DSpace Community:https://hdl.handle.net/2440/58702024-03-18T16:09:15Z2024-03-18T16:09:15ZThe Structural Response of the Human Head to a Vertex ImpactThompson-Bagshaw, D.W.Quarrington, R.D.Dwyer, A.M.Jones, N.R.Jones, C.F.https://hdl.handle.net/2440/1396222023-11-19T01:35:37Z2023-01-01T00:00:00ZTitle: The Structural Response of the Human Head to a Vertex Impact
Author: Thompson-Bagshaw, D.W.; Quarrington, R.D.; Dwyer, A.M.; Jones, N.R.; Jones, C.F.
Abstract: In experimental models of cervical spine trauma caused by near-vertex head-first impact, a surrogate headform may be substituted for the cadaveric head. To inform headform design and to verify that such substitution is valid, the force-deformation response of the human head with boundary conditions relevant to cervical spine head-first impact models is required. There are currently no biomechanics data that characterize the force-deformation response of the isolated head supported at the occiput and compressed at the vertex by a flat impactor. The effect of impact velocity (1, 2 or 3 m/s) on the response of human heads (N = 22) subjected to vertex impacts, while supported by a rigid occipital mount, was investigated. 1 and 2 m/s impacts elicited force-deformation responses with two linear regions, while 3 m/s impacts resulted in a single linear region and skull base ring fractures. Peak force and stiffness increased from 1 to 2 and 3 m/s. Deformation at peak force and absorbed energy increased from 1 to 2 m/s, but decreased from 2 to 3 m/s. The data reported herein enhances the limited knowledge on the human head's response to a vertex impact, which may allow for validation of surrogate head models in this loading scenario.
Description: Published online: 21 September 20232023-01-01T00:00:00ZCognitive decline is associated with an accelerated rate of bone loss and increased fracture risk in women: a prospective study from the Canadian Multicentre Osteoporosis StudyBliuc, D.Tran, T.Adachi, J.D.Atkins, G.J.Berger, C.van den Bergh, J.Cappai, R.Eisman, J.A.van Geel, T.Geusens, P.Goltzman, D.Hanley, D.A.Josse, R.Kaiser, S.Kovacs, C.S.Langsetmo, L.Prior, J.C.Nguyen, T.V.Solomon, L.B.Stapledon, C.et al.https://hdl.handle.net/2440/1389232023-11-20T04:57:46Z2021-01-01T00:00:00ZTitle: Cognitive decline is associated with an accelerated rate of bone loss and increased fracture risk in women: a prospective study from the Canadian Multicentre Osteoporosis Study
Author: Bliuc, D.; Tran, T.; Adachi, J.D.; Atkins, G.J.; Berger, C.; van den Bergh, J.; Cappai, R.; Eisman, J.A.; van Geel, T.; Geusens, P.; Goltzman, D.; Hanley, D.A.; Josse, R.; Kaiser, S.; Kovacs, C.S.; Langsetmo, L.; Prior, J.C.; Nguyen, T.V.; Solomon, L.B.; Stapledon, C.; et al.
Abstract: Abstract not available2021-01-01T00:00:00ZHip osteoarthritis: A novel network analysis of subchondral trabecular bone structuresDorraki, M.Muratovic, D.Fouladzadeh, A.Verjans, J.W.Allison, A.Findlay, D.M.Abbott, D.https://hdl.handle.net/2440/1385582023-11-19T21:44:23Z2022-01-01T00:00:00ZTitle: Hip osteoarthritis: A novel network analysis of subchondral trabecular bone structures
Author: Dorraki, M.; Muratovic, D.; Fouladzadeh, A.; Verjans, J.W.; Allison, A.; Findlay, D.M.; Abbott, D.
Editor: Yooseph, S.
Abstract: Hip osteoarthritis (HOA) is a degenerative joint disease that leads to the progressive destruction of subchondral bone and cartilage at the hip joint. Development of effective treatments for HOA remains an open problem, primarily due to the lack of knowledge of its pathogenesis and a typically late-stage diagnosis.We describe a novel network analysis methodology for microcomputed tomography (micro-CT) images of human trabecular bone.We explored differences between the trabecular bone microstructure of femoral heads with and without HOA. Large-scale automated extraction of the network formed by trabecular bone revealed significant network properties not previously reported for bone. Profound differences were discovered, particularly in the proximal third of the femoral head, where HOA networks demonstrated elevated numbers of edges, vertices, and graph components. When further differentiating healthy joint and HOA networks, the latter showed fewer small-world network properties, due to decreased clustering coefficient and increased characteristic path length. Furthermore,we found that HOA networks had reduced length of edges, indicating the formation of compressed trabecular structures. In order to assess our network approach,we developed a deep learningmodel for classifying HOA and control cases, and we fed it with two separate inputs: (i) micro-CT images of the trabecular bone, and (ii) the network extracted from them. The model with plain micro-CT images achieves 74.6% overall accuracy while the trained model with extracted networks attains 96.5% accuracy. We anticipate our findings to be a starting point for a novel description of bone microstructure in HOA, by considering the phenomenon from a graph theory viewpoint.2022-01-01T00:00:00ZThe effect of surgical change to hip geometry on hip biomechanics after primary total hip arthroplastyBahl, J.S.Arnold, J.B.Saxby, D.J.Taylor, M.Solomon, L.B.Thewlis, D.https://hdl.handle.net/2440/1368012023-11-19T23:45:40Z2023-01-01T00:00:00ZTitle: The effect of surgical change to hip geometry on hip biomechanics after primary total hip arthroplasty
Author: Bahl, J.S.; Arnold, J.B.; Saxby, D.J.; Taylor, M.; Solomon, L.B.; Thewlis, D.
Abstract: The aim of this study was to determine the effect of surgical change to the acetabular offset and femoral offset on the abductor muscle and hip contact forces after primary THA using computational methods. Thirty-five patients undergoing primary THA were recruited. Patients underwent a computed tomography scan of their pelvis and hip, and underwent gait analysis pre- and 6-months post-operatively. Surgically induced changes in acetabular and femoral offset were used to inform a musculoskeletal model to estimated abductor muscle and hip joint contact forces. Two experiments were performed: (1) influence of changes in hip geometry on hip biomechanics with preoperative kinematics; and (2) influence of changes in hip geometry on hip biomechanics with postoperative kinematics. Superior and medial placement of the hip centre of rotation during THA was most influential in reducing hip contact forces, predicting 63% of the variance (p<0.001). When comparing the preoperative geometry and kinematics model, with postoperative geometry and kinematics, hip contact forces increased after surgery (0.68 BW, p=0.001). Increasing the abductor lever arm reduced abductor muscle force by 28% (p<0.001) and resultant hip contact force by 17% (0.6 BW, p=0.003), with both preoperative and postoperative kinematics. Failure to increase abductor lever arm increased resultant hip contact force 11% (0.33 BW, p<0.001). In conclusion, increasing the abductor lever arm provides a substantial biomechanical benefit to reduce hip abductor and resultant hip joint contact forces. The magnitude of this effect is equivalent to the average increase in hip contact force seen with improved gait from pre-to post-surgery. This article is protected by copyright. All rights reserved.
Description: Published June 20232023-01-01T00:00:00Z