Stress analysis in a bone fracture fixed with topology-optimised plates

Al-Tamimi, Abdulsalam Abdulaziz; Quental, Carlos; Folgado, João; Peach, Ceri; Bartolo, Paulo Jorge Da Silva

doi:10.1007/s10237-019-01240-3

Cited by 26 publications

(15 citation statements)

References 23 publications

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“…As topology optimisation does not presume a priori material distribution, the algorithm has the liberty to leave specific locations void of material, whereas the corresponding size optimisation algorithm would be unable to remove unit elements from the lattice, merely reducing their sizes to a specified minimum. Such an approach has been demonstrated to reduced strain shielding in fracture plates [ 23 ], and has shown success in modelling the growth of internal bone structures when implemented with geometric constraints [ 24 ]. Thus, it holds great potential in producing implants that more closely match bone’s natural characteristics, reducing any strain shielding effect.…”

Section: Introductionmentioning

confidence: 99%

Topology Optimisation for Compliant Hip Implant Design and Reduced Strain Shielding

Tan

Arkel

2021

Materials

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Stiff total hip arthroplasty implants can lead to strain shielding, bone loss and complex revision surgery. The aim of this study was to develop topology optimisation techniques for more compliant hip implant design. The Solid Isotropic Material with Penalisation (SIMP) method was adapted, and two hip stems were designed and additive manufactured: (1) a stem based on a stochastic porous structure, and (2) a selectively hollowed approach. Finite element analyses and experimental measurements were conducted to measure stem stiffness and predict the reduction in stress shielding. The selectively hollowed implant increased peri-implanted femur surface strains by up to 25 percentage points compared to a solid implant without compromising predicted strength. Despite the stark differences in design, the experimentally measured stiffness results were near identical for the two optimised stems, with 39% and 40% reductions in the equivalent stiffness for the porous and selectively hollowed implants, respectively, compared to the solid implant. The selectively hollowed implant’s internal structure had a striking resemblance to the trabecular bone structures found in the femur, hinting at intrinsic congruency between nature’s design process and topology optimisation. The developed topology optimisation process enables compliant hip implant design for more natural load transfer, reduced strain shielding and improved implant survivorship.

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Section: Introductionmentioning

confidence: 99%

Topology Optimisation for Compliant Hip Implant Design and Reduced Strain Shielding

Tan

Arkel

2021

Materials

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“…This proves that using topology optimization is possible to obtain designs that are able to match the mechanical properties of native bone and thus, and eliminate the main cause to stress shielding. In addition, previous studies reported that using TO in designing generic fixation plates[ 26 ] and mandible fixation plates[ 27 ], which depends on the volume reduction and loading condition, is possible to reduce the plate’s stiffness while maintaining its mechanical stability to withstand stresses.…”

Section: Resultsmentioning

confidence: 99%

3D Topology Optimization and Mesh Dependency for Redesigning Locking Compression Plates Aiming to Reduce Stress Shielding

Al-Tamimi¹

2024

IJB

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Current fixation plates for bone fracture treatments are built with biocompatible metallic materials such as stainless steel, titanium, and its alloys (e.g., Ti6Al4V). The stiffness mismatch between the metallic material of the plate and the host bone leads to stress shielding phenomena, bone loss, and healing deficiency. This paper explores the use of three dimensional topology-optimization, based on compliance (i.e., strain energy) minimization, reshaping the design domain of three locking compression plates (four-screw holes, six-screw holes, and eight-screw holes), considering different volume reductions (25, 45, and 75%) and loading conditions (bending, compression, torsion, and combined loads). A finite-element study was also conducted to measure the stiffness of each optimized plate. Thirty-six designs were obtained. Results showed that for a critical value of volume reductions, which depend on the load condition and number of screws, it is possible to obtain designs with lower stiffness, thereby reducing the risk of stress shielding.

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“…The most common technique to solve the optimization problem is the Solid Isotropic Microstructure with Penalization (SIMP), which assumes a continuous function density as the design variable. This method has been employed for different applications such as structural [ 36 ], aerospace [ 37 ], architectural design [ 38 ] and medical applications [ 39 , 40 , 41 ]. The optimization process initiates by discretizing the design domain into a set of elements, assigning to each element a density (

) value of 0 or 1 (0 density means a void and 1 means a solid element) [ 40 , 41 ].…”

Section: Modeling and Simulationmentioning

confidence: 99%

Optimization of a Patient-Specific External Fixation Device for Lower Limb Injuries

et al. 2021

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The use of external fixation devices is considered a valuable approach for the treatment of bone fractures, providing proper alignment to fractured fragments and maintaining fracture stability during the healing process. The need for external fixation devices has increased due to an aging population and increased trauma incidents. The design and fabrication of external fixations are major challenges since the shape and size of the defect vary, as well as the geometry of the human limb. This requires fully personalized external fixators to improve its fit and functionality. This paper presents a methodology to design personalized lightweight external fixator devices for additive manufacturing. This methodology comprises data acquisition, Computer tomography (CT) imaging analysis and processing, Computer Aided Design (CAD) modelling and two methods (imposed predefined patterns and topology optimization) to reduce the weight of the device. Finite element analysis with full factorial design of experiments were used to determine the optimal combination of designs (topology optimization and predefined patterns), materials (polylactic acid, acrylonitrile butadiene styrene, and polyamide) and thickness (3, 4, 5 and 6 mm) to maximize the strength and stiffness of the fixator, while minimizing its weight. The optimal parameters were found to correspond to an external fixator device optimized by topology optimization, made in polylactic acid with 4 mm thickness.

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Stress analysis in a bone fracture fixed with topology-optimised plates

Cited by 26 publications

References 23 publications

Topology Optimisation for Compliant Hip Implant Design and Reduced Strain Shielding

Topology Optimisation for Compliant Hip Implant Design and Reduced Strain Shielding

3D Topology Optimization and Mesh Dependency for Redesigning Locking Compression Plates Aiming to Reduce Stress Shielding

Optimization of a Patient-Specific External Fixation Device for Lower Limb Injuries

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