scholarly journals An Analytical Calculation of Frictional and Bending Moments at the Head-Neck Interface of Hip Joint Implants during Different Physiological Activities

Materials ◽  
2016 ◽  
Vol 9 (12) ◽  
pp. 982 ◽  
Author(s):  
Hamidreza Farhoudi ◽  
Reza Oskouei ◽  
Ali Pasha Zanoosi ◽  
Claire Jones ◽  
Mark Taylor
Keyword(s):  
Hip Joint ◽  
Analytical Calculation ◽  
Bending Moments ◽  
Joint Implants ◽  
Head Neck

scholarly journals A Crevice Corrosion Model for Biomedical Trunnion Geometries and Surfaces Feature

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1005
Author(s):  
Angela Bermúdez-Castañeda ◽  
Anna Igual-Muñoz ◽  
Stefano Mischler
Keyword(s):  
Hip Joint ◽  
Crevice Corrosion ◽  
Medical Procedures ◽  
Ceramic Surface ◽  
Electrochemical Parameters ◽  
Model Predictions ◽  
Clinical Consequences ◽  
Joint Implants ◽  
Head Neck ◽  
Single Configuration

Modular hip joint implants were introduced in arthroplasty medical procedures because they facilitate the tailoring of patients’ anatomy, the use of different materials in one single configuration, as well as medical revision. However, in certain cases, such prostheses may undergo deterioration at the head–neck junctions with negative clinical consequences. Crevice-corrosion is commonly invoked as one of the degradation mechanisms acting at those junctions despite biomedical alloys such as Ti6Al4V and CoCr being considered generally resistant to this form of corrosion. To verify the occurrence of crevice corrosion in modular hip joint junctions, laboratory crevice-corrosion tests were conducted in this work under hip joint-relevant conditions, i.e., using similar convergent crevice geometries, materials (Ti6Al4V and CoCr alloys vs. ceramic), surface finish, NaCl solution pHs (5.6 and 2.3), and electrochemical conditions. A theoretical model was also developed to describe crevice-corrosion considering relevant geometrical and electrochemical parameters. To verify the model, a FeCr alloy, known to be sensitive to this phenomenon, was subjected to the crevice-corrosion test in sulfuric acid. The experiments and the model predictions clearly showed that, in principle, crevice corrosion of Ti6Al4V or CoCr is not supposed to occur in typical crevices formed at the stem-neck junction of hip implants.

Optimal parameters of abrasive flow finishing for hip joint implants

2021 ◽  
pp. 095440542199561
Author(s):  
Yahya Choopani ◽  
Mohsen Khajehzadeh ◽  
Mohammad Reza Razfar
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Femoral Head ◽  
Hip Joint ◽  
Spherical Shape ◽  
Shape Deviation ◽  
Head Surface ◽  
Joint Implants ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

Total hip arthroplasty (THA) is one of the most well-known orthopedic surgeries in the world which involves the substitution of the natural hip joint by prostheses. In this process, the surface roughness of the femoral head plays a pivotal role in the performance of hip joint implants. In this regard, the nano-finishing of the femoral head of the hip joint implants to achieve a uniform surface roughness with the lowest standard deviation is a major challenge in the conventional and advanced finishing processes. In the present study, the inverse replica fixture technique was used for automatic finishing in the abrasive flow finishing (AFF) process. For this aim, an experimental setup of the AFF process was designed and fabricated. After the tests, experimental data were modeled and optimized to achieve the minimum surface roughness in the ASTM F138 (SS 316L) femoral head of the hip joint through the use of response surface methodology (RSM). The results confirmed uniform surface roughness up to the range of 0.0203 µm with a minimum standard deviation of 0.00224 for the femoral head. Moreover, the spherical shape deviation of the femoral head was achieved in the range of 7 µm. The RSM results showed a 99.71% improvement in the femoral head surface roughness (0.0007) µm under the optimized condition involving the extrusion pressure of 9.10 MPa, the number of finishing cycles of 95, and SiC abrasive mesh number of 1000.

Metallographic Evaluation of Hip Joint Implants wear and Electrochemical Implants Potential

2014 ◽  
Vol 24 (6) ◽  
pp. 604-609
Author(s):  
Krzysztof Kmieć ◽  
Marcin Sibinski ◽  
Marek Synder ◽  
Marek Drobniewski ◽  
Piotr Kozłowski
Keyword(s):  
Hip Joint ◽  
Joint Implants

scholarly journals ON THE EFFECTIVENESS OF OBLIQUE CAISSON REINFORCED CONCRETE FLOORS

2021 ◽  
Vol 11 (3) ◽  
pp. 20-25
Author(s):  
Mikhail V. MOZGOLOV ◽  
Arina V. TURANOVA
Keyword(s):  
Reinforced Concrete ◽  
Calculation Method ◽  
Analytical Methods ◽  
Analytical Calculation ◽  
Computer Models ◽  
Bending Moments ◽  
Outer Contour ◽  
Complex Operation ◽  
Nite Element ◽  
Spatial System

The distribution of forces in the beams of a straight and oblique monolithic reinforced concrete caisson fl oor of a square plan is compared. The forces in the beams are determined by well-known analytical methods and using fi nite element models of the SCAD PC. The calculations showed that the forces in the beams of the oblique caisson fl oor, determined analytically and using computer models, diff er signifi cantly, which indicates the complex operation of the spatial system, which is not taken into account by the analytical calculation method based on the theory of calculating plates supported by the contour. The obtained data indicate that a square caisson fl oor with beams installed at an angle of 450 to the reference contour has greater rigidity and lower values of bending moments compared to straight caissons. When the ratio of the sides of the overlap L2 > 1,5 . L1 to ensure the eff ect of supporting the contour, the location of the beams in relation to the outer contour should be at an angle of 45°.

scholarly journals Heating of hip joint implants in MRI: The combined effect of RF and switched‐gradient fields

2021 ◽  
Vol 85 (6) ◽  
pp. 3447-3462
Author(s):  
Alessandro Arduino ◽  
Umberto Zanovello ◽  
Jeff Hand ◽  
Luca Zilberti ◽  
Rüdiger Brühl ◽  
...  
Keyword(s):  
Hip Joint ◽  
Combined Effect ◽  
Gradient Fields ◽  
Joint Implants
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