Finite Element Analysis of Customized Acetabular Implant and Bone after Pelvic Tumour Resection throughout the Gait Cycle

In pelvic reconstruction surgery, the hemipelvic prosthesis can cause significant changes in stress distribution due to its high stiffness, and its solid structure is not suitable for osseointegration. The purpose of this study was to identify a novel bone mineral density screw channel and design the structure of the prosthesis so as to improve the distribution of stress, promote bone growth, and enhance the biomechanical properties of the prosthesis. The mechanical characteristics of bone mineral density screw and traditional screw were compared by finite element analysis method, and redesigned by topology optimization. The direction of the newly proposed screw channel was the posterolateral entrance of the auricular surface, ending at the contralateral sacral cape. Compared to the original group, the maximum stress of the optimized prosthesis was decreased by 24.39%, the maximum stress of the sacrum in the optimized group was decreased by 27.23%, and the average strain energy density of the sacrum in the optimized group was increased by 8.43%. On the surface of screw and connecting plate, the area with micromotion more than 28 μm is reduced by 12.17%. On the screw surface, the area with micromotion more than 28 μm is reduced by 22.9%. The newly determined screw channel and optimized prosthesis design can effectively improve the biomechanical properties of a prosthesis and the microenvironment of osseointegration. This method can provide a reference for the fixation of prostheses in clinical pelvic reconstruction.

Section: Discussionmentioning

confidence: 99%

Improving the Stability of a Hemipelvic Prosthesis Based on Bone Mineral Density Screw Channel and Prosthesis Optimization Design

Zhou

Xue²,

Wang³

et al. 2022

“…The cross-section and integral view results show that this region experiences a greater stress increase, which is considered to yield a higher stress transfer to the bone to reduce stress shielding (Figure 3A, Figure 4). Mechanical stress is an essential factor in bone tissue remodeling, but an excessive load is one of the main inducers of fatigue damage (Maslov et al, 2021). According to the results in Figure 5, the maximum principal stress in the original group (bone,34.65 MPa;prosthesis,236.4 MPa) and optimized group (bone,44.88 MPa;prosthesis,225.2 MPa) were less than their corresponding fatigue strengths (cortical bone, 80-150 MPa; Ti 6 Al 4 V prosthesis, 310-610 MPa).…”

Section: Discussionmentioning

confidence: 99%

Novel Design of the Compound Sleeve and Stem Prosthesis for Treatment of Proximal Femur Bone Defects Based on Topology Optimization

Xue

Bai

Zhou

et al. 2022

The loosening of traditional prosthetics is among the leading causes of surgical failure of proximal femoral bone defects. A novel compound sleeve and stem prosthesis was designed using an optimization methodology that combined an octet-truss porous structure with density-based topology optimization to improve stability, promote bone ingrowth, and enhance biomechanical properties. Biomechanical changes were assessed using finite element analysis. The distribution of stress, the strain energy density, and the relative micromotion in the optimized group were considered. The optimized sleeve prosthesis achieved a 31.5% weight reduction. The maximum stresses in the optimized group were observed to decrease by 30.33 and 4.74% at the back sleeve and neck part of stem prosthesis, with a 29.52% increase in the femur, respectively. The average stress in most selected regions in the optimized group was significantly greater than that in the original group (p < 0.05). The maximum relative micromotion decreased by 15.18% (from 63.9 to 54.2 μm) in the optimized group. The novel designed compound sleeve and stem prosthesis could effectively improve the biomechanical performance of next-generation prosthetics and provide a microenvironment for bone ingrowth. The presented method could serve as a model for clinical practice and a platform for future orthopedic surgery applications.

“…The comparison of the five groups of maximum stresses shows that the maximum stress was 47.29 MPa, which is less than the ultimate stress of 80 MPa in cortical bone (Maslov et al, 2021). This indicates that translational misalignments of 2 mm or less do not result in fractures.…”

Section: Discussionmentioning

confidence: 87%

“…A similar pattern could be seen in regions C and F, when the tibial plateau prosthesis was transferred medially. Even with these stress concentrations, the stresses were not sufficient to cause significant effects on the proximal tibia (Maslov et al, 2021). Figure 7 demonstrates that, at the stem cavity border, the stresses are concentrated at the rear.…”

Section: Discussionmentioning

confidence: 99%

Medial-lateral translational malalignment of the prosthesis on tibial stress distribution in total knee arthroplasty: A finite element analysis

Zheng

Liu²,

Zhang³

et al. 2023

Background: Poor prosthesis alignment during total knee arthroplasty could cause problems such as polyethylene spacer wear, leading to surgical failure and revision surgery. The problems caused by the malalignment of the tibial plateau prosthesis in the medial and lateral planes are unclear. We aimed to investigate the stress distribution and micromotion of the tibia when the tibial plateau prosthesis is translated 1 and 2 mm medially and laterally, respectively, using finite element analysis (FEA).Method: A non-homogeneous tibia model was created and load conditions when standing on two legs were applied using FEA to simulate the misaligned prosthesis. The stresses, stress distribution, and micromotion of the proximal tibia were analyzed in five positions of the tibial plateau prosthesis: Lateral-2 mm; Lateral-1 mm; Medium; Medial-2 mm; Medial-1 mm.Result: The maximum stress in the five groups with different misalignments of the platform was 47.29 MPa (Lateral-2 mm). The maximum micromotion among the five groups in different positions was 7.215 μm (Lateral-2 mm).Conclusion: When placing the tibial plateau prosthesis during total knee arthroplasty, an error of 2 mm or less is acceptable as long as it does not overhang.