The Experts below are selected from a list of 30729 Experts worldwide ranked by ideXlab platform
Naiquan Nigel Zheng - One of the best experts on this subject based on the ideXlab platform.
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transtibial versus anteromedial portal technique in single bundle anterior cruciate ligament reconstruction outcomes of knee Joint Kinematics during walking
American Journal of Sports Medicine, 2013Co-Authors: Hongsheng Wang, James E Fleischli, Naiquan Nigel ZhengAbstract:Background:In anterior cruciate ligament (ACL) reconstruction, the transtibial (TT) technique often creates a nonanatomically placed femoral tunnel, which is a frequent cause of surgical failure and postsurgical knee instability. Several studies reported that drilling the femoral tunnel through an anteromedial portal (AMP) yields a more anatomic tunnel position compared with the TT technique.Purpose:To compare the effectiveness of these two surgical techniques in restoring the intact knee Joint Kinematics during a physiological loading situation.Study Design:Controlled laboratory study.Methods:Twenty-four patients (TT, n = 12; AMP, n = 12; sex, weight, and height matched, and half with dominant leg involved) who underwent unilateral single-bundle ACL reconstruction by the same surgeon were recruited. Twenty healthy patients with no history of lower limb injuries were recruited as the control group. Tibiofemoral Joint motion in 6 degrees of freedom (3 translations and 3 rotations) was determined during lev...
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alterations in three dimensional Joint Kinematics of anterior cruciate ligament deficient and reconstructed knees during walking
Clinical Biomechanics, 2010Co-Authors: Bo Gao, Naiquan Nigel ZhengAbstract:Abstract Background High risk of cartilage degeneration and premature osteoarthritis development has been clinically observed in anterior cruciate ligament (ACL) deficient knees. The risk has not been significantly reduced even after ACL reconstructive surgery. It was hypothesized that three-dimensional knee Joint Kinematics has been altered after ACL injury, and the biomechanical alteration has not been fully restored to a normal level after reconstructive surgery. Methods Spatiotemporal parameters and three-dimensional knee Joint rotations and translations were measured in ACL-deficient, ACL-reconstructed, and ACL-intact knees during level walking. The variables were compared between the ACL-deficient and ACL-intact knees, as well as between the ACL-reconstructed and ACL-intact knees. Findings Altered spatiotemporal variables and key event timings in a gait cycle were observed in both ACL-deficient and ACL-reconstructed subjects. Significant reduction of extension was observed in the ACL-deficient knees during midstance and in the ACL-reconstructed knees during swing phase. Greater varus and internal tibial rotation were identified in the ACL-deficient knees. Although being small in magnitude, these secondary kinematic alterations were consistent throughout the whole gait cycle, and such trends were not eliminated in the ACL-reconstructed knees. Interpretation Significant abnormalities of spatiotemporal performance and three-dimensional Joint Kinematics during walking were identified in the ACL-deficient knees. The ACL-reconstructed knees exhibited some improvement in Joint Kinematics, but not being fully restored to a normal level. Identification of biomechanical alterations during daily activities in ACL-deficient and ACL-reconstructed knees could help better understand clinical outcomes and seek improvement in surgical technique and rehabilitation regimen for ACL injury treatment.
Joseph P Iannotti - One of the best experts on this subject based on the ideXlab platform.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics during humeral axial rotation in total shoulder arthroplasty
Journal of Shoulder and Elbow Surgery, 2016Co-Authors: Bong Jae Jun, Michelle H. Mcgarry, Ryan J Quigley, Thay Q Lee, Sangjin Shin, Joseph P IannottiAbstract:Background A non-spherical humeral head has been shown to influence Kinematics and stability of the glenohumeral Joint; yet, most prosthetic humeral head components are designed to be a perfect sphere. The effect of humeral head shape on prosthetic Joint Kinematics after total shoulder arthroplasty is not well understood. We hypothesized that prosthetic Joint Kinematics during humeral axial rotation is dependent on humeral head shape, regardless of Joint conformity. Methods Four prosthetic configurations were investigated using a spherical and a non-spherical prosthetic humeral head articulated with a conforming and a non-conforming glenoid component. Testing was performed in the coronal, scapular, and forward flexion plane at 0°, 30°, and 60° of abduction. Prosthetic Joint Kinematics was measured in 10° intervals during a 100° arc of humeral axial rotation. Glenohumeral translation patterns, net glenohumeral translation, and averaged glenohumeral translation were compared for each of 4 configurations. Results Non-spherical head configurations increased the net glenohumeral translation during humeral axial rotation in multiple test positions compared with spherical head configurations ( P P > .05). Conclusion During humeral axial rotation, the non-spherical humeral head shape contributes to increased glenohumeral translation during humeral axial rotation. However, the spherical head shape does not show significant glenohumeral translation during humeral axial rotation, regardless of glenoid conformity.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics a comparison of non spherical and spherical prosthetic heads to the native humeral head
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Joseph P Iannotti, Michelle H. Mcgarry, Ryan J QuigleyAbstract:Background The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral Joint Kinematics. Methods Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation. Rotational range of motion was measured with 3.3 Nm of torque. Glenohumeral Joint Kinematics was quantified by the position vectors of the humeral head apex (HHA) and geometric center of the humeral head (GCHH) to calculate translation of HHA and GCHH per degree of humeral rotation. Results The non-spherical prosthetic head replicated the native head shape more accurately than the spherical prosthetic head. Between the non-spherical and native heads, there was no statistical difference in rotational range of motion (P > .05), but a statistical difference in HHA and GCHH translation was found at 60° of scapular plane abduction in the interval from 30° of internal rotation to neutral rotation and at 30° of forward flexion plane abduction in the interval from 30° of external rotation to maximum external rotation, respectively (P < .05). The spherical head significantly decreased rotational range of motion (P < .05), increased HHA translation per degree (P < .05), and decreased GCHH translation per degree (P < .05) in multiple positions compared with the native humeral head. Conclusion The custom, non-spherical prosthetic head more accurately replicated the head shape, rotational range of motion, and glenohumeral Joint Kinematics than the commercially available, spherical prosthetic head compared with the native humeral head.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics a comparison of non spherical and spherical prosthetic heads to the native humeral head
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Michelle H. Mcgarry, Joseph P Iannotti, Ryan J Quigley, Bong Jae Jun, Jae Chul Yoo, Thay Q LeeAbstract:Background The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral Joint Kinematics. Methods Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation. Rotational range of motion was measured with 3.3 Nm of torque. Glenohumeral Joint Kinematics was quantified by the position vectors of the humeral head apex (HHA) and geometric center of the humeral head (GCHH) to calculate translation of HHA and GCHH per degree of humeral rotation. Results The non-spherical prosthetic head replicated the native head shape more accurately than the spherical prosthetic head. Between the non-spherical and native heads, there was no statistical difference in rotational range of motion (P > .05), but a statistical difference in HHA and GCHH translation was found at 60° of scapular plane abduction in the interval from 30° of internal rotation to neutral rotation and at 30° of forward flexion plane abduction in the interval from 30° of external rotation to maximum external rotation, respectively (P Conclusion The custom, non-spherical prosthetic head more accurately replicated the head shape, rotational range of motion, and glenohumeral Joint Kinematics than the commercially available, spherical prosthetic head compared with the native humeral head.
Bong Jae Jun - One of the best experts on this subject based on the ideXlab platform.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics during humeral axial rotation in total shoulder arthroplasty
Journal of Shoulder and Elbow Surgery, 2016Co-Authors: Bong Jae Jun, Michelle H. Mcgarry, Ryan J Quigley, Thay Q Lee, Sangjin Shin, Joseph P IannottiAbstract:Background A non-spherical humeral head has been shown to influence Kinematics and stability of the glenohumeral Joint; yet, most prosthetic humeral head components are designed to be a perfect sphere. The effect of humeral head shape on prosthetic Joint Kinematics after total shoulder arthroplasty is not well understood. We hypothesized that prosthetic Joint Kinematics during humeral axial rotation is dependent on humeral head shape, regardless of Joint conformity. Methods Four prosthetic configurations were investigated using a spherical and a non-spherical prosthetic humeral head articulated with a conforming and a non-conforming glenoid component. Testing was performed in the coronal, scapular, and forward flexion plane at 0°, 30°, and 60° of abduction. Prosthetic Joint Kinematics was measured in 10° intervals during a 100° arc of humeral axial rotation. Glenohumeral translation patterns, net glenohumeral translation, and averaged glenohumeral translation were compared for each of 4 configurations. Results Non-spherical head configurations increased the net glenohumeral translation during humeral axial rotation in multiple test positions compared with spherical head configurations ( P P > .05). Conclusion During humeral axial rotation, the non-spherical humeral head shape contributes to increased glenohumeral translation during humeral axial rotation. However, the spherical head shape does not show significant glenohumeral translation during humeral axial rotation, regardless of glenoid conformity.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics a comparison of non spherical and spherical prosthetic heads to the native humeral head
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Michelle H. Mcgarry, Joseph P Iannotti, Ryan J Quigley, Bong Jae Jun, Jae Chul Yoo, Thay Q LeeAbstract:Background The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral Joint Kinematics. Methods Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation. Rotational range of motion was measured with 3.3 Nm of torque. Glenohumeral Joint Kinematics was quantified by the position vectors of the humeral head apex (HHA) and geometric center of the humeral head (GCHH) to calculate translation of HHA and GCHH per degree of humeral rotation. Results The non-spherical prosthetic head replicated the native head shape more accurately than the spherical prosthetic head. Between the non-spherical and native heads, there was no statistical difference in rotational range of motion (P > .05), but a statistical difference in HHA and GCHH translation was found at 60° of scapular plane abduction in the interval from 30° of internal rotation to neutral rotation and at 30° of forward flexion plane abduction in the interval from 30° of external rotation to maximum external rotation, respectively (P Conclusion The custom, non-spherical prosthetic head more accurately replicated the head shape, rotational range of motion, and glenohumeral Joint Kinematics than the commercially available, spherical prosthetic head compared with the native humeral head.
Ryan J Quigley - One of the best experts on this subject based on the ideXlab platform.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics during humeral axial rotation in total shoulder arthroplasty
Journal of Shoulder and Elbow Surgery, 2016Co-Authors: Bong Jae Jun, Michelle H. Mcgarry, Ryan J Quigley, Thay Q Lee, Sangjin Shin, Joseph P IannottiAbstract:Background A non-spherical humeral head has been shown to influence Kinematics and stability of the glenohumeral Joint; yet, most prosthetic humeral head components are designed to be a perfect sphere. The effect of humeral head shape on prosthetic Joint Kinematics after total shoulder arthroplasty is not well understood. We hypothesized that prosthetic Joint Kinematics during humeral axial rotation is dependent on humeral head shape, regardless of Joint conformity. Methods Four prosthetic configurations were investigated using a spherical and a non-spherical prosthetic humeral head articulated with a conforming and a non-conforming glenoid component. Testing was performed in the coronal, scapular, and forward flexion plane at 0°, 30°, and 60° of abduction. Prosthetic Joint Kinematics was measured in 10° intervals during a 100° arc of humeral axial rotation. Glenohumeral translation patterns, net glenohumeral translation, and averaged glenohumeral translation were compared for each of 4 configurations. Results Non-spherical head configurations increased the net glenohumeral translation during humeral axial rotation in multiple test positions compared with spherical head configurations ( P P > .05). Conclusion During humeral axial rotation, the non-spherical humeral head shape contributes to increased glenohumeral translation during humeral axial rotation. However, the spherical head shape does not show significant glenohumeral translation during humeral axial rotation, regardless of glenoid conformity.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics a comparison of non spherical and spherical prosthetic heads to the native humeral head
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Joseph P Iannotti, Michelle H. Mcgarry, Ryan J QuigleyAbstract:Background The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral Joint Kinematics. Methods Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation. Rotational range of motion was measured with 3.3 Nm of torque. Glenohumeral Joint Kinematics was quantified by the position vectors of the humeral head apex (HHA) and geometric center of the humeral head (GCHH) to calculate translation of HHA and GCHH per degree of humeral rotation. Results The non-spherical prosthetic head replicated the native head shape more accurately than the spherical prosthetic head. Between the non-spherical and native heads, there was no statistical difference in rotational range of motion (P > .05), but a statistical difference in HHA and GCHH translation was found at 60° of scapular plane abduction in the interval from 30° of internal rotation to neutral rotation and at 30° of forward flexion plane abduction in the interval from 30° of external rotation to maximum external rotation, respectively (P < .05). The spherical head significantly decreased rotational range of motion (P < .05), increased HHA translation per degree (P < .05), and decreased GCHH translation per degree (P < .05) in multiple positions compared with the native humeral head. Conclusion The custom, non-spherical prosthetic head more accurately replicated the head shape, rotational range of motion, and glenohumeral Joint Kinematics than the commercially available, spherical prosthetic head compared with the native humeral head.
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the effects of prosthetic humeral head shape on glenohumeral Joint Kinematics a comparison of non spherical and spherical prosthetic heads to the native humeral head
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Michelle H. Mcgarry, Joseph P Iannotti, Ryan J Quigley, Bong Jae Jun, Jae Chul Yoo, Thay Q LeeAbstract:Background The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral Joint Kinematics. Methods Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation. Rotational range of motion was measured with 3.3 Nm of torque. Glenohumeral Joint Kinematics was quantified by the position vectors of the humeral head apex (HHA) and geometric center of the humeral head (GCHH) to calculate translation of HHA and GCHH per degree of humeral rotation. Results The non-spherical prosthetic head replicated the native head shape more accurately than the spherical prosthetic head. Between the non-spherical and native heads, there was no statistical difference in rotational range of motion (P > .05), but a statistical difference in HHA and GCHH translation was found at 60° of scapular plane abduction in the interval from 30° of internal rotation to neutral rotation and at 30° of forward flexion plane abduction in the interval from 30° of external rotation to maximum external rotation, respectively (P Conclusion The custom, non-spherical prosthetic head more accurately replicated the head shape, rotational range of motion, and glenohumeral Joint Kinematics than the commercially available, spherical prosthetic head compared with the native humeral head.
Toshiki Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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the effects of alignment of an articulated ankle foot orthosis on lower limb Joint Kinematics and kinetics during gait in individuals post stroke
Journal of Biomechanics, 2019Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Lucas S. Lincoln, Grace Hunt, Nicholas Lecursi, Bo K ForemanAbstract:Abstract Mechanical tuning of an ankle-foot orthosis (AFO) is important in improving gait in individuals post-stroke. Alignment and resistance are two factors that are tunable in articulated AFOs. The aim of this study was to investigate the effects of changing AFO ankle alignment on lower limb Joint Kinematics and kinetics with constant dorsiflexion and plantarflexion resistance in individuals post-stroke. Gait analysis was performed on 10 individuals post-stroke under four distinct alignment conditions using an articulated AFO with an ankle Joint whose alignment is adjustable in the sagittal plane. Kinematic and kinetic data of lower limb Joints were recorded using a Vicon 3-dimensional motion capture system and Bertec split-belt instrumented treadmill. The incremental changes in the alignment of the articulated AFO toward dorsiflexion angles significantly affected ankle and knee Joint angles and knee Joint moments while walking in individuals post-stroke. No significant differences were found in the hip Joint parameters. The alignment of the articulated AFO was suggested to play an important role in improving knee Joint Kinematics and kinetics in stance through improvement of ankle Joint Kinematics while walking in individuals post-stroke. Future studies should investigate long-term effects of AFO alignment on gait in the community in individuals post-stroke.
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The effects of an articulated ankle-foot orthosis with resistance-adjustable Joints on lower limb Joint Kinematics and kinetics during gait in individuals post-stroke.
Clinical Biomechanics, 2018Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Lucas S. Lincoln, Grace Hunt, Nicholas Lecursi, K. Bo ForemanAbstract:Abstract Background Resistance is a key mechanical property of an ankle-foot orthosis that affects gait in individuals post-stroke. Triple Action® Joints allow independent adjustment of plantarflexion resistance and dorsiflexion resistance of an ankle-foot orthosis. Therefore, the aim of this study was to investigate the effects of incremental changes in dorsiflexion and plantarflexion resistance of an articulated ankle-foot orthosis with the Triple Action Joints on lower limb Joint Kinematics and kinetics in individuals post-stroke during gait. Methods Gait analysis was performed on 10 individuals who were post-stroke under eight resistance settings (four plantarflexion and four dorsiflexion resistances) using the articulated ankle-foot orthosis. Kinematic and kinetic data of the lower limb Joints were recorded while walking using a three-dimensional Vicon motion capture system and a Bertec split-belt instrumented treadmill. Findings Repeated measures analysis of variance revealed that adjustment of plantarflexion resistance had significant main effects on the ankle (P Interpretation This study demonstrated that the adjustments of resistance in the ankle-foot orthosis with the Triple Action Joints influenced ankle and knee Kinematics in individuals post-stroke. Further work is necessary to investigate the long-term effects of the articulated ankle-foot orthoses on their gait.
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the effect of varying the plantarflexion resistance of an ankle foot orthosis on knee Joint Kinematics in patients with stroke
Gait & Posture, 2013Co-Authors: Toshiki Kobayashi, Aaron K L Leung, Yasushi Akazawa, Stephen W HutchinsAbstract:Abstract Ankle-foot orthoses (AFOs) can improve gait in patients with hemiplegia. However, it is anecdotally known that excessive plantarflexion resistance of an AFO could induce undesired knee flexion at early stance. The aim of this study was to systematically investigate the effect of varying the degrees of plantarflexion resistance of an AFO on knee flexion angles at early stance in five subjects with chronic stroke who demonstrated two clear knee flexion peaks at early stance and swing. Each subject wore an experimental AFO constructed with an oil-damper type ankle Joint and was instructed to walk at their self-selected walking speed under five plantarflexion resistance conditions. The sagittal plane ankle and knee Joint Kinematics and gait speed were analyzed using a 3-D Motion Analysis System. A number of significant differences ( P
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the effect of varying the plantarflexion resistance of an ankle foot orthosis on knee Joint Kinematics in patients with stroke
Gait & Posture, 2013Co-Authors: Toshiki Kobayashi, Aaron K L Leung, Yasushi Akazawa, Stephen W HutchinsAbstract:Ankle-foot orthoses (AFOs) can improve gait in patients with hemiplegia. However, it is anecdotally known that excessive plantarflexion resistance of an AFO could induce undesired knee flexion at early stance. The aim of this study was to systematically investigate the effect of varying the degrees of plantarflexion resistance of an AFO on knee flexion angles at early stance in five subjects with chronic stroke who demonstrated two clear knee flexion peaks at early stance and swing. Each subject wore an experimental AFO constructed with an oil-damper type ankle Joint and was instructed to walk at their self-selected walking speed under five plantarflexion resistance conditions. The sagittal plane ankle and knee Joint Kinematics and gait speed were analyzed using a 3-D Motion Analysis System. A number of significant differences (P<0.005) in maximum knee flexion angles at early stance amongst different plantarflexion resistance conditions were revealed. The knee flexion angle was 23.80 (3.25) degrees under the free hinge Joint condition (condition 1), while that was 26.09 (3.79) degrees under the largest resistance condition (condition 5). It was therefore demonstrated that increasing the plantarflexion resistance of an AFO would induce more knee flexion at early stance phase in patients with stroke.
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design of a stiffness adjustable ankle foot orthosis and its effect on ankle Joint Kinematics in patients with stroke
Gait & Posture, 2011Co-Authors: Toshiki Kobayashi, Aaron K L Leung, Yasushi Akazawa, Stephen W HutchinsAbstract:Ankle-foot orthoses (AFOs) are commonly prescribed to improve gait. The stiffness of an AFO is central for successful prescription; however, the recommended level of stiffness is currently based on the experience of clinicians. Therefore, the aim of this study was to design an experimental AFO (EAFO) whose stiffness was adjustable using commercially available oil-damper Joints, and to demonstrate its potential capability in investigating the effects of altering AFO stiffness on gait. The influence of the EAFO stiffness on ankle Joint Kinematics in sagittal plane was evaluated in 10 patients with stroke by altering the stiffness of its oil-damper- type orthotic ankle Joints using the four levels pre-set and defined by the manufacturer in dorsi- and plantarflexion directions independently. The mean peak plantarflexion angle was reduced by 105%, showing a change from 8.18 (3.14) degrees of plantarflexion to 0.38 (4.17) degrees of dorsiflexion, whilst the mean peak dorsiflexion angle was reduced by 44%, showing a change from 11.46 (5.57) degrees of dorsiflexion to 6.47 (5.23) degrees of dorsiflexion by altering the EAFO stiffness. The EAFO would therefore serve as a convenient tool when investigating the influence of AFO stiffness on gait in both clinical and research settings.
