Femoral orthopedic implants in dogs with titanium - mechanical evaluation

Background: Orthopedic implants are commonly used for different types of surgical procedures to gain optimal functionand to provide stability to both bones and tendon structures. When inserting these implants, the characteristics of the material are important for surgical success, and the ideal implant must be biocompatible and nonallergenic. However, whenmolding an implant to the bone structure, its resistance can change significantly. Implants can be temporary or permanentin the body, and metal possesses properties that make it acceptable for bone repair. In biomedical implants, 2 types aremost common, commercially pure (CP)-Ti and Ti-6A1-4V. They both provide stable fixation and low risk of loosening.Implants made with the same material and composition can perform differently if the material has been altered by processing techniques for different scenarios. Stress, strain and elastic modulus are the primary metrics used in the description ofimplant materials. They can be calculated based on mechanical tests of specimens with defined geometry, most commonlytensile, bending and torsional tests. In order to better evaluate those changes, we compared the mechanical characteristicsof titanium bone plates, before and after they were molded to the bone, to verify and quantify the loss of stiffness andresistance after molding the plate.Materials, Methods & Results: The study was prospective. Orthopedic implant made of commercially pure titanium (CPTi) were divided into 2 groups, one group without plate molding and the other with plate molding to a dog femora bone.Thirty-six plates of different sizes (5.0, 6.5, 8.0, 9.0, 10.0- and 11.0-mm diameter) were divided into 6 groups containing6 plates of each size and submitted to the 4-point flexion test of resistance, using a piece of dog femur (weights of 5, 10,15, 20 and 25 kg) as the bone in which the...

Femoral orthopedic implants in dogs with titanium - mechanical evaluation

Background: Orthopedic implants are commonly used for different types of surgical procedures to gain optimal functionand to provide stability to both bones and tendon structures. When inserting these implants, the characteristics of the material are important for surgical success, and the ideal implant must be biocompatible and nonallergenic. However, whenmolding an implant to the bone structure, its resistance can change significantly. Implants can be temporary or permanentin the body, and metal possesses properties that make it acceptable for bone repair. In biomedical implants, 2 types aremost common, commercially pure (CP)-Ti and Ti-6A1-4V. They both provide stable fixation and low risk of loosening.Implants made with the same material and composition can perform differently if the material has been altered by processing techniques for different scenarios. Stress, strain and elastic modulus are the primary metrics used in the description ofimplant materials. They can be calculated based on mechanical tests of specimens with defined geometry, most commonlytensile, bending and torsional tests. In order to better evaluate those changes, we compared the mechanical characteristicsof titanium bone plates, before and after they were molded to the bone, to verify and quantify the loss of stiffness andresistance after molding the plate.Materials, Methods & Results: The study was prospective. Orthopedic implant made of commercially pure titanium (CPTi) were divided into 2 groups, one group without plate molding and the other with plate molding to a dog femora bone.Thirty-six plates of different sizes (5.0, 6.5, 8.0, 9.0, 10.0- and 11.0-mm diameter) were divided into 6 groups containing6 plates of each size and submitted to the 4-point flexion test of resistance, using a piece of dog femur (weights of 5, 10,15, 20 and 25 kg) as the bone in which the...(AU)

Association of rush pin and intramedular pin techniques for the stabilization of salter harris type I fracture in rabbit (Oryctolagus cuniculus)

Background: In domestic rabbits, fractures are usually the result of household accidents. Fractures of the distal femoral physis are frequently observed in animals with immature skeletons and may cause future orthopedic problems. With this type of fracture, early reduction and stabilization are necessary to prevent additional damage to the physis and to preserve the growth potential of the bone. This report aims to describe the clinical and radiographic findings, as well as the surgical method used that combined Rush pins with an intramedullary pin, associated with a Salter Harris type I fracture of the right distal femur in a rabbit.Case: A 4-month male domestic rabbit (Oryctolagus cuniculus) weighing 1.2 kg, was referred to the Veterinary Hospital with a right pelvic limb lameness after an episode of trauma. Orthopedic examination revealed swelling, instability, crepitation, and increased pain sensitivity in the distal aspect of the right femur. Following physical and radiographic examination, a Salter Harris type I fracture of the right distal femur was diagnosed. The patient was premedicated with a combination of xylazine (2 mg/kg IM) and ketamine (10 mg/kg IM), which allowed placement of an IV catheter for the administration of fluids and intubation using an endotracheal tube with an internal diameter of 2 mm. Anesthesia was maintained with isoflurane, and an epidural was performed with a combination of lidocaine (2 mg/kg) and bupivacaine (0.75 mg/kg). Osteosynthesis was performed with two Rush pins and an intramedullary pin. Radiographic examination 110 and 330 days after the surgical procedure showed good alignment of the bone and adequate healing of the fracture. The combination of techniques used in this case report proved to be effective, resulting in functional recovery of the limb and rapid bone healing.[...](AU)

Association of rush pin and intramedular pin techniques for the stabilization of salter harris type I fracture in rabbit (Oryctolagus cuniculus)

Background: In domestic rabbits, fractures are usually the result of household accidents. Fractures of the distal femoral physis are frequently observed in animals with immature skeletons and may cause future orthopedic problems. With this type of fracture, early reduction and stabilization are necessary to prevent additional damage to the physis and to preserve the growth potential of the bone. This report aims to describe the clinical and radiographic findings, as well as the surgical method used that combined Rush pins with an intramedullary pin, associated with a Salter Harris type I fracture of the right distal femur in a rabbit.Case: A 4-month male domestic rabbit (Oryctolagus cuniculus) weighing 1.2 kg, was referred to the Veterinary Hospital with a right pelvic limb lameness after an episode of trauma. Orthopedic examination revealed swelling, instability, crepitation, and increased pain sensitivity in the distal aspect of the right femur. Following physical and radiographic examination, a Salter Harris type I fracture of the right distal femur was diagnosed. The patient was premedicated with a combination of xylazine (2 mg/kg IM) and ketamine (10 mg/kg IM), which allowed placement of an IV catheter for the administration of fluids and intubation using an endotracheal tube with an internal diameter of 2 mm. Anesthesia was maintained with isoflurane, and an epidural was performed with a combination of lidocaine (2 mg/kg) and bupivacaine (0.75 mg/kg). Osteosynthesis was performed with two Rush pins and an intramedullary pin. Radiographic examination 110 and 330 days after the surgical procedure showed good alignment of the bone and adequate healing of the fracture. The combination of techniques used in this case report proved to be effective, resulting in functional recovery of the limb and rapid bone healing.[...]

Osteossíntese minimamente invasiva com placa bloqueada (Mipo) sem a utilização de intensificadores de imagem nas fraturas de tíbia em cães / Minimally invasive osteosynthesis with locked plate with no intraoperative imaging for tibial fractures in dogs

Avanços na compreensão da biologia óssea e das complicações das fraturas têm levado a modificações na abordagem da fixação interna, sendo a osteossíntese minimamente invasiva com placa (Mipo) uma das recentes evoluções para o manejo biológico das fraturas. O objetivo do presente estudo foi avaliar o uso de placas bloqueadas aplicadas de forma minimante invasivas em fraturas da tíbia de cães, sem a utilização de intensificadores de imagem intraoperatória. Foram utilizados 10 cães que apresentavam fraturas da tíbia, de idades e raças variadas. Os animais foram avaliados quanto à deambulação, à intensidade do edema, e exames radiográficos foram realizados nos períodos zero, 15, 30, 60, 90 e 120 dias de pós-operatório. Após 15 dias de pós-operatório, 80% dos cães já utilizavam o membro ao caminhar e apresentavam formação de edema discreto a ausente no membro operado. Após 30 dias de pós-operatório, todos os cães já apoiavam o membro ao caminhar e não apresentavam formação de edema. Todos os pacientes apresentaram sinais radiográficos de início de consolidação óssea após 15 dias de pós-operatório e pôde-se observar que a união clínica ocorreu em média aos 42,5 dias. O tratamento de fraturas de tíbia por meio da Mipo é alternativa eficaz, resultando em utilização precoce do membro e união clínica efetiva, e pode ser realizado sem uso de intensificadores de imagem.(AU)

Advances in the comprehension of bone healing and complications of treatment of fractures have occurred. Less invasive procedures have been advocated. A minimally invasive plate osteosynthesis (MIPO) is one of the ways to avoid tissue damage. The aim of this study was to evaluate the use of MIPO in tibial fractures in dogs, with no intraoperative imaging. Ten dogs presenting tibial fracture were used. Deambulation, swelling and radiographic changes were evaluated preoperatively, just after the procedure and at 15, 30, 60, 90 e 120 days postoperatively. After 15 days of surgery 80% dogs were able to walk with slight swelling or without swelling. After 30 days all dogs have supported the member to walk and had no swelling. All dogs presented initial radiographic signs of bone healing after 15 postoperative days and it can be seen that the average clinical union occurred at 42.5 days. The treatment of tibial fractures by MIPO is an effective alternative resulting in early and effective clinical union and can be performed without the use of image intensifiers.(AU)

ANÁLISE MECÂNICA COMPARATIVA DE DIFERENTES MÉTODOS DE ESTABILIZAÇÃO DE OSTEOTOMIA DO OLÉCRANO DE CÃO UTILIZANDO CORPOS DE PROVA IMPRESSOS 3D

Objetivou-se avaliar mecanicamente três técnicas de estabilização de osteotomia do olécrano (transversa) (haste intramedular bloqueada compressiva, banda de tensão e placa (LCP), utilizando corpos de prova prototipados padronizados (ulnas). Para tal foi utilizado corpos de prova (ulna de cão) (n=21) impressos em 3D (padronizados), manufaturados em PLA (ácido poliláctico). Após alocação dos implantes em cada um dos três grupos (n=7), grupo utilizando haste compressiva (GH), grupo com banda de tensão (GBT) e grupo placa (GP), testes mecânicos (teste de tração) foram realizados no intuito de averiguar qual das três técnicas forneceu maior resistência à força de tração. Os referidos testes foram realizados por máquina de ensaio universal para aquisição de dados a velocidade de 5 mm/minuto. Os dados foram avaliados entre os três Grupos (GH, GBT e GP), resultando em sete repetições a cada combinação. A análises de variância foram realizadas utilizando o Software R (versão 3.6.3) após comprovação dos supostos matemáticos (Teste de Shapiro-Wilk e Teste de Bartlett), considerando o delineamento inteiramente casualizado com três tratamentos (grupos) e sete repetições para os dados de força máxima e força de ruptura. O pós-teste Tukey foi aplicado quando a ANOVA indicou diferença significativa para a comparação das médias, e a significância foi declarada a p 0,05. O GH apresentou maior força máxima (N) do que os demais grupos (p<0,001). Adicionalmente, o GBT apresentou maior força máxima quando comparado ao GP. A força de ruptura exercida no ensaio mecânico não resultou na ruptura dos implantes no GP. Por outro lado, o GH apresentou maior força de ruptura quando comparado ao GBT (p<0,001).

The objective of this study was to evaluate mechanically three techniques for olecranon osteotomy stabilization (transverse) (compressed blocked intramedullary nail, tension band, and plate (PCL), using standardized prototyped specimens (ulnas). It was used specimens (dogs ulna) (n = 21) printed in 3D (standardized), manufactured in PLA (polylactic acid). After allocation of the implants in each of the three groups (n = 7), group using compressive nail (GH), group with tension band (GBT), and plate group (GP), mechanical tests (tensile test) were carried out in order to investigate which of the three techniques provided greater resistance to the tensile force. The mechanical tests were performed using the universal testing machine in a 5 mm/minute speed. The data were evaluated between the three groups (GH, GBT, and GP), considering the completely randomized design with three treatments (groups) and seven repetitions for maximum strength and breaking strength. The Shapiro-Wilk Test and Bartletts Test were performed to verify the data distribution and the homogeneity of variances. After that, analysis of variance was performed using the Software R (version 3.6.3). When ANOVA indicated a statistically significant difference for the comparison between means considering p 0.05 the Tukeys Test was performed. The GH showed the greatest maximum strength (N) when compared with the other groups (p <0.001). Additionally, the GBT showed greater maximum strength when compared to GP. The rupture force exerted in the mechanical test did not result in the rupture of the implants in the GP. On the other hand, GH presented greater breaking strength when compared to GBT (p <0.001).