Radiographic measurement of tibial joint angles in sheep.

The aim of this study was to establish normal reference values of anatomic and mechanical joint angles of the tibia in sheep at different age groups. Eighteen clinically healthy Santa Ines sheep were used. The animals were divided into three equal groups according to age: Group I - from six- to eight-months-old, Group II - 2-years-old, Group III - from three- to five-years-old. Anatomic medial proximal and lateral distal tibial angles, mechanical proximal and distal tibial angles, and anatomic caudal proximal and anatomic cranial distal tibial angles were measured from tibiae radiographs (n = 36). In the craniocaudal view, the mean values of the anatomic medial proximal, anatomic lateral distal, mechanical medial proximal, and mechanical lateral distal tibial joint angles were 89.6 masculine, 86.6 masculine, 91.4 masculine, and 85.19 masculine respectively. In mediolateral view, the mean values of the anatomic caudal proximal and anatomic cranial distal tibial angles were 64.55 masculine and 105.69 masculine, respectively. The joint orientation angles of the tibia in sheep showed similar values regardless of animal age for both anatomic and mechanical axes.

Tibial segmental bone defect treated with bone plate and cage filled with either xenogeneic composite or autologous cortical bone graft. An experimental study in sheep.

Tibia segmental defect healing in sheep were clinically, radiographically and histologically evaluated. Twelve young sheep aged four to five months were divided into two groups, G1 and G2. A 3.5 cm long segmental defect was created in the right tibial diaphysis with maintenance of the periosteum. The bone defects in both groups were stabilized with a bone plate combined with a titanium cage. In G1 the cage was filled with pieces of autologous cortical bone graft. In G2 it was filled with a composite biomaterial which consisted of inorganic bovine bone, demineralized bovine bone, a pool of bovine bone morphogenetic proteins bound to absorbable ultra-thin powdered hydroxyapatiteand bone-derived denaturized collagen. Except for one G1 animal, all of them showed normal limb function 60 days after surgery. Radiographic examination showed initial formation of periosteal callus in both groups at osteo-tomy sites, over the plate or cage 15 days postoperatively. At 60 and 90 days callus remodeling occurred. Histological and morphometric analysis at 90 days after surgery showed that the quantity of implanted materials in G1 and G2 were similar, and the quantity of new bone formation was less (p = 0.0048) and more immature in G1 than G2, occupying 51 +/- 3.46% and 62 +/- 6.26% of the cage space, respectively. These results suggest that the composite biomaterial tested was a good alternative to autologous cortical bone graft in this experimental ovine tibial defect. However, additional evaluation is warranted prior to its clinical usage.

Mistura de proteínas morfogenéticas ósseas, hidroxiapatita, osso inorgânico e colágeno envolta por membrana de pericárdio no preenchimento de defeito ósseo segmentar em coelhos / Mixture of bone morphogenetic protein, hydroxyapatite, inorganic bone and collagen interposed by pericardium barrier membrane in the filling of the segmental bone defect in rabbits

Avaliou-se o uso de biomaterial de origem bovina na regeneração de defeitos ósseos segmentares empregando-se 12 coelhos, fêmeas, da raça Norfolk, com idade de seis meses e pesos entre 3 e 4,5kg. Realizou-se falha segmentar bilateral de um centímetro de comprimento na diáfise do rádio, com inclusão do periósteo. No membro direito, o defeito foi delimitado por membrana de pericárdio liofilizada, contendo em seu interior mistura de proteínas morfogenéticas ósseas adsorvidas a hidroxiapatita, colágeno liofilizado e osso inorgânico. No membro esquerdo, o defeito não recebeu tratamento. Radiografias foram obtidas ao término do procedimento cirúrgico e aos sete, 30, 60, 90, 120 e 150 dias de pós-operatório. Após eutanásia de seis coelhos aos 60 dias e seis aos 150 dias de pós-cirúrgico, os resultados radiográficos e histológicos mostraram que a regeneração óssea foi inibida nos defeitos segmentares tratados com o biomaterial.

Biomaterials of bovine origin in regenerating segmental bone defects were evaluated. Twelve six-month old Norfolk rabbits, weighting 3 to 4.5kg were used. A 1cm long segmental defect was created in the radial diaphysis, including the periosteum, of both forelimbs. In the right forelimb, the defect was filled using a mixture of bone morphogenic proteins adsorbed to hydroxyapatite, agglutinant of lyophilized collagen in granules and anorganic cortical bone in granules delimited by a pericardial membrane. In the left forelimb, the defect did not receive treatment and served as a control. Radiographies were taken immediately after surgery and at seven, 30, 60, 90, 120 and 150 days post-operatively. Six rabbits were euthanized at 60 days and the other six at 150 days post-surgery for histological evaluation. Radiographic and histological results revealed that bone regeneration was inhibited in the segmental defects receiving biomaterials.

Reconstrução do ligamento cruzado cranial em cães, associado ou não ao sulfato de condroitina / Cranial cruciate ligament reconstruction in dogs associated or not to chondroitin sulfate

Avaliou-se o efeito da reconstrução do ligamento cruzado cranial, associado ou não ao sulfato de condroitina, na evolução da osteoartrite induzida experimentalmente em cães. Vinte cães hígidos, sem raça definida, machos e fêmeas, com peso corpóreo entre 19 e 25kg, foram submetidos à desmotomia do ligamento cruzado cranial. Trinta dias após, foram separados em dois grupos de 10 animais. Um grupo foi submetido à reconstrução do ligamento cruzado com uso de aloenxerto de ligamento patelar congelado, o outro não. Trinta e um dias após a desmotomia, cada grupo foi dividido em dois subgrupos de cinco animais. Um recebeu sulfato de condroitina, o outro não. Os cães foram avaliados clínica e radiograficamente antes da desmotomia e aos 30, 60 e 90 dias após a desmotomia. No último momento foram realizados exames macro e microscópico. Nos cães submetidos somente à desmotomia e tratados com sulfato de condroitina houve redução na progressão das alterações ósseas, ao exame radiográfico. A reconstrução do ligamento cruzado cranial melhorou a função do membro e, quando associada ao sulfato de condroitina, houve melhor resposta. Não houve diferença entre os subgrupos quanto aos exames macro e microscópico.

Treatment of segmental tibial defects using acute bone shortening followed by gradual lengthening with circular external fixator.

The aim of this study was to clinically and radiographically evaluate acute bone shortening followed by gradual lengthening in the treatment of large segmental tibia defects induced in seven clinically normal dogs. A circular external fixator was assembled with one proximal 5/8-circle ring, one middle ring and one distal ring connected with three rods. Thirty per cent of the tibia and fibula were removed in the middle and distal parts of the diaphyses, between the middle and distal rings. Acute bone shortening with compression of proximal and distal segments was performed. A subperiosteal osteotomy was performed between the half-ring and middle ring. Bone distraction started 7 days after surgery; after lengthening, the apparatus was left in place for 14 weeks for consolidation of regenerated bone. The frame was removed at the end of this period, and the dogs observed for four more weeks. Functional results were considered excellent in two, good in three and fair in the other two dogs. Bone regeneration within the distraction gap was obtained 14 weeks after neutral fixation period. We concluded that acute bone shortening followed by gradual lengthening by Ilizarov method can be used to treat extensive tibial defects in dogs, although it presents limb temporary abnormal limb shape and unequal length as early disadvantages.

Histopathological evaluation of treatment with chondroitin sulphate for osteoarthritis induced by continuous immobilization in rabbits.

The aim of this study was to evaluate histologically the action of chondroitin sulphate in osteoarthritis experimentally induced by continuous immobilization. Fourteen young female Norfolk rabbits aged 2.5-3 months at the beginning of the experiment were divided into two equitable groups submitted to immobilization of the right knee for a period of 12 weeks. The treated group received 1.0 ml/animal/s.c. of 12% chondroitin sulphate, once a week for 12 weeks, and the untreated group did not receive any treatment. Two additional animals were not submitted to knee immobilization (sham group). Microscopical examination of knee preparations stained with haematoxylin-eosin and Masson trichrome showed lesions of both joints in treated and untreated groups, with no significant difference between the scores obtained for the right and left knees. Examination of preparations stained with picrosirius red showed collagen fibre alignment and misalignment in the right and left knees of the animals of all groups, but statistic analysis could not be performed. It was not possible to differentiate the proteoglycan concentration between limbs or groups (treated and untreated) by safranin O or toluidine blue staining. It was possible to conclude that the chondroitin sulphate was not able to reduce the histological changes induced by this osteoarthritis experimental model.

Uso do transporte ósseo no tratamento de perda óssea segmentar extensa da tíbia. Estudo experimental em cães / Use of bone transport to treat tibial large segmental defects. Experimental study in dogs

Avaliou-se a técnica de transporte ósseo realizada com fixador externo de Ilizarov no tratamento de defeito ósseo segmentar extenso promovido na tíbia de sete cães. Após aplicação de montagem constituída de um semi-anel proximal, um anel médio e outro distal, ligados entre si por meio de hastes rosqueadas, foi excisado um segmento da diáfise média distal da tíbia e fíbula direitas de 30 por cento do comprimento ósseo. A reconstrução do defeito foi realizada por transporte de um segmento ósseo obtido por osteotomia subperiosteal da parte proximal da tíbia, entre o semi-anel proximal e o anel médio. O período de latência foi de seis dias e o ritmo do transporte foi de 0,5mm a cada 12 horas. Na área de acoplamento foi aplicada compressão. O fixador permaneceu em fase neutra por 14 semanas e, após a remoção do aparelho, os animais foram observados por mais quatro semanas. O resultado funcional foi considerado excelente em um animal, bom em um, satisfatório em três e deficiente nos outros dois. O transporte ósseo permitiu a reparação de falhas ósseas segmentares extensas, porém pode apresentar dificuldades no direcionamento do segmento ósseo transportado e de sua consolidação na área de acoplagem.

Radiography, computed tomography and magnetic resonance imaging at 0.5 Tesla of mechanically induced osteoarthritis in rabbit knees.

In the present experimental study we assessed induced osteoarthritis data in rabbits, compared three diagnostic methods, i.e., radiography (XR), computed tomography (CT) and magnetic resonance imaging (MRI), and correlated the imaging findings with those obtained by macroscopic evaluation. Ten young female rabbits of the Norfolk breed were used. Seven rabbits had the right knee immobilized in extension for a period of 12 weeks (immobilized group), and three others did not have a limb immobilized and were maintained under the same conditions (control group). Alterations observed by XR, CT and MRI after the period of immobilization were osteophytes, osteochondral lesions, increase and decrease of joint space, all of them present both in the immobilized and non-immobilized contralateral limbs. However, a significantly higher score was obtained for the immobilized limbs (XT: P = 0.016, CT: P = 0.031, MRI: P = 0.0156). All imaging methods were able to detect osteoarthritis changes after the 12 weeks of immobilization. Macroscopic evaluation identified increased thickening of joint capsule, proliferative and connective tissue in the femoropatellar joint, and irregularities of articular cartilage, especially in immobilized knees. The differences among XR, CT and MRI were not statistically significant for the immobilized knees. However, MRI using a 0.5 Tesla scanner was statistically different from CT and XR for the non-immobilized contralateral knees. We conclude that the three methods detected osteoarthritis lesions in rabbit knees, but MRI was less sensitive than XR and CT in detecting lesions compatible with initial osteoarthritis. Since none of the techniques revealed all the lesions, it is important to use all methods to establish an accurate diagnosis.

Radiography, computed tomography and magnetic resonance imaging at 0.5 Tesla of mechanically inducedosteoarthritis in rabbit knees

In the present experimental study we assessed induced osteoarthritis data in rabbits, compared three diagnostic methods, i.e., radiography (XR), computed tomography (CT) and magnetic resonance imaging (MRI), and correlated the imaging findings with those obtained by macroscopic evaluation. Ten young female rabbits of the Norfolk breed were used. Seven rabbits had the right knee immobilized in extension for a period of 12 weeks (immobilized group), and three others did not have a limb immobilized and were maintained under the same conditions (control group). Alterations observed by XR, CT and MRI after the period of immobilization were osteophytes, osteochondral lesions, increase and decrease of joint space, all of them present both in the immobilized and non-immobilized contralateral limbs. However, a significantly higher score was obtained for the immobilized limbs (XT: P = 0.016, CT: P = 0.031, MRI: P = 0.0156). All imaging methods were able to detect osteoarthritis changes after the 12 weeks of immobilization. Macroscopic evaluation identified increased thickening of joint capsule, proliferative and connective tissue in the femoropatellar joint, and irregularities of articular cartilage, especially in immobilized knees. The differences among XR, CT and MRI were not statistically significant for the immobilized knees. However, MRI using a 0.5 Tesla scanner was statistically different from CT and XR for the non-immobilized contralateral knees. We conclude that the three methods detected osteoarthritis lesions in rabbit knees, but MRI was less sensitive than XR and CT in detecting lesions compatible with initial osteoarthritis. Since none of the techniques revealed all the lesions, it is important to use all methods to establish an accurate diagnosis.

Large segmental radius and ulna defect treated by bone transportation with the Ilizarov technique.

An 8-year-old male Boxer with a severely contaminated open fracture of the left radius and ulna fracture, produced by a helicopter propeller, was treated using bone transport by the Ilizarov method. Extensive diaphyseal bone loss and soft-tissue vascular damage were present. The radius and ulna were stabilised with an Ilizarov ring external fixator. The bone defect was partially shortened and restored by gradual transport of a bone segment created from proximal segments of the radius and ulna. The external fixator was removed 4 fi months after the beginning of the latency period, due to instability caused by osteolysis around the wires. A cast was placed for 3 weeks. Although the bone transport had resulted in formation of approximately 4 cm of bone, the antebrachium showed approximately 50% shortening when compared to the contralateral limb. The infection was eradicated, and the dog was able to bear weight on the operated limb when walking.

Correçäo e prevençäo da deformidade em flexäo da articulaçäo antebraquiocárpica em cäes, decorrente do alongamento do antebraço pelo método de Ilizarov / Correction and prevention of deformity in flexion of the antebrachiocarpal joint in dogs because of antebrachium lengthening by Ilizarov's method

O objetivo do estudo foi comparar os resultados dos tratamentos cirúrgico e preventivo da deformidade em flexäo da articulaçäo antebraquiocárpica, decorrentes do alongamento simultâneo do rádio e ulna pelo método de Ilizarov. Foram utilizados 12 cäes, sem raça definida, adultos, com peso entre 19 e 28kg, divididos em quatro grupos segundo os tratamentos: A - alongamento ósseo, B - alongamento ósseo e posterior alongamento tendíneo, C - alongamento ósseo e estabilizaçäo da articulaçäo antebraquiocárpica, D - sem alongamento. O fixador básico empregado em todos os grupos foi composto por dois anéis e quatro hastes telescópicas, porém no grupo C foi incluído um semi-anel distal fixando a articulaçäo antebraquiocárpica. Os animais dos grupos A, B e C foram submetidos a 28 dias de alongamento, 60 dias de fase neutra com fixador e 45 dias sem o fixador. Os cäes do grupo D, considerados como controle, foram submetidos à fixaçäo e osteotomia e näo foram alongados. Mesmo com o emprego de exercícios passivos alternados com esparadrapo estendendo-se dos coxins à porçäo cranial do anel, os animais dos grupos A e B desenvolveram, durante o período de distraçäo, gradual e progressiva contratura em flexäo da articulaçäo antebraquiocárpica, que persistiu mesmo após a remoçäo do fixador. Nos cäes do grupo B, ao término do período sem fixador, efetuaram-se alongamento dos tendöes flexores, secçäo dos tecidos periarticulares e capsulotomia. Eles foram observados por mais 45 dias. O tratamento cirúrgico, tecnicamente difícil de ser feito, permitiu a correçäo da contratura. No grupo C, o tratamento preventivo com o semi-anel distal evitou a contratura, mas durante a fase de alongamento houve tendência à flexäo dos dígitos. Os cäes do grupo D näo desenvolveram contratura. Foi possível concluir que medidas preventivas, como o emprego do semi-anel nos metacarpianos, säo importantes para evitar o desenvolvimento de contratura durante o alongamento do antebraço em cäes

Alongamento simultâneo do rádio e ulna em cäes pelo método de Ilizarov / Simultaneous lengthening of radius and ulna in dogs with the Ilizarov method

Com o objetivo de avaliar a funcionalidade de uma montagem do aparelho de Ilizarov para o alongamento simultâneo do rádio e da ulna, foram utilizados 15 cäes, sem raça definida, adultos, com peso entre 17 e 27kg. Aplicado um fixador composto de dois anéis e quatro hastes telescópicas, realizaram-se osteotomia subperiosteal diafisária distal do rádio e ulna e distraçäo óssea, iniciada no sexto dia de pós-operatório. Os animais foram divididos em cinco grupos formados cada um por três cäes, submetidos às seguintes condutas: A- oito dias de alongamento, B- 15 dias de alongamento, C- 22 dias de alongamento, D- 28 dias de alongamento e oito dias de fase neutra com o fixador e E- 28 dias de alongamento, 60 dias de fase neutra com fixador e 45 dias sem fixador. No período de distraçäo os animais desenvolveram gradual e progressiva contratura em flexäo da articulaçäo antebraquiocárpica, que persistiu no grupo E após a remoçäo do fixador. Conclui-se que no alongamento do antebraço há tendência para o desenvolvimento de contratura, recomendando-se medidas preventivas e fisioterapia

Alteraçöes no líquido sinovial do joelho de cäes com osteoartrite induzida pelo modelo Pond e Nuki / Synovial fluid changes in the dog knee with osteoarthritis induced by Pond and Nuki model

Avaliaram-se as alteraçöes do líquido sinovial do joelho de 19 cäes submetidos à desmotomia unilateral do cruzado cranial, baseado no modelo experimental de Pond & Nuki, colhido e analisado aos 30 dias de pós-operatório. Cinco animais foram analisados novamente aos 90 dias de pós-operatório. As características analisadas foram volume, cor, aspecto, densidade, pH, proteínas, fibrinogênio, coágulo de mucina, contagem de hemácias e contagem total e diferencial de células nucleadas. O líquido sinovial apresentou padräo inflamatório que persistiu durante todo o período de observaçäo, com efusäo articular. Houve aumento na contagem de células nucleadas e na concentraçäo de fibrinogênio aos 90 dias. A qualidade da precipitaçäo da mucina apresentou melhora aos 90 dias quando comparada à de 30 dias, porém ainda marcadamente anormal. Foi possível concluir que até 90 dias de pós-operatório no modelo utilizado o fluído sinovial apresenta características inflamatórias e näo degenerativas