RESUMEN

Animals have been used as models to help to better understand biological and anatomical systems, and pathologies in both humans and non-human species, and sheep are often used as an in vivo experimental model for orthopedic research. Gait analysis has been shown to be an important tool in biomechanics research with clinical applications. The purpose of this study was to perform a kinematic analysis using a tridimensional (3D) reconstruction of the sheep hindlimb. Seven healthy sheep were evaluated for natural overground walking, and motion capture of the right hindlimb was collected with an optoelectronic system while the animals walked in a track. The analysis addressed gait spatiotemporal variables, hip, knee and ankle angle and intralimb joint angle coordination measures during the entire walking cycle. This study is the first that describes the spatiotemporal parameters from the hip, knee and ankle joints in a tridimensional way: flexion/extension; abduction/adduction and inter/external rotation. The results of this assessment can be used as an outcome indicator to guide treatment and the efficacy of different therapies for orthopedic and neurological conditions involving the locomotor system of the sheep animal model.

RESUMEN

The angular displacement sensor is a digital angular displacement measurement device that integrates optics, mechanics, and electronics. It has important applications in communication, servo control, aerospace, and other fields. Although conventional angular displacement sensors can achieve extremely high measurement accuracy and resolution, they cannot be integrated because complex signal processing circuitry is required at the photoelectric receiver, which limits their suitability for robotics and automotive applications. The design of a fully integrated line array angular displacement-sensing chip is presented for the first time using a combination of pseudo-random and incremental code channel designs. Based on the charge redistribution principle, a fully differential 12-bit, 1 MSPS sampling rate successive approximation analog-to-digital converter (SAR ADC) is designed for quantization and subdivision of the incremental code channel output signal. The design is verified with a 0.35 µm CMOS process and the area of the overall system is 3.5 × 1.8 mm2. The fully integrated design of the detector array and readout circuit is realized for the angular displacement sensing.

RESUMEN

OBJECTIVE: The effects of ROM manipulation on muscle strength and hypertrophy response remain understudied in long-term interventions. Thus, we compared the changes in strength and regional muscle hypertrophy after training in protocols with different ranges of motion (ROM) in the seated dumbbell preacher curl exercise using a within-participant experimental design. DESIGN AND METHODS: Nineteen young women had one arm randomly assigned to train in the initial ROM (INITIALROM: 0°-68°; 0° = extended elbow) while the contralateral arm trained in the final ROM (FINALROM: 68°-135°), three times per week over an eight-week study period. Pre- and post-training assessments included one repetition maximum (1RM) testing in the full ROM (0°-135°), and measurement of biceps brachii cross-sectional area (CSA) at 50% and 70% of humerus length. Paired t-tests were used to compare regional CSA changes between groups, the sum of CSA changes at 50% and 70% (CSAsummed), and the strength response between the training protocols. RESULTS: The INITIALROM protocol displayed a greater CSA increase than FINALROM protocol at 70% of biceps length (p = 0.001). Alternatively, we observed similar increases between the protocols for CSA at 50% (p = 0.311) and for CSAsummed (p = 0.111). Moreover, the INITIALROM protocol displayed a greater 1RM increase than FINALROM (p < 0.001). CONCLUSIONS: We conclude that training in the initial angles of elbow flexion exercise promotes greater distal hypertrophy of the biceps brachii muscle in untrained young women. Moreover, the INITIALROM condition promotes a greater dynamic strength increase when tested at a full ROM compared to the FINALROM.

RESUMEN

Here, we report an ultracompact angular displacement sensor based on the Talbot effect of optical microgratings. Periodic Talbot interference patterns were obtained behind an upper optical grating. By putting another grating within the Talbot region, the total transmission of the two-grating structure was found to be approximatively in a linear relationship with the relative pitch angle between the two gratings, which was explained by a transversal shift of the Talbot interference patterns. The influence of the grating parameters (e.g., the grating period, the number of grating lines and the gap between the two gratings) was also studied in both a simulation and an experiment, showing a tunable sensitivity and range by simply changing the grating parameters. A sensitivity of 0.19 mV/arcsec was experimentally obtained, leading to a relative sensitivity of 0.27%/arcsec within a linear range of ±396 arcsec with the 2 µm-period optical gratings. Benefitting from tunable properties and an ultracompact structure, we believe that the proposed sensor shows great potential in applications such as aviation, navigation, robotics and manufacturing engineering.

RESUMEN

PURPOSE: To determine if there is an association between pre-/postoperative translational and angular displacement with nonunion after intramedullary nail (IMN) fixation of tibial shaft fractures. METHODS: Retrospective review of 120 patients with tibial shaft fractures undergoing IMN at an urban level-one trauma center was performed. Demographics, injury characteristics, and pre-/postoperative translational and angular fracture displacement in the coronal and sagittal planes were recorded. True fracture translational and angular displacement (TTD and TAD) were calculated by combining sagittal and coronal displacement utilizing the Pythagorean theorem. RESULTS: 10.8% of patients (n = 13) developed nonunion with remaining patients serving as the control. Groups were similar across age, sex, and BMI. Univariate analysis revealed no difference in pre-/postoperative TAD between nonunion and union groups and an increased preoperative TTD (median difference (MD): 6.2 mm, CI: 1.4-10.8 mm) and postoperative TTD (MD: 1.8 mm, CI: 0-3.7 mm) in the nonunion group. On multivariate analysis, however, only tobacco use and type 2 or 3 open fractures were associated with nonunion (OR: 5.1, CI: 1.2-22.8 and OR: 4.9, CI: 1.2-19.2, respectively). CONCLUSION: True translational and angular displacement of tibial shaft fractures before and after IMN fixation were not independently associated with nonunion. Tobacco use and type 2 or 3 open fracture are independent factors for nonunion.

Asunto(s)

RESUMEN

Blood coagulation function is an essential index in clinical examination, and it is of great significance to evaluate blood coagulation function comprehensively. Based on the blood viscoelasticity theory and hydrodynamics, we proposed a method to monitor the whole blood coagulation process based on the reciprocating motion of the magnetic bead (magnetic bead method for short). We have established a mathematical model between the moment acting on the magnetic bead and the viscoelasticity of blood in the process of blood coagulation. The change of blood viscoelasticity acks on the magnetic bead in the form of moment changes, which shows that the amplitude of the motion of the magnetic bead varies with the change of blood viscoelasticity. Designed and verified a blood coagulation monitoring device based on the reciprocating movement of the magnetic bead and discussed the device's parameters through the orthogonal experiment. Lastly, the TEG5000 was used as the control group to test the thromboelasticity of four groups of thromboelastography quality control products in the same batch and 10 groups of human whole blood. It verified that our device has good repeatability, and has good consistency with TEG5000, it has particular application potential as a new blood coagulation monitoring method.

Asunto(s)

RESUMEN

The ball joint is a multi-degree-of-freedom transmission pair, if it can replace the inner frame in the aviation photoelectric pod to carry the optical load, which will greatly simplify the system structure of the photoelectric pod and reduce the space occupied by the inner frame. However, installation errors in ball joint siting introduce nonlinear errors that are difficult to correct and two degree of freedom angular displacement of the ball joint is difficult to detect, which limits application in the precision control of two degrees of freedom systems. Studies of spherical capacitive sensors to date have not tested sensors for use in an inner frame stabilisation mechanism nor have they analysed the influence of installation error on sensor output. A two-axis angular experimental device was designed to measure the performance of a ball joint capacitive sensor in a frame stabilisation mechanism in an aeronautical optoelectronic pod, and a mathematical model to compensate for ball joint capacitive sensor installation error was created and tested. The experimental results show that the resolution of the capacitive sensor was 0.02° in the operating range ±4°, the repeatability factor was 0.86%, and the pulse response time was 39 µs. The designed capacitive sensor has a simple structure, high measurement accuracy, and strong robustness, and it can be integrated into ball joint applications in the frames of aeronautical photoelectric pods.

RESUMEN

The spherical pair has an important role in the inner frame of the stabilization mechanism of the aviation optoelectronic pod. However, its two-degrees-of-freedom (2-DOF) angular displacement signal is difficult to detect, seriously restricting its application in aviation optoelectronic pods. Therefore, this study proposes a new method to measure a spherical pair's 2-DOF angular displacement using a spherical capacitive sensor. The capacitive sensor presented by this method realizes the measurement of the 2-DOF angular displacement of the spherical pair by integrating the spherical electrode groups in the ball head and the ball socket of the spherical pair. First, based on the geometric structure of the spherical pair, the structure of the capacitive sensor is designed, and the mathematical model for the capacitive sensor is deduced. Then, the sensor's output capacitance, in different directions, is simulated by Ansoft Maxwell software. Finally, an experiment device is built for the measurement experiments. The simulation analysis and experimental results show that the spherical capacitive sensor has an approximately linear output in different directions, and the measured output capacitance is as high as 89.7% of the theoretical value. Compared with the existing sensors that measure the 2-DOF angular displacement signal of the ball pair, the sensor proposed in this study has an integrated structure, which can be integrated into the spherical pair. That makes it possible to apply the spherical pair to the inner frame of the aviation optoelectronic pod.

RESUMEN

To fulfill the requirement of fields such as robotics, aviation, and special machining, motors with quill shafts or outer rotors have been used. For these special motors, the photoelectric encoder's volume is normally too big and easy to be polluted by oil or dust; magnetic encoder normally has poor accuracy, and alnico piece may not provide enough magnetic field coverage area. The aim of this essay is to find a new structure of magnetic encoder to improve the precision and magnetic field coverage area. By using two multi-pole alnico rings with a different number of pole pairs to provide a magnetic field, the coverage area could be improved. The position differences between two alnicos pole positions are used to calculate absolute angle value, so the accuracy of the encoder could be absolute and no less than that of a combined magnetic encoder with the same number of pole pairs. A special algorithm is proposed for decoding. This new kind of magnetic encoder could be used on special motors with quill shafts or outer rotors. Its volume and weight are less than the photoelectric encoder and have better performance on antipollution. The alnico ring is easy to modify to suit the structure of the motor.

RESUMEN

Motion tracking techniques have been extensively studied in recent years. However, capturing movements of the upper limbs is a challenging task. This document presents the estimation of arm orientation and elbow and wrist position using wearable flexible sensors (WFSs). A study was developed to obtain the highest range of motion (ROM) of the shoulder with as few sensors as possible, and a method for estimating arm length and a calibration procedure was proposed. Performance was verified by comparing measurement of the shoulder joint angles obtained from commercial two-axis soft angular displacement sensors (sADS) from Bend Labs and from the ground truth system (GTS) OptiTrack. The global root-mean-square error (RMSE) for the shoulder angle is 2.93 degrees and 37.5 mm for the position estimation of the wrist in cyclical movements; this measure of RMSE was improved to 13.6 mm by implementing a gesture classifier.

Asunto(s)

RESUMEN

BACKGROUND: Reduced trunk and lower limb movement and hip and trunk muscles weakness may compromise the athletes' performance on the modified Star Excursion Balance Test (mSEBT). OBJECTIVE: To investigate the relationship of trunk and lower limb kinematics and strength with the performance on the mSEBT of runners at high risk of injury. METHODS: Thirty-nine runners performed the mSEBT with the dominant limb as the support limb. An Inertial System was used to capture the trunk, hip, knee and ankle movement during the mSEBT. A handheld dynamometer was used to measure the strength of trunk extensors and lateral flexors muscles, and hip extensors, lateral rotators and abductors of the support limb. Multiple regressions were used to investigate if trunk and lower limbs kinematics and trunk and hip muscles strength are associated with performance during the mSEBT. RESULTS: Reduced hip flexion and greater knee flexion range of motion (ROM) were associated with anterior reach in the mSEBT (r2=0.45; p<.001), greater hip flexion ROM was associated with posteromedial reach (r2=0.15; p=.012) and greater knee flexion ROM was associated with posterolateral reach (r2=0.23; p<.001). Hip extensor strength was associated with posteromedial (r2=0.14; p=.017), posterolateral (r2=0.10; p=.038) and composite reaches (r2=0.16; p=.009). CONCLUSION: Hip and knee kinematics in the sagittal plane explained 15-45% of the runners' performance on the mSEBT and hip extensor strength explained 10-16% of the mSEBT performance. These findings provide useful information on the contribution of joints kinematics and strength when evaluating dynamic postural control in runners at high risk of injury.

Asunto(s)

RESUMEN

Parkinson's disease (PD) is one of the leading neurological disorders in the world with an increasing incidence rate for the elderly. Freezing of Gait (FOG) is one of the most incapacitating symptoms for PD especially in the later stages of the disease. FOG is a short absence or reduction of ability to walk for PD patients which can cause fall, reduction in patients' quality of life, and even death. Existing FOG assessments by doctors are based on a patient's diaries and experts' manual video analysis which give subjective, inaccurate, and unreliable results. In the present research, an automatic FOG assessment system is designed for PD patients to provide objective information to neurologists about the FOG condition and the symptom's characteristics. The proposed FOG assessment system uses an RGB-D sensor based on Microsoft Kinect V2 for capturing data for 5 healthy subjects who are trained to imitate the FOG phenomenon. The proposed FOG assessment system is called "Kin-FOG". The analysis of foot joint trajectory of the motion captured by Kinect is used to find the FOG episodes. The evaluation of Kin-FOG is performed by two types of experiments, including: (1) simple walking (SW); and (2) walking with turning (WWT). Since the standing mode has features similar to a FOG episode, our Kin-FOG system proposes a method to distinguish between the FOG and standing episodes. Therefore, two general groups of experiments are conducted with standing state (WST) and without standing state (WOST). The gradient displacement of the angle between the foot and the ground is used as the feature for discriminating between FOG and standing modes. These experiments are conducted with different numbers of FOGs for getting reliable and general results. The Kin-FOG system reports the number of FOGs, their lengths, and the time slots when they occur. Experimental results demonstrate Kin-FOG has around 90% accuracy rate for FOG prediction in both experiments for different tasks (SW, WWT). The proposed Kin-FOG system can be used as a remote application at a patient's home or a rehabilitation clinic for sending a neurologist the required FOG information. The reliability and generality of the proposed system will be evaluated for bigger data sets of actual PD subjects.

Asunto(s)

RESUMEN

Angular displacement sensor with shared magnetic field has strong environmental adaptability and high measurement accuracy. However, its 3-D structure is multi-pole double-layer structure, using time stepping finite element method (TSFEM) to optimize the structure is time-consuming and uneconomical. Therefore, a magnetic equivalent loop method (MELM) is proposed to simplify the optimal design of sensors. By reasonably setting the node position, the mechanical structure parameters, winding coefficients and input voltage of the sensor are integrated into a mathematical model to calculate of the induced voltage. The calculation results are compared with the simulation results, and a sensor prototype is made to test the optimized effect of the MELM.

RESUMEN

O presente estudo teve como objetivo verificar o efeito das diferentes intensidades sobre a atividade mioelétrica do vasto lateral, deslocamento angular e tempo sob tensão do membro preferido durante séries múltiplas na cadeira extensora. Participaram do estudo 9 mulheres de 24±3,4 anos, 62,4±11,7 kg,1,64±0,05 m praticantes de musculação (mínimo de 6 meses). Durante três dias não consecutivos as voluntárias foram avaliadas no exercício de extensão de joelho na máquina apenas com o membro preferido. No primeiro dia foram realizados o teste e reteste de 10 repetições máximas (RM). No segundo e terceiro dias foram realizadas sessões de quatros séries com intensidade de 80% ou 90% de 10RM de forma aleatória, com intervalo de um minuto entre as séries. A atividade mioelétrica do vasto lateral (VL) foi monitorada. O tempo sob tensão e deslocamento angular também foram registrados. Considerando o deslocamento angular, houve diferença significativa no P80 comparado ao P90 nas séries 2 (p = 0,049), 3 (p = 0,046) e 4 (p = 0,023), respectivamente. Adicionalmente, verificou-se uma atividade mioelétrica normalizada superior na série 3 no P80 comparada ao P90 (p = 0,004). Não houve diferença significativa entre os protocolos para o tempo sob tensão e desempenho de repetições (p > 0,05). Portanto, o aumento no sinal mioelétrico observado entre intensidades relativas a 10RM (80 vs 90%) parece não apresentar uma associação com desempenho de repetições múltiplas máximas, sugerindo que ambas as intensidades relativas podem ser aplicadas como variações em programas de treinamento ou reabilitação de lesões sem prejuízos no volume de treino no exercício cadeira extensora unilateral para o membro preferido...U)

The purpose of the present study was to verify the effect of the different training intensities on the myoelectric activity of the vastus lateralis, angular displacement and time under tension of the preferred member during multiple sets in unilateral leg extension exercise. A total of 9 women aged 24 ± 3.4 years, 62.4 ± 11.7 kg, 1.64 ± 0.05 m bodybuilders (minimum 6 months) participated in the study. For three nonconsecutive days the volunteers were evaluated in leg extension exercise. On the first day, the test and retest of 10 repetition maximum loads (RM) were performed. On the second and third days, four sets were performed with an intensity of 80% or 90% of 10RM in a randomized order, with a one-minute rest interval between the sets. The myoelectric activity of the vastus lateralis (VL) was monitored. The time under tension and angular displacement were also recorded. Considering the angular displacement, there was a significant difference in P80 compared to P90 in set 2 (p = 0.049), 3 (p = 0.046) and 4 (p = 0.023), respectively. Regarding the myoelectric activity, there was a significant increase in P80 versus P90 in set 3 (p ≤ 0.05). There was no significant difference between the protocols for time under tension and repetition performance (p> 0.05). Therefore, the increase in myoelectric signal observed between intensities relative to 10RM (80 vs 90%) does not appear to be associated with maximal multiple repetition performance, suggesting that both relative intensities can be applied as variations in training programs or injury rehabilitation without impairment in training volume in unilateral leg extension of the preferred member...AU)

Asunto(s)

RESUMEN

Objective: To explore the characteristics and treatment of intertrochanteric fracture, which the proximal part displaced forwardly and angularly. Methods: Between March 2015 and March 2016, 40 patients with intertrochanteric fracture with forwardly and angularly displaced proximal part were treated with open reduction and intramedullary nailing fixation. There were 11 males and 29 females with the age of 56-87 years (mean, 75.7 years). The causes of injury included traffic accident in 1 case and fall in 39 cases. The body mass index was 18.9-33.8 (mean, 24.3). The time from injury to admission was 2-360 hours. The type of fracture according to AO-OTA classification was A1.2 type in 7 cases, A1.3 type in 1 case, A2.1 type in 6 cases, A2.2 type in 9 cases, A2.3 type in 12 cases, A3.2 type in 2 cases, and A3.3 type in 3 cases. The haemoglobin (Hb) value at admission and the lowest values before and after operation were recorded; the amount of the transfused-blood during hospital stay and visible blood loss around operation were recorded. The short-form 36 health survey scale (SF-36) before injury and at 12 weeks after operation were recorded for evaluating the quality of living; the visual analogue scale (VAS) score at admission and 2 days after operation were recorded for evaluating the reduction of pain, the union after operation were evaluated by X-ray film and clinical examination, and the Harris hip scale at 12 weeks were used to evaluate the injuried hip function. Results: The lowest Hb value before operation was (99.10±16.48) g/L, which was significantly lower than that at admission ï¼»(114.33±14.93) g/Lï¼½ ( t=9.134, P=0.000). Eleven cases were treated with blood transfusion about (520.00±269.98) mL before operation. The amount of transfused blood during operation was (569.23±207.94) mL, and intraoperative blood loss was (373.08±154.68) mL. The lowest Hb value was (105.41±13.36) g/L after operation, and 8 cases were treated with second blood transfusion at amount of (500.00±185.16) mL. The reduction of fracture was rated as excellent in 16 cases, good in 18 cases, and poor in 6 cases according to the modified Baumgaertner criterion at 3 days after operation. Forty cases were followed up 12-15 weeks (mean, 12.8 weeks). No infection occurred in all cases. The VAS score at 2 days after operation was 3.2±0.5, which was significantly improved when compared with the value at admission (8.2±0.5) ( t=37.500, P=0.000). At 12 weeks after operation, all the fractures healed; the Harris score was 82.5±6.9; and the SF-36 score was 51.4±11.5, which was significantly decreased when compared with the score before injury (54.89±11.5) ( t=18.901, P=0.000). Delirium occurred in 4 cases, pneumonia in 8 cases, urinary infection in 5 cases, and venous thrombosis in 4 cases after operation, which were all cured after corresponding treatment. Conclusion: Intertrochanteric fracture with forwardly and angularly displaced proximal part is a type of unstable fracture, and it is difficult to reduction. It is necessary to achieve a good fracture reduction by means of auxiliary instrument. The anatomical alignment is the primary condition for the good effectiveness, and the anemia before and after the operation must be corrected.

Asunto(s)

RESUMEN

BACKGROUND: The trunk is often simplified as a small number of rigid-body segments to reduce the complexity of its multi-segmental structure. However, such rigid-body representations of the trunk may overlook its flexible movement owing to its multi-segmental structure. RESEARCH QUESTION: The purpose of this study is to quantitatively assess the effects of the deformability on the resultant trunk kinematics when the trunk is modeled with numerous rigid-body segments. METHODS: Three-dimensional kinematic data of 10 male subjects were obtained during static and dynamic trials. The trunk in both static and dynamic trials was modeled as a single rigid-body segment or as two, three, or six linked rigid-body segments, and a non-linear optimization analysis was performed to minimize the difference between the actual and modeled position data. Position errors were evaluated to assess the difference in three-dimensional positions between the actual and modeled data for each model. The total angular displacement was evaluated to examine to what extent each model describes the actual multi-segmental trunk movement. RESULTS: The position error between the modeled and actual kinematic data of the trunk was up to 12 mm and 11 mm when the trunk was simplified as one segment, but the error decreased to 5 mm and 7 mm when the trunk was modeled with six segments during the static and dynamic trials, respectively. The total angular displacement increased as the number of rigid-body segments increased during both trials. SIGNIFICANCE: These results imply that a small number of linked rigid-body representations underestimates the actual multi-segmental trunk movement during dynamic movement. These findings are useful in determining the optimal number of rigid-body segments for analysis of the trunk.

Asunto(s)

RESUMEN

Recently, Instantaneous Angular Speed (IAS) measurement is successfully established and prevalently applied to a wide variety of machines due to the hypothesis that the speed fluctuation of rotating machinery carries plentiful dynamic responses. Nevertheless, exploration and application based on angular signal are still insufficient. Under the same hypothesis, in this paper, we introduced an extended algorithm named Instantaneous Angular Phase Demodulation (IAPD), together with the selection of optimal sideband family to extract the Instantaneous Angular Displacement Fluctuation (IADF) signal. In order to evaluate the performance of IADF signal, an effective approach was demonstrated using IADF signal to address the fault detection and diagnosis issue. After extracting the IADF signal, a much effective method was developed to deal with the large amount of data generated during the signal collection process. Then, we used the well-developed techniques, i.e., empirical mode decomposition (EMD) and envelope analysis, to undertake the signal de-noising and feature extraction task. The effectiveness and capability of the IADF signal were evaluated by two kinds of gearboxes under differentconditions in practice. In particular, the prevalent IAS signal and vibration signal were also involved and testified by the proposed procedure. Experimental results demonstrated that by means of the IADF signal, the combination of EMD and envelope analysis not only provided accurate identification results with a higher signal-to-noise ratio, but was also capable of revealing the fault characteristics significantly and effectively. In contrast, although the IAS signal had the potential ability to diagnose the serious fault, it failed for the slight crack case. Moreover, the same procedure even its improvements, i.e., ensemble empirical mode decomposition and local mean decomposition, all failed to recognize the faults in terms of vibration signals.

RESUMEN

Objective: To explore the characteristics and treatment of intertrochanteric fracture, which the proximal part displaced forwardly and angularly. Methods: Between March 2015 and March 2016, 40 patients with intertrochanteric fracture with forwardly and angularly displaced proximal part were treated with open reduction and intramedullary nailing fixation. There were 11 males and 29 females with the age of 56-87 years (mean, 75.7 years). The causes of injury included traffic accident in 1 case and fall in 39 cases. The body mass index was 18.9-33.8 (mean, 24.3). The time from injury to admission was 2-360 hours. The type of fracture according to AO-OTA classification was A1.2 type in 7 cases, A1.3 type in 1 case, A2.1 type in 6 cases, A2.2 type in 9 cases, A2.3 type in 12 cases, A3.2 type in 2 cases, and A3.3 type in 3 cases. The haemoglobin (Hb) value at admission and the lowest values before and after operation were recorded; the amount of the transfused-blood during hospital stay and visible blood loss around operation were recorded. The short-form 36 health survey scale (SF-36) before injury and at 12 weeks after operation were recorded for evaluating the quality of living; the visual analogue scale (VAS) score at admission and 2 days after operation were recorded for evaluating the reduction of pain, the union after operation were evaluated by X-ray film and clinical examination, and the Harris hip scale at 12 weeks were used to evaluate the injuried hip function. Results: The lowest Hb value before operation was (99.10±16.48) g/L, which was significantly lower than that at admission ［(114.33±14.93) g/L］ ( t=9.134, P=0.000). Eleven cases were treated with blood transfusion about (520.00±269.98) mL before operation. The amount of transfused blood during operation was (569.23±207.94) mL, and intraoperative blood loss was (373.08±154.68) mL. The lowest Hb value was (105.41±13.36) g/L after operation, and 8 cases were treated with second blood transfusion at amount of (500.00±185.16) mL. The reduction of fracture was rated as excellent in 16 cases, good in 18 cases, and poor in 6 cases according to the modified Baumgaertner criterion at 3 days after operation. Forty cases were followed up 12-15 weeks (mean, 12.8 weeks). No infection occurred in all cases. The VAS score at 2 days after operation was 3.2±0.5, which was significantly improved when compared with the value at admission (8.2±0.5) ( t=37.500, P=0.000). At 12 weeks after operation, all the fractures healed; the Harris score was 82.5±6.9; and the SF-36 score was 51.4±11.5, which was significantly decreased when compared with the score before injury (54.89±11.5) ( t=18.901, P=0.000). Delirium occurred in 4 cases, pneumonia in 8 cases, urinary infection in 5 cases, and venous thrombosis in 4 cases after operation, which were all cured after corresponding treatment. Conclusion: Intertrochanteric fracture with forwardly and angularly displaced proximal part is a type of unstable fracture, and it is difficult to reduction. It is necessary to achieve a good fracture reduction by means of auxiliary instrument. The anatomical alignment is the primary condition for the good effectiveness, and the anemia before and after the operation must be corrected.

RESUMEN

BACKGROUND CONTEXT: Although it is generally believed that the magnitude of dens fracture displacement is proportional to the amount of force applied to the cervical spine during injury, the factors responsible for displacement have not been studied. PURPOSE: Our aim was to determine factors that contribute to horizontal and angular displacement of dens fractures. STUDY DESIGN/SETTING: We conducted a retrospective review of adult patients who were admitted to our level 1 trauma center between January 1, 2008 and December 31, 2013. PATIENT SAMPLE: Angular and horizontal displacements of the fractured dens in 57 patients were measured. Subjects were grouped based on mechanism of fracture: motor vehicle accident, ground level fall, and higher falls. OUTCOME MEASURES: Cervical lordosis was measured between C2 and T1. C3-C4, C4-C5, C5-C6, and C6-C7 disc inclination angles were measured. Anteroposterior sagittal balance was assessed by comparing the sagittal position of the C2 body with the C7 body. METHODS: Data were analyzed using Pearson correlations, independent t tests, and support vector regression to construct predictive models that determine factors contributing to the angular and horizontal displacements. RESULTS: The mean horizontal displacement of the fractured dens was not significantly different among groups. However, the dens in those with ground level falls had a significantly greater mean fracture angle compared with the higher energy trauma groups (p=.01). There were positive correlations between angular displacement and C5-C6 disc space inclination angle (r=0.67, p<.01) and C6-C7 disc space inclination angle (r=0.61, p<.01). There were positive correlations between horizontal displacement and C6-C7 inclination angle (r=0.40, p<.01) and sagittal alignment (r=0.32, p<.01). The predictive model using all variables demonstrated that angular fracture displacement was only dependent on C5-C6 disc space inclination angle. Horizontal displacement was only dependent on C6-C7 inclination angle and anteroposterior sagittal balance. CONCLUSIONS: Disc space inclination angles of the lower cervical spine and the cervical sagittal balance most contribute to the magnitude of angular and horizontal displacement of the dens after fracture.

Asunto(s)

RESUMEN

This paper provides a system and method for correction of relative angular displacements between an Unmanned Aerial Vehicle (UAV) and its onboard strap-down photoelectric platform to improve localization accuracy. Because the angular displacements have an influence on the final accuracy, by attaching a measuring system to the platform, the texture image of platform base bulkhead can be collected in a real-time manner. Through the image registration, the displacement vector of the platform relative to its bulkhead can be calculated to further determine angular displacements. After being decomposed and superposed on the three attitude angles of the UAV, the angular displacements can reduce the coordinate transformation errors and thus improve the localization accuracy. Even a simple kind of method can improve the localization accuracy by 14.3%.