Evaluation of the degradation of two bioabsorbable interference screws: an in-vivo study in sheep

Purpose: To evaluate in-vivo degradation of two bioabsorbable interference screws. Methods: Twenty-two crossbred Santa Inês ewes were used. A poly-DL-lactide (PDLLA) screw (70%/30%) was inserted in the right pelvic limb, and a PDLLA screw (70%) + ß-tri-calcium phosphate (ß-TCP) (30%) in the left pelvic limb. Animals were euthanized at one, four, seven and a half and 18 months after surgery. Plain radiography, computed tomography (CT), microCT, and histological analysis were accomplished. Results: PDLLA screw was hypodense at all evaluation moments, but with progressive density increase along the central axis, whereas PDLLA/ß-TCP was initially hyperdense and progressively lost this characteristic. No adverse reactions were observed on histological evaluation. Conclusions: The inclusion of ß-TCP favors screw degradation since the PDLLA/ß-TCP screws evidenced a more intense degradation process than the PDLLA screws at the last evaluation. PDLLA screws showed higher bone production, evident around the screw thread, inside the lateral perforations, and in the central canal, whereas the PDLLA/ß-TCP screws presented less bone tissue at the implantation site.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering

ABSTRACT Purpose To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. Methods A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. Results Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. Conclusions Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Surgical stabilization of canine lateralscapulohumeral luxation using extracapsular tension suture with screws and nylon wire – case report

A dog was consulted with functional disability of the right thoracic limb.Radiographic image showed lateral luxation of the scapulohumeral joint.The animal was submitted to surgical treatment using tension suture withscrews and Nylon wire, with satisfactory result and functional use of thelimb 30 days postoperatively.

Surgical stabilization of canine lateralscapulohumeral luxation using extracapsular tension suture with screws and nylon wire case report

A dog was consulted with functional disability of the right thoracic limb.Radiographic image showed lateral luxation of the scapulohumeral joint.The animal was submitted to surgical treatment using tension suture withscrews and Nylon wire, with satisfactory result and functional use of thelimb 30 days postoperatively.(AU)

Redução de fratura de côndilo lateral do úmero com parafuso leg e pino de Steinmann – relato de caso / Lateral condyle fracture reduction in the humerus of a dog with compressive screw and Steinmann pin – case report

Cases of fractures are very common in veterinary clinics and hospitals, often with small animals affected. A fracture can be defined as complete or incomplete disruption of the continuity of a bone or cartilage. The humerus form the skeleton arm. It is a long bone which lies obliquely against the ventral part of the thorax. It plays a central role in the movement of the forelimb. The goal of this study is to describe a case report of a lateral condylar fracture reduction in the humerus of a dog using the compressive screw technique and Steinmann pin.

Redução de fratura de côndilo lateral do úmero com parafuso leg e pino de Steinmann relato de caso / Lateral condyle fracture reduction in the humerus of a dog with compressive screw and Steinmann pin case report

Cases of fractures are very common in veterinary clinics and hospitals, often with small animals affected. A fracture can be defined as complete or incomplete disruption of the continuity of a bone or cartilage. The humerus form the skeleton arm. It is a long bone which lies obliquely against the ventral part of the thorax. It plays a central role in the movement of the forelimb. The goal of this study is to describe a case report of a lateral condylar fracture reduction in the humerus of a dog using the compressive screw technique and Steinmann pin.(AU)

In-vivo bone response to titanium screw implants anodized in sodium sulfate

To evaluate the early bone response to a nanotextured dental implant treated with sodium sulfate (Na2SO4), using a rabbit model. Twelve animals were randomly divided into group 1 (Control) - machined implants and group 2 (Test) - nanotextured implants. Extra-oral incision was performed to provide access to intended surgical site where the dental implant was inserted immediately after the extraction of the mandibular first premolar. Implant surface characterization was performed by scanning electron microscopy attached to energy dispersive spectroscopy and interferometry. Three weeks after surgery, the animals were induced to death and undecalcified sections of the samples were prepared for histological and histomorphometrical analysis. Surface characterization of the implant demonstrated enhanced surface area of anodized group compared to Control group with 19.2% ± 6.2 versus 1.6 ± 0.7, respectively. Histological evaluation demonstrated new bone formation starting from the buccal and lingual cortical walls on both groups. After three weeks, significant higher bone contact of 27% (p<0.05) was observed to nanotextured compared to machined implants (Control group). The anodization with sodium sulfate nanostructures to the implant surface that resulted in faster osseointegration.(AU)

Mechanical study in vitro of the resistance of axial forces of 3.5 mm cannulated and conventional screws in head and femoral neck fractures / Estudo mecânico in vitro da resistência a forças axiais dos parafusos canulado e convencional de 3, 5 mm de diâmetro em fraturas de cabeça e colo femoral

Background: Proximal femoral fractures account for 25% of all femoral fractures in dogs and are more common in younganimals. Osteosynthesis of femoral head and neck fractures is a complex procedure that can be performed using conventionalscrews or wires. However, proper fracture reduction and fi xation are diffi cult to achieve and, despite many advancements,such fractures remain challenging to solve. Cannulated screws have good compressive capacity and can be employed tosimplify the surgical procedure while optimizing outcomes. This study was designed to compare the resistance of conventional and cannulated screws to axial loading following experimental femoral neck fracture in dogs.Materials, Methods & Results: Fourteen cadaveric canine femurs were used in this study. Femurs were collected from dogsover 20 pounds in body weight with no gross or radiographic signs of orthopedic disease. Cadaveric femurs were submitted to experimental femoral neck fracture using a Gigli saw and allocated to osteosynthesis using either conventional orcannulated screws (seven bones each). All screws were inserted below the greater trochanter of the femur from the lateralaspect of the bone and screw topography confi rmed radiographically. Test specimens were then potted in polymethylmethacrylate, coupled to a hinged device and submitted to axial loading. Data on maximum load, maximum displacement, loadwithin the proportional limit, offset within the proportional limit and load required to produce a 3 mm displacement werecollected. Mean values were calculated and compared using the Students t test (P < 0.05). Mean values varied greatlywithin groups. Maximum load and displacement correspond to the critical point from which biomechanical testing becomesdestructive. Data were missing from one test specimen (conventional screw group) due to abrupt diaphyseal fracture atthe start of the axial loading trial...(AU)

Mechanical study in vitro of the resistance of axial forces of 3.5 mm cannulated and conventional screws in head and femoral neck fractures / Estudo mecânico in vitro da resistência a forças axiais dos parafusos canulado e convencional de 3, 5 mm de diâmetro em fraturas de cabeça e colo femoral

Background: Proximal femoral fractures account for 25% of all femoral fractures in dogs and are more common in younganimals. Osteosynthesis of femoral head and neck fractures is a complex procedure that can be performed using conventionalscrews or wires. However, proper fracture reduction and fi xation are diffi cult to achieve and, despite many advancements,such fractures remain challenging to solve. Cannulated screws have good compressive capacity and can be employed tosimplify the surgical procedure while optimizing outcomes. This study was designed to compare the resistance of conventional and cannulated screws to axial loading following experimental femoral neck fracture in dogs.Materials, Methods & Results: Fourteen cadaveric canine femurs were used in this study. Femurs were collected from dogsover 20 pounds in body weight with no gross or radiographic signs of orthopedic disease. Cadaveric femurs were submitted to experimental femoral neck fracture using a Gigli saw and allocated to osteosynthesis using either conventional orcannulated screws (seven bones each). All screws were inserted below the greater trochanter of the femur from the lateralaspect of the bone and screw topography confi rmed radiographically. Test specimens were then potted in polymethylmethacrylate, coupled to a hinged device and submitted to axial loading. Data on maximum load, maximum displacement, loadwithin the proportional limit, offset within the proportional limit and load required to produce a 3 mm displacement werecollected. Mean values were calculated and compared using the Student’s t test (P < 0.05). Mean values varied greatlywithin groups. Maximum load and displacement correspond to the critical point from which biomechanical testing becomesdestructive. Data were missing from one test specimen (conventional screw group) due to abrupt diaphyseal fracture atthe start of the axial loading trial...

Resultados clínicos e radiográficos de placas ósseas bloqueadas em 13 casos / Clinical and radiographics results of locking plates in 13 cases

A Placa Óssea Bloqueada (POB) consiste em um novo sistema de fixação interna, onde a placa apresenta orifícios duplos, um liso para compressão e outro rosqueado para fixação do parafuso que se fixa à placa. Promove grande estabilidade à fratura, sendo possível associar parafusos neutros e compressivos. Parafusos tradicionais comprimem a placa ao osso, nas placas bloqueadas não existe esta força e o encaixe da cabeça do parafuso à placa resulta em menores danos ao suporte vascular periosteal. Treze cães com distúrbios ortopédicos diversos foram tratados cirurgicamente com placa bloqueada com resultados satisfatórios. A placa bloqueada pode ser utilizada na medicina veterinária, porém, é técnica que requer cuidado e planejamento pré-operatório, especialmente na sequência de aplicação dos diferentes tipos de parafusos. Apresenta custo elevado, mas confere estabilidade rígida do foco de fratura e minimiza a possibilidade de perda prematura da interface parafuso e osso, diminuindo a possibilidade de instabilidade precoce e soltura do implante.(AU)

Locking plate is a new internal fixation system where the plate features has double holes, one smooth for compression and other threaded for screw fixing that attaches the plate. It leads to greater stability to the fracture being possible to associate neutral and compressive screws. Traditional screws compress the plate to the bone, in the locking plates there are no such strength and the fit of the screw head to the plate results in less damage to the vascular periosteal support. Thirteen dogs with various orthopedic disorders were treated surgically by locking plate with satisfactory results. The locking plate can be used in veterinary medicine, however, it is a technique that requires care and preoperative planning, especially in the order of applying different types of screws. It is expensive, but provides rigid stability of the fracture site and minimizes the likelihood premature loss of the screw and bone interface, reducing the possibility of instability and early loosening of the implant.(AU)

Histomorphometric analysis of bone tissue repair in rabbits after insertion of titanium screws under different torque / Estudo histomorfométrico do reparo tecidual ósseo de coelhos com parafusos de titânio inseridos sob diferentes intensidades de torques

PURPOSE: To evaluate the inflammatory response of rabbit bone after insertion of titanium screws under different torque values. METHODS: Four holes were made in the back tibia of fifteen New Zealand male albino rabbits; three screws were placed in each animal and a control hole remained without a screw. The screws were inserted with 0, 5 or 10 N.cm of torque. The animals were assigned to five groups according to the day of sacrifice after surgery (2, 7, 14, 21 or 42 days). The inflammatory cells and the thickness of the bone tissue around the screws was count. RESULTS: The screws were associated with a larger number of inflammatory cells when compared to the control hole. There was no statistically significant difference when several comparisons were made among the groups with different torque intensity. CONCLUSIONS: The histological changes were not statistically significant. There was a trend toward an increase in inflammatory cells found in local bone tissue surrounding the titanium screws installed with the highest torque. There was a tendency toward the formation of a lower thickness of tissue surrounding those bone screws that were inserted with higher torque.(AU)

OBJETIVO: Avaliar em variados períodos de tempo a resposta inflamatória do tecido ósseo de coelhos nos quais foram instalados parafusos de titânio com variadas intensidades de torque. MÉTODOS: 15 coelhos Nova Zelândia receberam três parafusos de titânio instalados em cada tíbia traseira e uma perfuração sem parafuso. Foram inseridos os parafusos com 0, 5 e 10 N.cm de torque. A eutanásia ocorreu 2, 7, 14, 21 e 42 dias pós-operatórios e foram analisados a em microscopia óptica a quantidade de células inflamatórias e espessura do tecido ósseo formado. RESULTADOS: Observou-se que a presença de parafusos apresentou uma quantidade significantemente maior de células inflamatórias quando comparado às perfurações controle. Houve um aumento na formação de tecido ósseo adjacente aos parafusos dos grupos 14, 21 e 42 dias quando comparados aos demais. CONCLUSÕES: Quanto maiores foram os torques de instalação dos parafusos de titânio, maiores foram as quantidades de células inflamatórias locais observadas nos tecidos ósseos circundantes e que com o passar dos períodos de tempo, foram diminuindo gradativamente. As espessuras de tecidos ósseos formadas observadas ao redor dos parafusos inseridos foram proporcionalmente menores quando a intensidade dos torques aplicados foram cada vez maiores.(AU)

Estudo biomecânico de tração (ex-vivo) em osteotomia da tuberosidade tibial de cães estabilizada com placa fixa por garfo ou parafuso / Biomechanical study of traction (ex-vivo) on the tibial tuberosity osteotomy in dogs stabilized with plates fixed by fork or screws

Avanço da tuberosidade tibial (ATT) é uma das técnicas para tratamento da ruptura do ligamento cruzado em cães desenvolvida por Montavon, Damur e Tepic (2002). O sucesso da técnica em reduzir ou eliminar as forças de deslocamento cranial da tíbia em joelhos com ruptura do ligamento cruzado cranial tem sido documentado em estudos experimentais e clínicos. No período pós-operatório a técnica, a falha do implante é relatada em 1 a 5% dos membros pélvicos operados. Este número foi atribuído a erro de técnica ou desenho inicial do implante que foi considerado insuficiente. Com objetivo de comparar a resistência biomecânica entre duas diferentes placas de ATT e minimizar a incidência de falhas de implante, foram realizados ensaios biomecânicos em 10 pares de membros pélvicos de cadáveres cães, no membro pélvico direito placa fixa por garfo e no membro pélvico esquerdo placa fixa por parafusos. Os ensaios foram realizados utilizando-se máquina universal de ensaios mecânicos Kratos® modelo 5002, dotada de célula de carga de 3000N com uma velocidade de ensaio de 20 mm/min. O parâmetro força e os gráficos gerados foram gravados por meio de sistema de aquisição analógica TRACOMP-W95 (TRCV61285). A média da carga máxima até a falha foi de 128,70 Kg/F (mínimo 104,55 Kg/F e máximo 151,80 Kg/F) e de 141,99 Kg/F (mínimo 111,60 Kg/F e máximo 169,65 Kg/F) no grupo utilizando garfo e parafusos respectivamente. O desvio padrão dos grupos garfo e parafuso foi baixo, 12,99 e 17,21 respectivamente. Foi encontrada diferença significativa (p = 0,0309) entre as médias dos grupos

Tibial tuberosity advancement (TTA) is one of the techniques for treatment of cruciate ligament rupture in dogs developed by Montavon, Damur and Tepic (2002). The success of the technique in reducing or eliminating the forces of cranial tibial displacement in knees with ruptured cranial cruciate ligament as been documented in experimental and clinical studies. In the post-operative technique, implant failure is reported in 1-5% of hindlimbs operated. This number was attributed to technical error or the initial design of the implant that was considered insufficient. To compare the biomechanical strength between two different plates ATT and minimize the incidence of implant failures, biomechanical tests were performed on 10 pairs of hindlimbs cadaver dogs, the right hindlimb fixed plate and a fork in the left pelvic limbplate fixed by screws. As says were performed using a universal mechanical testing Kratos ® model 5002, equipped with a load cell of 3000N with a test speed of 20 mm / min. The strength parameter and graphs generated were recorded via analog acquisition system TRACOMP-W95 (TRCV61285). The mean load to failure was 128.70 kg/F (minimum 104.55 Kg and maximum 151.80 Kg/F) and 141.99 Kg/F (minimum 111.60 Kg/F and maximum 169.65 Kg/F) in the group using fork and screws respectively. The standard deviation of the groups fork and bolt was low, 12.99 and 17.21 respectively. Significant difference (p = 0.0309) between the means of the groups

Estudo biomecânico de tração (ex-vivo) em osteotomia da tuberosidade tibial de cães estabilizada com placa fixa por garfo ou parafuso / Biomechanical study of traction (ex-vivo) on the tibial tuberosity osteotomy in dogs stabilized with plates fixed by fork or screws

Avanço da tuberosidade tibial (ATT) é uma das técnicas para tratamento da ruptura do ligamento cruzado em cães desenvolvida por Montavon, Damur e Tepic (2002). O sucesso da técnica em reduzir ou eliminar as forças de deslocamento cranial da tíbia em joelhos com ruptura do ligamento cruzado cranial tem sido documentado em estudos experimentais e clínicos. No período pós-operatório a técnica, a falha do implante é relatada em 1 a 5% dos membros pélvicos operados. Este número foi atribuído a erro de técnica ou desenho inicial do implante que foi considerado insuficiente. Com objetivo de comparar a resistência biomecânica entre duas diferentes placas de ATT e minimizar a incidência de falhas de implante, foram realizados ensaios biomecânicos em 10 pares de membros pélvicos de cadáveres cães, no membro pélvico direito placa fixa por garfo e no membro pélvico esquerdo placa fixa por parafusos. Os ensaios foram realizados utilizando-se máquina universal de ensaios mecânicos Kratos® modelo 5002, dotada de célula de carga de 3000N com uma velocidade de ensaio de 20 mm/min. O parâmetro força e os gráficos gerados foram gravados por meio de sistema de aquisição analógica TRACOMP-W95 (TRCV61285). A média da carga máxima até a falha foi de 128,70 Kg/F (mínimo 104,55 Kg/F e máximo 151,80 Kg/F) e de 141,99 Kg/F (mínimo 111,60 Kg/F e máximo 169,65 Kg/F) no grupo utilizando garfo e parafusos respectivamente. O desvio padrão dos grupos garfo e parafuso foi baixo, 12,99 e 17,21 respectivamente. Foi encontrada diferença significativa (p = 0,0309) entre as médias dos grupos (AU)

Tibial tuberosity advancement (TTA) is one of the techniques for treatment of cruciate ligament rupture in dogs developed by Montavon, Damur and Tepic (2002). The success of the technique in reducing or eliminating the forces of cranial tibial displacement in knees with ruptured cranial cruciate ligament as been documented in experimental and clinical studies. In the post-operative technique, implant failure is reported in 1-5% of hindlimbs operated. This number was attributed to technical error or the initial design of the implant that was considered insufficient. To compare the biomechanical strength between two different plates ATT and minimize the incidence of implant failures, biomechanical tests were performed on 10 pairs of hindlimbs cadaver dogs, the right hindlimb fixed plate and a fork in the left pelvic limbplate fixed by screws. As says were performed using a universal mechanical testing Kratos ® model 5002, equipped with a load cell of 3000N with a test speed of 20 mm / min. The strength parameter and graphs generated were recorded via analog acquisition system TRACOMP-W95 (TRCV61285). The mean load to failure was 128.70 kg/F (minimum 104.55 Kg and maximum 151.80 Kg/F) and 141.99 Kg/F (minimum 111.60 Kg/F and maximum 169.65 Kg/F) in the group using fork and screws respectively. The standard deviation of the groups fork and bolt was low, 12.99 and 17.21 respectively. Significant difference (p = 0.0309) between the means of the groups (AU)