Ghazaleh Moradkhani; Morad Karimpour; S Mahmoud Taheri
Abstract
Background: Porous titanium structures have recently gained considerable popularity among researchers in studies examining bone ingrowth and osseointegration. Porous implants fabricated using triply periodic minimal surface design (TPMS) and designed through 3D printing techniques exhibited remarkable ...
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Background: Porous titanium structures have recently gained considerable popularity among researchers in studies examining bone ingrowth and osseointegration. Porous implants fabricated using triply periodic minimal surface design (TPMS) and designed through 3D printing techniques exhibited remarkable mechanical strength and cell viability compared to conventional implants. This study aimed to evaluate the effect of pore size of titanium implants with gyroid structure.Methods: This study was conducted on Adult male Wistar rats weighing 350 and 450 g for the animal study by the calvarial defect model to investigate bone regeneration. Three disk-shaped implants were designed using a gyroid structure with pore sizes of 400, 500, and 600 micrometers. All implants were made by additive manufacturing (Selective Laser Melting) using Ti6Al4V medical-grade powder. Animals were sacrificed after 12 weeks, the skin was removed from the calvaria, and the implants were removed for histological examination.Results: Gyroid structures had a high surface-to-volume ratio and pore connectivity, facilitating cell adhesion and ossification. A significant amount of bone ingrowth was observed in the 400 mm group, so that bone penetrated into pores significantly more than in the other groups. However, the vascularization was more pronounced in the 600 μm group than in the other groups.Conclusion: According to the results, there was a positive effect of porosity in titanium implants in encouraging bone ingrowth. The porosity size of 400 μm was more suitable for the differentiation and proliferation of bone cells and thus the osseointegration in porous titanium implants with gyroid structure.
Armin Nikzad, BSc; Farid Abbaszade, MSc; Zahra Saghaei, MSc; Soheil Mehdipoor, MD; Firooz Madadi, MD; Morad Karimpoor, PhD
Abstract
Background: Total knee arthroplasty is an accepted method for treatment of osteoarthritis of the knee. Measuring the distal femoral rotation is one of the most important problems in such operations. In the conventional 2D method, measuring the angle is based on CT scan images but these methods usually ...
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Background: Total knee arthroplasty is an accepted method for treatment of osteoarthritis of the knee. Measuring the distal femoral rotation is one of the most important problems in such operations. In the conventional 2D method, measuring the angle is based on CT scan images but these methods usually contain errors. In this study, the three-dimensional measurement of the aforementioned angle was investigated.
Methods: In this research, using CT scans and 3D modeling, 3D lower extremity models of 40 patients were extracted. The rotation of distal femur was measured for plane perpendicular to the anatomical and the plane of mechanical axis of femur. Four axes were drawn on these planes using anatomical landmarks: posterior condylar line (PCL), anatomical and surgical transepicondylar line (ATEA+STEA), and the Whiteside line (WL).
Results: The mean difference of these measurements on the plane perpendicular to the mechanical axis of the femur, between PCL and WL, STEA, ATEA was 3.41, -1.31, 5.53; and angles on the plane perpendicular to the anatomical axis of femur were -0.74, -1.26, and 5.67, respectively. In addition, Bland-Altman diagram was plotted between every two measurements and no relationship found, except for STEA and ATEA.
Conclusions: The measurements between PCL, ATE, and STEA are not affected by the plane on which these measurements are carried out on, except for the 4 degrees difference present in WL axis. With a greater sample size and proper grouping, some relationship might be found between the aforementioned axes.
Pooneh Dehghan, MD; Zahra Saghaei ,MSc; Farid Abbaszadeh, MSc; Morad Karimpour, PhD; Soheil Mehdipoor, MD
Abstract
Background: Femoral neck anteversion is usually measured on the 2-dimensional (2D) images on CT slices. The 3D method uses 3-dimensional model of the femur reconstructed from CT scan images. The aim of this study was to compare these two methods of measurement of femoral ante-version. Methods: In ...
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Background: Femoral neck anteversion is usually measured on the 2-dimensional (2D) images on CT slices. The 3D method uses 3-dimensional model of the femur reconstructed from CT scan images. The aim of this study was to compare these two methods of measurement of femoral ante-version. Methods: In a retrospective study, CT scans of 40 patients (6 men, 34 women) of a teaching hospital in Tehran-Iran were included. Both methods use the same anatomical landmarks, i.e. center of femoral head, femoral neck axis and posterior apex of the femoral condyles. In the 3D method, anteversion angle was measured on a plane perpendicular to the anatomical axis of femur. Whereas in the 2D method the measurement is performed on CT scan slices.Results: Mean anteversion was found to be 9.8 for the 2D and 16.11 for the 3D method. Bland-Altman plot shows that the difference between the two methods is significant.Conclusions: This difference between 2D ad 3D measurement of femoral anteversion may be depend on the level of the selected CT slices, patients positioning during CT examination, and the impact of the deformity. The 3D method eliminates obvious sources of error, namely identifying landmarks and individual orientation of femur. Due to the lack of any gold standard there is a need to further review and study the measurement of this angle.
