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Considering that global awareness for sustainable development has risen to face environmental damages, different building materials have been considered from a mechanical perspective. In this sense, considering the richness of South America regarding its woods, the Guayacan and the Ecuadorian oak timbers have not been previously characterized. The present research has performed mechanical, thermal, and moisture content characterizations to acknowledge the benefits of considering these materials for the building industries. In this sense, Guayacan has been shown to have lower thermal conductivity, making it ideal for thermal insulation; the oak from Manabi showed the best compressive strength; while the oak from El Oro stands with the best tensile strength; and the oak from Loja showed the best modulus of elasticity. On the other hand, all the materials were compared by multicriteria decision methods to select the best, by using the COPRAS method driven by the objective entropy-weighted method, showing that the oak from Loja is the best choice considering the advantage that presents with the modulus of elasticity. In this sense, it is concluded that regarding the mechanical properties, there is not much difference for the compression, bending, and tensile strength; nevertheless, for the modulus of elasticity the oak from Loja stands out, making it a factor to be considered in the selection of a wood for building applications that is corroborated through multicriteria decision methods.

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This study refers to the development of hybrid briquettes using centrifuged sludge from the wastewater treatment of poultry and sawdust from furniture industry. The aim was to evaluate the performance of briquettes as a source of thermal energy, mitigating the risks of the current elimination and reducing the operational costs of their destination. To know the oxidizing characteristics of the briquettes and their mechanical resistance, superior calorific power, ash content, volatile materials, fixed carbon, and resistance to axial compression were evaluated. Thermogravimetric and differential exploratory calorimetry analyses were performed. Statistical treatments were carried out to verify the most significant factors to produce briquettes, the best proportions of the raw materials, and to evaluate whether there is interference from moisture and glue flour used as a binder. The best condition of the sludge-sawdust mixture was 15% and 85%, respectively, with 6.0% moisture. The best-case treatment had 23.82-MPa mechanical resistance, a calorific value of 17.20 MJ kg-1, and a density of 1374.15 kg m-3.

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Silvopastoral systems (SPS) are presented as an alternative for the protection and recovery of soils; however, the relationship between the tree component and the physical-chemical characteristics of the soil is unknown. Thus, the objective of this study was to evaluate the physical-chemical characteristics of the soil under four silvopastoral systems (SPS), alder (Alnus acuminata), pine (Pinus patula), cypress (Cupressus macrocarpa), and pona (Ceroxylon quindiuense), and a treeless system (TS) in the Amazonas region. A completely randomized design (CRD) with five treatments and three replicates was used. The experimental units were sampled at two depths, 0-15 and 15-30 cm. The parameters evaluated were pH, electrical conductivity (dS/m), organic matter (%), phosphorus (ppm), potassium (ppm), cation exchange capacity (meq/100 g), porosity (%), mechanical resistance (kg/cm2), bulk density (gr/cm3), moisture (%) and total carbon (t/ha). The results were analyzed by analysis of variance (α = 0.05 %) and Tukey's test of means (p ≤ 0.05). The systems presented strong acidic pH values (4.11-5.61), which resulted in high organic matter contents in all systems (6.74-9.99 %). The highest phosphorus content was in the SPS with alder (12.64 ppm), and the highest potassium content was in the SPS with cypress (382.33 ppm). Porosity in all systems was higher than 60 %. The highest bulk density was between 15 and 30 cm, and the highest percentage of moisture was in the surface layer (0-15 cm). The mechanical strength was higher in the SPS with cypress (2.62 kg/cm2). For all the systems evaluated, the highest carbon stock was found in the first 15 cm. The SPS with pine had the best soil characteristics and carbon sequestration (149.05 t/ha).

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Silver nanoparticles (AgNP L) synthesis using the active compounds of lemon juice was optimized. The obtained nanoparticles were included in starch-based film formulations, studying the relevant properties that condition their application in the packaging area. The optimized conditions for AgNP L' synthesis were 30 min at 90 °C, which led to the lowest nanoparticle size (5.5 nm) with the highest associated stability (ζ= -29.5 mV) up to 90 days. Nanocomposite films resulted with an orange tone that increased with AgNP L concentration (14.3-143 ppm). Water vapor permeability decreased while tensile mechanical resistance increased up to an aggregate of 71.5 ppm of AgNP L, indicating the nanoparticles' reinforcement of the polymer matrix. Besides, the citric acid content provided by lemon juice also affected the starch-based relevant film properties. Regarding antimicrobial capacity, a synergic effect between active compounds of lemon juice and silver nanoparticles was evidenced, being Salmonella spp. the most sensitive bacteria.

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Photobiomodulation therapy (PBMT) has been indicated for enforcement on healing skin wounds. This study evaluated the effects of PBMT on the healing of skin wounds during the proliferation phase in rats with a hypoproteic diet. Rats were randomized to one of the following groups (n = 10 per group): (i) injured normoproteic (25% protein) not subjected to PBMT; (ii) injured normoproteic who received PBMT; (iii) injured hypoproteic (8% protein) not subjected to PBMT; and (iv) injured hypoproteic who received PBMT. Rats were submitted to skin wounds and then treated with PBMT (low-level laser therapy: 660 nm, 50 mW, 1.07 W/cm2, 0.028 cm2, 72 J/cm2, 2 J). Analyses were performed at 7 and 14 days of follow-up: semi-quantitative histopathologic analysis, collagen type I and III expressions, immunohistochemical marking for matrix metalloproteinases-3 (MMP-3) and (matrix metalloproteinases-9) MMP-9, and mechanical resistance test. There were significant differences between the normoproteic groups and their respective treated groups (p < 0.05), as well as to treated and untreated hypoproteic groups in histopathologic analysis semi-quantitatively and immunohistochemistry for MMP-3 and 9, in which PBMT was able to decrease immunostaining. Moreover, there was a decrease in collagen deposition with the statistical difference (p < 0.05) for both collagen types III and I. In conclusion, PBMT application was proved effective in the treatment of cutaneous wounds in rats submitted to a hypoproteic diet. These alterations were more salient in the proliferation stage with the reduction of metalloproteinases providing better mechanical resistance of the injured area in the remodeling phase with an intensification of type I collagen.

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This work aimed to produce and characterize cellulose nanofibers obtained from cassava peel with a combination of pre-treatments with acid hydrolysis or TEMPO-mediated oxidation and ultrasonic disintegration. All nanofibers presented nanometric diameter (5-16 nm) and high negative zeta potential values (around -30 mV). Oscillatory rheology showed a gel-like behavior of the aqueous suspensions of nanofibers (1.0-1.8 % w/w), indicating their use as reinforcement for nanocomposite or as a thickening agent. Additionally aqueous suspensions of nanofibers obtained by acid hydrolysis presented higher gel strength than those produced by TEMPO-mediated oxidation. However, ultrasound application increased even more viscoelastic properties. Flow curves showed that suspensions of nanofibers obtained by acid hydrolysis presented a thixotropy behavior and viscosity profile with three regions. Therefore our results showed that it is possible to tune mechanical properties of cellulose nanofibers choosing and modifying chemical and physical process conditions in order to allow a number of applications.

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Osteoporosis is an osteometabolic disease, which promotes structural degradation of bone tissue and reduction of mineral density. We reported here a mechanical resistance assay from normal, osteopenic and osteoporotic trabecular vertebral bones of human cadavers. We performed a compressed test on ninety samples, evaluating Young's modulus and X-ray microtomography to measure bone volume fraction and trabecular thickness. This experimental data are employed for computing the orthotropic macroscopic behavior of vertebral trabecular bones using known analytical formulae that were obtained by Galka et al. (Arch Mech 51: 335-355, 1999) via an asymptotic homogenization model. A geometrical model with a periodic orthogonal plate-like structure is applied. The properties of the bone-trabecular mass are considered linear, homogeneous and orthotropic. Average values for all technical or engineering elastic properties are computed for three important regions of the trabecular bones corresponding to thirty individuals classified as normal, osteopenic or osteoporotic by calcaneus ultrassometry. This study could be useful for a better understanding of the elastic behavior of trabecular bones in human vertebral bodies, allowing an estimation of bone answer under stress in different directions and the risk of fracture associated with osteoporosis.HighlightsDescribing the elastic behavior of trabecular bones in human vertebral bodies at the micro and macroscopic.Allow a better estimation of the stress in different directions and risk of fracture associated with osteoporosis.Model request a very low computational cost.Offer a better understand the global effective coefficients of samples of trabecular bone, from the model of a periodic unit cell, in the format orthogonal plate-like structure with homogeneous bone mass.

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The objective of this work was to analyze the physical attributes of a Oxisol of different crop-livestock-forest integration systems implanted in 2012 and in use since then. The experimental design was a randomized complete block design, with four replications and four treatments: ILP - crop - livestock integration; ILPF 1L - agrosilvopastoral system, with one eucalyptus line; ILPF 3L - agrosilvopastoral system, with three eucalyptus lines; and EUC - exclusive plantation of eucalyptus (forest). From June 2017 to May 2018, mechanical penetration and gravimetric soil moisture evaluations were carried out to monitor soil compaction in three depths of soil: 0-0.05; 0.05-0.10 and 0.10-0.20 m. The results of the research show that there was a significant difference in the soil attributes studied, being the highest compaction found in the treatment ILPF 3L (0.05-0.10 m) near the limit considered ideal for a good development of the plants. Gravimetric soil moisture did not influence compaction results. In general, the results show that in the soil conditions of the region considered fragile and highly susceptible to compaction, the presence of the animals does not cause a very drastic compaction to the soil, with values lower than the critical limit of 2 MPa.

O objetivo deste trabalho foi analisar os atributos físicos de um Latossolo Vermelho Amarelo de diferentes sistemas de integração lavoura-pecuária-floresta implantados em 2012 e em uso desde então. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições e quatro tratamentos: ILP - integração lavoura-pecuária; ILPF 1L - sistema agrossilvipastoril, com uma linha de eucalipto; ILPF 3L - sistema agrossilvipastoril, com três linhas de eucalipto; e EUC - plantio exclusivo de eucalipto (bosque). No período de junho de 2017 a maio de 2018 foram realizadas avaliações da resistência mecânica à penetração e da umidade gravimétrica do solo, a fim de monitorar a compactação, em três camadas do solo: 0-0,05; 0,05-0,10 e 0,10-0,20 m de profundidade. Os resultados mostram que houve diferença significativa para os atributos do solo estudados, sendo a maior compactação encontrada no tratamento ILPF 3L (0,05-0,10 m) próximo ao limite considerado ideal para um bom desenvolvimento das plantas. A umidade gravimétrica do solo não influenciou os resultados de compactação. De modo geral, os resultados mostram que a presença dos animais não causa uma compactação muito drástica ao solo, com valores menores que o limite crítico de 2 MPa.

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RESUMO

The objective of this work was to analyze the physical attributes of a Oxisol of different crop-livestock-forest integration systems implanted in 2012 and in use since then. The experimental design was a randomized complete block design, with four replications and four treatments: ILP - crop - livestock integration; ILPF 1L - agrosilvopastoral system, with one eucalyptus line; ILPF 3L - agrosilvopastoral system, with three eucalyptus lines; and EUC - exclusive plantation of eucalyptus (forest). From June 2017 to May 2018, mechanical penetration and gravimetric soil moisture evaluations were carried out to monitor soil compaction in three depths of soil: 0-0.05; 0.05-0.10 and 0.10-0.20 m. The results of the research show that there was a significant difference in the soil attributes studied, being the highest compaction found in the treatment ILPF 3L (0.05-0.10 m) near the limit considered ideal for a good development of the plants. Gravimetric soil moisture did not influence compaction results. In general, the results show that in the soil conditions of the region considered fragile and highly susceptible to compaction, the presence of the animals does not cause a very drastic compaction to the soil, with values lower than the critical limit of 2 MPa.(AU)

O objetivo deste trabalho foi analisar os atributos físicos de um Latossolo Vermelho Amarelo de diferentes sistemas de integração lavoura-pecuária-floresta implantados em 2012 e em uso desde então. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições e quatro tratamentos: ILP - integração lavoura-pecuária; ILPF 1L - sistema agrossilvipastoril, com uma linha de eucalipto; ILPF 3L - sistema agrossilvipastoril, com três linhas de eucalipto; e EUC - plantio exclusivo de eucalipto (bosque). No período de junho de 2017 a maio de 2018 foram realizadas avaliações da resistência mecânica à penetração e da umidade gravimétrica do solo, a fim de monitorar a compactação, em três camadas do solo: 0-0,05; 0,05-0,10 e 0,10-0,20 m de profundidade. Os resultados mostram que houve diferença significativa para os atributos do solo estudados, sendo a maior compactação encontrada no tratamento ILPF 3L (0,05-0,10 m) próximo ao limite considerado ideal para um bom desenvolvimento das plantas. A umidade gravimétrica do solo não influenciou os resultados de compactação. De modo geral, os resultados mostram que a presença dos animais não causa uma compactação muito drástica ao solo, com valores menores que o limite crítico de 2 MPa.(AU)

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Arabic gum-based composite hydrogels reinforced with eucalyptus and pinus residues were synthesized via free-radical reaction aiming to controlled phosphorus release. All hydrogels were characterized by swelling kinetics (SK), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mechanical assays (MA). The water and solute transports through the hydrophilic three-dimensional networks of the hydrogels occur preferably by diffusion processes and macromolecular relaxation. Hemicellulose, lignin and cellulose fibers contained in eucalyptus and pinus residues affected the crosslinking density, crystalline structure, and water/solute diffusion due to reduction of free hydroxyl and amine groups in the hydrogel networks. Hence, the eucalyptus and pinus residues improved the mechanical and thermal resistances of the composite hydrogels. Finally, the Arabic gum-based hydrogel and Arabic gum-based composite hydrogels reinforced with eucalyptus and pinus residues demonstrated to be excellent alternatives for the controlled phosphorus release in agricultural nutrient-poor soils.

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BACKGROUND: The clinical measure of forefoot-shank alignment (FSA) predicts the amount of foot pronation during weight-bearing tasks. This may be mediated by a relationship between FSA and the mechanical resistance of the midfoot joint complex (MFJC) to forefoot inversion, which is a component of weight-bearing foot pronation. OBJECTIVE: To investigate if the clinical measure of FSA is associated with MFJC mechanical resistance to inversion. DESIGN: Cross-sectional observational study. METHOD: Forty-six healthy individuals (27 males; 19 females) with mean age of 26.4 years (SD 5.3) participated in this study. FSA was measured with photographs. The resistance torque of the MFJC against inversion was measured with a specially designed device. Mean torque, mean torque normalized by body mass, and joint resting position were calculated as variables related to MFJC mechanical resistance. Correlation analyses were carried out to test the association between each MFJC resistance variable and the FSA (α = 0.05). RESULTS: /findings: There were significant moderate correlations of FSA with mean torque (r = -0.44, p = 0.002), mean normalized torque (r = -0.42, p = 0.004) and resting position (r = 0.39, p = 0.007). The clinical measure of FSA is associated to the mechanical resistance of the MFJC: (a) the greater the FSA, the smaller the resistance torques; (b) the greater the FSA, the more inverted the forefoot resting position. CONCLUSIONS: These results showed that the clinical measure of FSA is moderately related to mechanical properties of the MFJC.

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The purpose of this study was to analyze the low-level laser therapy (LLLT) on metalloproteinase expression and the mechanical strength of skeletal muscle regeneration after peripheral nerve injury. Rats were subjected to crush injury of the right sciatic nerve, followed by LLLT (830 nm, 35, 70, 140, and 280 J/cm2) for 21 consecutive days. Functional gait analysis was performed at weekly intervals and the animals were sacrificed after the last evaluation at day 21 for collection of the gastrocnemius muscles, which were submitted to analysis of resistance, and the tibialis anterior, for evaluation of metalloproteinase-2 (MMP-2). The results were statistically analyzed at a significance level of 5%. The irradiated groups showed a significant decrease in the sciatic functional index and a significant increase in the mechanical strength when compared to the injured group with no treatment (p < 0.05), with no significant difference among the energy densities used. While no difference among groups was observed for the activity of MMP-2 in pro-active band, at the intermediate band, the activity was significantly higher (p < 0.05) for the groups irradiated with 35, 70, and 140 J/cm2, and at the active band, the activity was significantly more intense in the group irradiated with 280 J/cm2. The present study demonstrated that injury of the sciatic nerve, with consequent muscle denervation, are benefited by the laser therapy, which restores neuromuscular function, active MMP-2 and increases the maximum breaking strength.

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Thio-urethanes were synthesized by combining 1,6-hexanediol-diissocyante (aliphatic) with pentaerythritol tetra-3-mercaptopropionate (PETMP) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (aromatic) with trimethylol-tris-3-mercaptopropionate (TMP), at 1:2 isocyanate:thiol, leaving pendant thiols. Oligomers were added at 10-30 phr to BisGMA-UDMA-TEGDMA (5:3:2, BUT). 25 wt% silanated inorganic fillers were added. Commercial cement (Relyx Veneer, 3M-ESPE) was also evaluated with 10-20 phr of aromatic oligomer. Near-IR was used to follow methacrylate conversion (DC) and rate of polymerization (Rpmax). Mechanical properties were evaluated in three-point bending (ISO 4049) for flexural strength/modulus (FS/FM, and toughness), and notched specimens (ASTM Standard E399-90) for fracture toughness (KIC). Polymerization stress (PS) was measured on the Bioman. Volumetric shrinkage (VS, %) was measured with the bonded disk technique. Results were analyzed with ANOVA/Tukey's test (α=5%). In general terms, for BUT cements, conversion and mechanical properties in flexure increased for selected groups with the addition of thio-urethane oligomers. The aromatic versions resulted in greater FS/FM than aliphatic. Fracture toughness increased by two-fold in the experimental groups (from 1.17 ± 0.36 MPam(1/2) to around 3.23 ± 0.22 MPam(1/2)). Rpmax decreased with the addition of thio-urethanes, though the vitrification point was not statistically different from the control. VS and PS decreased with both oligomers. For the commercial cement, 20 phr of oligomer increased DC, vitrification, reduced Rpmax and also significantly increased KIC, and reduced PS and FM. Thio-urethane oligomers were shown to favorably modify conventional dimethacrylate networks. Significant reductions in polymerization stress were achieved at the same time conversion and fracture toughness increased.

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In this study, we examined the physiochemical properties of nasoenteral feeding tubes made from two different types of polymer: silicone materials and polyurethane. The internal surfaces of the nasoenteral feeding tubes were analyzed for their hydrophobicity, roughness, microtopography, rupture-tension and ability to stretch. We also studied the adhesion of an isolated, multi-drug resistant strain of S. aureus to these polymers. The polyurethane nasoenteral tube, which was classified as hydrophilic, was more resistant to rupture-tension and stretching tests than the silicone tube, which was classified as hydrophobic. Additionally, the polyurethane tube had a rougher surface than the silicone tube. Approximately 1.0 log CFU.cm-2 of S. aureus cells adhered to the tubes and this number was not statistically different between the two types of surfaces (p > 0.05). In future studies, new polymers for nasoenteral feeding tubes should be tested for their ability to support bacterial growth. Bacterial adhesion to these polymers can easily be reduced through modification of the polymer's physicochemical surface characteristics.

RESUMO

IN THIS STUDY, WE EXAMINED THE PHYSIOCHEMICAL PROPERTIES OF NASOENTERAL FEEDING TUBES MADE FROM TWO DIFFERENT TYPES OF POLYMER: silicone materials and polyurethane. The internal surfaces of the nasoenteral feeding tubes were analyzed for their hydrophobicity, roughness, microtopography, rupture-tension and ability to stretch. We also studied the adhesion of an isolated, multi-drug resistant strain of S. aureus to these polymers. The polyurethane nasoenteral tube, which was classified as hydrophilic, was more resistant to rupture-tension and stretching tests than the silicone tube, which was classified as hydrophobic. Additionally, the polyurethane tube had a rougher surface than the silicone tube. Approximately 1.0 log CFU.cm(-2) of S. aureus cells adhered to the tubes and this number was not statistically different between the two types of surfaces (p > 0.05). In future studies, new polymers for nasoenteral feeding tubes should be tested for their ability to support bacterial growth. Bacterial adhesion to these polymers can easily be reduced through modification of the polymer's physicochemical surface characteristics.

RESUMO

In this study, we examined the physiochemical properties of nasoenteral feeding tubes made from two different types of polymer: silicone materials and polyurethane. The internal surfaces of the nasoenteral feeding tubes were analyzed for their hydrophobicity, roughness, microtopography, rupture-tension and ability to stretch. We also studied the adhesion of an isolated, multi-drug resistant strain of S. aureus to these polymers. The polyurethane nasoenteral tube, which was classified as hydrophilic, was more resistant to rupture-tension and stretching tests than the silicone tube, which was classified as hydrophobic. Additionally, the polyurethane tube had a rougher surface than the silicone tube. Approximately 1.0 log CFU.cm-2 of S. aureus cells adhered to the tubes and this number was not statistically different between the two types of surfaces (p > 0.05). In future studies, new polymers for nasoenteral feeding tubes should be tested for their ability to support bacterial growth. Bacterial adhesion to these polymers can easily be reduced through modification of the polymer's physicochemical surface characteristics.

RESUMO

The present study aimed to evaluate a modification of the stabilization method of the tibial tuberosity advancement technique (TTA), originally described for stabilization of the cranial cruciate deficient stifle. Ten adult mongrel dogs with weights ranging from 25 to 30kg were used. After euthanasia, the hind-limbs were divided into two groups: G1 - test (n=10), and G2 - control (n=10) represented by the contra lateral limb. The test group was submitted to the modified TTA technique, stabilized by one shaft screw in craniocaudal position and a titanium cage inserted at the osteotomy site. The position of the patellar tendon, 90º in relation to the tibial plateau, and the correct position of all implants were confirmed radiographically after surgery. Posteriorly, in both groups, limbs were harvested and tibias collected with their respectively patellar tendon insertion preserved for the mechanical resistance test. The fixation of the tibial tuberosity with a shaft screw and titanium cage resulted in resistance compatible with the normal physiological forces transferred to the hind-limbs during locomotion. The biomechanical tests confirmed the viability of the method performed for the tibial tuberosity fixation and support future clinical trials to validate the technique.

O presente estudo teve por objetivo avaliar a resistência mecânica do método de estabilização da técnica de avanço da tuberosidade tibial (TTA), originalmente descrita para tratamento da ruptura do ligamento cruzado cranial. Foram avaliados 10 cães, sem raça definida e com massa corporal entre 25 e 30kg. Após a eutanásia, os membros pélvicos foram divididos em dois grupos, sendo que G1 era o grupo teste (n=10) e G2 o controle (n=10), representado pelo membro contralateral. O grupo operado foi submetido à técnica de avanço da tuberosidade tibial (TTA) modificada, com emprego de um parafuso especial em posição craniocaudal e um espaçador de titânio inserido no local de osteotomia. O posicionamento do tendão patelar perpendicularmente ao platô tibial e o correto posicionamento dos implantes foi confirmado radiograficamente em todos os espécimes. Posteriormente, em ambos os grupos foram coletadas as tíbias, com preservação da inserção dos seus respectivos tendões patelares, para realização dos testes de resistência mecânica. A estabilização da tuberosidade tibial por parafuso especial em sentido craniocaudal e espaçador de titânio demonstrou resistência compatível com as forças fisiológicas tradicionalmente impostas ao membro pélvico durante a locomoção. Os testes biomecânicos confirmam a viabilidade do método de estabilização e sustentam estudos clínicos futuros para validação da técnica cirúrgica.

Assuntos

RESUMO

The present study aimed to evaluate a modification of the stabilization method of the tibial tuberosity advancement technique (TTA), originally described for stabilization of the cranial cruciate deficient stifle. Ten adult mongrel dogs with weights ranging from 25 to 30kg were used. After euthanasia, the hind-limbs were divided into two groups: G1 - test (n=10), and G2 - control (n=10) represented by the contra lateral limb. The test group was submitted to the modified TTA technique, stabilized by one shaft screw in craniocaudal position and a titanium cage inserted at the osteotomy site. The position of the patellar tendon, 90° in relation to the tibial plateau, and the correct position of all implants were confirmed radiographically after surgery. Posteriorly, in both groups, limbs were harvested and tibias collected with their respectively patellar tendon insertion preserved for the mechanical resistance test. The fixation of the tibial tuberosity with a shaft screw and titanium cage resulted in resistance compatible with the normal physiological forces transferred to the hind-limbs during locomotion. The biomechanical tests confirmed the viability of the method performed for the tibial tuberosity fixation and support future clinical trials to validate the technique.

O presente estudo teve por objetivo avaliar a resistência mecânica do método de estabilização da técnica de avanço da tuberosidade tibial (TTA), originalmente descrita para tratamento da ruptura do ligamento cruzado cranial. Foram avaliados 10 cães, sem raça definida e com massa corporal entre 25 e 30kg. Após a eutanásia, os membros pélvicos foram divididos em dois grupos, sendo que G1 era o grupo teste (n=10) e G2 o controle (n=10), representado pelo membro contralateral. O grupo operado foi submetido à técnica de avanço da tuberosidade tibial (TTA) modificada, com emprego de um parafuso especial em posição craniocaudal e um espaçador de titânio inserido no local de osteotomia. O posicionamento do tendão patelar perpendicularmente ao platô tibial e o correto posicionamento dos implantes foi confirmado radiograficamente em todos os espécimes. Posteriormente, em ambos os grupos foram coletadas as tíbias, com preservação da inserção dos seus respectivos tendões patelares, para realização dos testes de resistência mecânica. A estabilização da tuberosidade tibial por parafuso especial em sentido craniocaudal e espaçador de titânio demonstrou resistência compatível com as forças fisiológicas tradicionalmente impostas ao membro pélvico durante a locomoção. Os testes biomecânicos confirmam a viabilidade do método de estabilização e sustentam estudos clínicos futuros para validação da técnica cirúrgica.

RESUMO

The present study aimed to evaluate a modification of the stabilization method of the tibial tuberosity advancement technique (TTA), originally described for stabilization of the cranial cruciate deficient stifle. Ten adult mongrel dogs with weights ranging from 25 to 30kg were used. After euthanasia, the hind-limbs were divided into two groups: G1 - test (n=10), and G2 - control (n=10) represented by the contra lateral limb. The test group was submitted to the modified TTA technique, stabilized by one shaft screw in craniocaudal position and a titanium cage inserted at the osteotomy site. The position of the patellar tendon, 90° in relation to the tibial plateau, and the correct position of all implants were confirmed radiographically after surgery. Posteriorly, in both groups, limbs were harvested and tibias collected with their respectively patellar tendon insertion preserved for the mechanical resistance test. The fixation of the tibial tuberosity with a shaft screw and titanium cage resulted in resistance compatible with the normal physiological forces transferred to the hind-limbs during locomotion. The biomechanical tests confirmed the viability of the method performed for the tibial tuberosity fixation and support future clinical trials to validate the technique.

O presente estudo teve por objetivo avaliar a resistência mecânica do método de estabilização da técnica de avanço da tuberosidade tibial (TTA), originalmente descrita para tratamento da ruptura do ligamento cruzado cranial. Foram avaliados 10 cães, sem raça definida e com massa corporal entre 25 e 30kg. Após a eutanásia, os membros pélvicos foram divididos em dois grupos, sendo que G1 era o grupo teste (n=10) e G2 o controle (n=10), representado pelo membro contralateral. O grupo operado foi submetido à técnica de avanço da tuberosidade tibial (TTA) modificada, com emprego de um parafuso especial em posição craniocaudal e um espaçador de titânio inserido no local de osteotomia. O posicionamento do tendão patelar perpendicularmente ao platô tibial e o correto posicionamento dos implantes foi confirmado radiograficamente em todos os espécimes. Posteriormente, em ambos os grupos foram coletadas as tíbias, com preservação da inserção dos seus respectivos tendões patelares, para realização dos testes de resistência mecânica. A estabilização da tuberosidade tibial por parafuso especial em sentido craniocaudal e espaçador de titânio demonstrou resistência compatível com as forças fisiológicas tradicionalmente impostas ao membro pélvico durante a locomoção. Os testes biomecânicos confirmam a viabilidade do método de estabilização e sustentam estudos clínicos futuros para validação da técnica cirúrgica.

RESUMO

The present study aimed to evaluate a modification of the stabilization method of the tibial tuberosity advancement technique (TTA), originally described for stabilization of the cranial cruciate deficient stifle. Ten adult mongrel dogs with weights ranging from 25 to 30kg were used. After euthanasia, the hind-limbs were divided into two groups: G1 - test (n=10), and G2 - control (n=10) represented by the contra lateral limb. The test group was submitted to the modified TTA technique, stabilized by one shaft screw in craniocaudal position and a titanium cage inserted at the osteotomy site. The position of the patellar tendon, 90° in relation to the tibial plateau, and the correct position of all implants were confirmed radiographically after surgery. Posteriorly, in both groups, limbs were harvested and tibias collected with their respectively patellar tendon insertion preserved for the mechanical resistance test. The fixation of the tibial tuberosity with a shaft screw and titanium cage resulted in resistance compatible with the normal physiological forces transferred to the hind-limbs during locomotion. The biomechanical tests confirmed the viability of the method performed for the tibial tuberosity fixation and support future clinical trials to validate the technique.

O presente estudo teve por objetivo avaliar a resistência mecânica do método de estabilização da técnica de avanço da tuberosidade tibial (TTA), originalmente descrita para tratamento da ruptura do ligamento cruzado cranial. Foram avaliados 10 cães, sem raça definida e com massa corporal entre 25 e 30kg. Após a eutanásia, os membros pélvicos foram divididos em dois grupos, sendo que G1 era o grupo teste (n=10) e G2 o controle (n=10), representado pelo membro contralateral. O grupo operado foi submetido à técnica de avanço da tuberosidade tibial (TTA) modificada, com emprego de um parafuso especial em posição craniocaudal e um espaçador de titânio inserido no local de osteotomia. O posicionamento do tendão patelar perpendicularmente ao platô tibial e o correto posicionamento dos implantes foi confirmado radiograficamente em todos os espécimes. Posteriormente, em ambos os grupos foram coletadas as tíbias, com preservação da inserção dos seus respectivos tendões patelares, para realização dos testes de resistência mecânica. A estabilização da tuberosidade tibial por parafuso especial em sentido craniocaudal e espaçador de titânio demonstrou resistência compatível com as forças fisiológicas tradicionalmente impostas ao membro pélvico durante a locomoção. Os testes biomecânicos confirmam a viabilidade do método de estabilização e sustentam estudos clínicos futuros para validação da técnica cirúrgica.