Mechanical loading characteristics of total hip prosthetics subjected to dynamic loading cycles

2018 ◽  
Vol 29 (6) ◽  
pp. 723-737
Author(s):  
M. Kalayarasan ◽  
S. Shankar ◽  
M. Manikandan ◽  
K. Adithan
Keyword(s):  
Dynamic Loading ◽  
Mechanical Loading ◽  
Total Hip ◽  
Hip Prosthetics

scholarly journals Application Of A Thermodynamic-Based Model To Investigate Bone Remodeling After Total Hip Arthroplasty Using Different Hip Implants

2021 ◽  
Author(s):  
Alireza Sayyidmousavi
Keyword(s):  
Total Hip Arthroplasty ◽  
Bone Remodeling ◽  
Mechanical Loading ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Irreversible Thermodynamics ◽  
Total Hip ◽  
Finite Element Software ◽  
Custom Made ◽  
Hip Stems

A new thermodynamic-based model for bone remodeling is introduced. This model is based on chemical kinetics and irreversible thermodynamics in which bone is treated as a self-organizing system capable of exchanging matter, energy and entropy with its surroundings. Unlike the previous works in which mechanical loading is regarded as the only stimulus for bone remodeling, this model establishes a coupling between mechanical loading and the chemical reactions involved in the process of bone remodeling. This model is then incorporated to the finite element software ANSYS in the form of a macro to study bone remodeling after total hip arthroplasty with four different implants: Custom-made titanium, composite, Exceter and Omnifit hip stems. Numerical computations of bone density distribution after total hip arthroplasty indicate that the Omnifit implant with carbon fiber polyamide 12 composite results in minimum resorption in the proximal femur and consequently minimum bone loss due to stress shielding.

scholarly journals Influence of Different Damage Patterns of the Stem Taper on Fixation and Fracture Strength of Ceramic Ball Heads for Total Hip Replacement

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Danny Vogel ◽  
Jessica Hembus ◽  
Mario Jackszis ◽  
Vera Bolte ◽  
Rainer Bader
Keyword(s):  
Dynamic Loading ◽  
Total Hip Replacement ◽  
Significant Influence ◽  
Fracture Strength ◽  
Hip Replacement ◽  
Ceramic Ball ◽  
Total Hip ◽  
Stem Taper ◽  
Dynamic Group ◽  
Prosthetic Head

Background. Modularity finds frequent application in total hip replacement, allowing a preferable individual configuration and a simplified revision by retaining the femoral stem and replacing the prosthetic head. However, micromotions within the interface between the head and the stem taper can arise, resulting in the release of wear debris and corrosion products. The aim of our experimental study was to evaluate the influence of different taper damages on the fixation and fracture stability of ceramic femoral heads, after static and dynamic implant loading. Methods. Ceramic ball heads (36 mm diameter) and 12/14 stem tapers made of titanium with various mild damage patterns (intact, scratched, and truncated) were tested. The heads were assembled on the taper with a quasistatic load of 2 kN and separated into a static and a dynamic group afterwards. The dynamic group (n=18) was loaded over 1.5 million gait cycles in a hip wear simulator (ISO 14242-1). In contrast, the static group (n=18) was not mechanically loaded after assembly. To determine the taper stability, all heads of the dynamic and static groups were either pulled off (ASTM 2009) or turned off (ISO 7206-16). A head fracture test (ISO 7206-10) was also performed. Subsequent to the fixation stability tests, the taper surface was visually evaluated in terms of any signs of wear or corrosion after the dynamic loading. Results. In 10 of the 18 cases, discoloration of the taper was determined after the dynamic loading and subsequent cleaning, indicating the first signs of corrosion. Pull-off forces as well as turn-off moments were increased between 23% and 54% after the dynamic loading compared to the unloaded tapers. No significant influence of taper damage was determined in terms of taper fixation strength. However, the taper damage led to a decrease in fracture strength by approximately 20% (scratched) and 40% (truncated), respectively. Conclusion. The results suggest that careful handling and accurate manufacturing of the stem taper are crucial for the ceramic head fracture strength, even though a mild damage showed no significant influence on taper stability. Moreover, our data indicate that a further seating of the prosthetic head may occur during daily activities, when the resulting hip force increases the assembly load.

Physiotherapeutic support of patients with dysplastic coxarthrosis after total hip prosthetics

2020 ◽  
pp. 7-16
Author(s):  
Oleg N. YAMSHCHIKOV ◽  
Nikita I. VORONIN ◽  
Dmitry A. MARKOV ◽  
Ksenia P. Zvereva
Keyword(s):  
Surgical Treatment ◽  
Comparison Group ◽  
Health Indicators ◽  
Main Group ◽  
Long Term Results ◽  
Average Score ◽  
Treatment Technique ◽  
Total Hip ◽  
Sf 36 ◽  
Hip Prosthetics

Today, the main method of surgical treatment of dysplastic coxarthrosis among adults is total hip prosthetics. Distant positive results according to foreign authors are 76–89%. One method of rehabilitation is physiotherapeutic treatment. The absence of standardized physiotherapeutic treatment protocols leads to a sharp reduction in the prescription of this type of rehabilitation measures. The aim of the study is to assess the long-term results of hip joint endoprosthetics among patients with dysplastic coxarthrosis using the developed physiotherapeutic treatment technique. Research materials and methods. For the period from 2010 to 2014, 205 patients were performed an operation with dysplastic coxarthrosis 1, 2, 3 degrees of Crowe. In the pre- and postoperative periods, patients of the main group were prescribed physiotherapeutic treatment according to the developed methodology. Evaluation of the results was carried out 12 months after surgical treatment using clinical and radiological methods, questionnaires using the Harris scale, SF-36. The obtained data were processed using statistical methods: Student coefficient, Pearson coefficient, correlation method. Results. When analyzing distant results, the average Harris score in the main group 85.82 (84.93–86.71) was significantly higher than in the comparison group 83.01 (82.02–84.00). The average score of the SF-36 questionnaire in the main group was significantly higher than in the comparison group (p < 0.001). Mental health indicators of patients were not significantly different from those of the postoperative period and were at a high level. Conclusions. Prescription of physiotherapeutic treatment promotes rapid healing of postoperative wounds and improves results of surgical treatment.

The Effect of Dynamic Loading from Routine Activities on Mechanical Behavior of the Total Hip Arthroplasty

2014 ◽  
pp. 73-87 ◽  
Author(s):  
Mohamed Mokhtar Bouziane ◽  
Smail Benbarek ◽  
Essadek Mohamed Houari Tabeti ◽  
Bel Abbes Bachir Bouiadjra ◽  
Noureddine Benseddiq ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Mechanical Behavior ◽  
Dynamic Loading ◽  
Hip Arthroplasty ◽  
Routine Activities ◽  
Total Hip

Physiotherapeutic support of patients with dysplastic coxarthrosis after total hip prosthetics

2020 ◽  
pp. 7-16
Author(s):  
Oleg N. YAMSHCHIKOV ◽  
Nikita I. VORONIN ◽  
Dmitry A. MARKOV ◽  
Ksenia P. ZVEREVA
Keyword(s):  
Surgical Treatment ◽  
Comparison Group ◽  
Health Indicators ◽  
Main Group ◽  
Long Term Results ◽  
Average Score ◽  
Treatment Technique ◽  
Total Hip ◽  
Sf 36 ◽  
Hip Prosthetics

Today, the main method of surgical treatment of dysplastic coxarthrosis among adults is total hip prosthetics. Distant positive results according to foreign authors are 76–89%. One method of rehabilitation is physiotherapeutic treatment. The absence of standardized physiotherapeutic treatment protocols leads to a sharp reduction in the prescription of this type of rehabilitation measures. The aim of the study is to assess the long-term results of hip joint endoprosthetics among patients with dysplastic coxarthrosis using the developed physiotherapeutic treatment technique. Research materials and methods. For the period from 2010 to 2014, 205 patients were performed an operation with dysplastic coxarthrosis 1, 2, 3 degrees of Crowe. In the pre- and postoperative periods, patients of the main group were prescribed physiotherapeutic treatment according to the developed methodology. Evaluation of the results was carried out 12 months after surgical treatment using clinical and radiological methods, questionnaires using the Harris scale, SF-36. The obtained data were processed using statistical methods: Student coefficient, Pearson coefficient, correlation method. Results. When analyzing distant results, the average Harris score in the main group 85.82 (84.93–86.71) was significantly higher than in the comparison group 83.01 (82.02–84.00). The average score of the SF-36 questionnaire in the main group was significantly higher than in the comparison group (p < 0.001). Mental health indicators of patients were not significantly different from those of the postoperative period and were at a high level. Conclusions. Prescription of physiotherapeutic treatment promotes rapid healing of postoperative wounds and improves results of surgical treatment.

scholarly journals Effects of chondrogenic priming duration on mechanoregulation of engineered cartilage anlagen

2020 ◽  
Author(s):  
Anna M. McDermott ◽  
Emily A. Eastburn ◽  
Daniel J. Kelly ◽  
Joel D. Boerckel
Keyword(s):  
Dynamic Loading ◽  
Mechanical Loading ◽  
Endochondral Ossification ◽  
Bone Development ◽  
Mechanical Compression ◽  
Dynamic Mechanical ◽  
Matrix Deposition ◽  
Static Conditions

AbstractBone development and repair occur by endochondral ossification of a cartilage anlage, or template. Endochondral ossification is regulated by mechanical cues. Recently, we found that in vivo mechanical loading promoted regeneration of large bone defects through endochondral ossification, in a manner dependent on the timing of load initiation. Here, we have developed an in vitro model of the cartilage anlage to test whether the chondrogenic differentiation state alters the response to dynamic mechanical compression. We cultured human bone marrow stromal cells (hMSCs) at high cell density in fibrin hydrogels under chondrogenic priming conditions for periods of 0, 2, 4, or 6 weeks prior to two weeks of dynamic mechanical loading. Samples were evaluated by biomechanical testing, biochemical analysis of collagen and glycosaminoglycan (GAG) deposition, gene expression analysis, and immunohistological analysis, in comparison to time-matched controls cultured under static conditions. We found that dynamic loading increased the mechanical stiffness of engineered anlagen in a manner dependent on the duration of chondrogenic priming prior to load initiation. For chondrogenic priming times of 2 weeks or greater, dynamic loading enhanced the expression of type II collagen and aggrecan, although no significant changes in overall levels of matrix deposition was observed. For priming periods less than 4 weeks, dynamic loading generally supressed markers of hypertrophy and osteogenesis, although this was not observed if the priming period was extended to 6 weeks, where loading instead enhanced the expression of type X collagen. Taken together, these data demonstrate that the duration of chondrogenic priming regulates the endochondral response to dynamic mechanical compression in vitro, which may contribute to the effects of mechanical loading on endochondral bone development, repair, and regeneration in vivo.

scholarly journals Application Of A Thermodynamic-Based Model To Investigate Bone Remodeling After Total Hip Arthroplasty Using Different Hip Implants

2021 ◽  
Author(s):  
Alireza Sayyidmousavi
Keyword(s):  
Total Hip Arthroplasty ◽  
Bone Remodeling ◽  
Mechanical Loading ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Irreversible Thermodynamics ◽  
Total Hip ◽  
Finite Element Software ◽  
Custom Made ◽  
Hip Stems

A new thermodynamic-based model for bone remodeling is introduced. This model is based on chemical kinetics and irreversible thermodynamics in which bone is treated as a self-organizing system capable of exchanging matter, energy and entropy with its surroundings. Unlike the previous works in which mechanical loading is regarded as the only stimulus for bone remodeling, this model establishes a coupling between mechanical loading and the chemical reactions involved in the process of bone remodeling. This model is then incorporated to the finite element software ANSYS in the form of a macro to study bone remodeling after total hip arthroplasty with four different implants: Custom-made titanium, composite, Exceter and Omnifit hip stems. Numerical computations of bone density distribution after total hip arthroplasty indicate that the Omnifit implant with carbon fiber polyamide 12 composite results in minimum resorption in the proximal femur and consequently minimum bone loss due to stress shielding.

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