RESUMO

Tendo em vista as vantagens das hastes intramedulares bloqueadas (HIB) em relação às placas ósseas na estabilização femoral, o presente estudo objetivou avaliar a exequibilidade e eficácia da aplicação da HIB pós osteotomia intertrocantérica varizante (OIV). Submeteu-se 10 cadáveres caninos à OIV. Nos antímeros esquerdos obteve-se a estabilização por meio de HIB (grupo HIB) e, nos direitos, com placas de compressão dinâmica (grupo placa). Foram comparados os ângulos de Norberg e de inclinação da cabeça e colo femoral (ICF) antes (T0) e após (T1) a OIV. O tempo dispendido para a colocação dos implantes e resultados de resistência biomecânica à compressão e torção também foram confrontados entre os grupos. Houve aumento do ângulo de Norberg entre T0 (106,84®5,55o) e T1 (111,22o®3,89), apenas no grupo HIB (p<0,05). No entanto, redução do ângulo de ICF após OIV (T1) foi observada tanto no grupo placa (T0=127,6®4,70o e T1=110,06®10,61o, p<0,05) quanto no grupo HIB (T0=126,43®5,87o e T1=116,87®8,62o, p<0,05). Os tempos de colocação dos implantes não diferiram estatisticamente e apenas o teste biomecânico de compressão revelou diferença entre os grupos, com maior resistência (P=0,033) do grupo placa (863,3®74,46N/mm) em relação ao grupo HIB (586,7®44,10N/mm). Deste modo, a estabilização por meio de HIB foi factível e eficaz. Embora o resultado biomecânico de compressão tenha demonstrado maior fragilidade da HIB em relação à placa de compressão, seus valores estão acima das forças atuantes, reportadas na literatura, na deambulação normal de cão.(AU)

Considering the advantages of the interlocking intramedullary nail (IN) in relation to bone plates in the femoral stabilization, this study aimed to evaluate the feasibility and effectiveness of IN application post intertrochanteric varus osteotomy (IVO). For this purpose, 10 canines cadavers were used. On the left femurs, the fixation was obtained with IN (IN group) and rights fixed with dynamic compression plates and screws (plate group). Was compared the angles of Norberg and inclination of the head and femoral neck (IHF) before (T0) and after (T1) IVO. The results of time spent for placement of implants and biomechanical resistance to compression and torsion were also confronted between groups. There was an increase of the Norberg angle between T0 (106.84®5.55o) and T1 (111.22o®3.89), only in IN group (p<0.05). However, reduction of IHF angle after IVO (T1) was observed in both, the plate group (T0=127.6®4.70o e T1=110.06®10.61o, p<0.05) and IN group (T0=126.43®5.87o e T1=116.87® 8.62 o, p<0.05). The placement times of the implants did not differ statistically and only the compression biomechanical test revealed differences between groups, with greater resistance (P=0.033) of the plate group (863.3®74.46N/mm) compared to IN group (586.7®44.10N/mm). Thus, stabilization through IN was feasible and effective. Although the compression biomechanical results has demonstrated a higher fragility of IN in relation to the compression plate, their values are above the forces, reported in literature, acting in normal dog gait.(AU)

Assuntos

RESUMO

Tendo em vista as vantagens das hastes intramedulares bloqueadas (HIB) em relação às placas ósseas na estabilização femoral, o presente estudo objetivou avaliar a exequibilidade e eficácia da aplicação da HIB pós osteotomia intertrocantérica varizante (OIV). Submeteu-se 10 cadáveres caninos à OIV. Nos antímeros esquerdos obteve-se a estabilização por meio de HIB (grupo HIB) e, nos direitos, com placas de compressão dinâmica (grupo placa). Foram comparados os ângulos de Norberg e de inclinação da cabeça e colo femoral (ICF) antes (T0) e após (T1) a OIV. O tempo dispendido para a colocação dos implantes e resultados de resistência biomecânica à compressão e torção também foram confrontados entre os grupos. Houve aumento do ângulo de Norberg entre T0 (106,84®5,55o) e T1 (111,22o®3,89), apenas no grupo HIB (p<0,05). No entanto, redução do ângulo de ICF após OIV (T1) foi observada tanto no grupo placa (T0=127,6®4,70o e T1=110,06®10,61o, p<0,05) quanto no grupo HIB (T0=126,43®5,87o e T1=116,87®8,62o, p<0,05). Os tempos de colocação dos implantes não diferiram estatisticamente e apenas o teste biomecânico de compressão revelou diferença entre os grupos, com maior resistência (P=0,033) do grupo placa (863,3®74,46N/mm) em relação ao grupo HIB (586,7®44,10N/mm). Deste modo, a estabilização por meio de HIB foi factível e eficaz. Embora o resultado biomecânico de compressão tenha demonstrado maior fragilidade da HIB em relação à placa de compressão, seus valores estão acima das forças atuantes, reportadas na literatura, na deambulação normal de cão.(AU)

Considering the advantages of the interlocking intramedullary nail (IN) in relation to bone plates in the femoral stabilization, this study aimed to evaluate the feasibility and effectiveness of IN application post intertrochanteric varus osteotomy (IVO). For this purpose, 10 canines cadavers were used. On the left femurs, the fixation was obtained with IN (IN group) and rights fixed with dynamic compression plates and screws (plate group). Was compared the angles of Norberg and inclination of the head and femoral neck (IHF) before (T0) and after (T1) IVO. The results of time spent for placement of implants and biomechanical resistance to compression and torsion were also confronted between groups. There was an increase of the Norberg angle between T0 (106.84®5.55o) and T1 (111.22o®3.89), only in IN group (p<0.05). However, reduction of IHF angle after IVO (T1) was observed in both, the plate group (T0=127.6®4.70o e T1=110.06®10.61o, p<0.05) and IN group (T0=126.43®5.87o e T1=116.87® 8.62 o, p<0.05). The placement times of the implants did not differ statistically and only the compression biomechanical test revealed differences between groups, with greater resistance (P=0.033) of the plate group (863.3®74.46N/mm) compared to IN group (586.7®44.10N/mm). Thus, stabilization through IN was feasible and effective. Although the compression biomechanical results has demonstrated a higher fragility of IN in relation to the compression plate, their values are above the forces, reported in literature, acting in normal dog gait.(AU)

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RESUMO

Introducción: El uso de la placa de compresión percutánea con técnica mínimamente invasiva es una alternativa válida para el tratamiento de las fracturas laterales de cadera. Se ha demostrado, sobre todo en el grupo de fracturas inestables, una reducción de las complicaciones intraoperatorias y posoperatorias (menor tiempo quirúrgico y menor sangrado). Materiales y Métodos: Se trataron, en forma consecutiva, 100 casos de fracturas laterales entre 2005 y marzo de 2013. El 74% eran fracturas inestables de tipos 31A2.2 y 31A2.3 y el 26%, fracturas estables 31A2.1 de la clasificación AO. La edad promedio era de 76.46 años. Resultados: En todos los pacientes, se consiguió una reducción anatómica tanto en el frente como en el perfil radiológicos. El tiempo promedio de cirugía fue de 29.94 minutos. El tiempo promedio de uso de radioscopia fue de 62.5 segundos. La media de transfusiones de sangre poscirugía fue de 0,06 unidades. El colapso promedio de la fractura fue de 1,94 mm. Se consideró que había curación radiológica a las 12 semanas, en todos los pacientes. Conclusiones: El empleo de placa de compresión percutánea para el tratamiento de las fracturas laterales inestables logró excelentes resultados, con una disminución ostensible del tiempo quirúrgico y una menor necesidad de transfusiones sanguíneas. La posibilidad de realizar una adecuada estabilización de las fracturas con compromiso de la pared lateral, en forma percutánea, con un mínimo daño muscular y tisular, determina que este método sea probablemente el nuevo patrón de referencia para este tipo de fracturas. Nivel de Evidencia: III

Introduction: The use of percutaneous compression plate with a minimally invasive technique is a valid alternative for the treatment of lateral hip fractures and a proven alternative in the group of unstable fractures, reducing the chances of intra and postoperative complications (less surgical time and minor bleeding). Methods: One hundred consecutive patients with lateral fractures were treated between 2005 and March 2013. 74% were unstable fractures (types 31A2.3 and 31A2.2) and 26% were stable fractures (type 31A2.1), according to AO classification. The mean age was 76.46 years. Results: An anatomic reduction was achieved in both the front and lateral radiographs in all patients. The average operative time was 29.94 minutes. The average fluoroscopy time was 62.5 seconds. Blood transfusions required after surgery: 0.06 units. The average fracture collapse was 1.94 mm. Radiological healing was obtained at 12 weeks in all patients. Conclusions: The use of percutaneous compression plate for the treatment of unstable lateral fractures achieved excellent results, considerably reducing surgical time and the need for blood transfusions. The possibility of adequate stabilization in fractures with involvement of the lateral wall with minimal muscle and tissue damage makes this method a probable new gold standard for this type of fracture. Level of Evidence: III

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La picnodisostosis es una enfermedad poco común que pertenece a las displasias esqueléticas que presentan fragilidad ósea y fracturas frecuentes. Radiológicamente se caracteriza por incremento de la densidad y fragilidad óseas. OBJETIVO: Presentar el caso de un escolar con displasia esquelética con fracturas en hueso patológico y manejo quirúrgico. CASO CLÍNICO: Escolar de sexo femenino, con antecedente de picnodisostosis detectado en etapa preescolar. Consulta posterior a caída de bicicleta con fractura de ambos fémures que se manejan quirúrgicamente con placa de compresión bloqueada.

Pycnodysostosis is a rare condition within skeletal dysplasias presenting with brittle bones and frequent fractures. Radiologically, it is characterised by increased bone density and fragility. OBJECTIVE: To present the case of a primary schoolchild with skeletal dysplasia with pathological bone fractures and their surgical management. CASE REPORT: A female primary schoolchild with a history of pycnodysostosis detected during the pre-school period. She was seen after bicycle fall that resulted in the fracture of both femurs, that were surgically managed with a locking compression plate.

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OBJECTIVE: AO/OTA 31-A3 intertrochanteric femoral fractures have completely different fracture line directions and biomechanical characteristics compared with other types of intertrochanteric fractures. The choice of the fixation method has been a focus of dispute among orthopedic trauma surgeons. The purpose of this study was to review the outcomes of these fractures treated with a percutaneous compression plate at our institute. METHOD: Seventeen patients with AO/OTA 31-A3 intertrochanteric femoral fractures were treated with a percutaneous compression plate at our institute from January 2010 to December 2011. The clinical data and imaging results were retrospectively analyzed. RESULTS: The medical complication of popliteal vein thrombosis occurred in one patient. Sixteen patients were followed up for 12 to 21 months. Two patients had malunion and mild pain. Fracture collapse occurred in two patients, with one having head penetration. These two patients had moderate pain. There were no occurrences of nonunion or reoperation. The mean Harris hip score obtained during the last follow-up was 84.1 (61-97). Patients with a poor quality of reduction were more likely to have pain results (p = 0.001). A trend existed toward the presence of a poor quality of reduction (p = 0.05) in patients with a collapse of fracture. Patients with poor preoperative mobility were more likely to have a lower Harris hip score (p = 0.000). CONCLUSION: The percutaneous compression plate is an alternative device for the treatment of AO/OTA 31-A3 intertrochanteric femoral fractures. Good fracture reduction and an ideal placement position of the neck screw are important in the success of the device. .

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Las fracturas de huesos largos encontradas más frecuentemente en animales pequeños son las del fémur. Por su posición anatómica, son difíciles de inmobilizar, entonces, la utilización de fijaciones internas es de gran utilidad. Las placas de compresión dinámica (PCD) proveen gran estabilidad, son durables y al producir compresión interfragmentaria, minimizan el movimiento fragmentario y promueven la cicatrización primaria del hueso. Sus ventajas están asociadas a la reconstrucción anatómica, movilidad temprana y capacidad de carga del miembro. El polimetilmetacrilato (PMMA) es una resina acrílica utilizada en prótesis dentales. Pero, estudios muestran otros usos, tratamientos de tumores óseos, prótesis en deformaciones craneales, vertebroplastias percutáneas y prótesis testiculares en animales, entre otros. El objetivo de este estudio fue fabricar PCD-PMMA y comprobar su resistencia a las distintas fuerzas que están presentes en una fractura. Se fabricaron 48 PCD de 3,5 milímetros de cuatro orificios a partir de un molde de alginato. Se obtuvieron seis fémures de cadáveres caninos de 10 a 20 kg de peso, a los cuales se les realizó una osteotomía que simulaba una fractura oblicua. Posteriormente, se posicionaron las placas en los huesos osteotomizados para someterlas a las distintas fuerzas que participan en una fractura. Las PCD-PMMA resistieron 2,83 newton/metro a la fuerza de torsión y 0,21 kilonewton a las fuerzas de compresión y flexión. La resistencia de la PCD-PMMA obtenida fue en promedio de 20 kg, a cada una de las fuerzas. Se pudo concluir que es posible fabricar una PCD-PMMA de 3,5 mm de cuatro orificios, cuya resistencia es de 20 kg de peso a las tres fuerzas aplicadas. Entonces, pueden ser utilizadas para la estabilización de fracturas de huesos largos que sean sometidos a una presión inferior a 20 kg de fuerza.

Femur fractures are the most frequent long bone fractures in small animals. Due to the femur’s anatomical position, it is difficult to immobilize, and therefore internal fixations are veryuseful. Dynamic compression plates (DCP) provide high stability, are durable, minimize fragment movement and promote primary healing of the bone. Advantages of this treatmentinclude anatomical reconstruction, early mobility and carrying capacity of the affected limb. Polymethylmethacrylate (PMMA) is an acrylic resin that has proved very useful in bone tumor treatment, cranial deformation prosthesis, percutaneous vertebroplasty and testicular prosthesis in animals. The purpose of this study was to manufacture DCP-PMMA and testits resistance to the different forces present in a fracture. Forty-eight (48) 3.5MM x 4-hole DCP were made from an alginate mold. Six (6) femurs were obtained from canine cadavers weighing from 10 to 20 kg, which underwent osteotomy simulating an oblique fracture. The plates were subsequently positioned in the osteotomized bones to submit them to the various forces involved in a fracture. The DCP-PMMA resisted a torque force of 2.83 newton/metres and a compression and flexion force of 0.21 kilonewton. The obtained resistance of the DCP-PMMA was an average of 20 kg per force. The results of this study show that it is possible to make a DCP-PMMA 3.5 mm x 4-hole, the resistance of which is of 20 kg against the three applied forces, and that it can be used to stabilize long bone fractures subjected to a pressure of less than 20 kg.

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