O fixador esquelético externo circular foi desenvolvido durante a guerra fria na Rússia, pelo Professor Gavril Abramovich Ilizarov. Esse tipo de fixação ganhou espaço como alternativa à fixação interna, devido a sua versatilidade e às suas características biomecânicas que otimizam a formação do calo ósseo. O objetivo desse estudo foi avaliar o fixador esquelético externo circular como método de fixação para fraturas metafisárias de rádio e tíbia de cães atendidos no Hospital de Clínicas Veterinárias da UFRGS. Os resultados a respeito do tipo e frequência de complicações associados a essa técnica foram documentados. No total 16 animais cumpriram os critérios para entrar no estudo sendo sete fêmeas e nove machos. A idade média dos animais foi de 50,87 ± 57,01 meses com peso médio dos animais foi de 8,6 ± 6,95kg. Três (18%) animais apresentaram fratura de tíbia e fíbula e treze (82%) fraturas de rádio e ulna. O aparelho de fixação esquelética utilizado consistiu de um aro proximal 5/8 e dois aros distais inteiros, com dois fios em cada anel. Os fios foram colocados de maneira divergente o mais próximo possível de 90°. O aparelho pesou em média 128 ± 49g, representando em média 4,09 ± 3,22% do peso do animal. O tempo médio de cirurgia foi de 115 ± 32 minutos. O tempo médio de permanência com o aparelho de fixação esquelética externa circular foi de 81,69 ± 23,14 dias. Entre as complicações encontradas estão: tratos de drenagem ao redor dos fios (37,5%), miíase (6,25%), encurtamento dos músculos flexores do antebraço (6,25%), hemorragia associada ao local de passagens dos pinos (6,25%) e quebra do fio com deslocamento do fixador levando a necessidade de sua remoção (6,25%). Não houve diferença estatística entre os tempos cirúrgicos necessários para a osteossíntese de rádio e tíbia. Não houve correlação entre as variáveis: tempo decorrido do trauma até a cirurgia e tempo de duração da cirurgia; tempo decorrido do trauma até a cirurgia e tempo de permanência com o aparelho de fixação esquelética externa circular; peso do animal e duração da cirurgia; proporção do peso do circular em relação ao peso do animal e o tempo de permanecia com o circular. Houve correlação positiva estatisticamente significativa entre as variáveis: duração da cirurgia e tempo de permanência com o aparelho de fixação esquelética externa circular. Essa modalidade de tratamento representa uma opção cirúrgica atrativa para a correção de fraturas de rádio e tíbia em cães, entretanto, devido à possibilidade complicações e necessidade de cuidados pós-operatórios intensivos uma seleção acurada dos pacientes e proprietários deve ser realizada previamente à cirurgia. / The circular external skeletal fixator was developed during the Cold War in Russia, by Professor Gavril Abramovich Ilizarov. This kind of fixation took place as an alternative to internal fixation, due to its versatility and its biomechanical characteristics that improves the formation of callus. The aim of this study was to evaluate the circular external skeletal fixator as a method of fixation for fractures of the radius and tibia of dogs treated at the Veterinary Teaching Hospital of UFRGS, corroborating the results, the type and frequency of complications associated with this technique. Sixteen animals met the criteria to participate on the study, seven females and nine males. The average age of the animals was 50.87 ± 57.01 months. The average weight of the animals was 8.6 ± 6.95 kg. Three (18%) animals showed fracture of tibia and fibula and thirteen (82%) fractures of the radius and ulna. The circular external skeletal fixation frame used consisted of a proximal ring ⅝ and two full distal rings, with two wires in each ring. The wires were placed divergently as close as possible to 90 °. The frame weighed on average 128 ± 49g, representing average 4.09 ± 3.22% of the weight of the animal. The mean time of the surgery was 115 ± 32 minutes. The average time spent with the circular was 81.69 ± 23.14 days. Among the complications found are drainage tracts around the pins (37.5%), myiasis (6.25%), shortening of the forearm flexors (6.25%), hemorrhage associated with the location of pins passages (6, 25%) and breakage of the device wire with displacement of the frame leading to its removal (6.25%). There was no statistical difference between the times required for the surgical fixation of the radius and tibia. There was no correlation between the variables: time elapsed from trauma to surgery and duration of surgery, time elapsed from trauma to surgery and time spent with the circular external skeletal fixation; animal weight and duration of surgery; the proportion of the circular weight in relation to the weight of the animal and the time remained with the circular. There was statistically significant positive correlation between the variables: duration of the surgery and the permanency with the circular external skeletal fixation. This treatment modality represents an attractive surgical option for fractures correction of the radius and tibia in dogs, however, due to possible complications and need for intensive post operative care accurate selection of patients and owners should be performed prior to surgery.

O fixador esquelético externo circular foi desenvolvido durante a guerra fria na Rússia, pelo Professor Gavril Abramovich Ilizarov. Esse tipo de fixação ganhou espaço como alternativa à fixação interna, devido a sua versatilidade e às suas características biomecânicas que otimizam a formação do calo ósseo. O objetivo desse estudo foi avaliar o fixador esquelético externo circular como método de fixação para fraturas metafisárias de rádio e tíbia de cães atendidos no Hospital de Clínicas Veterinárias da UFRGS. Os resultados a respeito do tipo e frequência de complicações associados a essa técnica foram documentados. No total 16 animais cumpriram os critérios para entrar no estudo sendo sete fêmeas e nove machos. A idade média dos animais foi de 50,87 ± 57,01 meses com peso médio dos animais foi de 8,6 ± 6,95kg. Três (18%) animais apresentaram fratura de tíbia e fíbula e treze (82%) fraturas de rádio e ulna. O aparelho de fixação esquelética utilizado consistiu de um aro proximal 5/8 e dois aros distais inteiros, com dois fios em cada anel. Os fios foram colocados de maneira divergente o mais próximo possível de 90°. O aparelho pesou em média 128 ± 49g, representando em média 4,09 ± 3,22% do peso do animal. O tempo médio de cirurgia foi de 115 ± 32 minutos. O tempo médio de permanência com o aparelho de fixação esquelética externa circular foi de 81,69 ± 23,14 dias. Entre as complicações encontradas estão: tratos de drenagem ao redor dos fios (37,5%), miíase (6,25%), encurtamento dos músculos flexores do antebraço (6,25%), hemorragia associada ao local de passagens dos pinos (6,25%) e quebra do fio com deslocamento do fixador levando a necessidade de sua remoção (6,25%). Não houve diferença estatística entre os tempos cirúrgicos necessários para a osteossíntese de rádio e tíbia. Não houve correlação entre as variáveis: tempo decorrido do trauma até a cirurgia e tempo de duração da cirurgia; tempo decorrido do trauma até a cirurgia e tempo de permanência com o aparelho de fixação esquelética externa circular; peso do animal e duração da cirurgia; proporção do peso do circular em relação ao peso do animal e o tempo de permanecia com o circular. Houve correlação positiva estatisticamente significativa entre as variáveis: duração da cirurgia e tempo de permanência com o aparelho de fixação esquelética externa circular. Essa modalidade de tratamento representa uma opção cirúrgica atrativa para a correção de fraturas de rádio e tíbia em cães, entretanto, devido à possibilidade complicações e necessidade de cuidados pós-operatórios intensivos uma seleção acurada dos pacientes e proprietários deve ser realizada previamente à cirurgia. / The circular external skeletal fixator was developed during the Cold War in Russia, by Professor Gavril Abramovich Ilizarov. This kind of fixation took place as an alternative to internal fixation, due to its versatility and its biomechanical characteristics that improves the formation of callus. The aim of this study was to evaluate the circular external skeletal fixator as a method of fixation for fractures of the radius and tibia of dogs treated at the Veterinary Teaching Hospital of UFRGS, corroborating the results, the type and frequency of complications associated with this technique. Sixteen animals met the criteria to participate on the study, seven females and nine males. The average age of the animals was 50.87 ± 57.01 months. The average weight of the animals was 8.6 ± 6.95 kg. Three (18%) animals showed fracture of tibia and fibula and thirteen (82%) fractures of the radius and ulna. The circular external skeletal fixation frame used consisted of a proximal ring ⅝ and two full distal rings, with two wires in each ring. The wires were placed divergently as close as possible to 90 °. The frame weighed on average 128 ± 49g, representing average 4.09 ± 3.22% of the weight of the animal. The mean time of the surgery was 115 ± 32 minutes. The average time spent with the circular was 81.69 ± 23.14 days. Among the complications found are drainage tracts around the pins (37.5%), myiasis (6.25%), shortening of the forearm flexors (6.25%), hemorrhage associated with the location of pins passages (6, 25%) and breakage of the device wire with displacement of the frame leading to its removal (6.25%). There was no statistical difference between the times required for the surgical fixation of the radius and tibia. There was no correlation between the variables: time elapsed from trauma to surgery and duration of surgery, time elapsed from trauma to surgery and time spent with the circular external skeletal fixation; animal weight and duration of surgery; the proportion of the circular weight in relation to the weight of the animal and the time remained with the circular. There was statistically significant positive correlation between the variables: duration of the surgery and the permanency with the circular external skeletal fixation. This treatment modality represents an attractive surgical option for fractures correction of the radius and tibia in dogs, however, due to possible complications and need for intensive post operative care accurate selection of patients and owners should be performed prior to surgery.

Αναδρομική μελέτη των 13 ασθενών με σηπτική ψευδάρθρωση κάτω πέρατος μηριαίου που αντιμετωπίστηκαν με ευρύ χειρουργικό καθαρισμό και με τη μέθοδο Ilizarov. Κατά την έναρξη της τελικής αντιμετώπισης όλοι οι ασθενείς είχαν σημαντικό περιορισμό της κίνησης της άρθρωσης του γόνατος. Ο μέσος όρος προηγούμενων χειρουργικών επεμβάσεων ήταν τρεις. Ο μέσος όρος οστικού ελλείμματος ήταν 8.3 εκ. Ο μέσος χρόνος εξωτερικής οστεοσύνθεσης ήταν 309.8 ημέρες. Σύμφωνα με τα κριτήρια Paley σε οκτώ ασθενείς είχαμε άριστο οστικό αποτέλεσμα, ενώ το λειτουργικό αποτέλεσμα ήταν σε τρεις περιπτώσεις άριστο, σε τέσσερις καλό. Πώρωση του κατάγματος, εκρίζωση της λοίμωξης και αποκατάσταση της στηρικτικής ικανότητας του σκέλους επιτεύχθηκε σε όλους τους ασθενείς. Η αύξηση του χρόνου εξωτερικής οστεοσύνθεσης παρατηρήθηκε: 1) η οριστική αντιμετώπιση εφαρμόστηκε 6 μήνες μετά από τον αρχικό τραυματισμό. 2) ο ασθενής υποβλήθηκε σε 4 τουλάχιστον προηγούμενες χειρουργικές επεμβάσεις 3) η αρχική αντιμετώπιση συμπεριλάμβανε ανοικτή ανάταξη και εσωτερική οστεοσύνθεση. Με την μέθοδο Ilizarov επιτυγχάνεται πλήρη εκρίζωση της οστικής λοίμωξης, υψηλό ποσοστό πώρωσης και αποκατάσταση της στηρικτικής ικανότητας του σκέλους. Ωστόσο συχνά η δυσκαμψία του γόνατος και η χωλότητα αποτελούν χρόνιο πρόβλημα για αρκετούς ασθενείς. / We retrospectively reviewed 13 patients with infected nonunion of the distal femur, which had been treated by radical surgical debridement and Ilizarov method. All had severely restricted movement of the knee and a mean of 3.1 previous operations. The mean bone defect was 8.3 cm and no patient was able to bear weight. The mean external fixation time was 309.8 days. According to the Paley’s grading system, eight patients had an excellent bone result and seven excellent and good functional results. Bone union, the ability to bear weight fully, and eradication of infection were achieved in all the patients. The external fixation time was increased when the definitive treatment started six months or more after the initial trauma, the patient had been subjected to more than four previous operations and the initial operation had been ORIF. The treatment of infected defect pseudarthrosis of the distal femur using the Ilizarov device is a salvage procedure, as it offers complete eradication of infection, high union rate and ability for full weight bearing. Nevertheless problems such as, impaired knee joint motion and limping bother the patients permanently.

Externe Fixateure werden häufig für die Stabilisierung und Behandlung schwerer Frakturen genutzt. Schraubenkanalinfektionen können dabei zu Komplikationen, wie Osteomyelitis und Stabilitätsverlusten führen. Es ist unklar, ob Schraubenkanalinfektionen zu Schraubenlockerungen führen, oder aber ob der Stabilitätsverlust von Schrauben in Schraubenkanalinfektionen resultiert. Das Ziel dieser Studie ist es, einen Zusammenhang zwischen der mechanischen Stabilität, dem Auftreten von Infektionen und der osseären Verankerung darzustellen. An 27 Schafen wurde eine standardisierte Osteotomie (3mm weiter Frakturspalt) der rechten Tibia durchgeführt und mit einem monolateralem Fixateur externe stabilisiert. Während der täglichen Pinpflege wurde die Haut um die Schraubeneintrittsstellen begutachtet. Radiologische Verlaufskontrollen erfolgten in wöchentlichen Abständen. Nach 3, 6 und 9 Wochen wurden die Tiere getötet, die Ausdrehmomente der Schrauben gemessen und mikrobiologische Abstriche genommen. Knochenschnitte durch die Schraubenkanäle wurden für histologische, histochemische und histomorphometrische Analysen genommen. In dieser Studie scheint es zu einer Zunahme der Stabilisierung der osseären Verankerung während des Heilungsverlaufes zu kommen. Da die kortikale Knochendichte über die Zeit abnimmt, kann die zunehmend stabilere Verankerung der Schrauben einzig über eine gleichzeitige periostale Kallusdichtezunahme erklärt werden. Die größten Ausdrehmomente des neugebildeten periostalen Kallus wurden zum Sechswochenzeitpunkt gemessen. Danach nimmt die periostale Kallusfläche ab, wohingegen die Kallusdichte zunimmt. Die mikrobiologische Besiedelungsrate (15%) war dreifach höher als die klinisch bestätigten Infektionen. Hingegen war die Osteolyserate (28%) doppelt so hoch wie die mikrobiologisch bestätigte Infektionsrate. Eine Korrelation zwischen Infektion, Osteolyse und Pinlockerung konnte nicht gefunden werden. / External fixators are frequently used for the stabilization and the treatment of problematic fractures. Pin track infections have been shown to cause complications such as osteomyelitis and loss of stability of osteosynthesis. It remains unclear, whether pin track infection provokes pin loosening, or loss of the pin stability results in pin track infections. The aim of this study was to investigate the correlation between the mechanical stability of pins, the incidence of pin track infections and the osseus anchorage of pins. 27 sheep underwent a standardized osteotomy (3 mm gap) of the right tibia. The tibiae were stabilized by a monolateral external fixator. Within the daily pin care routine, the skin around the pin entries was scored. Radiographs were taken at weekly intervals. After 3, 6 and 9 weeks, the animals were sacrificed, the extraction torque of all pins was determined and microbiological analyses were taken. Bone sections through the pintracks were taken for histological, histochemical and histomorphometrical analysis. This study reveals an increasing stability of osseous pinanchorage over the course of healing. As the cortical bone density decreased over time, the increased anchorage-stability of the pins can only be explained by the simultaneous increase of the periosteal callus bone density. The magnitude of the extraction force is determined by the newbuilt periosteal callus, which is at its biggest value at six weeks. Afterwards, the periosteal callus area abates, while the callus bone density accumulates. The microbiologically affirmed infection rate (15%) was three times higher than the one clinical ascertained. In contrast the evidence of osteolysis (28%) was twice as high as the microbiologically diagnosed infection-rate. Despite the low infection rate, evidence of cortical lysis coud not be prevented. No correlation could be found between infection, osteolysis and pin loosening.