Fatigue failure of plated osteoporotic proximal humerus fractures is predicted by the strain around the proximal screws

Варга, П.; Grünwald, Leonard; Inzana, Jason A.; Windolf, Markus

doi:10.1016/j.jmbbm.2017.07.004

Cited by 36 publications

(59 citation statements)

References 33 publications

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“…Non‐commercial screws lengths were implemented to ensure that the TJD remained constant regardless of anatomy. The FE models were meshed with tetrahedral elements using Simpleware v7.0 (Simpleware Ltd., Exeter, UK) with a previously determined appropriate mesh density . Material properties, including BMD‐based stiffness assignment for bone elements, and interface models were taken from a previous validation study .…”

Section: Methodsmentioning

confidence: 99%

“…The FE models were meshed with tetrahedral elements using Simpleware v7.0 (Simpleware Ltd., Exeter, UK) with a previously determined appropriate mesh density . Material properties, including BMD‐based stiffness assignment for bone elements, and interface models were taken from a previous validation study . The models were loaded in three physiological loading cases—45° abduction with 0° internal rotation, 45° abduction with 45° internal rotation, and 45° flexion with 0° internal rotation—where the joint and muscle forces were sourced from musculoskeletal simulations performed with Anybody software (v5.0, AnyBody Technology A/S, Aalborg, Denmark).…”

Section: Methodsmentioning

confidence: 99%

“…The FE analyses were run in Abaqus v6.13–3 (Simulia, Dassault Systemes, Velizy‐Villacoublay, France) and the average bone strain within cylindrical regions around the proximal screws tips was evaluated. This strain was reported to be an authenticated surrogate measure for prediction of biomechanical cyclic fixation failure . All pre‐processing, analysis and post‐processing methods used had been previously established …”

Section: Methodsmentioning

confidence: 99%

“…15 Material properties, including BMD-based stiffness assignment for bone elements, and interface models were taken from a previous validation study. 15 The models were loaded in three physiological loading cases-45˚abduction with 0˚internal rotation, 45˚abduction with 45˚internal rotation, and 45˚flexion with 0˚internal rotation-where the joint and muscle forces were sourced from musculoskeletal simulations performed with Anybody software (v5.0, Any-Body Technology A/S, Aalborg, Denmark). The FE analyses were run in Abaqus v6.13-3 (Simulia, Dassault Systemes, Velizy-Villacoublay, France) and the average bone strain within cylindrical regions around the proximal screws tips was evaluated.…”

Section: Methodsmentioning

confidence: 99%

“…This strain was reported to be an authenticated surrogate measure for prediction of biomechanical cyclic fixation failure. 15 All pre-processing, analysis and postprocessing methods used had been previously established. 15,16 Statistical analysis was performed with the use of "R" v3.3.3 (R Foundation for Statistical Computing).…”

Section: Methodsmentioning

confidence: 99%

See 4 more Smart Citations

Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations

Fletcher

Windolf

Richards

et al. 2019

Journal Orthopaedic Research

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Multifragmented proximal humeral fractures frequently require operative fixation. The locking plates commonly used are often placed relative to the greater tuberosity, however no quantitative data exists regarding the effect of positional changes. The aim of the study was to establish the effects from variations in proximal‐distal PHILOS humeral plate positioning on predicted fixation failure risk. Twenty‐one left‐sided low‐density virtual humeri models were created with a simulation framework from CT data of elderly donors and osteotomized to mimic an unstable three‐part malreduced AO/OTA 11‐B3.2 fracture with medial comminution. A PHILOS plate with either four or six proximal screws was used for fixation. Both configurations were modelled with plate repositioning 2 and 4 mm distally and proximally to its baseline position. Applying a validated computational model, three physiological loading situations were simulated and fixation failure predicted using average strain around the proximal screws—an outcome established as a surrogate for cycles to failure. Varying the craniocaudal plate position affected the peri‐implant strain for both four and six‐screw configurations. Even though significant changes were seen only in the latter, all tests suggested that more proximal plate positioning results in decreased peri‐screw strains whereas distalizing creates increases in strain. These results suggest that even a small distal PHILOS plate malpositioning may reduce fixation stability. Plate distalization increases the probability of being unable to insert all screws within the humeral head, which dramatically increases the forces acting on the remaining screws. Proximal plate shifting may be beneficial, especially for constructs employing calcar screws. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations

Fletcher

Windolf

Richards

et al. 2019

Journal Orthopaedic Research

Self Cite

View full text Add to dashboard Cite

show abstract

Assessing screw length impact on bone strain in proximal humerus fracture fixation via surrogate modelling

Mini,

Reynolds,

Taylor

2024

Numer Methods Biomed Eng

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A high failure rate is associated with fracture plates in proximal humerus fractures. The causes of failure remain unclear due to the complexity of the problem including the number and position of the screws, their length and orientation in the space. Finite element (FE) analysis has been used for the analysis of plating of proximal humeral fractures, but due to computational costs is unable to fully explore all potential screw combinations. Surrogate modelling is a viable solution, having the potential to significantly reduce the computational cost whilst requiring a moderate number of training sets. This study aimed to develop adaptive neural network (ANN)‐based surrogate models to predict the strain in the humeral bone as a result of changing the length of the screws. The ANN models were trained using data from FE simulations of a single humerus, and after defining the best training sample size, multiple and single‐output models were developed. The best performing ANN model was used to predict all the possible screw length configurations. The ANN predictions were compared with the FE results of unseen data, showing a good correlation (R2 = 0.99) and low levels of error (RMSE = 0.51%–1.83% strain). The ANN predictions of all possible screw length configurations showed that the screw that provided the medial support was the most influential on the predicted strain. Overall, the ANN‐based surrogate model accurately captured bone strains and has the potential to be used for more complex problems with a larger number of variables.

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The prediction of cyclic proximal humerus fracture fixation failure by various bone density measures

Варга

Grünwald

Windolf

2018

Journal Orthopaedic Research

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Fixation of osteoporotic proximal humerus fractures has remained challenging, but may be improved by careful pre-operative planning. The aim of this study was to investigate how well the failure of locking plate fixation of osteoporotic proximal humerus fractures can be predicted by bone density measures assessed with currently available clinical imaging (realistic case) and a higher resolution and quality modality (theoretical best-case). Various density measures were correlated to experimentally assessed number of cycles to construct failure of plated unstable low-density proximal humerus fractures (N = 18). The influence of density evaluation technique was investigated by comparing local (peri-implant) versus global evaluation regions; HR-pQCT-based versus clinical QCT-based image data; ipsilateral versus contralateral side; and bone mineral content (BMC) versus bone mineral density (BMD). All investigated density measures were significantly correlated with the experimental cycles to failure. The best performing clinically feasible parameter was the QCT-based BMC of the contralateral articular cap region, providing significantly better correlation (R = 0.53) compared to a previously proposed clinical density measure (R = 0.30). BMC had consistently, but not significantly stronger correlations with failure than BMD. The overall best results were obtained with the ipsilateral HR-pQCT-based local BMC (R = 0.74) that may be used for implant optimization. Strong correlations were found between the corresponding density measures of the two CT image sources, as well as between the two sides. Future studies should investigate if BMC of the contralateral articular cap region could provide improved prediction of clinical fixation failure compared to previously proposed measures. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

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Fatigue failure of plated osteoporotic proximal humerus fractures is predicted by the strain around the proximal screws

Cited by 36 publications

References 33 publications

Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations

Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations

Assessing screw length impact on bone strain in proximal humerus fracture fixation via surrogate modelling

The prediction of cyclic proximal humerus fracture fixation failure by various bone density measures

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