scholarly journals Contact pressure distribution of the hip joint during closed reduction of developmental dysplasia of the hip: a patient-specific finite element analysis

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhiqiang Zhang ◽  
Dashan Sui ◽  
Haiyi Qin ◽  
Hai Li ◽  
Ziming Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Head ◽  
Contact Pressure ◽  
Closed Reduction ◽  
Developmental Dysplasia ◽  
Abduction Angle ◽  
Lateral Part ◽  
Element Analysis ◽  
Dysplasia Of The Hip

Abstract Background Developmental dysplasia of the hip (DDH) is the most common deformity of the lower extremity in children. The biomechanical change during closed reduction (CR) focused on cartilage contact pressure (CCP) has not been studied. Thereby, we try to provide insight into biomechanical factors potentially responsible for the success of CR treatment sand complications by using finite element analysis (FEA) for the first time. Methods Finite element models of one patient with DDH were established based on the data of MRI scan on which cartilage contact pressure was measured. During CR, CCP between the femoral head and acetabulum in different abduction and flexion angles were tested to estimate the efficacy and potential risk factors of avascular necrosis (AVN) following CR. Results A 3D reconstruction by the FEA method was performed on a 16 months of age girl with DDH on the right side. The acetabulum of the involved side showed a long, narrow, and “flat-shaped” deformity, whereas the femoral head was smaller and irregular compared with the contralateral side. With increased abduction angle, the stress of the posterior acetabulum increased significantly, and the stress on the lateral part of the femoral head increased as well. The changes of CCP in the superior acetabulum were not apparent during CR. There were no detectable differences in terms of pressure on the femoral head. Conclusions Severe dislocation (IHDI grade III and IV) in children showed a high mismatch between the femoral head and acetabulum. Increased abduction angle corresponded with high contact pressure, which might relate to AVN, whereas increased flexion angle was not. Enhanced pressure on the lateral part of the femoral head might increase the risk of AVN.

scholarly journals Contact pressure distribution of the hip joint during closed reduction of developmental dysplasia of the hip: A Patient-Specific Finite Element Analysis

2020 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Hai Li ◽  
Dashan Sui ◽  
Haiyi Qin ◽  
Ziming Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Head ◽  
Contact Pressure ◽  
Closed Reduction ◽  
Developmental Dysplasia ◽  
Abduction Angle ◽  
Lateral Part ◽  
Element Analysis ◽  
Dysplasia Of The Hip

Abstract Background: Developmental dysplasia of the hip (DDH) is the most common deformity of the lower extremity in children. The biomechanical change during closed reduction (CR) focused on cartilage contact pressure (CCP) has not been studied. Thereby, we try to provide insight into biomechanical factors potentially responsible for the success of CR treatment sand complications by using finite element analysis (FEA) for the first time.Methods: Finite element models of one patient with DDH were established based on the data of MRI scan on which cartilage contact pressure was measured. During CR, CCP between the femoral head and acetabulum in different abduction and flexion angles were tested to estimate the efficacy and potential risk factors of avascular necrosis (AVN) following CR.Results: A 3D reconstruction by the FEA method was performed on a sixteen months of age girl with DDH on the right side. The acetabulum of the involved side showed a long, narrow, and "flat-shaped" deformity, whereas the femoral head was smaller and irregular compared with the contralateral side. With increased abduction angle, the stress of the posterior acetabulum increased significantly, and the stress on the lateral part of the femoral head increased as well. The changes of CCP in the superior acetabulum were not apparent during CR. There were no detectable differences in terms of pressure on the femoral head.Conclusions: Severe dislocation (IHDI grade III and IV) in children showed a high mismatch between the femoral head and acetabulum. Increased abduction angle corresponded with high contact pressure, which might relate to AVN, whereas increased flexion angle was not. Enhanced pressure on the lateral part of the femoral head might increase the risk of AVN.

scholarly journals Contact pressure distribution of the hip joint during closed reduction of developmental dysplasia of the hip: A Patient-Specific Finite Element Analysis

2020 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Hai Li ◽  
Dashan Sui ◽  
Haiyi Qin ◽  
Ziming Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Head ◽  
Contact Pressure ◽  
Closed Reduction ◽  
Developmental Dysplasia ◽  
Abduction Angle ◽  
Lateral Part ◽  
Element Analysis ◽  
Dysplasia Of The Hip

Abstract Background Developmental dysplasia of the hip (DDH) is the most common deformity of the lower extremity in children, and the etiology remains unclear. The biomechanical change during closed reduction (CR) focused on cartilage contact pressure (CCP) has not been studied. Thereby, we try to provide insight into biomechanical factors potentially responsible for CR treatment success and complications by using finite element analysis (FEA) for the first time. Methods Finite element models of one patient with DDH were established based on the data of MRI scan on which cartilage contact pressure was measured. During CR, CCP between the femoral head and acetabulum in different abduction and flexion angles were tested to estimate the efficacy and potential risk factors of avascular necrosis (AVN) following CR. Results A 3D reconstruction by the FEA method was performed on a sixteen-month-old girl with DDH on the right side. The acetabulum of the involved side showed a long, narrow, and "plate-shaped" deformity, whereas the femoral head was smaller and irregular compared with the contralateral side. With increased abduction angle, the stress of the posterior acetabulum increased significantly, and the stress on the lateral part of the femoral head increased as well. The changes of CCP in the superior acetabulum were not apparent during CR. There were no detectable differences in terms of pressure on the femoral head. Conclusions Severe dislocation (IHDI grade III and IV) in children showed a high mismatch between the femoral head and acetabulum. Increased abduction angle corresponded with high contact pressure, which might relate to avascular necrosis, whereas increased flexion angle was not. Enhanced pressure on the lateral part of the femoral head might increase the risk of AVN.

scholarly journals Contact Pressure Distribution of the Hip Joint During Closed Reduction of Developmental Dysplasia of the Hip

2020 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Hai Li ◽  
Dashan Sui ◽  
Haiyi Qin ◽  
Ziming Zhang
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Avascular Necrosis ◽  
Contact Pressure ◽  
Closed Reduction ◽  
Treatment Success ◽  
Developmental Dysplasia ◽  
Abduction Angle ◽  
Lateral Part ◽  
Dysplasia Of The Hip

Abstract Background: Developmental dysplasia of the hip (DDH) is the most common deformity of the lower extremity in children, and the etiology remains unclear. The biomechanical change during closed reduction (CR) focused on cartilage contact pressure (CCP) has not been studied. Thereby, we try to provide insight into biomechanical factors potentially responsible for CR treatment success and complications by using finite element analysis (FEA) for the first time.Methods: Finite element models of one patient with DDH were established based on the data of MRI scan on which cartilage contact pressure was measured. During CR, CCP between the femoral head and acetabulum in different abduction and flexion angles were tested to estimate the efficacy and potential risk factors of avascular necrosis (AVN) following CR.Results: A 3D reconstruction by the FEA method was performed on a sixteen-month-old girl with DDH on the right side. The acetabulum of the involved side showed a long, narrow, and "plate-shaped" deformity, whereas the femoral head was smaller and irregular compared with the contralateral side. With increased abduction angle, the stress of the posterior acetabulum increased significantly, and the stress on the lateral part of the femoral head increased as well. The changes of CCP in the superior acetabulum were not apparent during CR. There were no detectable differences in terms of pressure on the femoral head.Conclusions: Severe dislocation (IHDI grade III and IV) in children showed a high mismatch between the femoral head and acetabulum. Increased abduction angle corresponded with high contact pressure, which might relate to avascular necrosis, whereas increased flexion angle was not. Enhanced pressure on the lateral part of the femoral head might increase the risk of AVN.

scholarly journals Effect of coronal plane acetabular correction on joint contact pressure in Periacetabular osteotomy: a finite-element analysis

2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Kenji Kitamura ◽  
Masanori Fujii ◽  
Miho Iwamoto ◽  
Satoshi Ikemura ◽  
Satoshi Hamai ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Periacetabular Osteotomy ◽  
Anterior Wall ◽  
Coronal Plane ◽  
Patient Specific ◽  
Element Analysis ◽  
Joint Contact ◽  
Joint Contact Pressure

Abstract Background The ideal acetabular position for optimizing hip joint biomechanics in periacetabular osteotomy (PAO) remains unclear. We aimed to determine the relationship between acetabular correction in the coronal plane and joint contact pressure (CP) and identify morphological factors associated with residual abnormal CP after correction. Methods Using CT images from 44 patients with hip dysplasia, we performed three patterns of virtual PAOs on patient-specific 3D hip models; the acetabulum was rotated laterally to the lateral center-edge angles (LCEA) of 30°, 35°, and 40°. Finite-element analysis was used to calculate the CP of the acetabular cartilage during a single-leg stance. Results Coronal correction to the LCEA of 30° decreased the median maximum CP 0.5-fold compared to preoperatively (p <  0.001). Additional correction to the LCEA of 40° further decreased CP in 15 hips (34%) but conversely increased CP in 29 hips (66%). The increase in CP was associated with greater preoperative extrusion index (p = 0.030) and roundness index (p = 0.038). Overall, virtual PAO failed to normalize CP in 11 hips (25%), and a small anterior wall index (p = 0.049) and a large roundness index (p = 0.003) were associated with residual abnormal CP. Conclusions The degree of acetabular correction in the coronal plane where CP is minimized varied among patients. Coronal plane correction alone failed to normalize CP in 25% of patients in this study. In patients with an anterior acetabular deficiency (anterior wall index < 0.21) and an aspherical femoral head (roundness index > 53.2%), coronal plane correction alone may not normalize CP. Further studies are needed to clarify the effectiveness of multiplanar correction, including in the sagittal and axial planes, in optimizing the hip joint’s contact mechanics.

Femoral head necrosis: A finite element analysis of common and novel surgical techniques

2017 ◽  
Vol 48 ◽  
pp. 49-56 ◽  
Author(s):  
Myriam Cilla ◽  
Sara Checa ◽  
Bernd Preininger ◽  
Tobias Winkler ◽  
Carsten Perka ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Head ◽  
Surgical Techniques ◽  
Femoral Head Necrosis ◽  
Element Analysis

Evaluation of the Elliptical Flange Configurations for 24-Inch and 30-Inch Heater/Cooler Units

2007 ◽  
Author(s):  
Chris Alexander ◽  
Wade Armer ◽  
Stuart Harbert
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Exchanger ◽  
Contact Pressure ◽  
Parameter Study ◽  
Element Analysis ◽  
Iterative Design ◽  
Pressure Changes ◽  
Geometric Changes ◽  
Maximum Contact

KOCH Heat Transfer Company contracted Stress Engineering Services, Inc. to perform a design/parameter study of a return bonnet used in hairpin heat exchangers that employs an elliptical flange design. The return bonnet is an important component of the heat exchanger as it can be removed to permit inspection of the heat exchanger tubes. The return bonnet is bolted to the hairpin leg flange. To maintain sealing integrity a gasket is placed between the return bonnet flange and the hairpin leg flange. The sealing efficiency of two return bonnet sizes (24-inch and 30-inch) was investigated in this study using finite element analysis. The sealing efficiency is an indication of how the contact pressure changes circumferentially around the gasket and is calculated by dividing the local contact pressure by the maximum contact pressure calculated in the gasket for each respective design. The study assessed the effects of geometric changes to the mating flanges. Using an iterative design process using finite element analysis, the elliptical flanges were optimized to maximize sealing efficiency. Upon completion of the study, the manufacturer successfully employed the modifications as evidenced with multiple successful hydrotests.

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