The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Raphael Dumas - One of the best experts on this subject based on the ideXlab platform.
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Correcting lower limb segment axis misalignment in gait analysis: A simple Geometrical Method.
Gait & posture, 2019Co-Authors: Alexandre Naaim, Alice Bonnefoy-mazure, Stéphane Armand, Raphael DumasAbstract:Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. This study proposes an a posteriori Geometrical Method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. The proposed Method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation Method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Crosstalk was significantly reduced from r² = 0.67 to r² = 0.51 by the Geometrical Method but remained significantly higher than with the optimisation Method with a r² < 0.01. Both Methods allowed to improve the hip internal-external reproducibility from poor to moderate (original data: ICC = 0.34, Geometrical Method: ICC = 0.65, optimisation Method ICC = 0.73). One advantage of the Geometrical Method is that, unlike the optimisation Method, it does not require much movement, making it suitable for a wider range of patients. Copyright © 2019 Elsevier B.V. All rights reserved.
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Correcting lower limb segment axis misalignment in gait analysis: A simple Geometrical Method
Gait and Posture, 2019Co-Authors: Alexandre Naaim, Alice Bonnefoy-mazure, Stéphane Armand, Raphael DumasAbstract:Background Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. Research question This study proposes an a posteriori Geometrical Method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. Methods The proposed Method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation Method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Results Crosstalk was significantly reduced from r²?=?0.67 to r²?=?0.51 by the Geometrical Method but remained significantly higher than with the optimisation Method with a r²?
Claudio Lamartina - One of the best experts on this subject based on the ideXlab platform.
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Successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age
European Spine Journal, 2014Co-Authors: Pedro Berjano, Francesco Langella, Maryem-fama Ismael, Marco Damilano, Sergio Scopetta, Claudio LamartinaAbstract:Introduction Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several Methods of preoperative calculation for sagittal correction have been proposed, most of them are Geometrical. A non-Geometrical Method, based on data of spinopelvic relationships in normal subjects that uses the patient’s pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-Geometrical Method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment. Materials and Methods Retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms [Method a: LL = −(32.56 + PI × 0.54), Method b: LL = −(PI + 10°)]; in both TK = (PI/ r )-LL, see text for definitions] obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA
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successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age
European Spine Journal, 2014Co-Authors: Pedro Berjano, Francesco Langella, Maryem-fama Ismael, Marco Damilano, Sergio Scopetta, Claudio LamartinaAbstract:Introduction Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several Methods of preoperative calculation for sagittal correction have been proposed, most of them are Geometrical. A non-Geometrical Method, based on data of spinopelvic relationships in normal subjects that uses the patient’s pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-Geometrical Method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment.
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Successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age.
European spine journal : official publication of the European Spine Society the European Spinal Deformity Society and the European Section of the Cerv, 2014Co-Authors: Pedro Berjano, Francesco Langella, Maryem-fama Ismael, Marco Damilano, Sergio Scopetta, Claudio LamartinaAbstract:Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several Methods of preoperative calculation for sagittal correction have been proposed, most of them are Geometrical. A non-Geometrical Method, based on data of spinopelvic relationships in normal subjects that uses the patient's pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-Geometrical Method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment. Retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms [Method a: LL = -(32.56 + PI × 0.54), Method b: LL = -(PI + 10°)]; in both TK = (PI/r)-LL, see text for definitions] obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA < 50 mm and PT < 20°) achieved or not. 2 × 2 tables are built and odds ratio, sensitivity and specificity and predictive positive value/predictive negative value (PPV/NPV) are calculated for each planning Method. Different levels of tolerance for undercorrection are analyzed to refine the use of the Method. Of the 50 patients included in the study, 23 presented satisfactory alignment postoperatively. With a tolerance of hypocorrection of 10° (LL) and 30° (TK), correction target was achieved in 23 patients according to Method a [S = 0.89, Sp = 0.87 %, OR 53.33 (95 % CI 9.677-293.931), p < 0.001], 23 patients according to Method b [S = 0.93, Sp = 0.91, OR 131.25 (95 % CI 17-1013), p < 0.001]. The best prediction of satisfactory alignment was obtained with Method b and tolerance 0° (LL) and 10° (TK). All patients with complete correction of LL (both Methods) achieved good alignment. 22/24 (91 %) patients with less than 10° of undercorrection of LL (Method b) achieved good alignment. Calculation of the target lordosis and kyphosis based only in the value of PI and age is a reliable Method that can predict good outcomes in terms of alignment. The rule LL = -(PI + 10°) is an easy to calculate and very effective Method of planning for lumbar lordosis and good alignment can be expected with high confidence when the final lordosis is within 10° of undercorrection. Including TK in surgical planning can improve the results in terms of restoration of the less known "spinopelvic balance" parameter.
Alexandre Naaim - One of the best experts on this subject based on the ideXlab platform.
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Correcting lower limb segment axis misalignment in gait analysis: A simple Geometrical Method.
Gait & posture, 2019Co-Authors: Alexandre Naaim, Alice Bonnefoy-mazure, Stéphane Armand, Raphael DumasAbstract:Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. This study proposes an a posteriori Geometrical Method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. The proposed Method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation Method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Crosstalk was significantly reduced from r² = 0.67 to r² = 0.51 by the Geometrical Method but remained significantly higher than with the optimisation Method with a r² < 0.01. Both Methods allowed to improve the hip internal-external reproducibility from poor to moderate (original data: ICC = 0.34, Geometrical Method: ICC = 0.65, optimisation Method ICC = 0.73). One advantage of the Geometrical Method is that, unlike the optimisation Method, it does not require much movement, making it suitable for a wider range of patients. Copyright © 2019 Elsevier B.V. All rights reserved.
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Correcting lower limb segment axis misalignment in gait analysis: A simple Geometrical Method
Gait and Posture, 2019Co-Authors: Alexandre Naaim, Alice Bonnefoy-mazure, Stéphane Armand, Raphael DumasAbstract:Background Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. Research question This study proposes an a posteriori Geometrical Method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. Methods The proposed Method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation Method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Results Crosstalk was significantly reduced from r²?=?0.67 to r²?=?0.51 by the Geometrical Method but remained significantly higher than with the optimisation Method with a r²?
Pedro Berjano - One of the best experts on this subject based on the ideXlab platform.
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Successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age
European Spine Journal, 2014Co-Authors: Pedro Berjano, Francesco Langella, Maryem-fama Ismael, Marco Damilano, Sergio Scopetta, Claudio LamartinaAbstract:Introduction Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several Methods of preoperative calculation for sagittal correction have been proposed, most of them are Geometrical. A non-Geometrical Method, based on data of spinopelvic relationships in normal subjects that uses the patient’s pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-Geometrical Method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment. Materials and Methods Retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms [Method a: LL = −(32.56 + PI × 0.54), Method b: LL = −(PI + 10°)]; in both TK = (PI/ r )-LL, see text for definitions] obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA
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successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age
European Spine Journal, 2014Co-Authors: Pedro Berjano, Francesco Langella, Maryem-fama Ismael, Marco Damilano, Sergio Scopetta, Claudio LamartinaAbstract:Introduction Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several Methods of preoperative calculation for sagittal correction have been proposed, most of them are Geometrical. A non-Geometrical Method, based on data of spinopelvic relationships in normal subjects that uses the patient’s pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-Geometrical Method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment.
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Successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age.
European spine journal : official publication of the European Spine Society the European Spinal Deformity Society and the European Section of the Cerv, 2014Co-Authors: Pedro Berjano, Francesco Langella, Maryem-fama Ismael, Marco Damilano, Sergio Scopetta, Claudio LamartinaAbstract:Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several Methods of preoperative calculation for sagittal correction have been proposed, most of them are Geometrical. A non-Geometrical Method, based on data of spinopelvic relationships in normal subjects that uses the patient's pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-Geometrical Method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment. Retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms [Method a: LL = -(32.56 + PI × 0.54), Method b: LL = -(PI + 10°)]; in both TK = (PI/r)-LL, see text for definitions] obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA < 50 mm and PT < 20°) achieved or not. 2 × 2 tables are built and odds ratio, sensitivity and specificity and predictive positive value/predictive negative value (PPV/NPV) are calculated for each planning Method. Different levels of tolerance for undercorrection are analyzed to refine the use of the Method. Of the 50 patients included in the study, 23 presented satisfactory alignment postoperatively. With a tolerance of hypocorrection of 10° (LL) and 30° (TK), correction target was achieved in 23 patients according to Method a [S = 0.89, Sp = 0.87 %, OR 53.33 (95 % CI 9.677-293.931), p < 0.001], 23 patients according to Method b [S = 0.93, Sp = 0.91, OR 131.25 (95 % CI 17-1013), p < 0.001]. The best prediction of satisfactory alignment was obtained with Method b and tolerance 0° (LL) and 10° (TK). All patients with complete correction of LL (both Methods) achieved good alignment. 22/24 (91 %) patients with less than 10° of undercorrection of LL (Method b) achieved good alignment. Calculation of the target lordosis and kyphosis based only in the value of PI and age is a reliable Method that can predict good outcomes in terms of alignment. The rule LL = -(PI + 10°) is an easy to calculate and very effective Method of planning for lumbar lordosis and good alignment can be expected with high confidence when the final lordosis is within 10° of undercorrection. Including TK in surgical planning can improve the results in terms of restoration of the less known "spinopelvic balance" parameter.
Stéphane Armand - One of the best experts on this subject based on the ideXlab platform.
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Correcting lower limb segment axis misalignment in gait analysis: A simple Geometrical Method.
Gait & posture, 2019Co-Authors: Alexandre Naaim, Alice Bonnefoy-mazure, Stéphane Armand, Raphael DumasAbstract:Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. This study proposes an a posteriori Geometrical Method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. The proposed Method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation Method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Crosstalk was significantly reduced from r² = 0.67 to r² = 0.51 by the Geometrical Method but remained significantly higher than with the optimisation Method with a r² < 0.01. Both Methods allowed to improve the hip internal-external reproducibility from poor to moderate (original data: ICC = 0.34, Geometrical Method: ICC = 0.65, optimisation Method ICC = 0.73). One advantage of the Geometrical Method is that, unlike the optimisation Method, it does not require much movement, making it suitable for a wider range of patients. Copyright © 2019 Elsevier B.V. All rights reserved.
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Correcting lower limb segment axis misalignment in gait analysis: A simple Geometrical Method
Gait and Posture, 2019Co-Authors: Alexandre Naaim, Alice Bonnefoy-mazure, Stéphane Armand, Raphael DumasAbstract:Background Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. Research question This study proposes an a posteriori Geometrical Method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. Methods The proposed Method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation Method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Results Crosstalk was significantly reduced from r²?=?0.67 to r²?=?0.51 by the Geometrical Method but remained significantly higher than with the optimisation Method with a r²?