Publications
76 results found
Amadi HO, Sanghavi S, Kamineni S, et al., 2007, Definition of the Capsular Insertion Plane on the Proximal Humerus, 10th International Congress of Shoulder and Elbow Surgery
Amadi HO, Banerjee S, Hansen UN, et al., 2007, Glenoid version: new technique from quantitative comparison of classical methods, 10th International Congress of Shoulder and Elbow Surgery
Amadi HO, 2007, Engineering the shoulder joint, Seasonal scientific seminars, Nigerian Society of Engineers
Amadi HO, Bull AMJ, Hansen UN, 2006, A resultant force and limiting ligament strains approach to computing glenohumeral joint translations, 5th World Congress of Biomechanics, Publisher: Journal of Biomechanics, Pages: S496-S496
The aims of this study were (1) to create a tool to investigate the loading of the intracapsular ligaments of the GHJ during shoulder movement, and (2) to investigate how the humeral head may need to translate to minimise ligament overstraining.Imaging datasets were used to create surface geometries of the GHJ. A joint coordinate system (JCS) was applied for kinematics description1. Five ligaments were modelled with literature-provided properties and insertions2,3. An algorithm was developed to relate clinical shoulder position data to the JCS. Ligament paths were modelled as a straight line from glenoid to humeral insertion with spherical wrapping on the humeral head adjusted according to the actual surface contour. These were used to quantify a resultant effect of the ligament loading. Physiological kinematics data during passive clinical examinations of the arm4 were applied to the model. In order to limit the overstraining of the ligaments, translations were imposed on these kinematics data in the direction of the resultant forces due to the ligaments. These translation were limited when the ligament strains were below an experimentally-derived physiological threshold2,3. Individual ligament loads of up to 290 N were predicted during impingement test kinematics when translations were not taken into account. This same movement resulted in a computed 3.1 mm anteroinferior translation of the humeral head when limiting ligament strains. There were no predicted translations for pure abduction and forward flexion without humeral axial rotation.There is currently no direct measure of translations of the shoulder that can be applied clinically. This work is a novel method that allows the relative ligament restraints during physiological motion to be calculated taking into account possible GHJ translations. This can be applied in guiding clinical kinematics tests, as well as surgical interventions.1Wu et al, J Biomech, 20052Boardman et al, J Should Elb Surg, 19963Biglian
Amadi HO, Bull AMJ, Hansen UN, 2006, Glenohumeral translations during simulated clinical examinations, 20th Congress of the European Society for Surgery of the Shoulder and the Elbow
Amadi HO, Bull AMJ, Hansen UN, 2006, Glenohumeral translations during simulated clinical examinations, 20th Congress of the European Society for Surgery of the Shoulder and the Elbow
Amadi HO, Bull AMJ, Hansen UN, 2006, Numerical tool for the reconstruction of the glenohumeral joint physiological kinematics, MuscSkelNet poster conference, Institute of Biomedical Engineering
Amadi HO, Bull AMJ, Hansen UN, 2006, A resultant force and limiting ligament strains approach to computing glenohumeral joint translations, Journal of Biomechanics, Vol: 39
The aims of this study were (1) to create a tool to investigate the loading of the intracapsular ligaments of the GHJ during shoulder movement, and (2) to investigate how the humeral head may need to translate to minimise ligament overstraining.Imaging datasets were used to create surface geometries of the GHJ. A joint coordinate system (JCS) was applied for kinematics description1. Five ligaments were modelled with literature-provided properties and insertions2,3. An algorithm was developed to relate clinical shoulder position data to the JCS. Ligament paths were modelled as a straight line from glenoid to humeral insertion with spherical wrapping on the humeral head adjusted according to the actual surface contour. These were used to quantify a resultant effect of the ligament loading. Physiological kinematics data during passive clinical examinations of the arm4 were applied to the model. In order to limit the overstraining of the ligaments, translations were imposed on these kinematics data in the direction of the resultant forces due to the ligaments. These translation were limited when the ligament strains were below an experimentally-derived physiological threshold2,3. Individual ligament loads of up to 290 N were predicted during impingement test kinematics when translations were not taken into account. This same movement resulted in a computed 3.1 mm anteroinferior translation of the humeral head when limiting ligament strains. There were no predicted translations for pure abduction and forward flexion without humeral axial rotation.There is currently no direct measure of translations of the shoulder that can be applied clinically. This work is a novel method that allows the relative ligament restraints during physiological motion to be calculated taking into account possible GHJ translations. This can be applied in guiding clinical kinematics tests, as well as surgical interventions.
Amadi HO, Bull AMJ, Hansen UN, 2006, . A numerical tool for the reconstruction of the physiological kinematics of the glenohumeral joint, World Congress of Biomechanics
The aim of this study was to apply a joint coordinate system (JCS) to imaging datasets of the GHJ and to reconstruct the kinematics with six degrees of freedom (DOF) in order to elucidate shoulder pathologies related to instability.Visible human data was used. The surface geometries of the scapula and humerus were reconstructed. The following landmarks were used to define the body-fixed coordinate frames: a least-squares fit approximation to the line joining the centres of the elliptical cross-sections of the scapular lateral border (S1) and the humeral shaft (H1), through the centres of the triangular cross-sections of the spine-root (S2), a normal to the best-fit plane over the glenoid rim (S3), and a line from the centre of a least-squares sphere fit over the humeral head to the most proximal point on the greater tubercle (H2). These vectors were used to define body-fixed right-handed Cartesian coordinate frames for the scapula and humerus. Coordinate axes were directed anteriorly: Sa=S1xS2, Ha=H1xH2, superiorly: Ss=SaxS3, Hs=H1, and laterally: Sl=SaxSs, Hl=HaxHs, respectively. The JCS was defined with Sl, Ha and the floating axis: f=SlxHa. Humeral flexion and lateral translation, abduction and anterior translation, and internal rotation and compression relative to the scapula were implemented about and along Sl, f and Ha, respectively. Software was written that takes 6 DOF input data as defined above to rotate and translate the nodes of the surface geometry previously segmented. The instantaneous relative position and orientation of the humerus for a given set of variables was thus reconstructed on the bone models for graphical display. This tool can be used for graphical animation of shoulder kinematics, demonstrating clinical assessments, and allowing further analysis of the function of tissues within the joint.
Amadi HO, Bull AMJ, Hansen UN, 2005, Glenoid classification by vector analysis: 3-D scapular morphometry. Poster presentation, 16th Annual Scientific Conference, British Elbow and Shoulder Society
Amadi HO, Adimora GN, Pam SD, 2004, Digitally upgraded Incubators: better economic alternatives to the expensive modern systems in a developing economy, Annual conference of the Paediatrics Association of Nigeria
Amadi HO, Bull AMJ, Gupte CM, et al., 2004, Deficiency of meniscofemoral ligaments increases tibiofemoral contact pressure, 11th ESSKA Congress and 4th World Congress on Sports Trauma
Amadi HO, 2000, Systematic calculations in physics, ordinary level, Owerri, Nigeria, Publisher: Alphabets Publishers Nigeria, ISBN: 978-8008-68-2
Amadi HO, Bull AMJ, Emery RJH, Development and validation of a glenohumeral ligament functional strain analyser. Journal of Biomechanics, Journal of Biomechanics
Analysis of the function of glenohumeral ligaments (GHL) during physical joint manipulations is hindered by an inability to adequately image these tissues during the movements. This restricts functional biomechanics studies to only the manoeuvres that may be replicated cadaverically. There is, however, a clinical imperative to be able to investigate complex manoeuvres that exacerbate symptoms and cannot be easily conducted physically in the laboratory. The aim of this study was to develop and validate an algorithm for a computer simulation model that allows the quantification of GHL lengths during function. CT scans of a humerus and scapula pair were segmented to provide individual surface meshes of the bones and insertion points of each GHL on both bones. An algorithm was developed in which the GHL attachment-to-attachment length was divided into two straight lines plus an arc overlaying the spherical wrapping boney portions. The model was validated by simulating two previous cadaveric studies from the literature and comparing results.Predictions from the model were accurate by 91.7% and 81.8% based on the two cadaveric studies. The application of this algorithm will allow the investigation of functional loading of any capsular portion during simulated complex glenohumeral motions. This could then be used to provide diagnostic understanding and thus inform surgical reconstruction.
Amadi HO, Hansen UN, Bull AMJ, Scapular morphometry for clinical and kinematics analysis, 21st Congress of International Society of Biomechanics
Amadi HO, Bull AMJ, Hansen UN, Ligament loading during clinical examinations, British Elbow and Shoulder Society Conference, Pages: 357-358
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