Conselho Nacional de Desenvolvimento Científico e Tecnológico / The aim of this research was to evaluate the interlocking nails technique in femoral fractures in dogs and evaluate the use of femoral intramedullary reaming byproducts as an adjuvant to bone healing. Twelve dogs, weighing between 15 and 18 kg, were randomly distributed in three groups according to the type of graft used in the fracture denominated I (control- untreated), II (the byproducts of femoral intramedullary reaming) and III(autogenous cancellous bone). Transverse osteotomy was performed in the middle portion of the femur and posterior osteosynthesis with inrelocking nails. After was carried out the grafting with by-products of intramedullary reaming or autogenous cancellous bone in sufficient quantity to fill the surface of the fracture. In order to compare the performance of the groups treatment were performed radiographic evaluations at 15, 30, 60 and 90 days postoperatively (PO), and clinical evaluation of the daily march up to the 7th postoperative day, and after weekly until the 60th days after surgery. The radiographic analysis revealed that at 30 postoperatively day the mean scores of consolidation in the dogs of the group that received grafts of intramedullary reaming by-products were higher than the other groups. At 45 and 60 postoperative days radiographic images also indicated the superiority of group II in relation to other groups. Clinical evaluation of the march on the 15th postoperative day showed the best performance of the dogs treated with grafting of femoral reaming by-products. 75% of these animals were in grade V of lameness. There was no statistical difference between the grafting of femoral intramedullary reaming byproducts and autogenous cancellous bone in relation to radiographic consolidation scores and degrees of lameness, at different times after surgery. The interlocking nails were considered an efficient method for osteosynthesis of femoral diaphyseal fractures in dogs, without alterations or inconvenience in postoperative period. The grafting of femoral intramedullary reaming byproducts proved to be a viable and effective adjuvant in healing bone fractures of long bones of dogs and we recommend this technique to be evaluated in dogs from traumatic fractures. / O objetivo desta pesquisa foi avaliar a técnica de hastes bloqueadas na osteossíntese de fraturas femorais em cães e avaliar o uso de subprodutos da fresagem intramedular femoral como adjuvante na cicatrização óssea. Foram utilizados 12 cães, pesando entre 15 e 18 kg, distribuídos aleatoriamente em três grupos iguais de acordo com o tipo de enxerto utilizado no foco da fratura, denominados de I (controle não tratado), II (subprodutos da fresagem intramedular femoral) e III (osso esponjoso autógeno). Foi realizada osteotomia transversa na porção média da diáfise femoral e posterior osteossíntese com hastes bloqueadas. Após realizou-se a enxertia de subprodutos da fresagem intramedular ou de osso esponjoso autógeno em quantidade suficiente para preencher a superfície do foco da fratura. Para comparar o desempenho dos grupos tratados, foram realizadas avaliações radiográficas nos períodos de 15, 30, 60 e 90 dias de pós-operatório (PO), e avaliação clínica da marcha diária até o 7º dia de PO, e após semanalmente até os 60 dias de PO. A análise radiográfica revelou que aos 30 dias de PO a média dos escores de consolidação no grupo que recebeu enxerto dos subprodutos fresagem intramedular foi superior à dos outros grupos. Aos 45 e 60 dias de PO as imagens radiográficas também indicaram a superioridade do Grupo II em relação aos demais grupos. A avaliação clínica deambulatória no 15º dia de PO evidenciou o melhor desempenho dos cães tratados com enxerto de subprodutos da fresagem femoral, dos quais 75% dos animais encontravam-se em grau V de claudicação. Não foi encontrada diferença estatística entre a enxertia de subprodutos da fresagem intramedular femoral e de osso esponjoso autógeno com relação aos escores de consolidação radiográfica e graus de claudicação, nos diferentes tempos de PO. As hastes bloqueadas foram consideradas um método eficiente para a osteossíntese de fraturas femorais diafisárias em cães, não possuindo alterações ou inconvenientes no pós-operatório. O enxerto de subprodutos da fresagem intramedular femoral revelou-se uma opção viável e eficiente de adjuvante cicatricial ósseo em fraturas de ossos longos de cães, recomendando-se sua avaliação na rotina clínica.

Background: Open reduction and internal fixation with a plate is deemed to represent the gold standard of surgical treatment for displaced intra-articular calcaneal fractures. Standard plate fixation is usually placed through an extended lateral approach with high risk for wound complications. Minimally invasive techniques might avoid wound complications but provide limited construct stability. Therefore, 2 different types of locking nails were developed to allow for minimally invasive technique with sufficient stability. The aim of this study was to quantify primary stability of minimally invasive calcaneal interlocking nail systems in comparison to a variable-angle interlocking plate. Material and Methods: After quantitative CT analysis, a standardized Sanders type IIB fracture model was created in 21 fresh-frozen cadavers. For osteosynthesis, 2 different interlocking nail systems (C-Nail; Medin, Nov. Město n. Moravě, Czech Republic; Calcanail; FH Orthopedics SAS; Heimsbrunn, France) as well as a polyaxial interlocking plate (Rimbus; Intercus GmbH; Rudolstadt, Germany) were used. Biomechanical testing consisted of a dynamic load sequence (preload 20 N, 1000 N up to 2500 N, stepwise increase of 100 N every 100 cycles, 0.5 mm/s) and a load to failure sequence (max. load 5000 N, 0.5 mm/s). Interfragmentary movement was detected via a 3-D optical measurement system. Boehler angle was measured after osteosynthesis and after failure occurred. Results: No significant difference regarding load to failure, stiffness, Boehler angle, or interfragmentary motion was found between the different fixation systems. A ignificant difference was found with the dynamic failure testing sequence where 87.5% of the Calcanail implants failed in contrast to 14% of the C-Nail group (P < .01) and 66% of the Rimbus plate. The highest load to failure was observed for the C-Nail. Boehler angle showed physiologic range with all implants before and after the biomechanical tests. Conclusion: Both minimally invasive interlocking nail systems displayed a high primary stability that was not inferior to an interlocking plate. Clinical relevance: Based on our results, both interlocking nails appear to represent a viable option for treating displaced intra-articular calcaneal fractures.