【Abstract】 Objective To investigate the qual itative rotation al ignment of components in total knee arthroplastyand the accuracy and the effectiveness of Bone Morphing computer assisted system when qual itatively practicing. MethodsFrom November 2002 to June 2003, 21 patients with three compartments osteoarthritis(21 knees) were treated by primarytotal knee arthroplasty after the conservative medical treatment failed, with the assistance of a “Bone Morphing” CeravisionSystem, implanted posterior stabil ized total knee prosthesis. Twenty-one patients included 5 males (5 knees) and 16 females (16knees) with an average age of 72.4 years (64-79 years) . The locations were left knee in 10 cases and right knee in 11 cases. Thepatients suffered from knee pain and l imitation of movement from 2 to 10 years. There were 14 genu varum and 7 genu valgumpreoperatively. The relative preoperative, intraoperative and postoperative data from cl inical check-up, the X-ray films and theintraoperative components rotational al ignment real-time records in CD Rom were analyzed. Results All operative incisionshealed up by first intension. Twenty-one patients were followed up 12-16 months(mean 13.3 months). For the achievement ofproper lower l imb al ignment and normal frontal laxity of knee, rotational al ignment of femoral components was from internalrotation (IR)1° to external rotation (ER) 5°, tibial components from IR 0° to ER 5°. In patients with genu varum, the rotationalal ignment of the femoral components was ER 1°- ER 5°, of tibial components ER 2°- ER 5°. In patients with genu valgum, the rotationalal ignment of femoral components was IR 1°- ER 4°, of tibial components IR 0°-ER 4°. After 3 months of operation, themean flexion angle measured as range of motion (ROM) was 115°(105-130°), the frontal laxsity measured as 0.2-0.5 cm (mean0.27 cm) of internal laxity and 1.0-2.5 cm (mean 1.7 cm) for external laxity, there were no knee pain, paterllar instabil ity or dislocationand abnormal knee frontal laxity. Conclusion Using Bone Morphing computer-assisted system can optimise theindividual components rotation al ignment accurately.
The subpulmonary ventricular exclusion (Fontan) could effectively improve the living quality for the children patients with a functional single ventricle in clinical. However, postoperative Fontan circulation failure can easily occur, causing obvious limitations while clinically implementing Fontan. The cavopulmonary assist devices (CPAD) is currently an effective means to solve such limitations. Therefore, in this paper the in-silico and in-vitro experiment coupled model of Fontan circulation failure for the children patients with a single ventricle and CPAD is established to evaluate the effects of CPAD on the Fontan circulation failure. Then a sensorless feedback control algorithm is proposed to provide sufficient cardiac output and prevent vena caval suction due to CPAD constant pump speed. Based on the CPAD pump speed-an intrinsic parameter, the sensorless feedback control algorithm could accurately estimate the cavopulmonary pressure head (CPPH) using extended Kalman filter, eliminating the disadvantage for pressure sensors that cannot be used in long term. And a gain-scheduled, proportional integral (PI) controller is used to make the actual CPPH approach to the reference value. Results show that the CPAD could effectively increase physiological perfusion for the children patients and reduce the workload of a single ventricle, and the sensorless feedback control algorithm can effectively guarantee cardiac output and prevent suction. This study can provide theoretical basis and technical support for the design and optimization of CPAD, and has potential clinical application value.
ObjectiveSystemic lupus erythematosus (SLE) patients from a SLE family with homogeneity can provide experimental basis for individualized diagnosis and treatment by studying the characteristics of laboratory tests and symptoms.
MethodsLaboratory tests were analyzed for three SLE patients in the family, and set up the screen model by three laboratory tests (anitnuclear antibody positive, rheumatoid factor positive and IgE positive, ANA+RF+IgE+). All SLE cases were screened from latest four years as SLE subtype patients (named "similar family SLE patients"), then the family laboratory tests and clinical characteristics were analyzed.
ResultsA total of 55 patients (6.27%) were screened as similar family SLE patients from individual SLE patients according to model from 877 cases. The laboratory tests of similar family SLE patients including creatinine, WBC, CRP were significant lower than other SLE patients (P < 0.05), but significant higher for the IgG, positive rate of anti-SSA and anti-SSB (P < 0.05), and the alopecia and skin rashes were more common in similar family SLE patients than other SLE patients.
ConclusionsThe ANA+RF+IgE+ SLE patients are of lower inflammatory state and kidney involvement; Clinical symptom is priority to alopecia and skin rashes.
Objective To evaluate clinical efficacy of four-claw Ti-planes for internal fixation of multiple rib fractures and flail chest. Methods Clinical data of 93 patients with multiple rib fractures and flail chest who were admittedto Shanghai Pudong Hospital from December 2011 to November 2012 were retrospectively analyzed. There were 78 male and 15 female patients with their age of 20-80 years. All the patients received internal fixation of rib fractures using four-clawTi-planes. Finite element modeling and analysis were performed to investigate biomechanical behaviors of rib fractures after internal fixation with four-claw Ti-planes. Results The average number of rib fractures of the 93 patients was 5.9±2.1，and each patient received 3.8±1.3 four-claw Ti-planes for internal fixation. The operations were performed 6.3±3.2 days after admission. After the rib fractures were fixed with four-claw Ti-planes，rib dislocations and chest-wall collapse of flail chest were restored，and patients’ pain was relieved. Postoperative CT image reconstruction of the chest showed no dislocationor displacement at the fixation areas of the four-claw Ti-planes. Rib fractures were stabilized well，and normal contours of the chest were restored. Finite element analysis showed that the maximum bearable stress of the rib fractures after internal fixation with four-claw Ti-planes was twice as large as normal ribs. Conclusion Clinical outcomes of four-claw Ti-planesfor internal fixation of rib fractures are satisfactory with small incisions and less muscle injury of the chest wall，so this technique deserves wide clinical use.
During transfer tasks, the dual-arm nursing-care robot require a human-robot mechanics model to determine the balance region to support the patient safely and stably. Previous studies utilized human-robot two-dimensional static equilibrium models, ignoring the human body volume and muscle torques, which decreased model accuracy and confined the robot ability to adjust the patient’s posture in three-dimensional spatial. Therefore, this study proposes a three-dimensional spatial mechanics modeling method based on individualized human musculoskeletal multibody dynamics. Firstly, based on the mechanical features of dual-arm support, this study constructed a foundational three-dimensional human-robot mechanics model including body posture, contact position and body force. With the computed tomography data from subjects, a three-dimensional femur-pelvis-sacrum model was reconstructed, and the individualized musculoskeletal dynamics was analyzed using the ergonomics software, which derived the human joint forces and completed the mechanic model. Then, this study established a dual-arm robot transfer platform to conduct subject transfer experiments, showing that the constructed mechanics model possessed higher accuracy than previous methods. In summary, this study provides a three-dimensional human-robot mechanics model adapting to individual transfers, which has potential application in various scenarios such as nursing-care and rehabilitating robots.
The present paper proposed a central-driven structure of upper limb rehabilitation robot in order to reduce the volume of the robotic arm in the structure, and also to reduce the influence of motor noise, radiation and other adverse factors on upper limb dysfunction patient. The forward and inverse kinematics equations have been obtained with using the Denavit-Hartenberg (D-H) parameter method. The motion simulation has been done to obtain the angle-time curve of each joint and the position-time curve of handle under setting rehabilitation path by using SolidWorks software. Experimental results showed that the rationality with the central-driven structure design had been verified by the fact that the handle could move under setting rehabilitation path. The effectiveness of kinematics equations had been proved, and the error was less than 3°by comparing the angle-time curves obtained from calculation with those from motion simulation.
In the present study, a finite element model of L4-5 lumbar motion segment was established based on the CT images and a combination with image processing software, and the analysis of lumbar biomechanical characteristics was conducted on the proposed model according to different cases of flexion, extension, lateral bending and axial rotation. Firstly, the CT images of lumbar segment L4 to L5 from a healthy volunteer were selected for a three dimensional model establishment which was consisted of cortical bone, cancellous bone, posterior structure, annulus, nucleus pulposus, cartilage endplate, ligament and facet joint. The biomechanical analysis was then conducted according to different cases of flexion, extension, lateral bending and axial rotation. The results showed that the established finite element model of L4-5 lumbar segment was realistic and effective. The axial displacement of the proposed model was 0.23, 0.47, 0.76 and 1.02 mm, respectively under the pressure of 500, 1 000, 1 500 and 2 000 N, which was similar to the previous studies in vitro experiments and finite element analysis of other people under the same condition. The stress distribution of the lumbar spine and intervertebral disc accorded with the biomechanical properties of the lumbar spine under various conditions. The established finite element model has been proved to be effective in simulating the biomechanical properties of lumbar spine, and therefore laid a good foundation for the research of the implants of biomechanical properties of lumbar spine.
Objective To investigate effectiveness of applying the Bone Morphingbased image-free computer-assisted system for the ligament balancing managementin the total knee arthroplasty (TKA). Methods Between November 2002 and June 2003, twenty-one posterior stabilized total knee prostheses (Ceraver, France) were implanted in 21 patients using the Bone Morphing based image-free Ceravision system.This cohort included 5 men and 16 women with an average age of 72.4 years, two undergoing high tibial osteotomy and 1 undergoing distal femoral osteotomy before. The preoperative deviation was measured by the full-length AP X-rays. The knees were in varus deviation in 14 patients and in valgus deviation in 7 patients, with an average of 2.36°(varus 13°-valgus 13°). The frontal X-rays ofthe knee were assessed, the mean value of the varus force-stress test was 8.47°(varus 2°-varus 20°), and the mean value of the valgus forcestress test was 3.63°(varus 7°-valgus 12°). Results With the Ceravisionrecorded data, the intraoperative alignment was assessed, the mean lower limb axis was 3.33°(varus 12°-valgus 10°),and compared with the preoperative data, the difference was significant (Plt;0.05); the mean value of the varus force-stress test was 6.47°(varus 0°-varus 24°), the mean value of the valgus force-stress test was 4.32°(varus 8°- valgus 15°), and compared with the preoperative data, the difference was significant (Plt;0.05). The post-prosthetic alignment on Ceravision with a deviation of 0.175°(varus 2°- valgus 3°) was compared with the postoperative alignment by the full-length AP X-rays, with a deviation of 0.3°(varus 3.5°-valgus 1.5°), the difference wasn’t significant(Pgt;0.05).The clinical check-up performed 3 months after operation showed that the average range of movement (ROM) was 115°(105-130°), the mean frontal laxity was 0.27 mm(0.2-0.5 mm). The femoral and tibial components were implanted in the satisfactory 3 dimensional position without ligament imbalance in all the patients, andthere were no instability or patella complications.Conclusion Utilization of the Bone Morphing based image-free computer-assisted system can achieve an accurate component 3 dimensional alignment, optimal bone resection, optimal control of surgical decision in releasing the soft tissues, rotating the femoral component to gain an extension/flexion rectangular gap, and managing theligament balancing so as to achieve a satisfactory initial clinical outcome. This system can be routinely used in the TKA.
Virtual clinical trials are clinical trials conducted through computer simulation technology, which breaks through the limitations of traditional clinical trials and has the advantages of saving time, reducing costs, and reducing the risk of human trials. With the application of new computer technologies such as population pharmacokinetics, physiologically-based pharmacokinetics, quantitative systems pharmacology, and artificial intelligence, the field of virtual clinical trials in healthcare has become an important development direction. This article will give a preliminary review of the connotation, methods and future development trends of virtual clinical trials, aiming to provide reference for the application of new technologies and methods in clinical trials.
The dynamic coupling of stent degradation and vessel remodeling can influence not only the structural morphology and material property of stent and vessel, but also the development of in-stent restenosis. The research achievements of biomechanical modelling and analysis of stent degradation and vessel remodeling were reviewed; several noteworthy research perspectives were addressed, a stent-vessel coupling model was developed based on stent damage function and vessel growth function, and then concepts of matching ratio and risk factor were established so as to evaluate the treatment effect of stent intervention, which may lay the scientific foundation for the structure design, mechanical analysis and clinical application of biodegradable stent.
