Comparação biomecânica de CRIF e placa de reconstrução na estabilização de fraturas distais de fêmur em cães / Biomechanical comparison of CRIF and reconstruction plate for stabilization of distal femur fractures in dogs

O presente estudo objetivou comparar, biomecanicamente, por meio do ensaio de compressão excêntrica, a resistência dos implantes Clamp and Rod Internal Fixation (CRIF) 5,0mm e placa de reconstrução 3,5mm na fixação de fraturas distais de fêmur de cão. Foram utilizados 22 fêmures de 11 cadáveres de cão entre 2 e 7 anos de idade e peso corporal entre 20 e 40kg e subdivididos em dois grupos, denominados grupo CRIF (GC - 11 fêmures) e grupo placa (GP - 11 fêmures). Para realização dos testes, foi simulada falha que mimetizasse uma fratura distal nos corpos de prova, por meio de uma osteotomia de até 0,5cm, realizada com auxílio de serra oscilatória, imediatamente proximal ao início da tróclea. Os implantes foram fixados segundo os padrões AOSIF, lateralmente ao fêmur, sendo utilizados três parafusos distais e cinco proximais ao foco de fratura. Foi empregado o programa de computador PMI para calcular o ponto máximo de resistência antes da falha e avaliaram-se as variáveis força máxima, deformação máxima real, rigidez, força intermediária e deformação intermediária real. Não foram encontradas diferenças estatisticamente significativas entre os GC e GP quanto às variáveis avaliadas, sugerindo que ambos os implantes são boas opções de fixações para tais fraturas.(AU)

This study aims to compare the biomechanical properties, through compression eccentric test, of the resistance of the 5.0mm Clamp and Rod Internal Fixation Implants (CRIF) and 3.5mm reconstruction plate in fixing dog femur distal fracture. It was used 22 femurs from 11 dog cadavers with age between 2 and 7 years old and body weight between 20 and 40kg, subdivided into two groups, called CRIF Group (CG - 11 femurs) and plate group (PG - 11 femurs). A distal fracture in the specimens with a gap of 0.5cm osteotomy, was simulated to perform the test, performed by the oscillating saw, just proximal to the beginning of the trochlea. The implants were fixed by the standards AO / SIF, laterally to the femur, using three distal screws and five proximal to the fracture site. PMI computer program was used to calculate the maximum point of resistance before failure and evaluated the variables maximum strength, real maximum deformation, stiffness, intermediate strength and real intermediate deformation. No statistically significant differences were found between the GC and GP as the variables evaluated, suggesting that both implants are good fixation options for such fractures.(AU)

Comparação biomecânica de CRIF e placa de reconstrução na estabilização de fraturas distais de fêmur em cães / Biomechanical comparison of CRIF and reconstruction plate for stabilization of distal femur fractures in dogs

O presente estudo objetivou comparar, biomecanicamente, por meio do ensaio de compressão excêntrica, a resistência dos implantes Clamp and Rod Internal Fixation (CRIF) 5,0mm e placa de reconstrução 3,5mm na fixação de fraturas distais de fêmur de cão. Foram utilizados 22 fêmures de 11 cadáveres de cão entre 2 e 7 anos de idade e peso corporal entre 20 e 40kg e subdivididos em dois grupos, denominados grupo CRIF (GC - 11 fêmures) e grupo placa (GP - 11 fêmures). Para realização dos testes, foi simulada falha que mimetizasse uma fratura distal nos corpos de prova, por meio de uma osteotomia de até 0,5cm, realizada com auxílio de serra oscilatória, imediatamente proximal ao início da tróclea. Os implantes foram fixados segundo os padrões AOSIF, lateralmente ao fêmur, sendo utilizados três parafusos distais e cinco proximais ao foco de fratura. Foi empregado o programa de computador PMI para calcular o ponto máximo de resistência antes da falha e avaliaram-se as variáveis força máxima, deformação máxima real, rigidez, força intermediária e deformação intermediária real. Não foram encontradas diferenças estatisticamente significativas entre os GC e GP quanto às variáveis avaliadas, sugerindo que ambos os implantes são boas opções de fixações para tais fraturas.(AU)

This study aims to compare the biomechanical properties, through compression eccentric test, of the resistance of the 5.0mm Clamp and Rod Internal Fixation Implants (CRIF) and 3.5mm reconstruction plate in fixing dog femur distal fracture. It was used 22 femurs from 11 dog cadavers with age between 2 and 7 years old and body weight between 20 and 40kg, subdivided into two groups, called CRIF Group (CG - 11 femurs) and plate group (PG - 11 femurs). A distal fracture in the specimens with a gap of 0.5cm osteotomy, was simulated to perform the test, performed by the oscillating saw, just proximal to the beginning of the trochlea. The implants were fixed by the standards AO / SIF, laterally to the femur, using three distal screws and five proximal to the fracture site. PMI computer program was used to calculate the maximum point of resistance before failure and evaluated the variables maximum strength, real maximum deformation, stiffness, intermediate strength and real intermediate deformation. No statistically significant differences were found between the GC and GP as the variables evaluated, suggesting that both implants are good fixation options for such fractures.(AU)

Ensaio biomecânico para determinação do diâmetro de barra conectora de polimetilmetacrilato em fixador esquelético externo tipo Ia no úmero de suínos / Biomechanical test to determination the diameter of the polymethylmethacrylate bar in external skeletal fixator type Ia in swine humerusi

Fraturas ósseas podem ser corrigidas com a utilização de fixadores esqueléticos externos (FEE), método de estabilização bastante comum. Para tanto, têm-se utilizado barras conectoras de polimetilmetacrilato (PMMA) sem critério de diâmetro, as quais podem quebrar, se ficarem muito delgadas, ou ocasionar incômodo, quando muito pesadas e volumosas. O objetivo deste trabalho foi testar, por meio de ensaio biomecânico de compressão axial e flexão, qual é o diâmetro ideal da barra conectora de PMMA, correlacionado com o diâmetro ósseo para utilização em FEE tipo Ia. Utilizaram-se 24 úmeros para se realizarem medidas de comprimento, diâmetro, circunferência e ensaios biomecânicos. Após, foram confeccionadas barras de 1,5 vezes a média do diâmetro ósseo (grupo I), do mesmo diâmetro ósseo (grupo II) e de 0,5 vezes o diâmetro (grupo III). Com os resultados obtidos ao se compararem os valores dos ossos com os dos grupos II e III, verificou-se que as barras conectoras do grupo II mostraram-se mais resistentes do que o tecido ósseo no ensaio de compressão. No ensaio de flexão, os ossos resistiram mais quando comparados aos grupos II e III, sendo 4,3 vezes mais resistentes do que o grupo III nesse mesmo ensaio mecânico. Os resultados permitem um direcionamento para confecção de barras considerando-se o diâmetro ósseo como referência.(AU)

Bone fractures can be corrected from external skeletal fixators (ESF) in a fairly common internal stabilization method, in which connector bars polymethylmethacrylate (PMMA) is used. PMMA is used without criterion of diameter, and it can break if it is too thin or too heavy. It can be uncomfortable when bulky. The aim of this study was to test, through biomechanical axial compression and bending which is the ideal connector bar diameter PMMA, correlated to bone diameter for use in type Ia ESF. Twenty-four humerus were used to make measurements of length, diameter, circumference, and biomechanical testing. After the bars confected with 1.5 times the average diameter of the bone (group I), the same diameter (group II) and 0.5 times the diameter of the bone (group III). With the obtained results, using GII and GIII results, it was observed that the connector bars in group II were more resistant than the bones in the compression test. In the bending test, the bones resisted flexion strength when compared to group III and the group II was 4.3 times more resistant than group III in the same mechanical test. The results allow a direction for making bars considering bone diameter as a reference.(AU)

Ensaio biomecânico para determinação do diâmetro de barra conectora de polimetilmetacrilato em fixador esquelético externo tipo Ia no úmero de suínos / Biomechanical test to determination the diameter of the polymethylmethacrylate bar in external skeletal fixator type Ia in swine humerusi

Fraturas ósseas podem ser corrigidas com a utilização de fixadores esqueléticos externos (FEE), método de estabilização bastante comum. Para tanto, têm-se utilizado barras conectoras de polimetilmetacrilato (PMMA) sem critério de diâmetro, as quais podem quebrar, se ficarem muito delgadas, ou ocasionar incômodo, quando muito pesadas e volumosas. O objetivo deste trabalho foi testar, por meio de ensaio biomecânico de compressão axial e flexão, qual é o diâmetro ideal da barra conectora de PMMA, correlacionado com o diâmetro ósseo para utilização em FEE tipo Ia. Utilizaram-se 24 úmeros para se realizarem medidas de comprimento, diâmetro, circunferência e ensaios biomecânicos. Após, foram confeccionadas barras de 1,5 vezes a média do diâmetro ósseo (grupo I), do mesmo diâmetro ósseo (grupo II) e de 0,5 vezes o diâmetro (grupo III). Com os resultados obtidos ao se compararem os valores dos ossos com os dos grupos II e III, verificou-se que as barras conectoras do grupo II mostraram-se mais resistentes do que o tecido ósseo no ensaio de compressão. No ensaio de flexão, os ossos resistiram mais quando comparados aos grupos II e III, sendo 4,3 vezes mais resistentes do que o grupo III nesse mesmo ensaio mecânico. Os resultados permitem um direcionamento para confecção de barras considerando-se o diâmetro ósseo como referência.(AU)

Bone fractures can be corrected from external skeletal fixators (ESF) in a fairly common internal stabilization method, in which connector bars polymethylmethacrylate (PMMA) is used. PMMA is used without criterion of diameter, and it can break if it is too thin or too heavy. It can be uncomfortable when bulky. The aim of this study was to test, through biomechanical axial compression and bending which is the ideal connector bar diameter PMMA, correlated to bone diameter for use in type Ia ESF. Twenty-four humerus were used to make measurements of length, diameter, circumference, and biomechanical testing. After the bars confected with 1.5 times the average diameter of the bone (group I), the same diameter (group II) and 0.5 times the diameter of the bone (group III). With the obtained results, using GII and GIII results, it was observed that the connector bars in group II were more resistant than the bones in the compression test. In the bending test, the bones resisted flexion strength when compared to group III and the group II was 4.3 times more resistant than group III in the same mechanical test. The results allow a direction for making bars considering bone diameter as a reference.(AU)

Fratura cominutiva e articular distal de úmero tratada com fixador esquelético externo transarticular em três gatos / Comminuted articular fractures of the distal humerus of the three cats treated by transarticular skeletal fixators

Background: Humeral fractures account for 13% of all fractures in cats and commonly affect the middle diaphysis and supracondylar region with comminution. They are usually the result of high energy traumas such as falls, car accidents and firearm injuries. There are few treatment options for these types of fractures and since they are joint injuries, early surgical repair is mandatory to achieve perfect anatomical reduction, to maintain joint congruence and to allow early weight bearing. Our purpose is to report four subacute and chronic fractures of the distal diaphysis associated with comminuted supra and intercondylar fractures, stabilized with transarticular external skeletal fixator in three domestic felines. Cases: (1)- A 3-year-old male docile Siamese cat with 3.7 kg of body weight was presented for consultation with a 14-day history of high rise syndrome after falling from a 12-meter high. It presented distal comminuted humeral fracture that involved the inter and supracondylar regions. It also had right carpal-ulnar subluxation and comminuted right olecranon fracture involving the articular surface in the left thoracic limb. Fracture and joint stabilization was achieved by use of a transarticular hybrid external skeletal fixator on the right front limb. Fracture healing was observed at 150 days postoperatively. (2)- A 10-year-old female aggressive mixed breed cat with 4.1 kg of body weight was presented for consultation with a 16-day history of high rise syndrome after falling from a 9-meter high. The cat had a comminuted right humeral articular fracture with supra and intercondylar involvement and scapular fracture on the contralateral limb. The humerus fracture was treated with a transarticular linear external skeletal fixator and fracture healing was obtained at 240 postoperative days […]

Fratura cominutiva e articular distal de úmero tratada com fixador esquelético externo transarticular em três gatos / Comminuted articular fractures of the distal humerus of the three cats treated by transarticular skeletal fixators

Background: Humeral fractures account for 13% of all fractures in cats and commonly affect the middle diaphysis and supracondylar region with comminution. They are usually the result of high energy traumas such as falls, car accidents and firearm injuries. There are few treatment options for these types of fractures and since they are joint injuries, early surgical repair is mandatory to achieve perfect anatomical reduction, to maintain joint congruence and to allow early weight bearing. Our purpose is to report four subacute and chronic fractures of the distal diaphysis associated with comminuted supra and intercondylar fractures, stabilized with transarticular external skeletal fixator in three domestic felines. Cases: (1)- A 3-year-old male docile Siamese cat with 3.7 kg of body weight was presented for consultation with a 14-day history of high rise syndrome after falling from a 12-meter high. It presented distal comminuted humeral fracture that involved the inter and supracondylar regions. It also had right carpal-ulnar subluxation and comminuted right olecranon fracture involving the articular surface in the left thoracic limb. Fracture and joint stabilization was achieved by use of a transarticular hybrid external skeletal fixator on the right front limb. Fracture healing was observed at 150 days postoperatively. (2)- A 10-year-old female aggressive mixed breed cat with 4.1 kg of body weight was presented for consultation with a 16-day history of high rise syndrome after falling from a 9-meter high. The cat had a comminuted right humeral articular fracture with supra and intercondylar involvement and scapular fracture on the contralateral limb. The humerus fracture was treated with a transarticular linear external skeletal fixator and fracture healing was obtained at 240 postoperative days […](AU)

Mechanical analysis of transversal iliac fracture stabilization using dynamic compression plate or screws and PMM in polyurethane bone model / Avaliação mecânica de estabilização de fratura ilíaca transversa com placa de compressão dinâmica ou polimetilmecatrilato associado à parafusos utilizando modelo de osso sintético de poliuretano

Pelvic fractures correspond to 20 to 30 % of the fractures observed in dogs. Complete fractures, especially with bone axis deviation should be surgically treated. The mechanical study of surgical techniques is of utmost importance to assess the best way of treating these injuries. This study compared, biomechanically, the use of a dynamic compression plate (DCP) and screws (group 1) or screws and polymethylmethacrylate (PMMA) (group 2) to stabilize an iliac fracture using a static test. Sixteen canine synthetic hemi-pelvises (test specimens) with a transverse iliac osteotomy were used. After fixation with implants, a load was applied to the acetabulum until failure. Group 1 maximal compressive load was 133.9±18.60 N, displacement at yield 21.10±3.59mm and stiffness 125.22±12.25N/mm. Group 2 maximal compressive load was 183.50±27.38N, displacement at yield 16.66±5.42mm and stiffness 215.68±33.34N/mm. The stabilization with polymethylmethacrylate was stronger than dynamic compression plate since it resisted a greater load in all test specimens.(AU)

As fraturas da pelve são frequentes em cães, correspondendo a 20-30% das fraturas encontradas na espécie. A grande maioria delas é tratada cirurgicamente, principalmente aquelas que apresentam desvio ósseo. O estudo mecânico das técnicas cirúrgicas é de extrema importância para avaliação da melhor maneira de tratamento destas lesões. O objetivo deste estudo foi comparar, do ponto de vista biomecânico, a fixação das fraturas do ílio utilizando uma placa de compressão dinâmica ou parafusos associados ao polimetilmetacrilato, por meio de um teste estático. Foram utilizadas 16 hemipelves caninas de origem sintética, nas quais uma osteotomia transversa foi realizada no corpo do ílio. As fixações foram divididas em dois grupos: fixação com placa de compressão dinâmica e parafusos (grupo1) ou parafusos associados ao polimetilmetacrilato (grupo 2). Posteriormente à fixação dos implantes foi aplicada uma carga no acetábulo de cada corpo de prova até a falha. O grupo 2 apresentou força máxima de aplicação de carga a média de 133.9±18.60N, deflexão 21.10±3.59mm e rigidez 125.22±12.25N/mm. O grupo 2 apresentou força máxima de aplicação de carga a média de 183.50±27.38N, deflexão 16.66±5.42mm e rigidez 215.68±33.34N/mm. A estabilização com o polimetilmetacrilato mostrou ser mais resistente, pois resistiu a uma maior quantidade de carga em relação à placa de compressão dinâmica, em todos os corpos de prova.(AU)

Mechanical analysis of transversal iliac fracture stabilization using dynamic compression plate or screws and PMM in polyurethane bone model / Avaliação mecânica de estabilização de fratura ilíaca transversa com placa de compressão dinâmica ou polimetilmecatrilato associado à parafusos utilizando modelo de osso sintético de poliuretano

Pelvic fractures correspond to 20 to 30 % of the fractures observed in dogs. Complete fractures, especially with bone axis deviation should be surgically treated. The mechanical study of surgical techniques is of utmost importance to assess the best way of treating these injuries. This study compared, biomechanically, the use of a dynamic compression plate (DCP) and screws (group 1) or screws and polymethylmethacrylate (PMMA) (group 2) to stabilize an iliac fracture using a static test. Sixteen canine synthetic hemi-pelvises (test specimens) with a transverse iliac osteotomy were used. After fixation with implants, a load was applied to the acetabulum until failure. Group 1 maximal compressive load was 133.9±18.60 N, displacement at yield 21.10±3.59mm and stiffness 125.22±12.25N/mm. Group 2 maximal compressive load was 183.50±27.38N, displacement at yield 16.66±5.42mm and stiffness 215.68±33.34N/mm. The stabilization with polymethylmethacrylate was stronger than dynamic compression plate since it resisted a greater load in all test specimens.(AU)

As fraturas da pelve são frequentes em cães, correspondendo a 20-30% das fraturas encontradas na espécie. A grande maioria delas é tratada cirurgicamente, principalmente aquelas que apresentam desvio ósseo. O estudo mecânico das técnicas cirúrgicas é de extrema importância para avaliação da melhor maneira de tratamento destas lesões. O objetivo deste estudo foi comparar, do ponto de vista biomecânico, a fixação das fraturas do ílio utilizando uma placa de compressão dinâmica ou parafusos associados ao polimetilmetacrilato, por meio de um teste estático. Foram utilizadas 16 hemipelves caninas de origem sintética, nas quais uma osteotomia transversa foi realizada no corpo do ílio. As fixações foram divididas em dois grupos: fixação com placa de compressão dinâmica e parafusos (grupo1) ou parafusos associados ao polimetilmetacrilato (grupo 2). Posteriormente à fixação dos implantes foi aplicada uma carga no acetábulo de cada corpo de prova até a falha. O grupo 2 apresentou força máxima de aplicação de carga a média de 133.9±18.60N, deflexão 21.10±3.59mm e rigidez 125.22±12.25N/mm. O grupo 2 apresentou força máxima de aplicação de carga a média de 183.50±27.38N, deflexão 16.66±5.42mm e rigidez 215.68±33.34N/mm. A estabilização com o polimetilmetacrilato mostrou ser mais resistente, pois resistiu a uma maior quantidade de carga em relação à placa de compressão dinâmica, em todos os corpos de prova.(AU)

Tratamento de fratura exposta tipo Salter Harris I em felino através de artrodese temporária utilizando fixação externa / Treatment of exposed Salter Harris I fracture in feline by temporary arthrodesis using external fixation

A feline with a history of trauma for three days was diagnosed with Salter Harris I. The animal was then submitted to a surgical procedure where temporary joint arthrodesis was performed using pins and polymethylmethacrylate. The animal was followed by clinical orthopedic exams and radiographic evaluations.

Tratamento de fratura exposta tipo Salter Harris I em felino através de artrodese temporária utilizando fixação externa / Treatment of exposed Salter Harris I fracture in feline by temporary arthrodesis using external fixation

A feline with a history of trauma for three days was diagnosed with Salter Harris I. The animal was then submitted to a surgical procedure where temporary joint arthrodesis was performed using pins and polymethylmethacrylate. The animal was followed by clinical orthopedic exams and radiographic evaluations.(AU)

Osteossíntese de tibiotarso através de configuração tieinem Gavião Asa-De-Telha (Parabuteo unicinctus) - Relato de Caso / Tibiotarsus osteosynthesis in Harris's hawk using tie-in – a case report

The method of fixation should be well tolerated and its application must be made in theshortest possible surgery and anesthesia times. This report describes the surgicalmanagement of a Harris's hawk who, on orthopedic examination, had functional impotenceof the pelvic limb right. A transverse complete fracture of the tibiotarsus was observed onradiographic examination. Closed fracture reduction was chosen and osteosynthesis withhybrid external fixator with tied-in intramedullary pin. After 30 days it was bone healingwas confirmed.

Osteossíntese de tibiotarso através de configuração tieinem Gavião Asa-De-Telha (Parabuteo unicinctus) - Relato de Caso / Tibiotarsus osteosynthesis in Harris's hawk using tie-in a case report

The method of fixation should be well tolerated and its application must be made in theshortest possible surgery and anesthesia times. This report describes the surgicalmanagement of a Harris's hawk who, on orthopedic examination, had functional impotenceof the pelvic limb right. A transverse complete fracture of the tibiotarsus was observed onradiographic examination. Closed fracture reduction was chosen and osteosynthesis withhybrid external fixator with tied-in intramedullary pin. After 30 days it was bone healingwas confirmed.(AU)

External skeletal fixator intramedullary pin "tie-in" for the repair of comminuted tibial fracture in a Brazilian fox (Pseudalopex vetulus)

Background: The Brazilian fox (Pseudalopex vetulus, Lund 1842) is a naturally endemic specie of the Brazilian savanna vegetation. Due to the rapid destruction of its habitat, the specie is considered vulnerable and subject to different kinds of trauma that usually results in fractures and dislocations. Among the methods of fractures fixation, highlights the external skeletal fixator intramedullary pin tie-in which consists of the intramedullary pin associated to the external fixator. The aim of the present report was to describe the case of a Brazilian fox with a comminuted tibial fracture, submitted to osteosynthesis using an external skeletal fixator intramedullary pin tie-in. Case: It was attended an exemplar of Pseudalopex vetulus, male, young adult, with 3.9 kg body weight and history of functional impotence of the left hindlimb. At the physical and orthopedic evaluations were observed loss of bone continuity and crepitus in tibial region, and the presence of a contaminated lacerating skin wound about 3 cm in diameter in the lateral side of the injured limb. Craniocaudal and mediolateral radiographic projections of the left hindlimb revealed the presence of a complete comminuted fracture at the proximal and distal shaft of the left tibia; and a complete transverse fracture at mid shaft of the left fibula. Due to this, the animal was submitted to fracture fixation [...]

External skeletal fixator intramedullary pin "tie-in" for the repair of comminuted tibial fracture in a Brazilian fox (Pseudalopex vetulus)

Background: The Brazilian fox (Pseudalopex vetulus, Lund 1842) is a naturally endemic specie of the Brazilian savanna vegetation. Due to the rapid destruction of its habitat, the specie is considered vulnerable and subject to different kinds of trauma that usually results in fractures and dislocations. Among the methods of fractures fixation, highlights the external skeletal fixator intramedullary pin tie-in which consists of the intramedullary pin associated to the external fixator. The aim of the present report was to describe the case of a Brazilian fox with a comminuted tibial fracture, submitted to osteosynthesis using an external skeletal fixator intramedullary pin tie-in. Case: It was attended an exemplar of Pseudalopex vetulus, male, young adult, with 3.9 kg body weight and history of functional impotence of the left hindlimb. At the physical and orthopedic evaluations were observed loss of bone continuity and crepitus in tibial region, and the presence of a contaminated lacerating skin wound about 3 cm in diameter in the lateral side of the injured limb. Craniocaudal and mediolateral radiographic projections of the left hindlimb revealed the presence of a complete comminuted fracture at the proximal and distal shaft of the left tibia; and a complete transverse fracture at mid shaft of the left fibula. Due to this, the animal was submitted to fracture fixation [...](AU)

Estudo biomecânico comparativo entre parafusos associados a fio de aço e polimetilmetacrilato, dois tipos de placas bloqueadas e clamp and rod internal fixation (CRIF) para estabilização de osteotomias de acetábulo em gatos domésticos

O objetivo deste trabalho foi comparar a resistência de parafusos associados a fio de aço e polimetilmetacrilato (PMMA), placas bloqueadas de bloqueio convencional, placas bloqueadas de bloqueio cônico e clamp and rod internal fixation (CRIF) para estabilização de osteotomias de acetábulo em gatos domésticos por meio do ensaio de flexão em três pontos. Também foi avaliado qual método apresentou melhor redução das osteotomias. Foi definida como hipótese que as placas de bloqueio convencional seriam mais resistentes do que os demais implantes. Foram realizadas osteotomias transversas, na porção central de 32 hemipelves felinas separadas em quatro grupos, compostos por oito hemipelves cada: grupo parafuso (parafusos associados à cerclagem e PMMA), grupo bloqueio convencional (placas bloqueadas de bloqueio convencional), grupo CRIF (clamp and rod internal fixation) e grupo bloqueio cônico (placas bloqueadas de bloqueio cônico). A partir dos ensaios de flexão em três pontos foram obtidos os maiores valores de pico 1, momento 1, deformação para pico 1, momento máximo, deformação para pico máximo para o grupo bloqueio cônico, seguido pelos grupos bloqueio convencional, parafusos e CRIF. Já os valores de rigidez e rigidez estrutural foram maiores para o grupo boqueio cônico, seguido pelos grupos CRIF, parafuso e bloqueio convencional. O grupo que a presentou a melhor redução das osteotomias foi o grupo parafuso, enquanto a pior foi observada no grupo CRIF. Conclui-se que o o grupo bloqueio cônico foi o mais resistente aos testes biomecânicos, porém a utilização da associação de parafusos, fio de aço e PMMA foi uma técnica de fácil execução e tamanho adequado para os corpos de prova avaliados, promovendo resultados satisfatórios para redução da osteotomia e ensaio de flexão em três pontos.

The purpose of this study was to assess and compare accuracy of reduction and the resistance to failure of four methods of acetabular osteotomy fixation in domestic cats (screw/wire/polymethylmethacrylate composite fixation, two different locking plates and clamp and rod internal fixator - CRIF) using the three-point bending technique. The hypothesis was that the conventional locking plates would be more resistant to bending forces and would have better accuracy of reduction than the other constructs. Transverse acetabular osteotomies were created in 32 feline hemipelvis and the specimens were distributed into four groups of eight hemipelvis each: SWP group (associated with screw/wire/polymethylmethacrylate), conventional locking plate group, CRIF group (clamp and rod internal fixation) and conical locking plate group. Based on the three-point bending tests, the conical locking plate group has the highest values of peak 1, moment 1, deformation for peak 1, maximum moment and maximum peak deformation, followed by the conventional locking plate, SWP and CRIF groups. Values of structural rigidity and stiffness were higher for the conical locking plate, followed by CRIF, SWP and conventional locking plate groups. SWP group displayed more accuracy of acetabular reduction than the other groups, and the worst reductions were accounted for the CRIF group. In conclusion, the group treated with conical locking plates was biomechanically superior in resisting bending forces than the other groups, even though the association of screws/wire/ polymethylmethacrylate proved to be a feasible technique easily applied on the specimens, resulting in satisfactory outcomes for either acetabular reduction and three-point bending tests.

Tratamento conservativo e cirúrgico em 22 ruminantes com fraturas em membros / Conservative and surgical treatment in 22 ruminants with limb fractures

O objetivo do presente trabalho foi relatar os principais locais de fraturas em membros de 22 ruminantes e determinar a eficiência dos tratamentos utilizados. Foram incluídos no estudo oito caprinos, oito ovinos e seis bovinos Em casos de fraturas distais, o tratamento conservativo com imobilização foi o método de eleição. Em casos de fraturas proximais e fraturas expostas de metatarso ou metacarpo, os ruminantes foram tratados cirurgicamente. Observou-se maior frequência de fraturas envolvendo o metacarpo ou metatarso (54,5%), seguido por fraturas de tíbia (22,7%), fêmur (9%) e casos isolados de fraturas de falange medial, úmero, rádio e ulna (4,5% cada). O índice de recuperação total alcançou 95,4%. A imobilização com gesso associada à tala de Thomas, ou apenas com talas de madeira em animais jovens, foi eficiente na redução de fraturas de metacarpo, metatarso, tíbia, úmero e rádio nos ruminantes tratados. Enquanto no caso de fratura de falange medial, a imobilização com uso apenas de gesso foi suficiente para proporcionar reparação óssea adequada. A fixação esquelética externa ou interna deve ser considerada uma opção no tratamento de fraturas metacárpicas, metatársicas, tibiais e femorais em ruminantes, principalmente quando o animal for de baixo peso corporal.(AU)

The aim of the present study was to report the main locations of limb fractures in 22 ruminants and to determine the efficiency of the treatment choices. Eight goats, eight sheep and six cattle were included. In cases of distal fractures, the conservative treatment with immobilization was the method of choice. In cases of proximal, exposed metatarsal or metacarpal fractures, the ruminants were treated surgically. The higher frequency of fractures involved the metacarpal or metatarsal (54.5%) followed by fractures of the tibia (22.7%), femur (9%) and isolated cases of medial phalanx, humerus, radius and ulna fractures (4.5% each). Total recovery rate reached 95.4%. Immobilization with plaster associated with Thomas splint, or just with wooden splints in young animals, was efficient in reducing fractures of metacarpal, metatarsal, tibia, humerus, and radio in the treated ruminants. In the case of medial phalanx fracture, immobilization using only plaster was sufficient to provide adequate bone repair. The internal or external skeletal fixation should be considered an option in the treatment of metacarpal, metatarsal, tibial and femoral fractures in ruminants, especially in low body weight animals.(AU)

Tratamento conservativo e cirúrgico em 22 ruminantes com fraturas em membros / Conservative and surgical treatment in 22 ruminants with limb fractures

O objetivo do presente trabalho foi relatar os principais locais de fraturas em membros de 22 ruminantes e determinar a eficiência dos tratamentos utilizados. Foram incluídos no estudo oito caprinos, oito ovinos e seis bovinos Em casos de fraturas distais, o tratamento conservativo com imobilização foi o método de eleição. Em casos de fraturas proximais e fraturas expostas de metatarso ou metacarpo, os ruminantes foram tratados cirurgicamente. Observou-se maior frequência de fraturas envolvendo o metacarpo ou metatarso (54,5%), seguido por fraturas de tíbia (22,7%), fêmur (9%) e casos isolados de fraturas de falange medial, úmero, rádio e ulna (4,5% cada). O índice de recuperação total alcançou 95,4%. A imobilização com gesso associada à tala de Thomas, ou apenas com talas de madeira em animais jovens, foi eficiente na redução de fraturas de metacarpo, metatarso, tíbia, úmero e rádio nos ruminantes tratados. Enquanto no caso de fratura de falange medial, a imobilização com uso apenas de gesso foi suficiente para proporcionar reparação óssea adequada. A fixação esquelética externa ou interna deve ser considerada uma opção no tratamento de fraturas metacárpicas, metatársicas, tibiais e femorais em ruminantes, principalmente quando o animal for de baixo peso corporal.(AU)

The aim of the present study was to report the main locations of limb fractures in 22 ruminants and to determine the efficiency of the treatment choices. Eight goats, eight sheep and six cattle were included. In cases of distal fractures, the conservative treatment with immobilization was the method of choice. In cases of proximal, exposed metatarsal or metacarpal fractures, the ruminants were treated surgically. The higher frequency of fractures involved the metacarpal or metatarsal (54.5%) followed by fractures of the tibia (22.7%), femur (9%) and isolated cases of medial phalanx, humerus, radius and ulna fractures (4.5% each). Total recovery rate reached 95.4%. Immobilization with plaster associated with Thomas splint, or just with wooden splints in young animals, was efficient in reducing fractures of metacarpal, metatarsal, tibia, humerus, and radio in the treated ruminants. In the case of medial phalanx fracture, immobilization using only plaster was sufficient to provide adequate bone repair. The internal or external skeletal fixation should be considered an option in the treatment of metacarpal, metatarsal, tibial and femoral fractures in ruminants, especially in low body weight animals.(AU)

Torsional force applied to the tibia of living lambs in an attempt to change the bone rotational axis

To evaluate the effects of torsional force on the rotational axis of living lamb tibias. METHODS: An external fixator device was designed to apply rotation to the tibias of lambs. Once a week, the bone distal extremity was rotated 2º. After achieving ~20º of internal rotation, the turning was discontinued and the device was maintained in situ for one month and euthanasia occurred in group A (n=10) after this. In group B (n=9) euthanasia occurred three months after removing the device. Computed tomography scans evaluated the rotational angle; dual-energy X-ray absorptiometry assessed the bone mineral density, and conventional and polarized light microscopy studied the bone microstructure. RESULTS: In group A, the mean angle of the external rotation in the control tibias was 24º and 8º in the twisted tibias (p<0.0001); in group B, the angle was 23º (control) and 7º (twisted, p<0.0001), with no differences between groups A and B (p=0.9567). The BMD increased in the twisted tibias in group A (p<0.0001) and in group B (p=0.0023), with no between-group differences (p>0.05). Microscopically, the twisted tibias showed asymmetrical subperiosteal bone deposition on the lateral cortex surface. CONCLUSION: Gradual torsion applied to the immature tibia significantly modified its rotational axis.(AU)

Tarsometatarsal partial arthrodesis with use of circular skeletal fixator on a dog / Artrodese parcial tarsometatársica com uso de fixador esquéletico externo circular em cão

Background: Trauma to the canine foot may result in injury to soft tissue or bone or both. Foot injury often results in fractures and joint instability because of disruption to carpal or tarsal ligaments. Several fi xation methods have been described for stabilizing tarsometatarsal arthrodesis. The aim of this paper is to report the case of a unilateral tarsometatarsal arthrodesis with use of circular skeletal fi xator on the left pelvic limb of a dog.Case: A 5-year-old intact male dog weighting 25 kg was referred to the veterinary hospital with a left tarsal degloving injury. The previous history revealed that the dog had been bitten by another dog seven days prior to the referral. On physical exam it had swelling and severe pain on the left foot, crepitus of the intertarsal/tarsometatarsal region, instability, bone exposure and myiasis larvae on the wound. The dog was non-weight-bearing on the affected limb. No other abnormalities were found. Radiographs revealed it to be an open fracture of the left tarsal distal line with tarsometatarsal luxation. Adherent dressings were changed for seven days to minimize the contamination before surgery. The dog was treated by open reduction and internal fixation using a circular skeletal fixator. After general anesthesia was induced, a lateral approach to the tarsometatarsal joint was made. The tarsometatarsal joint then was exposed. Arti

Background: Trauma to the canine foot may result in injury to soft tissue or bone or both. Foot injury often results in fractures and joint instability because of disruption to carpal or tarsal ligaments. Several fi xation methods have been described for stabilizing tarsometatarsal arthrodesis. The aim of this paper is to report the case of a unilateral tarsometatarsal arthrodesis with use of circular skeletal fi xator on the left pelvic limb of a dog.Case: A 5-year-old intact male dog weighting 25 kg was referred to the veterinary hospital with a left tarsal degloving injury. The previous history revealed that the dog had been bitten by another dog seven days prior to the referral. On physical exam it had swelling and severe pain on the left foot, crepitus of the intertarsal/tarsometatarsal region, instability, bone exposure and myiasis larvae on the wound. The dog was non-weight-bearing on the affected limb. No other abnormalities were found. Radiographs revealed it to be an open fracture of the left tarsal distal line with tarsometatarsal luxation. Adherent dressings were changed for seven days to minimize the contamination before surgery. The dog was treated by open reduction and internal fixation using a circular skeletal fixator. After general anesthesia was induced, a lateral approach to the tarsometatarsal joint was made. The tarsometatarsal joint then was exposed. Arti

Artrodese parcial tarsometatársica com uso de fixador esquéletico externo circular em cão / Tarsometatarsal Partial Arthrodesis with Use of Circular Skeletal Fixator on a Dog

Background: Trauma to the canine foot may result in injury to soft tissue or bone or both. Foot injury often results in fractures and joint instability because of disruption to carpal or tarsal ligaments. Several fixation methods have been described for stabilizing tarsometatarsal arthrodesis. The aim of this paper is to report the case of a unilateral tarsometatarsal arthrodesis with use of circular skeletal fixator on the left pelvic limb of a dog. Case: A 5-year-old intact male dog weighting 25 kg was referred to the veterinary hospital with a left tarsal degloving injury. The previous history revealed that the dog had been bitten by another dog seven days prior to the referral. On physical exam it had swelling and severe pain on the left foot, crepitus of the intertarsal/tarsometatarsal region, instability, bone exposure and myiasis larvae on the wound. The dog was non-weight-bearing on the affected limb. No other abnormalities were found. Radiographs revealed it to be an open fracture of the left tarsal distal line with tarsometatarsal luxation. Adherent dressings were changed for seven days to minimize the contamination before surgery. The dog was treated by open reduction and internal fixation using a circular skeletal fixator. After general anesthesia was induced, a lateral approach to the tarsometatarsal joint was made. The tarsometatarsal joint then was exposed. Articular cartilage was removed with a pneumatic burr. Manual reduction was performed. There were placed two rings proximal to the fracture and one distal with Kirschner wires were angled 45° between them through the bone. One of them was a semi-ring in the shape of a horseshoe. The 1,5 mm Kirschner wires were tensioned by a dynamometer loaded at 30 kg. For wound closure a free skin graft from the thorax was used. Articular anchylosis was reached in three months but the implant removal was posterior to that time due to the owner's choice. Discussion: Traumatic injury is the most important cause for fracture and instability of the tarsometatarsal joint and was the cause of injury for this case. Partial arthrodesis is considered the treatment of choice for tarsal instabilities with ligament disruption. Implant problems following union can complicate arthrodeses stabilized with internal fixation, and they may require a second surgery for implant removal. In this case the size of the rings conformed well to the proximal tarsus, and allowed sufficient space for wire placement in the metatarsal bones and did not interfere with ambulation. The dog recovered good limb function soon after the surgery and articular anchylosis was reached within three months as expected. In a study three of ten dogs undergoing tarsometatarsal arthrodesis due to continued lameness after bony union, using a laterally applied plate required a second surgery for implant removal. Implant failure is a common complication of tarsocrural and tarsometatarsal arthrodeses stabilized with bone screws, Steinmann pins or plate fi xation. Tarsometatarsal partial arthrodesis with use of circular skeletal fixator is a proper option for contaminated wounds without enough skin for closure. The limiting factor is the surgeon experience for this choice of fixation, material availability and the owner's commitment with the treatment.