational framework for designing gait rehabilitation patterns. A feed forward artificial neural network (FFANN) was trained based on a number of experimental gait trials obtained from literature. The trained network was then hired to calculate the appropriate kinematic waveforms (output) needed to achieve desired knee joint loading patterns (input). An auxiliary neural network was also developed to update the ground reaction force and moment profiles with respect to the predicted kinematic waveforms. The feasibility and efficiency of the predicted kinematic patterns were then evaluated through MBD analysis. Results showed that FFANN-based predicted kinematics could effectively decrease the total knee joint reaction forces. Peak values of the resultant knee joint forces, with respect to the bodyweight (BW), were reduced by 20% BW and 25% BW in the midstance and the terminal stance phases. Impulse values of the knee joint loading patterns were also decreased by 17% BW*s and 24%BW*s in the corresponding phases. The FFANN-based framework suggested a cost-effective forward solution which directly calculated the kinematic variations needed to implement a given desired knee joint loading pattern. It is therefore expected that this approach provides potential advantages and further insights into knee rehabilitation designs.

  11. The Effects of Knee Joint and Hip Abduction Angles on the Activation of Cervical and Abdominal Muscles during Bridging Exercises.

    PubMed

    Lee, Su-Kyoung; Park, Du-Jin

    2013-07-01

    [Purpose] The purpose of this study was to examine the effects of the flexion angle of the knee joint and the abduction angle of the hip joint on the activation of the cervical region and abdominal muscles. [Subjects] A total of 42 subjects were enrolled 9 males and 33 females. [Methods] The bridging exercise in this study was one form of exercise with a knee joint flexion angle of 90°. Based on this, a bridging exercise was conducted at the postures of abduction of the lower extremities at 0, 5, 10, and 15°. [Result] The changes in the knee joint angle and the hip abduction angle exhibited statistically significant effects on the cervical erector spinae, adductor magnus, and gluteus medius muscles. The abduction angles did not result in statistically significant effects on the upper trapezium, erector spinae, external oblique, and rectus abdominis muscles. However, in relation to the knee joint angles, during the bridging exercise, statistically significant results were exhibited. [Conclusion] When patients with both cervical and back pain do a bridging exercise, widening the knee joint angle would reduce cervical and shoulder muscle activity through minimal levels of abduction, permitting trunk muscle strengthening with reduced cervical muscle activity. This method would be helpful for strengthening trunk muscles in a selective manner. PMID:24259870

  12. The effect of co-stabilizer muscle activation on knee joint position sense: a single group pre-post test

    PubMed Central

    Nam, Yeongyo; Lee, Ho Jun; Choi, Myongryol; Chung, Sangmi; Park, Junhyung; Yu, Jaeho

    2016-01-01

    [Purpose] The purpose of this study was to investigate the effect of co-stabilizer muscle activation on knee joint position sense. [Subjects and Methods] This study was a pre-post, single-blinded randomly controlled trial (angle sequence randomly selected) design. Seven healthy adults with no orthopaedic or neurological problems participated in this study. Knee joint position sense was measured by a target matching test at target angles of 30°, 45° and 80° of knee flexion a using digital inclinometer under two conditions: erect sitting, which is known to highly activate co-stabilizer muscle and slump sitting, which is known to little activate the co-stabilizer muscle. [Results] A significant difference in joint position matching error at the knee flexion angle of 45° was founded between two conditions erect sitting: (3.83 ± 1.47) and slump sitting: (1.00 ± 0.63). There were no significant differences in joint position matching error at the other target angles. [Conclusion] Knee joint position sense at 45° is likely to be affected by activation of co-stabilizer muscle, and this value is suitable for facilitation of joint position sense with skilled movement. PMID:27512279

  13. Influence of orthopaedic-technical aid on the kinematics and kinetics of the knee joint of patients with neuro-orthopaedic diseases.

    PubMed

    Lampe, Renée; Mitternacht, Jürgen; Schrödl, Silvia; Gerdesmeyer, Ludger; Natrath, Michaela; Gradinger, Reiner

    2004-06-01

    In our gait laboratory, the gait pattern of 18 youths with neurogenic foot deformities as a result of spina bifida or cerebral palsy was examined. The influence of technical orthopaedic devices for the foot and ankle on kinematics and kinetics of the gait and especially of the knee joint were analyzed. Kinematic data were derived from 3D-video analysis, kinetic data from force plates and pressure distribution plates. Muscle activities were measured with eight-channel EMG. The data were examined to see if there were differences when using the technical devices. All patients had already been supported externally with the different devices like orthopaedic shoes, insoles, Nancy Hilton orthoses and orthoses for the lower leg extremity. The devices restricted to the foot and the ankle joint improved the feeling of gait stability of the patients. In this investigation, the different supports had various but little effects on the kinematics and kinetics of the knee joint, depending on the type of orthoses used and the kind of handicap of the youths. Because of the great expenditure, the data obtained in this study were taken from a small number of patients. Therefore, they are individual findings and are of restricted general significance.

  14. Knee joint position sense of roller hockey players: a comparative study.

    PubMed

    Venâncio, João; Lopes, Diogo; Lourenço, Joaquim; Ribeiro, Fernando

    2016-06-01

    This study aimed to compare knee joint position sense of roller hockey players with an age-matched group of non-athletes. Forty-three male participants voluntarily participated in this cross-sectional study: 21 roller hockey players (mean age: 23.2 ± 4.2 years old, mean weight: 81.8 ± 9.8 kg, mean height: 180.5 ± 4.1 cm) and 22 age-matched non-athletes (mean age: 23.7 ± 3.9 years old, mean weight: 85.0 ± 6.2 kg, mean height: 181.5 ± 5.0 cm). Knee joint position sense of the dominant limb was evaluated using a technique of open-kinetic chain and active knee positioning. Joint position sense was reported using absolute, relative and variable angular errors. The main results indicated that the group of roller hockey players showed significantly lower absolute (2.4 ± 1.2º vs. 6.5 ± 3.2º, p ≤ 0.001) and relative (1.7 ± 2.1º vs. 5.8 ± 4.4º, p ≤ 0.001) angular errors in comparison with the non-athletes group. In conclusion, the results from this present study suggest that proprioceptive acuity, assessed by measuring joint position sense, is increased in roller hockey players. The enhanced proprioception of the roller hockey players could contribute to injury prevention and improved performance during sporting activities. PMID:27111126

  15. Medicare Reimbursement Attributable to Periprosthetic Joint Infection Following Primary Hip and Knee Arthroplasty.

    PubMed

    Yi, Sarah H; Baggs, James; Culler, Steven D; Berríos-Torres, Sandra I; Jernigan, John A

    2015-06-01

    This study estimated Medicare reimbursement attributable to periprosthetic joint infection (PJI) across the continuum of covered services four years following hip or knee arthroplasty. Using 2001-2008 Medicare claims data, total and annual attributable reimbursements were assessed using generalized linear regression, adjusting for potential confounders. Within one year following arthroplasty, 109 (1.04%) of 10,418 beneficiaries were diagnosed with PJI. Cumulative Medicare reimbursement in the PJI arm was 2.2-fold (1.9-2.6, P<.0001) or $53,470 ($39,575-$68,221) higher than that of the non-PJI arm. The largest difference in reimbursement occurred the first year (3.2-fold); differences persisted the second (2.3-fold) and third (1.9-fold) follow up years. PJI following hip or knee arthroplasty appears costly to Medicare, with cost traversing several years and health care service areas.

  16. [Pseudothrombophlebitis, a rare complication following total replacement of the knee joint (author's transl)].

    PubMed

    Köhler, G; Kampshoff, N

    1982-02-01

    Pseudothrombophlebitis secondary to rupture of a Baker's cyst had been described repeatedly in the literature of rheumatology. If this condition is mistaken for deep venous thrombosis and treated with anticoagulation, serious complication may result, like hematoma of the lower legs or retroperitoneal and gastrointestinal bleeding. The case demonstrated here shows that this condition is not limited to patients with chronic rheumatoid polyarthritis. Qur patient with an endoprosthesis of the knee suffered from marked reaction to metal (= metallosis) in addition to malacia patellae. The resulting severe synovitis was the cause for pseudothrombophlebitis. Therefore, in cases of suspected venous thrombosis in combination with gonarthritis, and arthrogram of the knee joint or a cystogram should be obtained in order to exclude the possibility of pseudothrombophlebitis.

  17. Inequalities in access to knee joint replacements for people in need

    PubMed Central

    Yong, P; Milner, P; Payne, J; Lewis, P; Jennison, C

    2004-01-01

    Objectives: To quantify the effects of socioeconomic deprivation and rurality on evidence of need for total knee joint replacement and the use of health services, after adjusting for age and sex. Methods: A random stratified sample of 15 000 people aged ⩾65 years taken from central age/sex registers for the geographical areas covered by the previous Sheffield and Wiltshire Health Authorities. A self completion validated questionnaire was then mailed directly to subjects to assess need for knee joint replacement surgery and whether general practice and hospital services were being used. Subjects were followed up for 18 months to evaluate access to surgery. Results: The response rate was 78% after three mailings. In those aged 65 years and over (with and without comorbidity), the proportion with no comorbid factors and in need of knee replacement was 5.1%; the rate of need among subjects without comorbidity was 7.9%. There were inequalities in health and access to health related to age, sex, geography, and deprivation but not rurality. People who were more deprived had greater need. Older and deprived people were less likely to access health services. Only 6.4% of eligible people received knee replacement surgery after 18 months of follow up. Conclusions: There is an important unmet need in older people, with significant age, sex, geographical, and deprivation inequalities in levels of need and access to services. The use of waiting list numbers as a performance indicator is perverse for this procedure. There is urgent need to expand orthopaedic services and training. PMID:15479899

  18. Depression and the Overall Burden of Painful Joints: An Examination among Individuals Undergoing Hip and Knee Replacement for Osteoarthritis.

    PubMed

    Gandhi, Rajiv; Zywiel, Michael G; Mahomed, Nizar N; Perruccio, Anthony V

    2015-01-01

    The majority of patients with hip or knee osteoarthritis (OA) report one or more symptomatic joints apart from the one targeted for surgical care. Therefore, the purpose of the present study was to investigate the association between the burden of multiple symptomatic joints and self-reported depression in patients awaiting joint replacement for OA. Four hundred and seventy-five patients at a single centre were evaluated. Patients self-reported joints that were painful and/or symptomatic most days of the previous month on a homunculus, with nearly one-third of the sample reporting 6 or more painful joints. The prevalence of depression was 12.2% (58/475). When adjusted for age, sex, education level, hip or knee OA, body mass index, chronic condition count, and joint-specific WOMAC scores, each additional symptomatic joint was associated with a 19% increased odds (odds ratio: 1.19 (95% CI: 1.08, 1.31, P < 0.01)) of self-reported depression. Individuals reporting 6 or more painful joints had 2.5-fold or greater odds of depression when compared to those patients whose symptoms were limited to the surgical joint. A focus on the surgical joint alone is likely to miss a potentially important determinant of postsurgical patient-reported outcomes in patients undergoing hip or knee replacement.

  19. Chondroprotective effects of pomegranate juice on monoiodoacetate-induced osteoarthritis of the knee joint of mice.

    PubMed

    Hadipour-Jahromy, Mahsa; Mozaffari-Kermani, Reza

    2010-02-01

    To study the effectiveness of pomegranate juice on osteoarthritis, mono-iodoacetate induced loss of articular cartilage in the mouse tibiofemoral joint was used as a model. Mono-iodoacetate is an inhibitor of glycolysis which promotes osteoarthritis similar to that noted in human osteoarthritis. The histopathology of the subchondral bone and cartilage of mouse knee joints treated with a single intra-articular injection of mono-iodoacetate (0.1 mg) and killed at 1, 14 and 28 days post injection was investigated. The effect of pomegranate juice (4 mL/kg, 10 mL/kg, 20 mL/kg, orally) was studied in different groups. Histopathological changes in knee joints were seen after 2 weeks. Early osteoarthritis was characterized by areas of chondrocyte degeneration, which sometimes involved the entire thickness of the articular cartilage in the tibial plateaus and femoral condyles. Changes to the subchondral bone and proteoglycan contents, focal fragmentation and collapse of bony trabeculae with fibrosis and necrosis, and synovial cell proliferation were observed. The administration of pomegranate juice dose dependently prevented the negative effects of iodoacetate. Chondrocyte damage was significantly prevented, with proteoglycan less affected, especially in the groups receiving a high amount of pomegranate juice. No cell proliferation or inflammatory cells were detected in the synovial fluid. The effectiveness of pomegranate juice in improving histopathological damage is emphasized and its chondroprotective effect in vivo highlighted.

  20. Supramolecular Organization of Collagen Fibrils in Healthy and Osteoarthritic Human Knee and Hip Joint Cartilage

    PubMed Central

    Raiteri, Roberto; Loparic, Marko; Düggelin, Marcel; Mathys, Daniel; Friederich, Niklaus F.; Bruckner, Peter

    2016-01-01

    Cartilage matrix is a composite of discrete, but interacting suprastructures, i.e. cartilage fibers with microfibrillar or network-like aggregates and penetrating extrafibrillar proteoglycan matrix. The biomechanical function of the proteoglycan matrix and the collagen fibers are to absorb compressive and tensional loads, respectively. Here, we are focusing on the suprastructural organization of collagen fibrils and the degradation process of their hierarchical organized fiber architecture studied at high resolution at the authentic location within cartilage. We present electron micrographs of the collagenous cores of such fibers obtained by an improved protocol for scanning electron microscopy (SEM). Articular cartilages are permeated by small prototypic fibrils with a homogeneous diameter of 18 ± 5 nm that can align in their D-periodic pattern and merge into larger fibers by lateral association. Interestingly, these fibers have tissue-specific organizations in cartilage. They are twisted ropes in superficial regions of knee joints or assemble into parallel aligned cable-like structures in deeper regions of knee joint- or throughout hip joints articular cartilage. These novel observations contribute to an improved understanding of collagen fiber biogenesis, function, and homeostasis in hyaline cartilage. PMID:27780246

  1. Mathematical study on the guidance of the tibiofemoral joint as theoretical background for total knee replacements.

    PubMed

    Fiedler, Christoph; Gezzi, Riccardo; Frosch, Karl-Heinz; Wachowski, Martin Michael; Kubein-Meesenburg, Dietmar; Dörner, Jochen; Fanghänel, Jochen; Nägerl, Hans

    2011-01-01

    The mathematical approach presented allows main features of kinematics and force transfer in the loaded natural tibiofemoral joint (TFJ) or in loaded knee endoprostheses with asymmetric condyles to be deduced from the spatial curvature morphology of the articulating surfaces. The mathematical considerations provide the theoretical background for the development of total knee replacements (TKR) which closely reproduce biomechanical features of the natural TFJ. The model demonstrates that in flexion/extension such kinematic features as centrodes or slip ratios can be implemented in distinct curvature designs of the contact trajectories in such a way that they conform to the kinematics of the natural TFJ in close approximation. Especially the natural roll back in the stance phase during gait can be reproduced. Any external compressive force system, applied to the TFJ or the TKR, produces two joint reaction forces which--when applying screw theory--represent a force wrench. It consists of a force featuring a distinct spatial location of its line and a torque parallel to it. The dependence of the geometrical configuration of the force wrench on flexion angle, lateral/medial distribution of the joint forces, and design of the slopes of the tuberculum intercondylare is calculated. The mathematical considerations give strong hints about TKR design and show how main biomechanical features of the natural TFJ can be reproduced.

  2. Moments of muscular strength of knee joint extensors and flexors during physiotherapeutic procedures following anterior cruciate ligament reconstruction in males.

    PubMed

    Czamara, Andrzej

    2008-01-01

    The objective of this paper was to evaluate maximal muscular strength moments of knee joint extensors and flexors in males subjected to physiotherapeutic procedures. 120 males were selected for the study. The first group consisted of 54 patients who underwent a 6 month physiotherapy programme following anterior cruciate ligament (ACL) reconstruction. The control group comprised 54 males without knee joint injuries. The measurement of muscular strength moments was performed in healthy and affected knee joint flexor and extensor muscles postoperatively, during the 13th and 21st week of physiotherapy. The patients' results were next compared with the results obtained in the control group. During the 13th week of physiotherapy, the values of postoperative maximal strength moments in knee joints were significantly lower compared to the results obtained in non-operated limbs and in the control group. The introduction of individual loads adjusted to the course of ACL graft reconstruction and fixation in the bone tunnel resulted in the improvement of maximal muscle strength values in the patients' knee joints from 13 to 21 weeks postoperatively. During the 21st week of physiotherapy, the values of the muscular strengths in the operated limbs were similar to those obtained in non-operated limbs of the patients and in the control group.

  3. Design of a knee and leg muscle exerciser for paraplegics using a shape memory alloy rotary joint actuator

    NASA Astrophysics Data System (ADS)

    Wang, Guoping; Shahinpoor, Mohsen

    1998-07-01

    This paper presents a design of an active knee and leg muscle exerciser using a shape memory alloy (SMA) rotary joint actuator. This active exerciser is designed for a paraplegic to exercise his or her knee and leg muscles. The exerciser is composed of a lower extremity orthosis or a knee brace, an SMA rotary joint actuator, and an electronic control unit. The lower extremity orthosis and knee brace are commercially available. The analysis model of the SMA rotary joint actuator is introduced and the design formulas are derived. A quasi-static analysis of the SMA rotary joint actuator is assumed in this design. The actuating component of the SMA rotary joint actuator is a bundle of lengthy SMA wires which are wrapped on several wrapping pulleys. A constant force spring is incorporated in this actuator to provide the SMA wires with a bias force to maintain a recoverable initial position of the actuator. A prototype of the active knee and leg muscle exerciser is designed, and an electronic control unit in the prototype provides users with a means of adjusting forward rotation speed and cycle time of the exerciser.

  4. Racial variations in the utilization of knee and hip joint replacement: an introduction and review of the most recent literature

    PubMed Central

    Ibrahim, Said A.

    2010-01-01

    Elective knee and hip joint replacements are cost-effective treatment options in the management of end-stage knee and hip osteoarthritis. Yet there are marked racial disparities in the utilization of this treatment even though the prevalence of knee and hip osteoarthritis does not vary greatly by race or ethnicity. This article briefly reviews the rationale for understanding this disparity, the evidence-base that supports the existence of racial or ethnic disparity as well as some known potential explanations. Also, briefly summarized here are the most recent original research articles that focus on race and ethnicity and total joint replacement in the management of chronic knee or hip pain and osteoarthritis. The article concludes with a call for more research, examining patient, provider and system-level factors that underlie this disparity and the design of evidence-based, targeted interventions to eliminate or reduce any inequities. PMID:21132110

  5. Three-dimensional knee joint moments during performance of the bodyweight squat: effects of stance width and foot rotation.

    PubMed

    Almosnino, Sivan; Kingston, David; Graham, Ryan B

    2013-02-01

    The purpose of this investigation was to assess the effects of stance width and foot rotation angle on three-dimensional knee joint moments during bodyweight squat performance. Twenty-eight participants performed 8 repetitions in 4 conditions differing in stance or foot rotation positions. Knee joint moment waveforms were subjected to principal component analysis. Results indicated that increasing stance width resulted in a larger knee flexion moment magnitude, as well as larger and phase-shifted adduction moment waveforms. The knee's internal rotation moment magnitude was significantly reduced with external foot rotation only under the wide stance condition. Moreover, squat performance with a wide stance and externally rotated feet resulted in a flattening of the internal rotation moment waveform during the middle portion of the movement. However, it is speculated that the differences observed across conditions are not of clinical relevance for young, healthy participants.

  6. Effect of the single-leg, lateral oblique, decline squat exercise on sacroiliac joint pain with knee pain

    PubMed Central

    Yoo, Won-gyu

    2016-01-01

    [Purpose] This study investigated the effect of the single-leg, lateral oblique, decline squat exercise on sacroiliac joint pain with knee pain. [Subjects and Methods] A 39-year-old female had severe pain in the right medial buttock and right anterior knee. This study assessed the anterior pelvic tilt angle and pain provocation tests before and after single-leg, lateral oblique, decline squat exercise for 4 weeks. [Results] Following the course of exercise, the anterior pelvic tilt angles were increased, and the visual analog scale pain scores for both the right buttock and right knee were 2/10. [Conclusion] Single-leg, lateral oblique, decline squat exercise may be effective for treating SI joint pain with knee pain in females. PMID:27799721

  7. Comparative study on isokinetic capacity of knee and ankle joints by functional injury.

    PubMed

    Jeon, Kyoungkyu; Seo, Byoung-Do; Lee, Sang-Ho

    2016-01-01

    [Purpose] To collect basic data for exercise programs designed to enhance functional knee and ankle joint stability based on isokinetic measurement and muscle strength evaluations in normal and impaired functional states. [Subjects and Methods] Twenty-four subjects were randomly assigned to the athlete group and the control group (n = 12 each). Data were collected of isokinetic knee extensor and flexor strength at 60°/sec, 180°/sec, and 240°/sec and ankle plantar and dorsiflexor strength at 30°/sec and 120°/sec. [Results] Significant intergroup differences were observed in peak torque of the right extensors at 60°/sec, 180°/sec, and 240°/sec and the right flexors at 240°/sec. Significant differences were observed in peak torque/body weight in the right extensors at 60°/sec, 180°/sec, and 240°/sec and in the right flexors at 180°/sec and 240°/sec. Significant peak torque differences were noted in the left ankle joint dorsiflexor at 30°/sec and 120°/sec, right plantar flexor at 120°/sec, left plantar flexor at 30°/sec, left dorsiflexor at 30°/sec and 120°/sec, and right dorsiflexor at 120°/sec. [Conclusion] Isokinetic evaluation stimulates muscle contraction at motion-dependent speeds and may contribute to the development of intervention programs to improve knee and ankle joint function and correct lower-extremity instability.

  8. An EMG-driven musculoskeletal model to estimate muscle forces and knee joint moments in vivo.

    PubMed

    Lloyd, David G; Besier, Thor F

    2003-06-01

    This paper examined if an electromyography (EMG) driven musculoskeletal model of the human knee could be used to predict knee moments, calculated using inverse dynamics, across a varied range of dynamic contractile conditions. Muscle-tendon lengths and moment arms of 13 muscles crossing the knee joint were determined from joint kinematics using a three-dimensional anatomical model of the lower limb. Muscle activation was determined using a second-order discrete non-linear model using rectified and low-pass filtered EMG as input. A modified Hill-type muscle model was used to calculate individual muscle forces using activation and muscle tendon lengths as inputs. The model was calibrated to six individuals by altering a set of physiologically based parameters using mathematical optimisation to match the net flexion/extension (FE) muscle moment with those measured by inverse dynamics. The model was calibrated for each subject using 5 different tasks, including passive and active FE in an isokinetic dynamometer, running, and cutting manoeuvres recorded using three-dimensional motion analysis. Once calibrated, the model was used to predict the FE moments, estimated via inverse dynamics, from over 200 isokinetic dynamometer, running and sidestepping tasks. The inverse dynamics joint moments were predicted with an average R(2) of 0.91 and mean residual error of approximately 12 Nm. A re-calibration of only the EMG-to-activation parameters revealed FE moments prediction across weeks of similar accuracy. Changing the muscle model to one that is more physiologically correct produced better predictions. The modelling method presented represents a good way to estimate in vivo muscle forces during movement tasks.

  9. The effect of low frequency pulsing electromagnetic field in treatment of patients with knee joint osteoarthritis.

    PubMed

    Pavlović, Aleksandar S; Djurasić, Ljubomir M

    2012-01-01

    Pulsing electromagnetic field represents effective rocedure in treating of diverse diseases and p pathologic conditions, especially in rheumatology, orthopaedics and traumatology. The goal of this research is the objective evaluation of the treapeutic effect of low frequency pulsing electromagnetic field (LFEMF), in comparison with the effect of the other physical procedure: interfererence currents (IFC) and the medicamentous therapy, in treating of patients with knee joint osteoarthritis. This study was made as experimental, randomized, controlled clinical trial, opened type. The examination included 60 patients (40 females and 20 males) with osteoarthritis of the knee joint. All patients were divided in three groups. The first group of 20 persons, composed of patients treated with medicamentous therapy (Diklofenak of 100 mg, 2 tablets per day). The second group consisted of 20 patients treated by LFPEMF and the third group consisted of 20 patients treated by IFC. All procedures were implemented during 10 days All of patients had also the same duration therapeutic exercise. As observing parameter was used: Lattinen test for the evaluation of the pain sensitivity, before and after therapy. For the statistical analysis of the aquired data, was used Student's t-test. After therapy the pain was considerably reduced in each group, but this effect was the most significant in the II group of the examinees, treated by LFPEMF (p< 0.001), than the effects in other groups of patients: I group (p< 0.05) and III group (p< 0.01). According to the results of this study it can be concluded that LFPEMF is very effective therapeutic procedure in treatment of patients with knee joint osteoarthritis.

  10. Comparative study on isokinetic capacity of knee and ankle joints by functional injury

    PubMed Central

    Jeon, Kyoungkyu; Seo, Byoung-Do; Lee, Sang-Ho

    2016-01-01

    [Purpose] To collect basic data for exercise programs designed to enhance functional knee and ankle joint stability based on isokinetic measurement and muscle strength evaluations in normal and impaired functional states. [Subjects and Methods] Twenty-four subjects were randomly assigned to the athlete group and the control group (n = 12 each). Data were collected of isokinetic knee extensor and flexor strength at 60°/sec, 180°/sec, and 240°/sec and ankle plantar and dorsiflexor strength at 30°/sec and 120°/sec. [Results] Significant intergroup differences were observed in peak torque of the right extensors at 60°/sec, 180°/sec, and 240°/sec and the right flexors at 240°/sec. Significant differences were observed in peak torque/body weight in the right extensors at 60°/sec, 180°/sec, and 240°/sec and in the right flexors at 180°/sec and 240°/sec. Significant peak torque differences were noted in the left ankle joint dorsiflexor at 30°/sec and 120°/sec, right plantar flexor at 120°/sec, left plantar flexor at 30°/sec, left dorsiflexor at 30°/sec and 120°/sec, and right dorsiflexor at 120°/sec. [Conclusion] Isokinetic evaluation stimulates muscle contraction at motion-dependent speeds and may contribute to the development of intervention programs to improve knee and ankle joint function and correct lower-extremity instability. PMID:26957768

  11. Characterisation of a knee-joint energy harvester powering a wireless communication sensing node

    NASA Astrophysics Data System (ADS)

    Kuang, Yang; Zhu, Meiling

    2016-05-01

    Human-based energy harvesters are attractive as sustainable replacements for batteries to power wearable or implantable devices and body sensor networks. In the work presented here, a knee-joint energy harvester (KEH) was introduced to power a customer-built wireless communication sensing node (WCSN). The KEH used a mechanical plucking technique to provide sufficient frequency up-conversion—from a few Hz to the resonant frequency of the KEH—so as to generate the high power required. It was actuated by a knee-joint simulator, which reproduced the knee-joint motion of human gaits at a walking frequency of 0.9 Hz. The energy generated was first stored in a reservoir capacitor and then released to the WCSN in a burst mode with the help of an energy aware interface. The WCSN was deployed with a three-axis accelerometer, a temperature sensor, and a light detector for data sensing. A Jennic microcontroller was utilised to collect and transmit the measured data to a base station placed at a distance of 4 m. The energy generation by the KEH and the energy distribution in the system was characterised in real time by an in-house-built set-up. The results showed that the KEH generated an average power output of 1.76 mW when powering the WCSN. After charging the reservoir capacitor for 28.4 s, the KEH can power the WCSN for a 46 ms period every 1.25 s. The results also clearly illustrated how the energy generated by the KEH was distributed in the system and highlighted the importance of using a high performance power management approach to improve the performance of the whole system.

  12. Correlation study of knee joint proprioception test results using common test methods

    PubMed Central

    Li, Lin; Ji, Zhong-Qiu; Li, Yan-Xia; Liu, Wei-Tong

    2016-01-01

    [Purpose] To study the correlation of the results obtained from different proprioception test methods, namely, the joint angle reset method, the motion minimum threshold measurement method, and the force sense reproduction method, performed on the same subjects’ knees. [Subjects and Methods] Different proprioception test methods, the joint angle reset method, the motion minimum threshold measurement method and the force sense reproduction method were used to test the knees of 30 healthy young men. [Results] Correlations were found in the following descending order from strong to weak: the correlation between the joint angle reset method and the force sense reproduction method (correlation coefficient of 0.41), the correlation between the joint angle reset method and the motion minimum threshold measurement method (correlation coefficient of 0.29), the correlation between the motion minimum threshold measurement method and the force sense reproduce method (correlation coefficient of 0.15). [Conclusion] No correlation was found among the results obtained using the joint angle reset method, the motion minimum threshold measurement method and the force sense reproduction method. Therefore, no correlation was found among the position sense, the motion sense and the force sense represented by these methods. Using the results of only one of the test methods to represent proprioception is one-sided. Force sensation depends more on the sensory input of information from the Golgi tendon organs, motion sense depends more on the input information of the muscle spindles, and position sense relies on the double input information of the muscle spindles and the Golgi tendon organs. PMID:27065533

  13. The prevalence of symptomatic knee and distal interphalangeal joint osteoarthritis in the urban population of Antalya, Turkey.

    PubMed

    Kaçar, C; Gilgil, E; Urhan, S; Arikan, V; Dündar, U; Oksüz, M C; Sünbüloglu, G; Yildirim, C; Tekeoglu, I; Bütün, B; Apaydin, A; Tuncer, T

    2005-04-01

    The aim of this cross-sectional study was to estimate the prevalence and risk factors of symptomatic knee and distal interphalangeal (DIP) joint osteoarthritis (OA) in the elderly (> or =50 years of age) urban population of Antalya, Turkey. According to the 1997 national census, Antalya's population was 508,840. By random cluster sampling, 655 individuals aged 50 years or more were interviewed face-to-face and subjected to structured interviews regarding knee pain, worsening pain on exertion, and the gelling phenomenon. They were also asked about performing namaz (a fundamental act of worship in Islam performed five times a day), smoking, type of residence, type of toilet, work style, and duration of walking per day. They were also questioned about swelling in DIP joints. In the case of suspicion of knee OA, the individuals were invited to the hospital for further evaluation by physical examination and direct roentgenogram. The diagnosis of knee OA was based on clinical or clinical and radiographic findings. The prevalence of symptomatic knee OA was determined as 14.8% in the population aged 50 years or over. Advanced age, female sex, namaz, and type of residence were found to be associated with knee OA. The rate of symptomatic knee OA was significantly lower in smokers and those walking more than 2 h per day. Female sex was also strongly associated with OA DIP joints. OA of DIP joints was found significantly associated with symptomatic knee OA. The latter is a major health problem in the elderly population, especially in about one fourth of women aged 50 years or over. These data suggest that advanced age, female sex, and type of residence are risk factors.

  14. [A computer system for the systematization of MR findings in knee joint diseases].

    PubMed

    Sparacia, G; Lo Casto, A; Mercurio, G; Brancato, M; Bartolotta, T; Lagalla, R

    1996-01-01

    An inexpensive, easy-access computer-based system is proposed, which was developed for the systematization of the clinical series of knee joint disorders studied with Magnetic Resonance Imaging (MRI). The system is based upon the integration of multimedia technology and Data Base Management Systems (DBMS). The hardware configuration for this project included an Apple Macintosh workstation based on a Motorola 68040 microprocessor and a customized application developed by the authors with the 4th Dimension software. The MR images available only on film were digitized off-line with a solid-state Charge Coupled Device (CCD) scanner with back-light cover for transparency. Otherwise, MR images were acquired on-line through an Ethernet-based local area network from the MR unit or from a SparcStation-Advantage Windows workstation connected with the MR unit. Image post-processing was performed with the Adobe PhotoShop software. The system was devoted to the systematization and analysis of a clinical series of 800 MR studies of the knee. A mean of 10 significant MR images were stored for each examination with a standard image compression algorithm--the Joint Photographic Experts Group (JPEG). This permitted us to save the system's storage space and at the same time to preserve image quality for consultation and teaching purposes, not for diagnosis which is made on the backboard or on the MR unit's or Advantage Window's monitor. Finally, MR findings were indexed with a customized check-list specific for knee joint disorders. On the basis of stored and selected information, it was thus possible to carry out a statistical analysis and to make detailed reports which are useful for scientific purposes, such as the preparation of lectures and papers. Moreover, the system was very useful for patients' follow-up and for the preparation of hypermedia teaching applications on knee joint disorders which are available on the Internet at our World-Wide Web server (URL: http

  15. Post-trial anatomical frame alignment procedure for comparison of 3D joint angle measurement from magnetic/inertial measurement units and camera-based systems.

    PubMed

    Li, Qingguo; Zhang, Jun-Tian

    2014-11-01

    Magnetic and inertial measurement units (MIMUs) have been widely used as an alternative to traditional camera-based motion capture systems for 3D joint kinematics measurement. Since these sensors do not directly measure position, a pre-trial anatomical calibration, either with the assistance of a special protocol/apparatus or with another motion capture system is required to establish the transformation matrices between the local sensor frame and the anatomical frame (AF) of each body segment on which the sensors are attached. Because the axes of AFs are often used as the rotational axes in the joint angle calculation, any difference in the AF determination will cause discrepancies in the calculated joint angles. Therefore, a direct comparison of joint angles between MIMU systems and camera-based systems is less meaningful because the calculated joint angles contain a systemic error due to the differences in the AF determination. To solve this problem a new post-trial AF alignment procedure is proposed. By correcting the AF misalignments, the joint angle differences caused by the difference in AF determination are eliminated and the remaining discrepancies are mainly from the measurement accuracy of the systems themselves. Lower limb joint angles from 30 walking trials were used to validate the effectiveness of the proposed AF alignment procedure. This technique could serve as a new means for calibrating magnetic/inertial sensor-based motion capture systems and correcting for AF misalignment in scenarios where joint angles are compared directly.

  16. Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault-perturbed stress fields

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon A.; Aydin, Atilla; Pollard, David D.

    2000-01-01

    Structural methods based on homogeneous stress states predict that joints growing in an extending crust form with strike orientations identical to normal faults. However, we document a field example where the strikes of genetically related normal faults and joints are almost mutually perpendicular. Field relationships allowed us to constrain the fracture sequence and tectonic environment for fault and joint growth. We hypothesize that fault slip can perturb the surrounding stress field in a manner that controls the orientations of induced secondary structures. Numerical models were used to examine the stress field around normal faults, taking into consideration the effects of 3-D fault shape, geometrical arrangement of overlapping faults, and a range of stress states. The calculated perturbed stress fields around model normal faults indicate that it is possible for joints to form at high angles to fault strike. Such joint growth may occur at the lateral tips of an isolated fault, but is most likely in a relay zone between overlapping faults. However, the angle between joints and faults is also influenced by the remote stress state, and is particularly sensitive to the ratio of fault-parallel to fault-perpendicular stress. As this ratio increases, joints can propagate away from faults at increasingly higher angles to fault strike. We conclude that the combined remote stress state and perturbed local stress field associated with overlapping fault geometries resulted in joint growth at high angles to normal fault strike at a field location in Arches National Park, Utah.

  17. Fully automated system for the quantification of human osteoarthritic knee joint effusion volume using magnetic resonance imaging

    PubMed Central

    2010-01-01

    Introduction Joint effusion is frequently associated with osteoarthritis (OA) flare-up and is an important marker of therapeutic response. This study aimed at developing and validating a fully automated system based on magnetic resonance imaging (MRI) for the quantification of joint effusion volume in knee OA patients. Methods MRI examinations consisted of two axial sequences: a T2-weighted true fast imaging with steady-state precession and a T1-weighted gradient echo. An automated joint effusion volume quantification system using MRI was developed and validated (a) with calibrated phantoms (cylinder and sphere) and effusion from knee OA patients; (b) with assessment by manual quantification; and (c) by direct aspiration. Twenty-five knee OA patients with joint effusion were included in the study. Results The automated joint effusion volume quantification was developed as a four stage sequencing process: bone segmentation, filtering of unrelated structures, segmentation of joint effusion, and subvoxel volume calculation. Validation experiments revealed excellent coefficients of variation with the calibrated cylinder (1.4%) and sphere (0.8%) phantoms. Comparison of the OA knee joint effusion volume assessed by the developed automated system and by manual quantification was also excellent (r = 0.98; P < 0.0001), as was the comparison with direct aspiration (r = 0.88; P = 0.0008). Conclusions The newly developed fully automated MRI-based system provided precise quantification of OA knee joint effusion volume with excellent correlation with data from phantoms, a manual system, and joint aspiration. Such an automated system will be instrumental in improving the reproducibility/reliability of the evaluation of this marker in clinical application. PMID:20846392

  18. Morphologic Analysis of the Temporomandibular Joint Between Patients With Facial Asymmetry and Asymptomatic Subjects by 2D and 3D Evaluation

    PubMed Central

    Zhang, Yuan-Li; Song, Jin-Lin; Xu, Xian-Chao; Zheng, Lei-Lei; Wang, Qing-Yuan; Fan, Yu-Bo; Liu, Zhan

    2016-01-01

    Abstract Signs and symptoms of temporomandibular joint (TMJ) dysfunction are commonly found in patients with facial asymmetry. Previous studies on the TMJ position have been limited to 2-dimensional (2D) radiographs, computed tomography (CT), or cone-beam computed tomography (CBCT). The purpose of this study was to compare the differences of TMJ position by using 2D CBCT and 3D model measurement methods. In addition, the differences of TMJ positions between patients with facial asymmetry and asymptomatic subjects were investigated. We prospectively recruited 5 patients (cases, mean age, 24.8 ± 2.9 years) diagnosed with facial asymmetry and 5 asymptomatic subjects (controls, mean age, 26 ± 1.2 years). The TMJ spaces, condylar and ramus angles were assessed by using 2D and 3D methods. The 3D models of mandible, maxilla, and teeth were reconstructed with the 3D image software. The variables in each group were assessed by t-test and the level of significance was 0.05. There was a significant difference in the horizontal condylar angle (HCA), coronal condylar angle (CCA), sagittal ramus angle (SRA), medial joint space (MJS), lateral joint space (LJS), superior joint space (SJS), and anterior joint space (AJS) measured in the 2D CBCT and in the 3D models (P < 0.05). The case group had significantly smaller SJS compared to the controls on both nondeviation side (P = 0.009) and deviation side (P = 0.004). In the case group, the nondeviation SRA was significantly larger than the deviation side (P = 0.009). There was no significant difference in the coronal condylar width (CCW) in either group. In addition, the anterior disc displacement (ADD) was more likely to occur on the deviated side in the case group. In conclusion, the 3D measurement method is more accurate and effective for clinicians to investigate the morphology of TMJ than the 2D method. PMID:27043669

  19. Morphologic Analysis of the Temporomandibular Joint Between Patients With Facial Asymmetry and Asymptomatic Subjects by 2D and 3D Evaluation: A Preliminary Study.

    PubMed

    Zhang, Yuan-Li; Song, Jin-Lin; Xu, Xian-Chao; Zheng, Lei-Lei; Wang, Qing-Yuan; Fan, Yu-Bo; Liu, Zhan

    2016-03-01

    Signs and symptoms of temporomandibular joint (TMJ) dysfunction are commonly found in patients with facial asymmetry. Previous studies on the TMJ position have been limited to 2-dimensional (2D) radiographs, computed tomography (CT), or cone-beam computed tomography (CBCT). The purpose of this study was to compare the differences of TMJ position by using 2D CBCT and 3D model measurement methods. In addition, the differences of TMJ positions between patients with facial asymmetry and asymptomatic subjects were investigated. We prospectively recruited 5 patients (cases, mean age, 24.8 ± 2.9 years) diagnosed with facial asymmetry and 5 asymptomatic subjects (controls, mean age, 26 ± 1.2 years). The TMJ spaces, condylar and ramus angles were assessed by using 2D and 3D methods. The 3D models of mandible, maxilla, and teeth were reconstructed with the 3D image software. The variables in each group were assessed by t-test and the level of significance was 0.05. There was a significant difference in the horizontal condylar angle (HCA), coronal condylar angle (CCA), sagittal ramus angle (SRA), medial joint space (MJS), lateral joint space (LJS), superior joint space (SJS), and anterior joint space (AJS) measured in the 2D CBCT and in the 3D models (P < 0.05). The case group had significantly smaller SJS compared to the controls on both nondeviation side (P = 0.009) and deviation side (P = 0.004). In the case group, the nondeviation SRA was significantly larger than the deviation side (P = 0.009). There was no significant difference in the coronal condylar width (CCW) in either group. In addition, the anterior disc displacement (ADD) was more likely to occur on the deviated side in the case group. In conclusion, the 3D measurement method is more accurate and effective for clinicians to investigate the morphology of TMJ than the 2D method. PMID:27043669

  20. High systemic bone mineral density increases the risk of incident knee OA and joint space narrowing, but not radiographic progression of existing knee OA: The MOST study

    PubMed Central

    Nevitt, Michael C.; Zhang, Yuqing; Javaid, M. Kassim; Neogi, Tuhina; Curtis, Jeffrey R.; Niu, Jingbo; McCulloch, Charles E.; Segal, Neil A.; Felson, David T.

    2010-01-01

    Objectives Previous studies suggest that high systemic bone mineral density (BMD) is associated with incident knee OA defined by osteophytes, but not with joint space narrowing (JSN), and are inconsistent regarding BMD and progression of existing OA. We tested the association of BMD with incident and progressive tibiofemoral OA in a large, prospective study of men and women ages 50–79 with, or at risk for, knee OA. Methods Baseline and 30-month weight-bearing PA and lateral knee x-rays were scored for K–L grade, JSN and osteophytes. Incident OA was defined as the development of K–L grade ≥2 at follow-up. All knees were classified for increases in grade of JSN and osteophytes from baseline. The association of gender-specific quartiles of baseline BMD with risk of incident and progressive OA was analyzed using logistic regression, adjusting for covariates. Results The mean age of 1,754 subjects was 63.2 (SD, 7.8) and BMI 29.9 (SD, 5.4). In knees without baseline OA, higher femoral neck and whole body BMD were associated with an increased risk of incident OA and increases in grade of JSN and osteophytes (p < 0.01 for trends); adjusted odds were 2.3 to 2.9-fold greater in the highest vs. the lowest BMD quartiles. In knees with existing OA, progression was not significantly related to BMD. Conclusions In knees without OA, higher systemic BMD was associated with a greater risk of the onset of JSN and K–L grade ≥2. The role of systemic BMD in early knee OA pathogenesis warrants further investigation. PMID:19147619

  1. Multi-Joint Compensatory Effects of Unilateral Total Knee Arthroplasty During High-Demand Tasks.

    PubMed

    Gaffney, Brecca M; Harris, Michael D; Davidson, Bradley S; Stevens-Lapsley, Jennifer E; Christiansen, Cory L; Shelburne, Kevin B

    2016-08-01

    Patients with total knee arthroplasty (TKA) demonstrate quadriceps weakness and functional limitations 1 year after surgery during daily tasks such as walking and stair climbing. Most biomechanical analyses of patients after TKA focus on quadriceps function and rarely investigate other lower-extremity muscles or high-demand ambulatory activities of daily living. The purpose of this investigation was to quantify lower-extremity muscle forces in patients with unilateral TKA during high-demand tasks of pivoting and descending stairs. Five patients with unilateral TKA and five age and sex-matched controls performed three bilateral high-demand tasks: (1) step down from an 8-inch platform, (2) inside pivot: 90° direction change toward planted limb, and (3) outside pivot: 90° direction change away from planted limb. Subject-specific musculoskeletal simulations were created in OpenSim to determine joint angles, moments, and lower-extremity muscle forces. The results indicate that patients with TKA adopt compensatory strategies at both the hip and knee. Patients with TKA demonstrated increased hip external rotation, decreased knee flexion, decreased quadriceps force, and decreased hip abductor force in all three tasks. These strategies are likely a result of quadriceps avoidance, which may stem from instability after TKA or a habitual strategy developed during the late stages of osteoarthritis.

  2. Biological activity and migration of wear particles in the knee joint: an in vivo comparison of six different polyethylene materials.

    PubMed

    Utzschneider, S; Lorber, V; Dedic, M; Paulus, A C; Schröder, C; Gottschalk, O; Schmitt-Sody, M; Jansson, V

    2014-06-01

    Wear of polyethylene causes loosening of joint prostheses because of the particle mediated activity of the host tissue. It was hypothesized that conventional and crosslinked polyethylene particles lead to similar biological effects around the knee joint in vivo as well as to a similar particle distribution in the surrounding tissues. To verify these hypotheses, particle suspensions of six different polyethylene materials were injected into knee joints of Balb/C mice and intravital microscopic, histological and immunohistochemical evaluations were done after 1 week. Whereas the biological effects on the synovial layer and the subchondral bone of femur and tibia were similar for all the polyethylenes, two crosslinked materials showed an elevated cytokine expression in the articular cartilage. Furthermore, the distribution of particles around the joint was dependent on the injected polyethylene material. Those crosslinked particles, which remained mainly in the joint space, showed an increased expression of TNF-alpha in articular cartilage. The data of this study support the use of crosslinked polyethylene in total knee arthroplasty. In contrast, the presence of certain crosslinked wear particles in the joint space can lead to an elevated inflammatory reaction in the remaining cartilage, which challenges the potential use of those crosslinked polyethylenes for unicondylar knee prostheses.

  3. Effects of soft tissue artifacts on differentiating kinematic differences between natural and replaced knee joints during functional activity.

    PubMed

    Lin, Cheng-Chung; Lu, Tung-Wu; Lu, Hsuan-Lun; Kuo, Mei-Ying; Hsu, Horng-Chaung

    2016-05-01

    Functional performance of total knee replacement (TKR) is often assessed using skin marker-based stereophotogrammetry, which can be affected by soft tissue artifacts (STA). The current study aimed to compare the STA and their effects on the kinematics of the knee between twelve patients with TKR and twelve healthy controls during sit-to-stand, and to assess the effects of STA on the statistical between-group comparisons. Each subject performed the sit-to-stand task while motions of the skin markers and the knees were measured by a motion capture system integrated with a three-dimensional fluoroscopy technique. The bone motions measured by the three-dimensional fluoroscopy were taken as the gold standard, with respect to which the STA of the markers were obtained. The STA were found to affect the calculated segmental poses and knee kinematics between the groups differently. The STA resulted in artefactual posterior displacements of the knee joint center, with magnitudes significantly greater in TKR than controls (p<0.01). The STA-induced knee external rotations in TKR were smaller than those in controls with mean differences of 2.3-3.0°. These between-group differences in the STA effects on knee kinematics in turn concealed the true between-group differences in the anterior-posterior translation and internal/external rotation of knee while leading to false significant between-group differences in the abduction/adduction and proximal-distal translation.

  4. Knee and Hip Joint Kinematics Predict Quadriceps and Hamstrings Neuromuscular Activation Patterns in Drop Jump Landings

    PubMed Central

    Malfait, Bart; Dingenen, Bart; Smeets, Annemie; Staes, Filip; Pataky, Todd; Robinson, Mark A.; Vanrenterghem, Jos; Verschueren, Sabine

    2016-01-01

    Purpose The purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ). Methods Fifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping. Results The peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001). Conclusion This study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an

  5. Pattern of joint damage in persons with knee osteoarthritis and concomitant ACL tears.

    PubMed

    Stein, Verena; Li, Ling; Lo, Grace; Guermazi, Ali; Zhang, Yuqing; Kent Kwoh, C; Eaton, Charles B; Hunter, David J

    2012-05-01

    Anterior cruciate ligament (ACL) tears are known to be a risk factor for incident knee osteoarthritis (OA). At the present time, it is unknown whether an incidental ACL tear in those with established knee OA alters the pattern of synovial joint damage. Therefore, our aim was to assess whether ACL tears in persons with knee OA are associated with specific patterns of cartilage loss, meniscal degeneration, and bone marrow lesion (BML) location. We included 160 participants from the progression subcohort of the Osteoarthritis Initiative (OAI) Study, an ongoing 4-year, multicenter study, focusing on knee OA. Regional cartilage morphometry measures including cartilage volume (mm(3)), denuded area, normalized cartilage volume, bone surface area, as well as location of meniscal pathology and BMLs in index knees on the same side were compared between those with and without ACL tears. Of the 160 subjects (51% women, age 62.1 (±9.9), BMI 30.3 (±4.7) kg/m(2)), 14.4% had an ACL tear. After adjusting for age, BMI and gender participants with ACL tears had significantly greater cartilage volume in the posterior lateral femur (P = 0.04) and the central medial tibia (0.001) compared to those without ACL tears. Normalized cartilage volume was not different between those with and without ACL tears. In addition, individuals with ACL tears had significantly larger bone surface areas in the medial tibia (P = 0,006), the central medial tibia (P = 0.008), the posterior lateral femur (P = 0.004), and the posterior medial femur (P = 0.04). Furthermore, participants with ACL tears showed significantly more meniscal derangement in the lateral posterior horn (P = 0.019) and significantly more BMLs in the lateral femur (P = 0.0025). We found clear evidence of predominant lateral tibiofemoral involvement, with OA-associated findings on MRI, including increased denuded area and bone surface area, BMLs, and meniscal derangement in knees of individuals with ACL tears compared to those without.

  6. The contribution of activated peripheral kappa opioid receptors (kORs) in the inflamed knee joint to anti-nociception.

    PubMed

    Moon, Sun Wook; Park, Eui Ho; Suh, Hye Rim; Ko, Duk Hwan; Kim, Yang In; Han, Hee Chul

    2016-10-01

    The systemic administration of opioids can be used for their strong analgesic effect. However, extensive activation of opioid receptors (ORs) beyond the targeted tissue can cause dysphoria, pruritus, and constipation. Therefore, selective activation of peripheral ORs present in the afferent fibers of the targeted tissue can be considered a superior strategy in opioid analgesia to avoid potential adverse effects. The purpose of this study was to clarify the role of peripheral kappa opioid receptors (kORs) in arthritic pain for the possible use of peripheral ORs as a target in anti-nociceptive therapy. We administered U50488 or nor-BNI/DIPPA, a selective agonist or antagonist of kOR, respectively into arthritic rat knee joints induced using 1% carrageenan. After the injection of U50488 or U50488 with nor-BNI or DIPPA into the inflamed knee joint, we evaluated nociceptive behavior as indicated by reduced weight-bearing on the ipsilateral limbs of the rat and recorded the activity of mechanosensitive afferents (MSA). In the inflamed knee joint, the intra-articular application of 1μM, 10nM, or 0.1nM U50488 resulted in a significant reduction in nociceptive behavior. In addition, 1μM and 10nM U50488 decreased MSA activity. However, in a non-inflamed knee joint, 1μM U50488 had no effect on MSA activity. Additionally, intra-articular pretreatment with 20μM nor-BNI or 10μM DIPPA significantly blocked the inhibitory effects of 1μM U50488 on nociceptive behavior and MSA activity in the inflamed knee joint. These results implicate that peripheral kORs can contribute to anti-nociceptive processing in an inflamed knee joint. PMID:27378583

  7. Altered Knee Joint Mechanics in Simple Compression Associated with Early Cartilage Degeneration

    PubMed Central

    Dabiri, Y.; Li, L. P.

    2013-01-01

    The progression of osteoarthritis can be accompanied by depth-dependent changes in the properties of articular cartilage. The objective of the present study was to determine the subsequent alteration in the fluid pressurization in the human knee using a three-dimensional computer model. Only a small compression in the femur-tibia direction was applied to avoid numerical difficulties. The material model for articular cartilages and menisci included fluid, fibrillar and nonfibrillar matrices as distinct constituents. The knee model consisted of distal femur, femoral cartilage, menisci, tibial cartilage, and proximal tibia. Cartilage degeneration was modeled in the high load-bearing region of the medial condyle of the femur with reduced fibrillar and nonfibrillar elastic properties and increased hydraulic permeability. Three case studies were implemented to simulate (1) the onset of cartilage degeneration from the superficial zone, (2) the progression of cartilage degeneration to the middle zone, and (3) the progression of cartilage degeneration to the deep zone. As compared with a normal knee of the same compression, reduced fluid pressurization was observed in the degenerated knee. Furthermore, faster reduction in fluid pressure was observed with the onset of cartilage degeneration in the superficial zone and progression to the middle zone, as compared to progression to the deep zone. On the other hand, cartilage degeneration in any zone would reduce the fluid pressure in all three zones. The shear strains at the cartilage-bone interface were increased when cartilage degeneration was eventually advanced to the deep zone. The present study revealed, at the joint level, altered fluid pressurization and strains with the depth-wise cartilage degeneration. The results also indicated redistribution of stresses within the tissue and relocation of the loading between the tissue matrix and fluid pressure. These results may only be qualitatively interesting due to the small

  8. A comprehensive joint replacement program for total knee arthroplasty: a descriptive study

    PubMed Central

    Cook, Jon R; Warren, Meghan; Ganley, Kathleen J; Prefontaine, Paul; Wylie, Jack W

    2008-01-01

    Background Total knee arthroplasty (TKA) is a commonly performed surgical procedure in the US. It is important to have a comprehensive inpatient TKA program which maximizes outcomes while minimizing adverse events. The purpose of this study was to describe a TKA program – the Joint Replacement Program (JRP) – and report post-surgical outcomes. Methods 74 candidates for a primary TKA were enrolled in the JRP. The JRP was designed to minimize complications and optimize patient-centered outcomes using a team approach including the patient, patient's family, and a multidisciplinary team of health professionals. The JRP consisted of a pre-operative class, standard pathways for medical care, comprehensive peri-operative pain management, aggressive physical therapy (PT), and proactive discharge planning. Measures included functional tests, knee range of motion (ROM), and medical record abstraction of patient demographics, length of stay, discharge disposition, and complications over a 6-month follow-up period. Results All patients achieved medical criteria for hospital discharge. The patients achieved the knee flexion ROM goal of 90° (91.7 ± 5.4°), but did not achieve the knee extension ROM goal of 0° (2.4 ± 2.6°). The length of hospital stay was two days for 53% of the patients, with 39% and 7% discharged in three and four days, respectively. All but three patients were discharged home with functional independence. 68% of these received outpatient physical therapy compared with 32% who received home physical therapy immediately after discharge. Two patients (< 3%) had medical complications during the inpatient hospital stay, and 9 patients (12%) had complications during the 6-month follow-up period. Conclusion The comprehensive JRP for TKA was associated with satisfactory clinical outcomes, short lengths of stay, a high percentage of patients discharged home with outpatient PT, and minimal complications. This JRP may represent an efficient, effective and safe

  9. Non-invasive, non-radiological quantification of anteroposterior knee joint ligamentous laxity

    PubMed Central

    Russell, D. F.; Deakin, A. H.; Fogg, Q. A.; Picard, F.

    2013-01-01

    Objectives We performed in vitro validation of a non-invasive skin-mounted system that could allow quantification of anteroposterior (AP) laxity in the outpatient setting. Methods A total of 12 cadaveric lower limbs were tested with a commercial image-free navigation system using trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° of knee flexion and 100 N of force was applied perpendicular to the tibia. Acceptable coefficient of repeatability (CR) and limits of agreement (LOA) of 3 mm were set based on diagnostic criteria for anterior cruciate ligament (ACL) insufficiency. Results Reliability and precision within the individual invasive and non-invasive systems was acceptable throughout the range of flexion tested (intra-class correlation coefficient 0.88, CR 1.6 mm). Agreement between the two systems was acceptable measuring AP laxity between full extension and 40° knee flexion (LOA 2.9 mm). Beyond 40° of flexion, agreement between the systems was unacceptable (LOA > 3 mm). Conclusions These results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard validated commercial system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative evaluation of ACL pathology. Cite this article: Bone Joint Res 2013;2:233–7. PMID:24184443

  10. Environmental disruption of circadian rhythm predisposes mice to osteoarthritis-like changes in knee joint.

    PubMed

    Kc, Ranjan; Li, Xin; Voigt, Robin M; Ellman, Michael B; Summa, Keith C; Vitaterna, Martha Hotz; Keshavarizian, Ali; Turek, Fred W; Meng, Qing-Jun; Stein, Gary S; van Wijnen, Andre J; Chen, Di; Forsyth, Christopher B; Im, Hee-Jeong

    2015-09-01

    Circadian rhythm dysfunction is linked to many diseases, yet pathophysiological roles in articular cartilage homeostasis and degenerative joint disease including osteoarthritis (OA) remains to be investigated in vivo. Here, we tested whether environmental or genetic disruption of circadian homeostasis predisposes to OA-like pathological changes. Male mice were examined for circadian locomotor activity upon changes in the light:dark (LD) cycle or genetic disruption of circadian rhythms. Wild-type (WT) mice were maintained on a constant 12 h:12 h LD cycle (12:12 LD) or exposed to weekly 12 h phase shifts. Alternatively, male circadian mutant mice (Clock(Δ19) or Csnk1e(tau) mutants) were compared with age-matched WT littermates that were maintained on a constant 12:12 LD cycle. Disruption of circadian rhythms promoted osteoarthritic changes by suppressing proteoglycan accumulation, upregulating matrix-degrading enzymes and downregulating anabolic mediators in the mouse knee joint. Mechanistically, these effects involved activation of the PKCδ-ERK-RUNX2/NFκB and β-catenin signaling pathways, stimulation of MMP-13 and ADAMTS-5, as well as suppression of the anabolic mediators SOX9 and TIMP-3 in articular chondrocytes of phase-shifted mice. Genetic disruption of circadian homeostasis does not predispose to OA-like pathological changes in joints. Our results, for the first time, provide compelling in vivo evidence that environmental disruption of circadian rhythms is a risk factor for the development of OA-like pathological changes in the mouse knee joint.

  11. Shod landing provides enhanced energy dissipation at the knee joint relative to barefoot landing from different heights.

    PubMed

    Yeow, C H; Lee, P V S; Goh, J C H

    2011-12-01

    Athletic shoes can directly provide shock absorption at the foot due to its cushioning properties, however it remains unclear how these shoes may affect the level of energy dissipation contributed by the knee joint. This study sought to investigate biomechanical differences, in terms of knee kinematics, kinetics and energetics, between barefoot and shod landing from different heights. Twelve healthy male recreational athletes were recruited and instructed to perform double-leg landing from 0.3-m and 0.6-m heights in barefoot and shod conditions. The shoe model tested was Brooks Maximus II. Markers were placed on the subjects based on the Plug-in Gait Marker Set. Force-plates and motion-capture system were used to capture ground reaction force (GRF) and kinematics data respectively. 2×2-ANOVA (barefoot/shod condition×landing height) was performed to examine differences in knee kinematics, kinetics and energetics between barefoot and shod conditions from different landing heights. Peak GRF was not significantly different (p=0.732-0.824) between barefoot and shod conditions for both landing heights. Knee range-of-motion, flexion angular velocity, external knee flexion moment, and joint power and work were higher during shod landing (p<0.001 to p=0.007), compared to barefoot landing for both landing heights. No significant interactions (p=0.073-0.933) were found between landing height and barefoot/shod condition for the tested parameters. While the increase in landing height can elevate knee energetics independent of barefoot/shod conditions, we have also shown that the shod condition was able to augment the level of energy dissipation contributed by the knee joint, via the knee extensors, regardless of the tested landing heights.

  12. Changes in Joint Gap Balances between Intra- and Postoperation in Total Knee Arthroplasty.

    PubMed

    Nakajima, Arata; Aoki, Yasuchika; Murakami, Masazumi; Nakagawa, Koichi

    2014-01-01

    Achieving correct soft tissue balance and preparing equal and rectangular extension and flexion joint gaps are crucial goals of TKA. Intraoperative gap balances would change postoperatively; however, changes in joint gap balances between pre- and postoperation remain unclear. To explore these changes associated with TKA, we prospectively investigated 21 posterior cruciate ligament retaining TKAs for varus knees. Intraoperative extension gap balance (iEGB) was 2.6 ± 2.0° varus versus postoperative extension gap balance (pEGB) of 0.77 ± 1.8° valgus (P < 0.01), while no significant difference between intraoperative flexion gap balance (iFGB) and postoperative flexion gap balance (pFGB) was observed. We also explored correlations between intraoperative and postoperative gap balances but found no significant correlations. These observations indicate that (i) surgeons should avoid excessive release of the medial soft tissue during TKA for varus knees and (ii) intraoperative gap balance may not be necessarily reflected on postoperative gap balance.

  13. Knee joint vibration signal analysis with matching pursuit decomposition and dynamic weighted classifier fusion.

    PubMed

    Cai, Suxian; Yang, Shanshan; Zheng, Fang; Lu, Meng; Wu, Yunfeng; Krishnan, Sridhar

    2013-01-01

    Analysis of knee joint vibration (VAG) signals can provide quantitative indices for detection of knee joint pathology at an early stage. In addition to the statistical features developed in the related previous studies, we extracted two separable features, that is, the number of atoms derived from the wavelet matching pursuit decomposition and the number of significant signal turns detected with the fixed threshold in the time domain. To perform a better classification over the data set of 89 VAG signals, we applied a novel classifier fusion system based on the dynamic weighted fusion (DWF) method to ameliorate the classification performance. For comparison, a single leastsquares support vector machine (LS-SVM) and the Bagging ensemble were used for the classification task as well. The results in terms of overall accuracy in percentage and area under the receiver operating characteristic curve obtained with the DWF-based classifier fusion method reached 88.76% and 0.9515, respectively, which demonstrated the effectiveness and superiority of the DWF method with two distinct features for the VAG signal analysis.

  14. EMG profiles of knee joint musculature during walking: changes induced by anterior cruciate ligament deficiency.

    PubMed

    Limbird, T J; Shiavi, R; Frazer, M; Borra, H

    1988-01-01

    A tear of the anterior cruciate ligament (ACL) disrupts the delicate balance of static stabilizers of the knee, leading to significant alterations in joint kinematics. Little is known about the dynamic compensatory responses of the patient to these kinematic alterations. This lack of quantitative information on the muscle synergy patterns has limited the surgeon's ability to evaluate various operative and rehabilitative techniques. Twelve subjects with documented ACL deficiency for at least 1 year and 15 normal participants were studied. Each subject was asked to walk at free and fast speeds on a 12 m walkway. The right and left foot contact patterns and the linear envelopes from the surface electromyogram (EMG) patterns of the gastrocnemius, medial and lateral hamstrings, rectus femoris, and vastus lateralis were measured. Significant differences were found in the muscle synergy patterns during walking. During the swing-to-stance transition, the ACL-deficient subjects showed significantly less activity in the quadriceps and gastrocnemius muscles and more activity in the biceps femoris than in the normal group. During early swing, the vastus lateralis is more active than normal, and during midstance and terminal stance, the hamstrings appear to be less active than normal subjects. These dynamic compensatory mechanisms suggest that use of the hamstring tendons in reconstructive procedures may alter important compensatory mechanisms about the knee joint. Application of dynamic EMG techniques to the study of reconstructive procedures should provide additional information that will assist the clinician in the rational choice of a surgical procedure.

  15. Knee Joint Vibration Signal Analysis with Matching Pursuit Decomposition and Dynamic Weighted Classifier Fusion

    PubMed Central

    Cai, Suxian; Yang, Shanshan; Zheng, Fang; Lu, Meng; Wu, Yunfeng; Krishnan, Sridhar

    2013-01-01

    Analysis of knee joint vibration (VAG) signals can provide quantitative indices for detection of knee joint pathology at an early stage. In addition to the statistical features developed in the related previous studies, we extracted two separable features, that is, the number of atoms derived from the wavelet matching pursuit decomposition and the number of significant signal turns detected with the fixed threshold in the time domain. To perform a better classification over the data set of 89 VAG signals, we applied a novel classifier fusion system based on the dynamic weighted fusion (DWF) method to ameliorate the classification performance. For comparison, a single leastsquares support vector machine (LS-SVM) and the Bagging ensemble were used for the classification task as well. The results in terms of overall accuracy in percentage and area under the receiver operating characteristic curve obtained with the DWF-based classifier fusion method reached 88.76% and 0.9515, respectively, which demonstrated the effectiveness and superiority of the DWF method with two distinct features for the VAG signal analysis. PMID:23573175

  16. Sodium inversion recovery MRI on the knee joint at 7 T with an optimal control pulse

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Seung; Xia, Ding; Madelin, Guillaume; Regatte, Ravinder R.

    2016-01-01

    In the field of sodium magnetic resonance imaging (MRI), inversion recovery (IR) is a convenient and popular method to select sodium in different environments. For the knee joint, IR has been used to suppress the signal from synovial fluids, which improves the correlation between the sodium signal and the concentration of glycosaminoglycans (GAGs) in cartilage tissues. For the better inversion of the magnetization vector under the spatial variations of the B0 and B1 fields, the IR sequence usually employ adiabatic pulses as the inversion pulse. On the other hand, it has been shown that RF shapes robust against the variations of the B0 and B1 fields can be generated by numerical optimization based on optimal control theory. In this work, we compare the performance of fluid-suppressed sodium MRI on the knee joint in vivo, between one implemented with an adiabatic pulse in the IR sequence and the other with the adiabatic pulse replaced by an optimal-control shaped pulse. While the optimal-control pulse reduces the RF power deposited to the body by 58%, the quality of fluid suppression and the signal level of sodium within cartilage are similar between two implementations.

  17. Computational wear prediction of artificial knee joints based on a new wear law and formulation.

    PubMed

    Abdelgaied, Abdellatif; Liu, Feng; Brockett, Claire; Jennings, Louise; Fisher, John; Jin, Zhongmin

    2011-04-01

    Laboratory joint wear simulator testing has become the standard means for preclinical evaluation of wear resistance of artificial knee joints. Recent simulator designs have been advanced and become successful at reproducing the wear patterns observed in clinical retrievals. However, a single simulator test can be very expensive and take a long time to run. On the other hand computational wear modelling is an alternative attractive solution to these limitations. Computational models have been used extensively for wear prediction and optimisation of artificial knee designs. However, all these models have adopted the classical Archard's wear law, which was developed for metallic materials, and have selected wear factors arbitrarily. It is known that such an approach is not generally true for polymeric bearing materials and is difficult to implement due to the high dependence of the wear factor on the contact pressure. Therefore, these studies are generally not independent and lack general predictability. The objective of the present study was to develop a new computational wear model for the knee implants, based on the contact area and an independent experimentally determined non-dimensional wear coefficient. The effects of cross-shear and creep on wear predictions were also considered. The predicted wear volume was compared with the laboratory simulation measurements. The model was run under two different kinematic inputs and two different insert designs with curved and custom designed flat bearing surfaces. The new wear model was shown to be capable of predicting the difference of the wear volume and wear pattern between the two kinematic inputs and the two tibial insert designs. Conversely, the wear factor based approach did not predict such differences. The good agreement found between the computational and experimental results, on both the wear scar areas and volumetric wear rates, suggests that the computational wear modelling based on the new wear law and the

  18. Spontaneous Recurrent Hemarthrosis of the