Distribution and amount of stresses caused by insertion or removal of orthodontic miniscrews into the maxillary bone: A finite element analysis.

OBJECTIVE: Initial stability of miniscrews is an important factor in their success as orthodontic anchorages. One of the factors affecting this stability is the stresses exerted to the bone by the screw. Since the distribution and extent of stresses and strains produced during insertion or removal of miniscrews had not been measured before, this study used finite element analysis (FEA) to measure these parameters in tapered versus cylindrical screws with or without pilot sockets. MATERIALS AND METHODS: An FEA model of maxilla, pilot hole, and tapered/cylindrical miniscrews were created from 875 CT scan data. The bone cortex was considered 2mm thick. The cancellous bone was reconstructed below the cortical bone. Miniscrews were modelled on the basis of commercial titanium tapered and cylindrical miniscrews (1.6mm wide, 8mm long). The diameter and length of the guiding hole were considered to be 1.1 and 1.5mm, respectively. The miniscrews were inserted (and removed) between the maxillary second premolar and first molar. Stress/strain produced in the bones or screws were measured. RESULTS: During screw insertion, in all setups, the highest stress existed within both the bone and screw, when the screw was in the cortical bone; after insertion into the cancellous bone, the stress suddenly dropped. In cylindrical screws, the highest amount of stress was distributed around the neck which was used for screw driving. In tapered screws, the stress was mostly distributed around the front one-third of the screw. During screw removal, the results of four setups were rather similar with stresses concentrated around screw necks, in the depth of the screw hole, and around the bone surface. The greatest bone stress during insertion was caused by the pilot-less tapered screw (10.18MPa) and the lowest stress was exerted by a pilot-less cylindrical screw (0.74MPa). CONCLUSION: Most of the stress and strain is tolerated by the cortical bone and not the cancellous one. Using cylindrical miniscrews might be more bone-friendly. However, all cases had stresses below tolerable thresholds, and hence are safe.

Three-dimensional finite element analysis to evaluate biomechanical effects of different alveolar decortication approaches on rate of canine retraction.

INTRODUCTION: The aim of this study was to compare different corticotomy approaches and determine their biomechanical effects on rate of canine displacement when compared to conventional orthodontics. METHOD: Three-dimensional Finite Element Models with conventional non-corticotomy approach (model 1) and three corticotomy approaches ensuing buccal and palatal vertical cuts (model 2), interseptal bone reduction (model 3), buccal vertical cuts (model 4) were fabricated. Displacement of the canine and von Mises stresses in the canine and trabecular bone were calculated and compared under a distal retraction force of 1.5N. RESULTS: The maximum displacement of canine with minimum anchorage loss was seen in model 3 followed by model 2, model 4 and model 1. The maximum equivalent (von Mises) stress was concentrated mainly on the distal side of canine in model 3 and had a uniform distribution of stresses on entire root surface. CONCLUSIONS: Corticotomy approaches effectively accelerated maxillary canine retraction, exhibiting twice the rate of canine movement with minimum anchorage loss when compared to non-corticotomy approach. Corticotomy with interseptal bone reduction was most effective in terms of canine displacement and stress distribution.

3-dimensional finite element analysis of the outcomes of Alexander, Gianelly, Roth and MBT bracket prescription.

The purpose of this study was to compare the effect of a 4-bracket system including Alexander, Roth, MBT (Maxillary Transverse Bioadaptation), and Gianelly on the upper anterior tooth movement in sliding mechanics with the help of a 3-Dimensional (3D) Finite Element Method. METHODS: Displacement, stress, strain, centre of rotation and resistance on the incise edge and apex of the maxillary central incisor were calculated when 100, 200, 300, 400grams of retraction force were applied. RESULTS: The amount of incise edge displacement was 2.609×10-4mm 2.682×10-4mm 2.875×10-4mm and 2.881×10-4mm in Alexander, Gianelly, Roth and MBT respectively with 100gr of retraction force. The value of apex root movement was 3.485×10-4mm 3.547×10-4mm 3.852×10-4mm and 3.864×10-4mm in Alexander, Gianelly, Roth and MBT respectively with 400g of retraction force. CONCLUSIONS: The MBT system had the maximum apex root and incisal edge movement in all 100, 200, 300, 400grams of retraction force. The Alexander system had the lowest apex and incisal edge movement in all retraction forces.

Effects of mechanical vibration on miniscrew implants and bone: Fem analysis.

OBJECTIVE: The aim of this FEM study was to assess the effect of mechanical vibration force on miniscrews and stress distribution in cortical and trabecular bone around miniscrews. METHODS: A 3D model was created using a CBCT image of a patient. Three different analyses were performed on a single model. Material properties, boundary conditions and the quality of applied forces (direction and magnitude) were defined. 150 gf, 150 gf and 30Hz (0.2N), 150 gf and 111Hz (0.06N) were applied to miniscrew from distal to mesial and from sulcus to alveolar crest direction like a power arm application. The first moment effect of force and vibration were evaluated by using Algor Fempro FEM analysis program. Von Mises and principal stress distribution on miniscrews and bone layers were evaluated by different force and vibration applications. RESULTS: It was seen that Von Mises stress distribution on miniscrew was located on the neck region and the highest stress levels were observed in the 1st analysis (27,0159N (mm2)), which was only force application. The loading of the cortical bone in the proximity of the miniscrew was clearly greater with only force application rather than force and vibration application together. Maximum and minimum principle stress values gradually decreased while vibration value increased. CONCLUSION: It was concluded that mechanical vibration force might reduce the peri-implant loading of the bone and stress levels on the miniscrews.

A novel sax-stent method in treatment of ascending aorta and aortic arch aneurysms evaluated by finite element simulations.

OBJECTIVES: A novel stent method to simplify treatment of proximal ascending aorta and aortic arch aneurysms was developed and investigated by finite element analysis. Therapy of ascending aortic and aortic arch aneurysms is difficult and challenging and is associated with various complications. METHODS: A 55mm wide×120mm long stent was designed without the stent graft and the stent was deployed by an endovascular method in a virtual patient-specific aneurysm model. The stress-strain analysis and deployment characteristics were performed in a finite element analysis using the Abaqus software. RESULTS: The stent, when embedded in the aortic wall, significantly reduced aortic wall stresses, while preserving the side coronary ostia and side branches in the aortic arch. When tissue growth was modeled computationally over the stent struts the wall stresses in aorta was reduced. This effect became more pronounced when increasing the thickness of the tissue growth. There were no abnormal stresses in the aorta, coronary ostium and at the origin of aortic branches. The stent reduced aneurysm expansion cause by hypertensive condition from 2mm without stenting to 1.3mm after stenting and embedding. CONCLUSION: In summary, we uncovered a simple treatment method using a bare nitinol stent without stent graft in the treatment of the proximal aorta and aortic arch aneurysms, which could eventually replace the complex treatment methods for this disease.

Comparison between isotropic linear-elastic law and isotropic hyperelastic law in the finite element modeling of the brachial plexus.

Augmented reality could help the identification of nerve structures in brachial plexus surgery. The goal of this study was to determine which law of mechanical behavior was more adapted by comparing the results of Hooke's isotropic linear elastic law to those of Ogden's isotropic hyperelastic law, applied to a biomechanical model of the brachial plexus. A model of finite elements was created using the ABAQUS® from a 3D model of the brachial plexus acquired by segmentation and meshing of MRI images at 0°, 45° and 135° of shoulder abduction of a healthy subject. The offset between the reconstructed model and the deformed model was evaluated quantitatively by the Hausdorff distance and qualitatively by the identification of 3 anatomical landmarks. In every case the Hausdorff distance was shorter with Ogden's law compared to Hooke's law. On a qualitative aspect, the model deformed by Ogden's law followed the concavity of the reconstructed model whereas the model deformed by Hooke's law remained convex. In conclusion, the results of this study demonstrate that the behavior of Ogden's isotropic hyperelastic mechanical model was more adapted to the modeling of the deformations of the brachial plexus.

Deformation of the corona radiata and internal capsule in normal pressure hydrocephalus.

BACKGROUND AND PURPOSE: The pathophysiology of the clinical manifestations in normal pressure hydrocephalus (NPH) remains obscure. Ventricular dilatation could generate forces on the paracentral fibers of the corona radiata (CR), hence interfering with their function and producing the classical clinical triad. The analysis of the regional displacement and deformation of the white matter bundles, forming the corona radiata and internal capsule, may clarify the relationship between ventricular dilatation and clinical manifestations in NPH. METHOD: An experimental finite element (FE) analysis was used to simulate ventricular dilatation in 3 dimensions (3D) and to calculate the strain and deformation on the surrounding parenchyma. Magnetic resonance diffusion tensor imaging-based white matter tractography was then applied to retrieve the displacement and deformation exerted along various fiber bundles of the corona radiata and internal capsule. Anterior and posterior limb displacements and elongations were compared using a paired samples t-test. RESULTS: The internal capsule, hence the corona radiata, of each cerebral hemisphere was segmented into anterior and posterior limbs. Mean displacements and elongations were calculated for each limb. Mean displacement was significantly larger in the anterior limb whereas mean deformation was larger in the posterior limb (P<0.01). CONCLUSION: The present simulation demonstrates that ventricular dilatation does not have a homogeneous effect on the periventricular fibre tracts, with a particular load on the corticospinal tract. The affection of this tract remains thereby a potential factor in the generation of the NPH gait disorders.

Estudio biomecánico hueso-implante DHS y fijador externo en la consolidación de la fractura de cadera / Étude biomécanique de la vis-plaque dynamique (DHS) et du fixateur externe dans la consolidation de la fracture de hanche / Biomechanical study of bone-DHS implant and external fixator in hip fracture

Objetivos: determinar el comportamiento biomecánico de los conjuntos placa Dinámic Hip Screw-hueso y fijador externo monolateral-hueso y la influencia de estos en la distribución del estado tensional, antes, durante y después de retirado el implante. Métodos: se realizó el estudio aplicando el método de los elementos finitos, se tuvo en cuenta la acción de los músculos y el peso corporal en la fase monopodal del ciclo de marcha, así como las propiedades anisotrópicas en el tejido cortical, e isotrópicas para la parte esponjosa del hueso. Se ejecutó un estudio comparativo del estado tensional del implante y su influencia en la variación del estado tensional-deformacional del hueso, durante el tiempo en que se mantiene el implante en este y luego de ser retirado Resultados: se obtuvo la variación porcentual de las zonas sometidas a tracción y compresión en el hueso sano durante el estado de carga correspondiente a la marcha monopodal, el valor de las tensiones actuantes en cada elemento de los implantes analizados durante la consolidación de la fractura, así como la influencia de estos en la distribución del estado tensional del hueso, durante su funcionamiento y después de retirado el implante. Conclusiones: en relación con el comportamiento mecánico del implante Dinámic Hip Screw y el fijador externo, la situación más desfavorable la presenta el primero, al mostrar tensiones por encima del límite elástico del material en el tornillo inferior de fijación al hueso. Se nota en ambos casos una ligera variación del estado tensional del hueso después de haberse colocado el implante. Al retirar los implantes se produjo una elevación de las tensiones de compresión en los bordes de los agujeros que fijaban uno y otro implante(AU)

Objective: to determine the biomechanical behavior of the bone-Dynamic Hip Screw plate and the bone- monolateral external fixator sets and their influence on the distribution of stress before, during and after the removal of implant. Methods: the study was based on the finite element model, taking into account the muscle actions and the body weight at the monopodal phase of the gait cycle as well as the anisotropic properties of the cortical tissue and the isotropic properties of the spongy part of the bone. A comparative study was also conducted on the stress condition of the implant and its influence over changes in the stress-deformation condition of the bone as long as the implant remains in the bone and after being removed. Results: the variation percentage of the areas under traction and compression in the healthy bone was estimated for the loading condition in the monopodal gait along with the acting stresses in each element of the implants analyzed during the consolidation of fracture and the their influence in the distribution of stresses in the bone during the functioning of implant and after its removal. Conclusions: regarding the mechanical behavior of the Dynamic Hip Screw implant and the external fixator, the most unfavorable situation was found in the first system since stresses were greater than the material's elastic limit in the lower fixation screw. A slight variation of the bone stress was noticed after placing the implant. When both implants were removed, there was a rise of compressive stresses at the borders of the holes they fixed(AU)

Objectif: le but de cette étude est de déterminer le comportement biomécanique de la vis-plaque dynamique (DHS) et du fixateur externe unilatéral, et l'influence de ceux-ci sur la distribution de la tension avant, pendant et après l'enlèvement de l'implant. Méthodes: une étude a été réalisée en utilisant la méthode des éléments finis. On a tenu compte de l'action des muscles et du poids corporel dans la phase d'appui de la marche, ainsi que des propriétés anisotropiques du tissu cortical et isotropiques du corps spongieux de l'os. Une étude comparative de la tension de l'implant et son influence sur la variation de tension et de déformation de l'os avant et après son enlèvement, est effectuée. Résultats: on a obtenu une variation des pourcentages entre les zones soumises à traction et celles soumises à compression de l'os sain au cours de l'état de charge correspondant à la phase d'appui de la marche; un taux des tensions agissant sur chaque élément des implants analysés pendant la consolidation de la fracture, ainsi que leur influence sur la distribution de l'état de tension de l'os au cours son fonctionnement et après l'enlèvement de l'implant. Conclusions: par rapport au comportement mécanique de la vis-plaque dynamique (DHS) et du fixateur externe, on peut conclure que la situation la plus défavorable est présentée par la DHS, dû à ses tensions surmontant la limite élastique du matériel de la vis inférieure de fixation à l'os. Dans tous les deux, on peut constater une légère variation de la tension de l'os après le placement de l'implant. Une fois que les implants sont enlevés, les tensions de compression sur les bords des trous de fixation s'élèvent(AU)

Estudio biomecánico hueso-implante DHS y fijador externo en la consolidación de la fractura de cadera / Biomechanical study of bone-DHS implant and external fixator in hip fracture

Objetivos: determinar el comportamiento biomecánico de los conjuntos placa Dinámic Hip Screw-hueso y fijador externo monolateral-hueso y la influencia de estos en la distribución del estado tensional, antes, durante y después de retirado el implante. Métodos: se realizó el estudio aplicando el método de los elementos finitos, se tuvo en cuenta la acción de los músculos y el peso corporal en la fase monopodal del ciclo de marcha, así como las propiedades anisotrópicas en el tejido cortical, e isotrópicas para la parte esponjosa del hueso. Se ejecutó un estudio comparativo del estado tensional del implante y su influencia en la variación del estado tensional-deformacional del hueso, durante el tiempo en que se mantiene el implante en este y luego de ser retirado Resultados: se obtuvo la variación porcentual de las zonas sometidas a tracción y compresión en el hueso sano durante el estado de carga correspondiente a la marcha monopodal, el valor de las tensiones actuantes en cada elemento de los implantes analizados durante la consolidación de la fractura, así como la influencia de estos en la distribución del estado tensional del hueso, durante su funcionamiento y después de retirado el implante. Conclusiones: en relación con el comportamiento mecánico del implante Dinámic Hip Screw y el fijador externo, la situación más desfavorable la presenta el primero, al mostrar tensiones por encima del límite elástico del material en el tornillo inferior de fijación al hueso. Se nota en ambos casos una ligera variación del estado tensional del hueso después de haberse colocado el implante. Al retirar los implantes se produjo una elevación de las tensiones de compresión en los bordes de los agujeros que fijaban uno y otro implante(AU)

Objective: to determine the biomechanical behavior of the bone-Dynamic Hip Screw plate and the bone- monolateral external fixator sets and their influence on the distribution of stress before, during and after the removal of implant. Methods: the study was based on the finite element model, taking into account the muscle actions and the body weight at the monopodal phase of the gait cycle as well as the anisotropic properties of the cortical tissue and the isotropic properties of the spongy part of the bone. A comparative study was also conducted on the stress condition of the implant and its influence over changes in the stress-deformation condition of the bone as long as the implant remains in the bone and after being removed. Results: the variation percentage of the areas under traction and compression in the healthy bone was estimated for the loading condition in the monopodal gait along with the acting stresses in each element of the implants analyzed during the consolidation of fracture and the their influence in the distribution of stresses in the bone during the functioning of implant and after its removal. Conclusions: regarding the mechanical behavior of the Dynamic Hip Screw implant and the external fixator, the most unfavorable situation was found in the first system since stresses were greater than the material's elastic limit in the lower fixation screw. A slight variation of the bone stress was noticed after placing the implant. When both implants were removed, there was a rise of compressive stresses at the borders of the holes they fixed(AU)

Empleo de elementos finitos en un estudio comparativo de dos sistemas de fijación interna para la fractura de cadera / Emploi des éléments finis dans une étude comparative de deux systèmes de fixation interne pour la fracture de hanche / Use of finite elements in a comparative study of two internal fixation systems for hip fractures

Introducción: existe una gran variedad de sistemas de fijación interna para el tratamiento de las fracturas, por lo que es común que un fijador pueda ser utilizado en diferentes fracturas. Esto trae consigo, que no se sepa con exactitud cuál de los sistemas de fijación interna tendrá mejor comportamiento desde el punto de vista del estado tensional. Objetivo: analizar mediante elementos finitos, el comportamiento de los dispositivos de fijación interna placa DHS y placa a compresión dinámica, utilizados en el tratamiento de las fracturas de cadera. Métodos: el modelo de fémur se obtuvo con autorización del reservorio de modelos óseos del cuerpo humano: The finite element meshes repository of the international society of biomechanics y luego, una tomografía axial computarizada. En los cálculos, se tuvieron en cuenta la acción muscular y el peso corporal en la fase monopodal del ciclo de la marcha, se determinó el estado tensional y el número de ciclos en que los sistemas de fijación interna causaron fallas por fatiga. Resultados: los resultados más desfavorables se encontraron en la placa a compresión dinámica angulada a 130º ya que se alcanzaron los valores de tensiones más altos y el número de ciclos más bajo. Conclusiones: la placa a compresión dinámica angulada a 130º sufre roturas con frecuencia, de ahí que es conveniente utilizar la placa DHS en el tratamiento de la fractura de cadera 31B2.1, siempre que sea posible desde el punto de vista clínico(AU)

Introduction: due to the wide variety of internal fixation systems for the treatment of fractures, it is common practice that the same fixator is used for various fracture types. As a result, it is difficult to tell which of the internal fixation systems will perform better in terms of tensional status. Objective: applying the finite-element method, analyze the behavior of the internal fixation devices DHS plate and dynamic compression plate, used in the treatment of hip fractures. Methods: the model femur was obtained with authorization by the human bone model repository (International Society of Biomechanics FiniteElement Mesh Repository), and studied by computerized axial tomography. Estimations took into account both muscle action and body weight in the monopodal phase of the gait cycle. Determination was made of the tensional status and the number of cycles undergoing fatigue failure. Results: the most unfavorable results corresponded to the 130º-angled dynamic compression plate, which exhibited the highest tension values and the smallest number of cycles. Conclusions: the 130º-angled dynamic compression plate frequently breaks. Hence the advisability of using the DHS plate in the treatment of 31B2.1 hip fractures whenever it is clinically possible(AU)

Introduction: Il y a plusieurs systèmes de fixation interne pour la traitement des fractures, c'est pourquoi l'utilisation de fixateurs est très fréquente. Cela provoque des doutes au moment de choisir le système de fixation interne le plus efficace du point de vue tensionnel. Objectif: Le but de cette étude est d'analyser au moyen des éléments finis le comportement des appareils de fixation interne, tels que la plaque DHS (Dynamic Hip Screw) et la plaque à compression dynamique, utilisés dans le traitement des fracture de hanche. Méthodes: Le modèle du fémur est obtenu sous l'autorisation du réservoir de modèles osseux du corps humain: The finite element meshes repository of the International Society of Biomechanics, et puis une tomographie axiale informatisée. Dans les estimations, l'action musculaire et le poids corporel sont tenus en considération dans la phase d'appui du cycle de la marche, et l'état de tension et le nombre de cycles provoquant l'échec à cause de la fatigue sont déterminés. Résultats: La plaque à compression dynamique sous angle de 130° a eu les résultats les plus défavorables, puisque les valeurs de tension ont été les plus hautes et le nombre de cycles le plus bas. Conclusions: La plaque à compression dynamique sous angle de 130° se brise fréquemment, c'est pourquoi la plaque DHS est conseillée, dès que possible, dans le traitement clinique de la fracture de hanche 31B2.1(AU)

Modelado por elementos finitos del deslizamiento epifisiario / Modélisation par éléments finis du déplacement épiphysaire / Finite element modeling of epiphyseal gliding

Objetivo: desarrollar un análisis por elementos finitos de la influencia del ángulo fisis-diáfisis, la masa corporal y la actividad física con el fin de observar su predominancia en la incidencia de deslizamiento epifisiario. Métodos: se elaboraron los modelos correspondientes a las combinaciones entre cada uno de los parámetros definidos (ángulo, masa y actividad física), generando 20 casos diferentes, y se evaluaron los esfuerzos presentes a lo largo de la placa de crecimiento. Resultados: se muestra un comportamiento uniforme y similar entre cada combinación, así como un aumento en las tensiones en la medida en que se incrementaba el valor de la carga y del ángulo. Conclusiones: el esfuerzo tiende a aumentar cuando se incrementa tanto el ángulo como la masa física, lo cual sugiere que estos dos factores podrían influir de manera decisiva en el origen del deslizamiento epifisiario(AU)

Objective: to develop a finite element analysis of the influence of physis-diaphysis angle, body mass and physical activity to observe its predominance in the incidence of epiphyseal gliding. Methods: models corresponding to the combinations among each of the defined parameters (angle, mass and physical activity) were developed, generating 20 different cases and efforts present through the growth plate were evaluated. Results: a similar and uniform behaviour between each of the combinations is shown as well as an increase in tension at the same time as the value of the load and angle increases. Conclusions: effort tends to increase when there is an increment in both the angle and the physical mass what suggests that these two factors could have a decisive influence on the origin of the epiphyseal gliding(AU)

But: en s'appuyant sur la technique des éléments finis, une analyse de l'influence de l'angle physe-diaphyse, la masse corporelle et l'activité physique a été réalisée afin d'observer cette influence sur l'incidence du déplacement épiphysaire. Méthodes: des modèles correspondant aux combinaisons entre chaque paramètre défini (angle, masse et activité physique), en résultant 20 cas différents, ont été élaborés, et les efforts présents tout au long de la plaque de croissance ont été évalués. Résultats: un comportement uniforme et similaire entre chaque combinaison est montré, ainsi qu'une élevée des tensions au fur et à mesure que la valeur de la charge et l'angle augmentaient. Conclusions: l'effort tend à augmenter lorsque l'angle et la masse physique s'accroissent, ce qui indique que ces deux facteurs pourraient influer certainement sur l'origine du déplacement épiphysaire(AU)

Análisis de la funcionabilidad de prótesis ortopédicas transfemorales / Analysis of the functional qualities of trans-femoral orthopedic prostheses

Introducción: la funcionabilidad de los artificios protésicos de miembros inferiores suele expresarse en términos de relacionar sus beneficios operacionales con aquellas necesidades funcionales y de bienestar del amputado. Este bienestar se relaciona fundamentalmente con un mínimo gasto energético del paciente y con la ausencia de enfermedades en las articulaciones residuales y que se inducen por la prótesis durante el régimen de marcha. Objetivo: evaluar la funcionabilidad de prótesis transfemorales utilizadas en Cuba mediante la integración de los resultados del análisis cinemático de la marcha del amputado, combinados con análisis de mecánica de sólidos rígidos aplicando simulaciones numéricas. Métodos: el análisis de la marcha de 8 pacientes con amputaciones unilaterales transfemorales y 5 sujetos normales (control) se realizó mediante técnicas videográficas. Se efectuó la estimación dinámica de las fuerzas que actúan en los segmentos articulares y se determinaron las tensiones y deformaciones que sufren las zonas del muñón y de la articulación del tobillo mediante el método de los elementos finitos. Resultados: cambios significativos en la dinámica de los segmentos articulados del tobillo-rodilla y cadera se reflejan como el resultado de la asimetría de la marcha del miembro protésico y el sano. Tal desequilibrio sugiere ser una de las principales causas de las enfermedades degenerativas de la cadera observadas en este tipo de paciente. Conclusiones: el análisis de la funcionabilidad de los artificios protésicos transfemorales solo es posible mediante la integración de los métodos cinemáticos de caracterización de la marcha, métodos dinámicos que establezcan la posibilidad de replicar la actividad del miembro sano. Mediante este estudio fue posible además el estudio de la resistencia mecánica y se vincularon todos los resultados a la aparición de enfermedades tanto en el miembro intacto como en el residual

Introduction: the functional quality of the prosthetic devices of lower extremities is usually expressed in terms to relate the functional benefits to those functional needs and the wellbeing of the amputee. This wellbeing is related mainly to a minimal energetic output of patient and to the lack of diseases of residual joints induced by the prosthesis during the gait. Objective: to assess the functional qualities of trans-femoral prostheses used in Cuba by the integration of results of kinematics analysis of the gait of amputee, combined with mechanics analysis of rigid solids applying numerical simulations. Methods: the gait's analysis of 8 patients with trans-femoral unilateral amputations and 5 normal subjects (controls) was made by videographic techniques. The dynamics estimation of strengths acting on the articular segments was carried out and determination of strain and deformations suffering the stump zones and of the ankle joint by finite elements method. Results: the significant changes in the dynamics of ankle-knee-hip articulation segments are present as the result of gait asymmetry of the prosthetic limb and the healthy one. This imbalance may be one of the leading causes of degenerative diseases of hip observed in this type of patient. Conclusions: the analysis of functional qualities of trans-femoral prosthetic devices only is possible by means of the integration of cinematic methods of gait characterization, dynamic methods establishing the possibility to replicate to the activity of healthy limb. Using this study also it was possible the mechanical resistance study linking all results to the appearance of diseases of intact limb as well as the residual one