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OBJECTIVE: Many adolescents suffer from depressive and anxiety disorders simultaneously and current treatment methods do not put enough emphasis on comorbidity of these disorders. The unified protocol for treating emotional disorders in adolescents is a transdiagnostic therapy which targets mutual fundamental factors. Therefore, the current study aims to compare the effectiveness of the unified protocol alone with the unified protocol combined with mindfulness as an additional treatment in adolescents suffering from emotional disorders. METHOD: A quasi-experimental study was conducted with adolescents. The participants had been diagnosed with emotional disorders and were divided into a control group (15 participants) and an experimental group (16 participants). Both groups were offered 14 sessions of therapy. They were assessed at pre-test, post-test, and two-month follow-up. Scales used in the study included the Child Behavior Checklist (CBCL), the Children's Depression Inventory (CDI), and the Youth Anxiety Measure for DSM-5 (YAM-5). RESULTS: The results showed that both of the treatment methods effectively reduced adolescents' emotional problems, but improvements were more significant in the group administered the additional mindfulness program. Among the variables assessed, non-phobic anxiety disorders and depression improved more than specific phobia and behavioral problems. Between-subjects (Group) partial etas for non-phobic anxiety, depression, specific phobia, and behavioral problems were 0.67, 0.50, 0.23, and 0.16, respectively. CONCLUSION: According to the findings of this study, additional treatment methods such as mindfulness could increase the effectiveness of the unified transdiagnostic protocol for adolescents (UP-A). The therapeutic implications are discussed.
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Atención Plena , Adolescente , Ansiedad , Trastornos de Ansiedad/terapia , Niño , Humanos , Trastornos del Humor , Resultado del TratamientoRESUMEN
Abstract Objective Many adolescents suffer from depressive and anxiety disorders simultaneously and current treatment methods do not put enough emphasis on comorbidity of these disorders. The unified protocol for treating emotional disorders in adolescents is a transdiagnostic therapy which targets mutual fundamental factors. Therefore, the current study aims to compare the effectiveness of the unified protocol alone with the unified protocol combined with mindfulness as an additional treatment in adolescents suffering from emotional disorders. Method A quasi-experimental study was conducted with adolescents. The participants had been diagnosed with emotional disorders and were divided into a control group (15 participants) and an experimental group (16 participants). Both groups were offered 14 sessions of therapy. They were assessed at pre-test, post-test, and two-month follow-up. Scales used in the study included the Child Behavior Checklist (CBCL), the Children's Depression Inventory (CDI), and the Youth Anxiety Measure for DSM-5 (YAM-5). Results The results showed that both of the treatment methods effectively reduced adolescents' emotional problems, but improvements were more significant in the group administered the additional mindfulness program. Among the variables assessed, non-phobic anxiety disorders and depression improved more than specific phobia and behavioral problems. Between-subjects (Group) partial etas for non-phobic anxiety, depression, specific phobia, and behavioral problems were 0.67, 0.50, 0.23, and 0.16, respectively. Conclusion According to the findings of this study, additional treatment methods such as mindfulness could increase the effectiveness of the unified transdiagnostic protocol for adolescents (UP-A). The therapeutic implications are discussed.
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Adolescente , Niño , Humanos , Atención Plena , Ansiedad , Trastornos de Ansiedad/terapia , Resultado del Tratamiento , Trastornos del HumorRESUMEN
OBJECTIVE: Acceptance and commitment therapy has been used to treat anxiety disorders recently. The purpose of this study was to investigate the effectiveness of acceptance and commitment therapy for psychological symptoms in students with social anxiety disorder, including difficulty in emotion regulation, psychological flexibility based on experiential avoidance, self-compassion, and external shame. METHODS: This study was a semi-experimental clinical trial. Twenty four students with social anxiety disorder were randomly divided into two groups after initial evaluations: an experimental group (12 subjects) and a control group (12 subjects). The experimental group received 12 treatment sessions based on a protocol of acceptance and commitment therapy for anxiety disorders, and the control group was put on a waiting list. Self-Compassion (SCS), Difficulty in Emotion Regulation (DERS), External Shame (ESS), Social Anxiety (SPIN), and Acceptance and Action (AAQ-II) questionnaires were used to assess participants. Data were analyzed using SPSS. RESULTS: Acceptance and commitment therapy was shown to be effective at the post-test and follow up stages for reducing external shame, social anxiety, and difficulty in emotion regulation and its components, and for increasing psychological flexibility and self-compassion (p < 0.05). The largest effect size of treatment was for increase of psychological flexibility and the lowest efficacy was for the components "difficulty in impulse control" and "limited access to emotional strategies" at the post-test and follow-up stages, respectively. CONCLUSION: Acceptance and commitment therapy may be an appropriate psychological intervention for reducing the symptoms of students with social anxiety disorder and helping them to improve psychological flexibility. Emotion and related problems can be identified as one of the main targets of this treatment. CLINICAL TRIAL REGISTRATION: Iranian Registry of Clinical Trials, IRCT20180421039369N1.
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Terapia de Aceptación y Compromiso , Adaptación Psicológica , Regulación Emocional , Evaluación de Resultado en la Atención de Salud , Fobia Social/terapia , Adulto , Femenino , Humanos , Irán , Masculino , Estudiantes , Universidades , Adulto JovenRESUMEN
Abstract Objective Acceptance and commitment therapy has been used to treat anxiety disorders recently. The purpose of this study was to investigate the effectiveness of acceptance and commitment therapy for psychological symptoms in students with social anxiety disorder, including difficulty in emotion regulation, psychological flexibility based on experiential avoidance, self-compassion, and external shame. Methods This study was a semi-experimental clinical trial. Twenty four students with social anxiety disorder were randomly divided into two groups after initial evaluations: an experimental group (12 subjects) and a control group (12 subjects). The experimental group received 12 treatment sessions based on a protocol of acceptance and commitment therapy for anxiety disorders, and the control group was put on a waiting list. Self-Compassion (SCS), Difficulty in Emotion Regulation (DERS), External Shame (ESS), Social Anxiety (SPIN), and Acceptance and Action (AAQ-II) questionnaires were used to assess participants. Data were analyzed using SPSS. Results Acceptance and commitment therapy was shown to be effective at the post-test and follow up stages for reducing external shame, social anxiety, and difficulty in emotion regulation and its components, and for increasing psychological flexibility and self-compassion (p < 0.05). The largest effect size of treatment was for increase of psychological flexibility and the lowest efficacy was for the components "difficulty in impulse control" and "limited access to emotional strategies" at the post-test and follow-up stages, respectively. Conclusion Acceptance and commitment therapy may be an appropriate psychological intervention for reducing the symptoms of students with social anxiety disorder and helping them to improve psychological flexibility. Emotion and related problems can be identified as one of the main targets of this treatment. Clinical trial registration: Iranian Registry of Clinical Trials, IRCT20180421039369N1.
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Adulto , Femenino , Humanos , Masculino , Adulto Joven , Adaptación Psicológica , Evaluación de Resultado en la Atención de Salud , Terapia de Aceptación y Compromiso , Fobia Social/terapia , Regulación Emocional , Estudiantes , Universidades , IránRESUMEN
The authors report a unique recurrent septated cystic hygroma (CH), on two successive pregnancies, at five years interval. The chromosome analysis of the first fetus showed an increase in length of heterochromatin on the long arm of chromosome 1 - 1qh+, a chromosomal polymorphism inherited from mother, 46XX,1qh+,14ps+,21ps+. The karyotype of the second CH, with more severe ultrasound (US) imaging, showed a 69XXX triploidy. The patient took no risk and underwent each time a termination of pregnancy (TOP). The first karyotype is generally considered "normal", although there are few reports linking 1qh+ with low fertility, but this was not the case, the patient having, from a previous marriage, a healthy boy and two TOPs. So, this "particular", but "healthy" karyotype was not a cause for the first CH. The second karyotype highlights a possible causality between the 69XXX triploidy, usually associated with partial hydatidiform mole, and a more severe septated CH in the last fetus. Neither the CHs' appearance nor their recurrence seemed to be family linked, as the two CHs had distinct genetic profiles. We recommend that, once CH is diagnosed, a careful US examination is compulsory for the determination of subcutaneous edema, ascites, pleural and pericardial effusions and cardiac or renal abnormalities; an early genetic work-up is mandatory, by chorionic villus sampling or amniocentesis. However, a "healthy" karyotype does not exclude a severe form, as in our first case of CH. Due to the very poor outcome of fetuses with CH, the patient must be thoroughly informed about the short and the long-term fetal prognosis.
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Linfangioma Quístico , Cromosomas Humanos Par 1 , Femenino , Feto , Humanos , Hidropesía Fetal , Linfangioma Quístico/genética , Masculino , Embarazo , Triploidía , Ultrasonografía PrenatalRESUMEN
BACKGROUND: Sacroiliac screw fixation in elderly patients with pelvic fractures is prone to failure owing to impaired bone quality. Cement augmentation has been proposed as a possible solution, because in other anatomic areas this has been shown to reduce screw loosening. However, to our knowledge, this has not been evaluated for sacroiliac screws. QUESTIONS/PURPOSES: We investigated the potential biomechanical benefit of cement augmentation of sacroiliac screw fixation in a cadaver model of osteoporotic bone, specifically with respect to screw loosening, construct survival, and fracture-site motion. METHODS: Standardized complete sacral ala fractures with intact posterior ligaments in combination with ipsilateral upper and lower pubic rami fractures were created in osteoporotic cadaver pelves and stabilized by three fixation techniques: sacroiliac (n = 5) with sacroiliac screws in S1 and S2, cemented (n = 5) with addition of cement augmentation, and transsacral (n = 5) with a single transsacral screw in S1. A cyclic loading protocol was applied with torque (1.5 Nm) and increasing axial force (250-750 N). Screw loosening, construct survival, and sacral fracture-site motion were measured by optoelectric motion tracking. A sample-size calculation revealed five samples per group to be required to achieve a power of 0.80 to detect 50% reduction in screw loosening. RESULTS: Screw motion in relation to the sacrum during loading with 250 N/1.5 Nm was not different among the three groups (sacroiliac: 1.2 mm, range, 0.6-1.9; cemented: 0.7 mm, range, 0.5-1.3; transsacral: 1.1 mm, range, 0.6-2.3) (p = 0.940). Screw subsidence was less in the cemented group (3.0 mm, range, 1.2-3.7) compared with the sacroiliac (5.7 mm, range, 4.7-10.4) or transsacral group (5.6 mm, range, 3.8-10.5) (p = 0.031). There was no difference with the numbers available in the median number of cycles needed until failure; this was 2921 cycles (range, 2586-5450) in the cemented group, 2570 cycles (range, 2500-5107) for the sacroiliac specimens, and 2578 cycles (range, 2540-2623) in the transsacral group (p = 0.153). The cemented group absorbed more energy before failure (8.2 × 105 N*cycles; range, 6.6 × 105-22.6 × 105) compared with the transsacral group (6.5 × 105 N*cycles; range, 6.4 × 105-6.7 × 105) (p = 0.016). There was no difference with the numbers available in terms of fracture site motion (sacroiliac: 2.9 mm, range, 0.7-5.4; cemented: 1.2 mm, range, 0.6-1.9; transsacral: 2.1 mm, range, 1.2-4.8). Probability values for all between-group comparisons were greater than 0.05. CONCLUSIONS: The addition of cement to standard sacroiliac screw fixation seemed to change the mode and dynamics of failure in this cadaveric mechanical model. Although no advantages to cement were observed in terms of screw motion or cycles to failure among the different constructs, a cemented, two-screw sacroiliac screw construct resulted in less screw subsidence and greater energy absorbed to failure than an uncemented single transsacral screw. CLINICAL RELEVANCE: In osteoporotic bone, the addition of cement to sacroiliac screw fixation might improve screw anchorage. However, larger mechanical studies using these findings as pilot data should be performed before applying these preliminary findings clinically.
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Cementos para Huesos , Tornillos Óseos , Fijación Interna de Fracturas/instrumentación , Ilion/cirugía , Fracturas Osteoporóticas/cirugía , Hueso Púbico/cirugía , Sacro/cirugía , Fracturas de la Columna Vertebral/cirugía , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Cadáver , Fijación Interna de Fracturas/efectos adversos , Humanos , Ilion/fisiopatología , Fracturas Osteoporóticas/diagnóstico por imagen , Fracturas Osteoporóticas/fisiopatología , Diseño de Prótesis , Falla de Prótesis , Hueso Púbico/diagnóstico por imagen , Hueso Púbico/lesiones , Hueso Púbico/fisiopatología , Sacro/diagnóstico por imagen , Sacro/lesiones , Sacro/fisiopatología , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/fisiopatología , Estrés Mecánico , TorqueRESUMEN
Concerns have been raised about the adverse impact of dusty air pollution (DAP) on human health. The aim of this study was to find the association between dusty air pollution based on air quality index (AQI) and the risk of allergic diseases in southwestern provinces of Iran, with assessing cytokine profiles and lymphocyte immunophenotypes.In this case control study 148 individuals participated. The sampling was done in hazardous condition (AQI>300) as the case and clean air (AQI<50) as the control. We measured cytokine production by using ELISA method and phenotypes of T-lymphocytes (CD4+ and CD8+), CD19+ B-lymphocytes, CD25+, CD4+ CD25+ cells by FACSort flow cytometer.The mean serum level of IL-4 (33.4 ± 2.9 vs 0.85 ± 0.65 pg/dl) and IL-13 (15.1 ± 4.4 vs. 0.12 ± 0.7 pg/dl) in the subjects exposed to ambient DAP was increased significantly compared to the individuals in the clean air condition. Also, CD19+ B-lymphocytes (12.6 ± 4.9 vs 8.9 ± 3.2%) and CD4+ CD25+ cell count (13.6 ± 4.6 vs 7.7 ± 3.8%) in peripheral blood were increased significantly in subjects exposed to ambient DAP compared with the controls.The result of our study suggested that ambient DAP affected immune system in a way that might lead to allergic diseases in the population.
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Contaminación del Aire/efectos adversos , Polvo , Hipersensibilidad/etiología , Adulto , Citocinas/sangre , Femenino , Humanos , Inmunofenotipificación , Irán , Recuento de Linfocitos , Masculino , RiesgoRESUMEN
BACKGROUND: Accurate comparison of outcomes regarding various surgical options in knee arthroplasty can benefit from an improved method for joint line analysis that takes into account the preoperative joint space. METHODS: This article describes a new preoperative-based registration method that measures changes in the joint line by overlaying the 3D models of the bones with implants using preoperative CT along with preoperative and postoperative biplanar radiography. The method was tested on six cadaveric specimens for measuring alteration to the medial and lateral joint lines in extension and flexion. RESULTS: The joint line shift, when measured using the new method, was in the range of -0.2 to 1.3 mm on average (SD=1.3 to 3.8 mm, for medial and lateral, in flexion and extension positions). This was significantly different (p≤0.01) from the results of a previous postoperative-based registration method which did not account for the cartilage thickness in calculating alterations of the joint line (mean=3.9 to 6.8mm, SD=1.2 to 4.3 mm). CONCLUSION: These results further highlight the importance of considering the preoperative joint space in analyzing the joint line, and demonstrate the utility of the newly introduced method for accurate assessment of changes in the joint line after arthroplasty. CLINICAL RELEVANCE: The introduced method provides accurate means for investigating joint line alterations in relation to different surgical techniques and the subsequent biomechanical effects after knee arthroplasty.
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Artroplastia de Reemplazo de Rodilla , Imagenología Tridimensional , Articulación de la Rodilla/diagnóstico por imagen , Prótesis de la Rodilla , Cadáver , Fémur/diagnóstico por imagen , Fémur/cirugía , Humanos , Procesamiento de Imagen Asistido por Computador , Articulación de la Rodilla/cirugía , Periodo Posoperatorio , Periodo Preoperatorio , Ajuste de Prótesis , Programas Informáticos , Tibia/diagnóstico por imagen , Tibia/cirugía , Tomografía Computarizada por Rayos XRESUMEN
PURPOSE: C-arm fluoroscopy is frequently used in clinical applications as a low-cost and mobile real-time qualitative assessment tool. C-arms, however, are not widely accepted for applications involving quantitative assessments, mainly due to the lack of reliable and low-cost position tracking methods, as well as adequate calibration and registration techniques. The solution suggested in this work is a tracked C-arm (TC-arm) which employs a low-cost sensor tracking module that can be retrofitted to any conventional C-arm for tracking the individual joints of the device. METHODS: Registration and offline calibration methods were developed that allow accurate tracking of the gantry and determination of the exact intrinsic and extrinsic parameters of the imaging system for any acquired fluoroscopic image. The performance of the system was evaluated in comparison to an Optotrak[Formula: see text] motion tracking system and by a series of experiments on accurately built ball-bearing phantoms. Accuracies of the system were determined for 2D-3D registration, three-dimensional landmark localization, and for generating panoramic stitched views in simulated intraoperative applications. RESULTS: The system was able to track the center point of the gantry with an accuracy of [Formula: see text] mm or better. Accuracies of 2D-3D registrations were [Formula: see text] mm and [Formula: see text]. Three-dimensional landmark localization had an accuracy of [Formula: see text] of the length (or [Formula: see text] mm) on average, depending on whether the landmarks were located along, above, or across the table. The overall accuracies of the two-dimensional measurements conducted on stitched panoramic images of the femur and lumbar spine were 2.5 [Formula: see text] 2.0 % [Formula: see text] and [Formula: see text], respectively. CONCLUSION: The TC-arm system has the potential to achieve sophisticated quantitative fluoroscopy assessment capabilities using an existing C-arm imaging system. This technology may be useful to improve the quality of orthopedic surgery and interventional radiology.
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Fluoroscopía/instrumentación , Imagenología Tridimensional/instrumentación , Cirugía Asistida por Computador/instrumentación , Calibración , Humanos , Imagenología Tridimensional/métodos , Vértebras Lumbares , Fantasmas de Imagen , Cirugía Asistida por Computador/métodosRESUMEN
An intraoperative imaging tool for total knee arthroplasty could help avoid poor clinical outcomes related to malalignment. We investigated the feasibility of using isocentric (ISO-C) fluoroscopic imaging for this purpose. Three-dimensional ISO-C and computed tomographic (CT) images were acquired from 6 cadaveric specimens implanted with standard knee arthroplasty components and analyzed to determine rotational alignments. In comparison with standard CT measures, the ISO-C-based measures had overall accuracies (determined as root mean square error) of 0.8° and 1.3° and corresponding SDs of 1.3° and 1.4° for the femoral and tibial components, respectively. With ISO-C imaging, it is possible to measure rotational alignment in knee arthroplasty with accuracy and repeatability comparable with CT. Isocentric imaging has strong potential as an intraoperative tool to accurately align arthroplasty components.
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Artroplastia de Reemplazo de Rodilla/métodos , Articulación de la Rodilla/diagnóstico por imagen , Prótesis de la Rodilla , Cirugía Asistida por Computador , Cadáver , Estudios de Factibilidad , Fémur/diagnóstico por imagen , Fluoroscopía , Humanos , Imagenología Tridimensional , Rotación , Tibia/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
Bicruciate retaining knee arthroplasty, although has shown improved functions and patient satisfaction compared to other designs of total knee replacement, remains a technically demanding option for treating severe cases of arthritic knees. One of the main challenges in bicruciate retaining arthroplasty is proper balancing of the soft tissue during the surgery. In this study biomechanics of soft tissue balancing was investigated using a validated computational model of the knee joint with high fidelity definitions of the soft tissue structures along with a Taguchi method for design of experiments. The model was used to simulate intraoperative balancing of soft tissue structures following the combinations suggested by an orthogonal array design. The results were used to quantify the corresponding effects on the laxity of the joint under anterior-posterior, internal-external, and varus-valgus loads. These effects were ranked for each ligament bundle to identify the components of laxity which were most sensitive to the corresponding surgical modifications. The resulting map of sensitivity for all the ligament bundles determined the components of laxity most suitable for examination during intraoperative balancing of the soft tissue. Ultimately, a sequence for intraoperative soft tissue balancing was suggested for a bicruciate retaining knee arthroplasty.
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Artritis/diagnóstico , Artroplastia de Reemplazo de Rodilla/métodos , Articulación de la Rodilla/cirugía , Artritis/fisiopatología , Fenómenos Biomecánicos , Simulación por Computador , Fémur/fisiopatología , Humanos , Inestabilidad de la Articulación/cirugía , Articulación de la Rodilla/fisiopatología , Ligamentos/fisiopatología , Modelos Teóricos , Diseño de Prótesis/métodos , Rango del Movimiento Articular , Tibia/fisiopatologíaRESUMEN
Correct orientation of the acetabular cup considering patient-specific functional pelvic angles is an important factor for improving outcomes and avoiding complications after total hip arthroplasty. This study introduces a new, noninvasive radiographic tool for accurately determining a patient's specific pelvic tilt angle preoperatively, as well as accurately assessing acetabular cup orientation with respect to bony landmarks intraoperatively and postoperatively. The method was validated by imaging a bone replica model of the pelvis with implanted hip components, in comparison to digitized references, and verified with a cadaveric specimen. Pelvic tilt was measured with an accuracy of 0.1 deg and SD of 0.4 deg. Operative cup inclination and anteversion showed accuracies of 0.6 deg and 2.5 deg, with SD of 0.4 deg and 0.6 deg, respectively; these could be improved further by subtracting systematic bias. The method shows accuracy advantages over existing radiographic and fluoroscopic methods and exposes the subjects to a lower radiation dose compared to the similar computed tomography methods. These results suggest that the proposed method is feasible for assessing cup placement with reference to the functional and anatomical references. Furthermore, the ability to reference the same bony landmarks preoperatively, intraoperatively, and postoperatively has important research and clinical advantages.
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Acetábulo/anatomía & histología , Acetábulo/diagnóstico por imagen , Artroplastia de Reemplazo de Cadera , Radiografía/métodos , Acetábulo/cirugía , Estudios de Factibilidad , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Periodo Intraoperatorio , Persona de Mediana Edad , Periodo Posoperatorio , Dosis de Radiación , Radiografía/instrumentaciónRESUMEN
Fluoroscopic imaging is commonly used for assessing relative motions of orthopaedic implants. One limiting factor to in vivo model-based roentgen stereophotogrammetric analysis of total knee arthroplasty is the need for 3D models of the implants.The 3D models of the implant components must be reverse-engineered, if not provided by the company, which makes this method impractical for a clinical study involving many types or sizes of implants. This study introduces a novel feature-based methodology that registers the features at the implant-bone or implant-cement interface of the components that have elementary shapes. These features include pegs with hemispherical heads, and straight, circular or curved edges located on flat faces of the box of the femoral component or the stem geometry of the tibial component. Software was developed to allow easy registration of these features through a graphical user interface. The accuracy and precision of registration for multiple flexion angles from 0 to 120 deg was determined with reference to registered poses of the implants through experiments on bone replica models and also on a cadaver specimen implanted with total knee prostheses. When compared to an equivalent bi-planar model-based registration, the results were comparable: The mean accuracy of this feature-based method was 1.45 deg and 1.03 mm (in comparison to 0.95 deg and 1.32 mm for the model-based approach), and the mean precision was 0.57 deg and 0.26 mm (in comparison to 0.42 deg and 0.44 mm for the model-based approach).The methodology and the developed software can easily accommodate different design of implants with various fixation features. This method can facilitate in vivo kinematic analysis of total knee arthroplasty by eliminating the need for 3D models of the implant components.
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Artroplastia de Reemplazo de Rodilla , Fenómenos Mecánicos , Fotogrametría/métodos , Fenómenos Biomecánicos , Humanos , Imagenología Tridimensional , Articulación de la Rodilla/anatomía & histología , Modelos AnatómicosRESUMEN
Determining the 3D pose of the patella after total knee arthroplasty is challenging. The commonly used single-plane fluoroscopy is prone to large errors in the clinically relevant mediolateral direction. A conventional fixed bi-planar setup is limited in the minimum angular distance between the imaging planes necessary for visualizing the patellar component, and requires a highly flexible setup to adjust for the subject-specific geometries. As an alternative solution, this study investigated the use of a novel multi-planar imaging setup that consists of a C-arm tracked by an external optoelectric tracking system, to acquire calibrated radiographs from multiple orientations. To determine the accuracies, a knee prosthesis was implanted on artificial bones and imaged in simulated 'Supine' and 'Weightbearing' configurations. The results were compared with measures from a coordinate measuring machine as the ground-truth reference. The weightbearing configuration was the preferred imaging direction with RMS errors of 0.48 mm and 1.32 ° for mediolateral shift and tilt of the patella, respectively, the two most clinically relevant measures. The 'imaging accuracies' of the system, defined as the accuracies in 3D reconstruction of a cylindrical ball bearing phantom (so as to avoid the influence of the shape and orientation of the imaging object), showed an order of magnitude (11.5 times) reduction in the out-of-plane RMS errors in comparison to single-plane fluoroscopy. With this new method, complete 3D pose of the patellofemoral and tibiofemoral joints during quasi-static activities can be determined with a many-fold (up to 8 times) (3.4mm) improvement in the out-of-plane accuracies compared to a conventional single-plane fluoroscopy setup.
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Artroplastia de Reemplazo de Rodilla/métodos , Fémur/fisiología , Procesamiento de Imagen Asistido por Computador/métodos , Rótula/fisiología , Radiografía/métodos , Tibia/fisiología , Algoritmos , Artroplastia/métodos , Fenómenos Biomecánicos , Calibración , Electrónica , Diseño de Equipo , Fémur/diagnóstico por imagen , Fluoroscopía/métodos , Humanos , Articulación de la Rodilla/fisiología , Modelos Anatómicos , Movimiento (Física) , Rótula/diagnóstico por imagen , Fantasmas de Imagen , Tibia/diagnóstico por imagenRESUMEN
Measurements of elongations of the cruciate ligaments have been used to study the behaviors of these ligaments in-vitro and in-vivo, mostly based on simplified two-bundle models of the cruciates. The complex fiber anatomy of the cruciates may suggest a complex deformation behavior across the continuum of their substance that cannot be captured by only two measurement points. In this study, a new methodology was introduced to include more detailed fiber anatomy and to take into consideration the wrapping of the PCL around the intercondylar notch of the femur in deep flexion. The method was used in comparison to the conventional two-bundle models on three sample cadaver knees that underwent a passive flexion up to 150°. The elongation ratios of the bundles were measured as the ratio of change in the length of the bundles over their lengths at 0° flexion. The multiple-bundle models showed ranges of variations across the attachment sites of the cruciates which at all flexion angles were significantly larger than those observed from the conventional two-bundle models. When expressed in percentages, at 150° flexion the ranges of variations in the elongation ratio of the bundles were 32.7%±31.9% and 34%±8.6% for the ACL and PCL, respectively. Results of this study showed that important variations of elongation across the body of the cruciates can be obscured to the conventional two-bundle model of the cruciates, and therefore a more detailed bundle configuration is suggested for the purpose of studying elongation behaviors of these ligaments.
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Ligamento Cruzado Anterior/fisiología , Articulación de la Rodilla/fisiología , Ligamento Cruzado Posterior/fisiología , Anciano , Anciano de 80 o más Años , Ligamento Cruzado Anterior/anatomía & histología , Cadáver , Femenino , Fémur/anatomía & histología , Fémur/fisiología , Humanos , Articulación de la Rodilla/anatomía & histología , Masculino , Modelos Biológicos , Ligamento Cruzado Posterior/anatomía & histología , Rango del Movimiento Articular/fisiología , Estrés MecánicoRESUMEN
The aim of this research was to investigate the optimization of the geometry of an UHMWPE type of knee implant in the sagittal plane with minimum amount of wear. Finite element analysis has been used to analyze our proposed 780 models consisting of different design parameters. Maximum stress occurring in the whole tibial component, on the surface or subsurface of the plate, was considered as a design parameter to evaluate the wear condition. By avoiding the small contact area and high stresses in the tibial part, the maximum safe flexion angles have been determined. Other effective design factors such as implant stability, roll back distance, patella lever arm, and minimum bone resection have also been considered. Taking into account the variable parameters in the geometry of the implant parts, all possible models for the femoral component, which is made from metal, and the tibial component, which is made from UHMWPE, have been built in ANSYS and analyzed in the sagittal plane. By considering the effective mechanisms of wear in polyethylene, the results of the analyses were used to find the optimized geometry of a knee implant. This is the model, which is expected to experience the minimum wear, besides having some other properties of an ideal knee prosthesis.