Background: Tibial fractures are associated with prolonged recovery. The aim of this study was to identify predictors of long-term physical functioning after tibial shaft fracture. Methods: We used data from the Trial to Re-evaluate Ultrasound in the Treatment of Tibial Fractures (TRUST) to determine, in patients with unilateral, open or closed tibial shaft fracture, the association between baseline factors and physical functioning at 1-year. All fractures were fixed using intramedullary nails. Physical functioning was measured using the 100-point Short Form-36 (SF-36) Physical Component Summary (PCS) score; higher is better; minimally important difference is 2 to 5 points. Results: There were 299 tibial fracture patients with complete data available for analysis. In an adjusted analysis, the factors associated with lower physical functioning at 1-year were: (1) current smokers (mean difference [MD] -2.55, 95% confidence interval [95%CI] -4.63 to -0.46, p=0.017), (2) body mass index >30 kg/m² (MD -2.57, 95% CI -4.86, -0.27, p = 0.029), and (3) patients who were receiving disability benefits or involved in litigation, or planned to be (MD -2.65, 95% CI -4.58 to -0.72, p = 0.007). Patients who were employed at the time of their fracture reported significantly higher physical functioning at 1-year (MD 4.56, 95% CI 2.32 to 6.80, p= <0.001) and those who were allowed to partial or full weight-bear post-operatively (MD 1.98, 95% CI 0.13 to 3.82, p=0.036). Neither age, sex, fracture severity or receipt of physical therapy were associated with long-term physical functioning. Conclusions: Among patients undergoing surgical repair of tibial fractures, partial or full weight-bearing post-operatively and employment at the time of injury predict better long-term functioning, whereas smoking, obesity, and receipt of disability benefits or involvement in litigation (or plans to be) predict worse long-term functioning. / Thesis / Master of Science (MSc)

The purpose of this study is to investigate the effect of loading during long bone fracture healing in-vitro and in-vivo. Fracture healing has until now only been monitored using radiographs and ultrasound. An intramedullary nail instrumented with strain gauges has the potential to monitor loading in-vivo during bone fracture healing. Strain has been previously monitored over time though external fixation devices however there has been no published data about monitoring through a nail. The load carried by a telemetric intramedullary nail during simulated fracture healing is monitored in-vitro with the aid of custom designed jigs, integrated in a biomechanical test frame. Clinically predetermined loading conditions are applied to the construct and synthetic bone composites are used developed to simulate mechanical strength of early to mature osteogenic bone, approximating natural healing processes. Four different synthetic bone composites have been designed and developed to mimic the mechanical properties of granulation tissue, fibrous tissue, cartilaginous tissue and immature bone. Three different generations (GEN I – IIIa) of intramedullary nails were developed and biomechanically tested in-vitro. GEN I and II were purely biomechanical nails that underwent compression, torsional and 4pt bend tests. Different fracture patterns and callus morphology were simulated and tested biomechanically. Circumferential and segmental application of the synthetic materials were applied on the artificial fractured bone instrumented with GEN I. Observations from live animal study provided x-rays from which callus growth patterns were extracted and repeated in-vitro. Cadaveric biomechanical tests and pre-clinical trial of GEN IIIa was conducted. The aim was to repeat the biomechanical tests while at the same time monitoring healing with an instrumented nail implanted in an induced fractured, ovine left hind limb. A loading rig was designed for the in-vivo test. The hypothesis proposed is that forces experienced by an intramedullary nail will progressively decrease as fracture heals. Results from GEN I have shown that strain measurement can be monitored during fracture healing in-vitro. The GEN IIIa nail is yet to be tested in-vivo for the same biomechanical tests for comparison. There is currently no published study on simulating fracture healing with accuracy.

[pt] O comportamento de uma escavação grampeada em solo residual de gnaisse foi avaliado por um programa de monitoramento geotécnico do maciço reforçado. Diversas obras estão sendo realizadas no país, sem conhecimentos detalhados sobre as deformações inerentes à técnica e sobre os mecanismos de interação solo-grampo. No Brasil, menos de 10% das obras de solo grampeado utilizaram algum tipo de instrumentação. Esta pesquisa teve por objetivo a análise de uma escavação em solo residual reforçada com grampos. A escavação foi instrumentada para o monitoramento dos deslocamentos do maciço e dos esforços nos grampos. Um extenso programa experimental de ensaios de campo e laboratório foi executado para fornecer os parâmetros geotécnicos utilizados nas análises computacionais. A escavação grampeada teve cerca de 40m de altura, constituindo uma experiência inédita no país e talvez no mundo. Devido a esta altura, os grampos superiores foram instalados com comprimentos de até 24m. O comportamento do talude foi influenciado pelo processo executivo e por uma outra escavação no terreno vizinho. O monitoramento indicou que os deslocamentos do maciço e os esforços nos grampos cresceram significativamente com o avanço da escavação e não cessaram ao final da obra. Os grampos trabalharam predominantemente à tração, com momentos fletores pouco significativos. Os valores de tração estimados na fase de projeto diferiram dos resultados obtidos na instrumentação. A distribuição dos esforços de tração foi influenciada pelas características geológicas do maciço. A tração máxima (Tmáx) teve uma posição variando com a profundidade e a inclinação do talude, e uma magnitude aumentando exponencialmente com o avanço da escavação. A tração na face (To) foi de 0,3 a 0,6 de Tmáx. A resistência mobilizada no contacto solo- grampo não ultrapassou 35% do valor de qs medido nos ensaios de campo. / [en] The behavior of a nailed excavation in gneissic residual soil has been studied by a comprehensive research program, including instrumentation, field and laboratory tests and numerical analyses. Soil nailing is becoming a popular stabilization technique in Brazil. However, a solid knowledge about the soil-nail interaction is still lacking. There are a few studies about the inherent deformations of the reinforced mass and the magnitude of nail`s stresses. In Brazil, less than 10% of stabilization works have some type of instrumentation. The main objective of this research was monitoring and analysing a 40m high soil nailed slope excavation. Due to this unique height, the upper nails were installed with 24m length. The slope behavior was influenced by several factors, such as the construction technique and a subsequent excavation at one adjacent site. The results indicated a significant increase of reinforced mass displacements and of the nail s mobilized tension during the progress of the excavation. These did not cease after the end of the excavation, due to the adjacent work. During and after construction, the nails worked predominantly in tension. Estimated tension loads in the project phase were compared with the instrumentation s results. The stress distribution was influenced by local geology. The maximum axial force (Tmáx) increased exponentially with the progress of the excavation and its position, in each nail, varies with the slope s depth and inclination. The magnitude of the axial load in the excavation face is observed to be between 0,3 and 0,6 of Tmáx. The mobilization of the reinforcement elements was smaller than 35% qs.

Apesar do largo emprego da técnica de solo pregado em nosso país, pouquíssima pesquisa foi realizada sobre a resistência ao cisalhamento de interface solo-reforço (qs) e sobre a importância deste parâmetro no desempenho desta técnica de reforço in situ de taludes e escavações. Busca-se com esta tese, avaliar experimentalmente, a influência de diferentes metodologias executivas do chumbador (número de injeções) neste parâmetro. As informações para o desenvolvimento deste trabalho foram obtidas a partir de ensaios de arrancamento realizados em chumbadores construídos em duas obras nas cercanias da cidade de São Paulo, ou seja, em escala real. De forma complementar, também foi construído uma estrutura de solo pregado em laboratório. A partir dos ensaios realizados, observaram-se melhorias significativas na resistência ao cisalhamento de interface a partir das injeções do chumbador e estabelecer equações que relacionam o valor de qs com o volume injetado de calda de cimento, sendo uma importante ferramenta para analisar o desempenho do chumbador. O monitoramento ao longo do ensaio permitiu analisar os mecanismos de distribuição das cargas. Por fim, é apresentada uma proposta de metodologia para a realização do controle de qualidade do chumbador. / Besides the soil nailing technique being common practice in Brazil, there is little research on the shear strength of the soil-reinforcement interface (qs) and on the importance of this parameter on the performance of this in situ reinforcement technique of slopes and excavations. Accordingly, this study has the objective to experimentally evaluate the influence of different executive methodologies of the nail (i.e. number of grout injections) on the parameter qs. Data were obtained from in situ, full scale pullout tests performed on nails built in two construction sites near Sao Paulo city. Additionally, a soil nailing structure was built in laboratory. The results show that significant improvement is achieved on the soil-nail interface shear strenght by the number of grout injections. Moreover, the pullout tests on the nails provided quantification of this improvement. Consequently, it was possible to establish equations that relate the value of qs to the volume of cement grout injected, which is as important tool to evaluate the performance of the nail. Monitoring of the instrumentation during execution of the pullout tests allowed evaluation of the mechanisms of load distribution along the nails. Finally, a methodology is proposed for a quality control procedure on soil-nailed walls.

Solo grampeado é uma alternativa eficiente utilizada em obras de reforço de solos. É resultante da inclusão de reforços, denominados grampos, em um maciço em corte. A resistência ao cisalhamento da interface solo-grampo é um dos parâmetros mais importantes para fins de projeto. Este parâmetro é determinado a partir da experiência dos projetistas e se baseia principalmente no tipo de solo e em ensaios de campo (arrancamento, sondagens a percussão e pressiométricos). Neste contexto, a realização de ensaios de arrancamento in situ é extremamente importante para a quantificação deste parâmetro e, conseqüentemente, para a elaboração de projetos mais econômicos e seguros. A execução de ensaios de arrancamento em laboratório permite verificar condições muitas vezes não encontradas em campo. Este trabalho apresenta os resultados de ensaios de arrancamento de grampos realizados em laboratório. Também foi analisada a evolução da força nos grampos e dos deslocamentos do solo. Os grampos foram instalados em um protótipo de solo grampeado sobre o qual se aplicou uma sobrecarga de 50 kPa através de uma bolsa de ar comprimido. Os ensaios de arrancamento permitiram quantificar valores de resistência ao cisalhamento de interface da ordem de 145 kPa, mobilizados com pequenos deslocamentos dos grampos. O arrancamento de grampos instrumentados indicou que cerca de 90% do comprimento total dos grampos foi solicitado. Ao final dos ensaios de arrancamento, os grampos foram extraídos completamente do maciço de solo o que permitiu comprovar a sua integridade física. Os deslocamentos do solo foram máximos próximo ao topo do protótipo e na direção horizontal. Os resultados demonstram a viabilidade de estudar o comportamento do maciço reforçado a partir do comportamento do protótipo de solo grampeado construído em laboratório. / Soil nailing is an efficient soil reinforcement technique which uses inclusions, namely nails, in soil slopes. Unit skin friction is one of the most important parameters used in soil nailing design. The definition of this parameter is commonly based on local experience and correlations to some in situ tests. This work presents the results obtained from the pullout test carried out in a soil nailed wall prototype built in laboratory. Forces acting in nails were measured by strain gage instrumentation. Soil displacement was measured in short and long terms. The pullout tests were carried out after the application of a uniform surcharge given by a compressed air bag. The results showed that unit skin friction was about 145 kPa, mobilized with little nail displacements. About 90% of nail length were solicited during pullout tests, according to tests performed in strain gage instrumented nails. Nail extraction showed a high level of nail integrity. Soil displacements were higher close to the wall top, near the face. These results demonstrate the feasibility of using of laboratory prototype studies to investigate the geotechnical behavior of soil nailing structures.

O uso de sistemas de faceamento flexíveis com malhas metálicas é uma alternativa viável ao uso do concreto projetado como faceamento em sistemas de solo grampeado. Vários modelos de malhas são empregados hoje para este uso, sendo classificados pela resistência à tração no sentido longitudinal. Mesmo que relevante, segundo Cala et al., (2012), somente este dado é insuficiente para o correto dimensionamento destas soluções. A presente pesquisa busca identificar quais os parâmetros de resistência são necessários para o dimensionamento de um faceamento em malha metálica. Para tanto foram avaliadas duas metodologias desenvolvidas especificamente para as malhas aplicadas junto com a solução de solo grampeado, os métodos Ruvolum e Macro1. Foram então desenvolvidos equipamentos, similares aos utilizados por Roduner (2011) e Cala et al. (2012), para caracterizar 4 diferentes modelos de malhas, avaliando a resistência das mesmas frente aos esforços considerados nos modelos de cálculo investigados, tração e o cisalhamento no contato malha/grampo. Deste modo, foram utilizados resultados de ensaios em escala real com a simulação de um talude em solo tratado com as 4 malhas, para a validação dos métodos de dimensionamento, e para investigar quais os parâmetros de resistência da malha são mais importantes. Como resultado foram determinadas as resistências das malhas avaliadas, sendo a de tração no sentido longitudinal entre 50 e 140 kN, e a resistência no contato malha/grampo, que variou entre 10 e 30 kN. Por fim foi realizada uma análise paramétrica com o método Ruvolum a fim de verificar a influência na variação da coesão, espessura instável e ângulo de atrito, dados nem sempre bem definidos em projeto. Os resultados mostram, como era esperado, a grande sensibilidade da variação nos resultados frente aos efeitos da coesão, sendo então recomendado, como em qualquer análise de estabilidade cautela no uso deste parâmetro. A análise destes resultados permite concluir que o método mais adequado para modelar um talude em solo grampeado com face em tela foi o Ruvolum, com previsões que se aproximaram das medições reais dos ensaios de campo. / The use of flexible facing systems with steel meshes is a viable alternative to the use of shotcrete as facing in soil nailing systems. Currently several different models meshes are being used today for this purpose, being classified only by the tensile strength in the longitudinal direction of the mesh. Even though this parameter is quite relevant, alone it cannot be used to design the flexible facing systems. So this research aims to identify which steel mesh strength parameters are really needed for the correct dimensioning of such solutions. In order to do so two calculation methodologies, specially developed for steel meshes design, were investigated. The design models are called Ruvolum and Macro1 Equipments were developed, similar to those presented in Cala et al. (2012), to investigate four different models of mesh, in order to find the strength parameters presented on the studied calculation models, being than tensile and shear. Thus, to validate the investigated design methodologies, field tests results were compared to the models predictions. As product of the research it was possible to determine the tensile strength of the 4 meshes models, being then ranging from 50 and 140 kN. Also it was possible to define the shear resistance in the nail head/mesh contact, which ranges from 10 to 30 kN. The last step of the research was a parametric analysis, performed with the Ruvolum method to evaluate the influence on the variation of cohesion, unstable thickness and friction angle in the predictions, since this data aren’t always available in ordinary projects. These analysis have showed that the most influent parameter is cohesion, one that is very hard to determine. Also it was found by the results analysis that the appropriate calculation model to simulate a slope stabilized with soil nail and steel meshes facing is the Ruvolum, due the closeness of the predictions to the real field data.

Os métodos de equilíbrio limite comumente utilizados no dimensionamento de estruturas de solo grampeado não oferecem informação sobre as tensões e deformações na estrutura. No entanto, o êxito da técnica pressupõe deslocamentos para que a resistência dos grampos seja mobilizada. Portanto, seria desejável conhecer: os deslocamentos que a estrutura. sofre durante e depois de realizado o processo da escavação; os esforços mobilizados nos grampos; e a distribuição de tensões atrás da parede da escavação. A importância deste estudo é maior em situações em que a previsão do comportamento é a responsável por garantir a segurança de construções e de instalações de serviço público próximas às escavações grampeadas. Análises bidimensionais e tridimensionais de tensão-deformação com elementos finitos foram realizadas para um melhor entendimento do comportamento da estrutura. As comparações dos resultados das modelagens numéricas permitiram conhecer várias vantagens e desvantagens de um e de outro tipo de modelagem. Realizaram-se também comparações entre resultados de modelagens numéricas que utilizaram os seguintes modelos constitutivos: elasto-plástico (com critério de ruptura de Mohr-Coulomb), hiperbólico e elástico-linear, sendo que para este último realizou-se uma análise incremental. Para a aplicação do modelo elástico-linear foi necessária a divisão do maciço em regiões em função do tipo de trajetória de tensão. Essas comparações permitiram concluir que, desde que com a correta especificação dos parâmetros elásticos, a modelagem baseada na Teoria da Elasticidade pode representar bem o comportamento de escavações grampeadas. / The limit equilibrium methods that are frequently used for design of soi nailing structures do not provide information about the structure\'s stress and strain. However, the technique\'s success depends on the displacements that mobilize the nails strength. Therefore it is desirable to predict the structure\'s displacement, during and after the excavation; the forces avting on nails; and the stress distribution behind the excavation wall. This study has its importance increased in situations in which the prediction of the behavior is needed to guarantee the safety of adjacent buildings and municipal installations near to the excavation. Three dimensional and two-dimensional fine element stress-strain analyses were carried out for a better understanding of the behavior of the structure. Comparisons of the results of different numerical models led to a clear picture of advantages and disadvantages of different approaches. Numerical comparisons were also carried out between analyses with different constitutive models: elasto-plastic (Mohr-Coulomb), hyperbolic and incremental linear elastic. Application of the linear elastic model required the division of the soil mass in regions, according to stress path. Those comparisons led to the conclusion that, given correctly specified elastic parameters, Theory of Elasticity is able to correctly model the behavior of nailed excavations.

This dissertation is concerned with a study of soil nailing, in particular the interaction mechanism between the soil and a nail and the failure mechanism and suitable design procedure for nailed slopes in sand. The interaction mechanism of a nail was studied by carrying out a number of pull-out tests, direct shear tests of nailed sand and interface tests using two uniform sands. Major parameters of the tests were flexibility, surface roughness and diameter of a nail. From the tests, it was found that: (1) flexibility of a nail significantly influences the interaction mechanism. Both the interaction parameter and apparent friction coefficient differ between a flexible and a stiff nail. Theoretical consideration indicates that the mobilization of nail forces is dominated by the relative stiffness between soil and nail. (2) a smooth-surface nail produces smaller bond friction than the critical state friction angle and mineral-to-mineral angle of the soil. This is due to the very thin rupture surface developed around the nail. On the other hand, a rough-surface nail was observed to produce two to four times larger bond friction than the direct shear friction angle of sand, due to the thick rupture surface developed and the dilatancy of the soil. (3) increasing the diameter of a nail produces a smaller apparent friction coefficient. Restrained dilatancy was found to play an important role. (4) the pull-out test, direct shear test of nailed sand and interface test produce different values of apparent friction coefficient , due to the different amount of restrained dilatancy effect around the nail (or reinforcement). The overall behaviour of nailed slopes was studied by carrying out a comprehensive series of centrifuge tests. Excavation of soil was simulated by draining water from two rubber bags in front of the facing wall. The centrifuge tests have provided much useful information on the mechanics of soil nailing. From the tests, it was found that: (1) draining of the water significantly influences both the earth pressure on the facing wall and the displacements of the nailed slope. Horizontal displacements of the facing wall were decreased by increasing the length and/or friction (bond) of the nail. (2) earth pressures on the facing wall do not exhibit a simple hydrostatic distribution. The deviations of the earth pressure are not negligible especially near the top and bottom of the facing wall. (3) roughness and bending stiffness of the facing wall considerably influence the stability and displacement of the nailed slope, respectively. (4) the observed failure surfaces were well described by a logarithmic spiral passing through the toe of the facing wall. (5) fairly good predictions for the failure acceleration were made using stability analysis of the nailed slopes based on the limit equilibrium method, provided an accurate friction angle for the sand and pull-out resistance of each nail could be determined. The factor of safety F5 of the nailed slopes was estimated by comparing the total available force and the total required force based on the observed failure surfaces.

Σκοπός της παρούσας μελέτης είναι η εκτίμηση και αξιολόγηση της αποτελεσματικότητας της αντικατάστασης της εξωτερικής οστεοσύνθεσης με ενδομυελικό ήλο, κατά την φάση ωρίμανσης του πώρου μετά από οστική επιμήκυνση. Σε πειραματικό επίπεδο διενεργήθηκε, σε 12 σκελετικά ώριμα θηλυκά πρόβατα τα οποία χωρίσθηκαν σε δύο όμοιες ομάδες (ομάδα Α και ομάδα Β), οστεοτομία κνήμης και σταδιακή επιμήκυνση 2cm με τη χρήση συσκευής Ilizarov και ρυθμό 0,5mm/12ώρο. Στην ομάδα Α, αμέσως μετά το τέλος της επιμήκυνσης, γινόταν αφαίρεση της συσκευής Ilizarov και τοποθέτηση, υπό ακτινοσκοπικό έλεγχο στατικού ενδομυελικού ήλου, χωρίς γλυφανισμό. Στην ομάδα Β (ομάδα ελέγχου), η συσκευή Ilizarov παρέμεινε (κατά την συνήθη τεχνική) έως το τέλος της φάσης ωρίμανσης του πώρου. Η πορεία της ωρίμανσης του πώρου, μελετήθηκε και στις δύο ομάδες, σε συγκεκριμένες χρονικές στιγμές, με ακτινολογικούς ελέγχους, υπερηχογραφήματα, triplex, και ψηφιακή αγγειογραφία. Όλα τα πειραματόζωα θυσιάστηκαν την 70η ημέρα μετά την οστεοτομία και τα οστικά παρασκευάσματα μελετήθηκαν με υπολογιστική αξονική τομογραφία και ιστοπαθολογική ανάλυση . Όλα τα πειραματόζωα της ομάδας Α, ανέχθηκαν επιτυχώς την ενδομυελική ήλωση, και διατήρησαν τον άξονα του σκέλους, ενώ βελτιώθηκε η κινητικότητα και η ποιότητα διαβίωσή τους μετά την αφαίρεση της συσκευής. Σε όλα είχε αναπτυχθεί ώριμος πώρος στο τέλος της φάσης σταθεροποίησης, με έντονη παρουσία στοιχείων οστικής ανακατασκευής (remodeling). Στην ομάδα Β, στο ίδιο χρονικό διάστημα, 5 στα 6 ανέπτυξαν σκληρό δευτερογενή ώριμο πώρο, 3 είχαν διαταραχή στον άξονα του σκέλους, 3 παρουσίασαν επιπολής λοίμωξη στις εισόδους των βελονών ενώ 1 ανέπτυξε εν τω βάθη λοίμωξη. Σε κλινικό επίπεδο, σε 30 ασθενείς (33 περιπτώσεις), η συσκευή εξωτερικής επιμήκυνσης (Ilizarov ή μονόπλευρη) αντικαταστάθηκε σε κάποια χρονική στιγμή κατά την διάρκεια της φάσης σταθεροποίησης μετά το τέλος της οστικής επιμήκυνσης από στατική ενδομυελική ήλωση. Τα κύρια αίτια που οδήγησαν σ’ αυτή την αντικατάσταση ήταν: α) καθυστέρηση πώρωσης στο σημείο οστικής συμπλησίασης (17 ασθενείς), β) γωνιακή παραμόρφωση του πώρου ή κάταγμα (8 ασθενείς), γ) δυσανεξία της συσκευής (5 ασθενείς), σε συνδυασμό ή όχι με καθυστέρηση ωρίμανσης του πώρου επιμήκυνσης. Ο μέσος χρόνος παρακολούθησης των ασθενών ήταν 4 χρόνια (2-13 χρόνια). H συσκευή επιμήκυνσης παρέμεινε κατά μέσο όρο 340 ημέρες (148-630 ημέρες) ή κατά αναλογία με το μέγεθος του οστικού ελλείμματος 38 ημέρες/cm ελλείμματος. Σε έναν ασθενή (3,03%) συνέβη ενδομυελική λοίμωξη μετά την τοποθέτηση του ήλου ενώ σε 5 περιπτώσεις (15,2%) μικρή απώλεια του μήκους του πώρου. Σε μία περίπτωση (3,03%) υπήρξε αποτυχία πώρωσης στο σημείο της οστικής συμπλησίασης. Στους υπόλοιπους ασθενείς επήλθε ολοκλήρωση της ωρίμανσης του πώρου είτε στην περιοχή της επιμήκυνσης είτε στην περιοχή της τελικής συμπλησίασης σε μέσο χρονικό διάστημα 5,9 μηνών. Η δευτερογενής ενδομυελική ήλωση μετά από διατατική οστεογένεση μειώνει τη διάρκεια εφαρμογής της εξωτερικής οστεοσύνθεσης, επιλύει προβλήματα δυσανεξίας στη συσκευή της εξωτερικής οστεοσύνθεσης, ενώ προάγει τη διαδικασία πώρωσης στην περιοχή της τελικής συμπλησίασης και στην περιοχή του επιμηκυνθέντος πώρου επιταχύνοντας την λειτουργική αποκατάσταση του σκέλους. / The purpose of the study is to evaluate the effectiveness of external fixation exchange by intramedullary nailing during consolidation phase following callus distraction phase in distraction osteogenesis. In 12 skeletally mature sheep, divided in two groups (group A and group B), tibial shaft osteotomy and 2cm gradual callus distraction using Ilizarov external fixator was performed. In group A, Ilizarov fixator was removed immediately after lengthening completion and static unreamed intramedullary nail was inserted. In group B (control group), Ilizarov device remained during consolidation phase (according to the usual technique). Formatted callus was studied by radiographs, ultrasonograms, triplex and digital angiograms. All animals were sacrificed 70 days after osteotomy and bone specimens, were evaluated by computed tomograms and histopathologic examination. In group A, all animals successfully tolerated intramedullary nailing attaining limb alignment and formatted mature callus (which had started the remodeling phase), before being sacrificed. In group B, 5/6 formatted mature callus, 3 had serious axis disorder, 3 persistent superficial pin-track infections and 1 deep infection. The method decreases the total duration of external fixation, limits joint stiffness, pin-track infections and axial deformities, and provides protection against re-fracture. We also evaluated the outcome in 30 patients (33 segments) with secondary intramedullary nailing during the consolidation phase after callus distraction using an external device. Docking site nonunion (17 patients), angular deformity or fracture of the lengthened area (8 patients), or intolerance to the external device (5 patients), in combination or not with a delayed distracted callus maturation, were the main reasons for nailing. The average follow-up time was 4 (2-12 years). Intramedullary infection after nailing occurred in 1 case, and slight callus length loss in 5 cases. Failure of union at the docking site with nail breakage occurred in 1 case. In the other patients, consolidation in the lengthened callus area as well as union at the docking site was achieved average 6 months after nailing. Secondary intramedullary nailing during the consolidation phase of distraction osteogenesis is a treatment option for intolerance of the external fixator, delayed callus maturation or docking site nonunion, reducing the prolonged use of the external fixator.

Μελέτη της ανάστροφης ενδομυελικής ήλωσης στα κατάγματα του περιφερικού μηριαίου, στα υπερκονδύλια περιπροθετικά κατάγματα του μηριαίου και η εξέλιξη της χειρουργικής τεχνικής. Υλικό-Μέθοδος: Μελετήθηκαν 57 κατάγματα του περιφερικού μηριαίου σε 53 ασθενείς, 10 περιπροθετικά κατάγματα σε 9 ασθενείς ενώ η εξελιγμένη μορφή της τεχνικής εφαρμόστηκε σε 9 ασθενείς κατά την περίοδο 1997-2004. Αποτελέσματα: Στην ομάδα των καταγμάτων του περιφερικού μηριαίου υπήρξαν 2 ψευδαρθρώσεις και 3 επιπολής μικροβιακές φλεγμονές. Στα περιπροθετικά κατάγματα το ποσοστό πώρωσης ανήλθε στο 100%, ενώ με την αρθροσκοπικά υποβοηθούμενη τεχνική μειώθηκε σημαντικά η περιεγχειρητική θνησιμότητα. Συμπεράσματα: Η ανάστροφη ενδομυελική ήλωση αποτελεί μία αξιόπιστη τεχνική με υψηλό ποσοστό πώρωσης και μικρή συχνότητα επιπλοκών. Με την αρθροσκοπικά υποβοηθούμενη τεχνική μειώνεται σημαντικά η περιεγχειρητική θνησιμότητα. / To evaluate the retrograde intramedullary nailing in distal femoral fractures, in supracondylar periprosthetic fractures and to present the arthroscopically assisted technique. Material-Method: Between 1997 and 2004 we have treated 57 distal femoral fractures in 53 patients, 10 supracondylar periprosthetic fractures in 9 patients and we have applied the arthroscopically assisted technique in 9 patients. Results: In the distal femoral fracture group there were 2 nonunions and 3 superficial infections. In the supracondylar periprosthetic fractures the union rate was 100%. With the arthroscopically assisted technique the postoperative morbidity was reduced significantly. Conclusions: Retrograde intramedullary nailing is a reliable technique to treat distal femoral fractures. It is accompanied by a high union rate and low complication rate. The arthroscopically assisted technique has also reduced significantly the postoperative morbidity.