Radiographic texture of the trabecular bone of the proximal phalanx in horses with metacarpophalangeal osteoarthritis.

Osteoarthritis (OA) is a prevalent condition in horses, leading to changes in trabecular bone structure and radiographic texture. Although fractal dimension (FD) and lacunarity have been applied to quantify these changes in humans, their application in horses remains nascent. This study evaluated the use of FD, bone area fraction (BA/TA), and lacunarity in quantifying trabecular bone differences in the proximal phalanx (P1) in 50 radiographic examinations of equine metacarpophalangeal joints with varying OA degrees. In the dorsopalmar view, regions of interest were defined in the trabecular bone of the proximal epiphysis, medial and lateral to the sagittal groove of P1. Lower BA/TA values were observed medially in horses with severe OA (P=0.003). No significant differences in FD and lacunarity were found across OA degrees (P>0.1). FD, BA/TA, and lacunarity were not effective in identifying radiographic texture changes in the P1 trabecular bone in horses with different metacarpophalangeal OA degrees.

Locking conical coupling plates in small animal orthopedics: A review.

Conical coupling locking plates (CCP) have become an interesting alternative in veterinary orthopedics and traumatology. Available data in this regard, however, must be interpreted with caution, and several studies are still required to reach definitive conclusions on the clinical use of these implants. In this context, this review aims to discuss CCP applications and mechanical aspects in small animals and summarize in vivo, in vitro and ex vivo study results.

Knowledge and practice of radiation safety in Brazilian equine veterinarians are less than optimal: An online survey.

Exposure to ionizing radiation is an occupational risk for veterinarians due to the potential for carcinogenesis, reproductive disorders, cataracts, and hereditary genetic changes. This survey study aimed to identify the radiological protection practices routinely used by veterinarians who work with portable digital X-ray equipment in horses in Brazil and assess their knowledge regarding current legislation. A total of 120 voluntary participation questionnaires were sent to veterinarians who used portable digital radiographic equipment in horses nationwide. The frequencies of the answers were analyzed using the chi-square test and logistic regression models. Thirty-five veterinarians responded (29% response rate). Of these, there was a greater participation of professionals in public institutions (40%, 14/35, p < .001), with 69% from the southeast region (24/35, p < .001) and 69% (24/35, p = .028) being male. We found that self-employed veterinarians had a higher odds ratio (OR) (9.00; 95% confidence interval (CI) [1.39-58.44]; p = .021) of not using personal protective equipment compared with those in professional public institutions. In addition, not knowing the current legislation Collegiate Directorate Resolution 611/22 was a potential risk factor for lower radiological protection (OR, 8.00; 95% CI, [0.79-81.33]; p = 0.079). In conclusion, findings indicated that Brazilian equine veterinarians generally do not adopt adequate radiological protection against ionizing radiation during radiographic examinations and have low knowledge of the current legislation. Results can be used as background for the formulation of specific radiation protection guidelines for veterinarians and incentive educational and training strategies to reduce risks inherent to occupational exposure.

Proximal Interphalangeal Arthrodesis in Horses: A Meta-Analysis of Retrospective Studies.

The aim of this study was to determine the clinical outcomes reported in retrospective studies of proximal interphalangeal arthrodesis (PIA) in horses through a meta-analysis of retrospective studies. CAB Abstracts, PubMed, ScienceDirect, Web of Science, and Scopus were searched. The primary outcomes included survival and surgical site infection (SSI) rates, return to activities, and time of hospital stay and casting. Subgroups were formed for fractures and other conditions. Meta-analyses were performed with fixed and random effects models to estimate proportions, mean values, and effect size by odds ratio (OR) with 95% confidence intervals (CI). Twenty-one full articles were included, totaling 458 horses. The survival rate was 90% (95% CI [86%-93%]), return to activities was 65% (95% CI [61%-70%]), and SSI was 12% (95% CI [8%-16%]). The mean hospitalization was 25 days (95% CI [18-35 days]) and time of casting was 29 days (95% CI [21-42 days]). The OR of survival (P = .769), return to activities (P = .576), and SSI (P = .467) were similar between cases of fractures and other conditions. PIA is an efficient and safe method to treat injuries in the pastern region, with a high survival rate and low SSI. However, the rate of return to soundness for intended use was modest, being potentially lower for fracture cases. Thus, investigations of more efficient interventions are needed to improve this outcome.

Treatment of a Mandibular Diastemal Fracture Using Locking Compression Plate and Cerclage Wire in a Mare.

This report describes the combination of two surgical fracture repair techniques and the postoperative management of a mandibular diastemal fracture in a two-year-old mare. The mare was referred to a veterinary hospital with a laceration over the body of the right mandible. Radiographic assessment revealed two mesial fracture lines involving the second premolar tooth and a ventrally displaced bone fragment. The mare was treated under general anesthesia and the fracture was corrected using open reduction and plate fixation. A 3.5 mm narrow 15-hole locking compression plate with seven locking screws were used in a bridge form. Cerclage wire was also used to anchor the incisor teeth to the second and third premolar teeth. The cerclage wire and incisor teeth were covered with polymethylmethacrylate to prevent implant failure and avoid injury to the oral mucosa. Implants were removed 55 days after surgery and the mare was discharged from hospital five days later. The mare returned for cerclage wire removal after 90 days and was allowed to resume exercise thereafter. The combination of two surgical techniques, proper implant choice and appropriate postoperative management, including use of pelleted feed, contributed to successful bone healing and return to function.

Anatomical position of the palmar/plantar nerves at the metacarpal/metatarsal distal level in horses: An in vivo study by means of ultrasonography.

The neurovascular bundle of the equine distal cannon can dynamically vary with limb position, and this can affect the performance of low 4- or 6-point block. This study aims to identify and describe the anatomical position and variations of the lateral and medial palmar/plantar nerve at the metacarpal/metatarsal distal level in horses by ultrasonography. Eight mares underwent ultrasound examination on the lateral and medial palmar/plantar sides of the metacarpus/metatarsus. Images were obtained for measurements of the cross-sectional area of the nerve, distances between the nerve and the skin surface, branch of the suspensory ligament (SL), deep digital flexor tendon (DDFT) and superficial digital flexor tendon (SDFT) with limbs supported and elevated. The distance to the skin for forelimbs was higher on the lateral side when the limb was elevated (p < 0.001). The comparisons between supported and elevated limbs on the same side showed longer distances to the skin with the limb supported on the medial side (p < 0.001). Hindlimbs showed longer distances to the skin with the limb supported on the medial face (p = 0.027). The anatomical position of palmar/plantar nerves was similar between the lateral and medial sides of the limb, generally being in contact with the dorsal edge of DDFT. The strategy of elevating the limb during the injection of the low 4- or 6-point block can lead to a higher risk of puncture of the digital sheath.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering.

PURPOSE: To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. METHODS: A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. RESULTS: Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. CONCLUSIONS: Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering

ABSTRACT Purpose To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. Methods A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. Results Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. Conclusions Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Proximal interphalangeal joint arthrodesis in horses: concepts, indications, and techniques / Artrodese interfalangeana proximal em equinos: conceitos, indicações e técnicas

Surgical arthrodesis is effective for treating proximal interphalangeal joint (PIJ) injuries in horses. Despite several techniques described so far, the use of a 3-hole, 4.5mm-locking compression plate, associated with two 5.5-mm transarticular cortex screws, is currently considered the "gold standard." This review describes the anatomy of the pastern, as well as causes, indications, and possibilities for arthrodesis in the equine PIJ. A description of the current surgical technique for joint fixation is also presented.(AU)

A artrodese cirúrgica é efetiva para o tratamento de condições da articulação interfalangeana proximal (AIP) em equinos. Diversas técnicas são descritas, e o uso de uma placa de compressão bloqueada de três orifícios e 4,5 mm associada com dois parafusos corticais transarticulares de 5,5 mm é atualmente o padrão ouro. Esta revisão tem por objetivo descrever a anatomia da região da quartela, bem como as causas, indicações e possibilidades para a artrodese da AIP nos equinos. É apresentada também a descrição da técnica cirúrgica atualmente utilizada para realização da fixação da articulação.(AU)

In vitro evaluation of hydroxyapatite, chitosan, and carbon nanotube composite biomaterial to support bone healing / Avaliação in vitro do biomaterial compósito à base de hidroxiapatita, quitosana e nanotubo de carbono como adjuvante no reparo ósseo

Hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were developed to improve bone healing. Previous studies suggested that a combination of biomaterials and mesenchymal stem cells (MSCs) can potentially help promote bone regeneration. In the present study, we first developed hydroxyapatite, chitosan, and carbon nanotube composite biomaterial. Then, the effect of different concentrations of the extract on the viability of Vero cells (ATCC CCL-81) and MSCs obtained from sheep bone marrow using methylthiazol tetrazolium (MTT) and propidium iodide (PI) assays were evaluated. The biomaterial group demonstrated an absence of cytotoxicity, similar to the control group. Samples with 50% and 10% biomaterial extract concentrations showed higher cell viability compared to samples from the control group (MTT assay). These results suggest that the presence of this composite biomaterial can be used with MSCs. This study also concluded that hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were not cytotoxic. Therefore, these could be used for performing in vivo tests.(AU)

O compósito à base de hidroxiapatita, quitosana e nanotubo de carbono foi desenvolvido com o intuito de auxiliar na consolidação óssea. Estudos anteriores sugerem que a combinação de substitutos ósseos e células-tronco mesenquimais (CTM) podem auxiliar a potencializar e promover a regeneração óssea. No presente estudo, o biomaterial foi desenvolvido e a viabilidade e a citotoxicidade de células Vero (ATCC CCL-81) e CTM obtidas de medula óssea provenientes de ovinos utilizando ensaios metil-tiazol-tetrazólio, MTT e iodeto de propídeo (PI) foram avaliadas em diferentes concentrações de extrato desse compósito. O compósito demonstrou ausência de citotoxicidade com comportamento semelhante ao grupo controle. Amostras com 50% e 10% de concentração de extrato do compósito mostraram resultados maiores comparados ao grupo controle (ensaio MTT). Esses resultados também sugerem que a presença do biomaterial pode ser utilizada em associação a CTM. Assim, esse estudo conclui que o compósito apresentado de hidroxiapatita, quitosana e nanotubo de cabono não foi considerado citotóxico e pode ser utilizado em teste in vivo.(AU)

Proximal interphalangeal arthrodesis in seven horses: A retrospective study in Brazil (2011-2019) / Artrodese interfalangeana proximal em sete equinos: um estudo retrospectivo no Brasil (2011-2019)

ABSTRACT: This study discussed several cases of proximal interphalangeal arthrodesis in horses at a veterinary hospital in Brazil. The medical records of seven horses that underwent proximal interphalangeal arthrodesis between 2011 and 2019 were analyzed for indication, technique, and complications. Short- and long-term outcomes were obtained from both the medical records and telephone interviews with the owners. A dynamic compression plate (DCP) was used in one of the seven horses that underwent surgical arthrodesis, and locking compression plates (LCP) were used in the others. Hospital discharge was recorded in 71.4% (5/7) of the horses, with an average hospital stay of 79 ± 45 days. Casting was maintained for 59 ± 26 days. Contact with owners was possible in four cases, two of which regained their prior level of function. The proximal interphalangeal arthrodesis may improve a horse's well-being, especially when it is considered an early intervention, minimizing the chances of immediate postoperative complications. Additional cases of surgical arthrodesis should be evaluated in long term to better characterize the outcomes of this procedure in Brazil.

RESUMO: Este estudo teve como objetivo apresentar e discutir casos de artrodese interfalangeana proximal em equinos atendidos em um Hospital Veterinário no Brasil. Os prontuários de sete equinos submetidos à artrodese interfalangeana proximal foram analisados quanto à indicação, técnica e complicações, entre 2011 e 2019. As informações sobre os desfechos de curto e longo prazo foram obtidas pela avaliação dos prontuário e entrevista telefônica com os proprietários. Em um dos sete cavalos submetidos à artrodese cirúrgica foi utilizado implantes DCP, e nos demais, LCP. A alta hospitalar foi registrada em 71,4% (5/7), com média de permanência hospitalar de 79±45 dias. A imobilização externa durou 59±26 dias. O contato com os proprietários foi possível em quatro casos, dos quais, em dois, os animais voltaram às suas funções. A artrodese interfalangeana proximal pode melhorar a qualidade de vida dos equinos, principalmente quando se considera a intervenção precoce, minimizando as chances de complicações pós-operatórias imediatas. Casos adicionais devem ser avaliados ao longo prazo para melhor caracterizar os resultados desse procedimento no Brasil.

Comparison of a 3-hole 4.5-mm Dynamic Compression Plate and a 7-hole 5.5-mm Y Locking Compression Plate for Arthrodesis of the Proximal Interphalangeal Joint in Horses-an Ex Vivo Biomechanical Study.

The objective of this study was to compare the biomechanical properties in a single cycle axial loading test and the types of failures in two constructs (a 3-hole 4.5-mm dynamic compression plate (DCP) and 7-hole 5.5-mm Y locking compression plate (Y-LCP)) in equine proximal interphalangeal joint (PIJ) arthrodesis. One limb in each pair was randomly assigned to PIJ arthrodesis using a 3-hole 4.5-mm DCP combined with two transarticular 5.5-mm cortical screws, whereas the contralateral limb was submitted to PIJ arthrodesis using a 7-hole Y-shaped 5.0-mm LCP in conjunction with one transarticular 4.5-mm cortical screw inserted through the central plate hole. Cortical screws were inserted in lag fashion. Constructs were submitted to a single axial load cycle to failure. Construct stiffness, load, and deformation were analyzed. Dynamic compression plate and Y-LCP arthrodesis constructs did not differ significantly and were equally resistant to axial loading under the conditions studied (DCP and Y-LCP group stiffness, 5685.22 N/mm and 6591.10 N/mm, respectively). Arthrodesis of the PIJ using a DCP and two transarticular 5.5-mm cortical screws or a Y-LCP yielded biomechanically equivalent outcomes under the test conditions considered. However, Y-LCP provides less impact in the palmar/plantar bone. Application of Y-LCP with unicortical screws has equivalent biomechanical characteristics of DCP and may be a safe option for PIJ arthrodesis, where potential trauma secondary to applying bicortical screws in the palmar/plantar aspect of the pastern can be avoided.

What is the Evidence of Hyaluronic Acid and Polyacrylamide Hydrogel in Intra-articular Therapy in Equines? Systematic Literature Review.

A systematic review was conducted to investigate evidence to support or refute the use of hyaluronic acid and polyacrylamide hydrogel as intra-articular therapy in equines, which are frequent treatment options in the routine of veterinarians of equines in cases of osteoarthritis. In total, 19 studies were included, among clinical and in vitro studies, as well as a retrospective series of cases. The outcomes of the included studies provided fragile evidence supporting the recommendation for intra-articular use of hyaluronic acid. No study was included showing any clinical outcome in diseased synovial tissues of the polyacrylamide hydrogel. There is no concrete evidence of benefits, treatment protocols, and mechanisms of action of hyaluronic acid in the joint therapy in equines.

Using tilapia skin (Oreochromis niloticus) as an occlusive biological curative in equine wounds: short communication / Uso da pele de tilápia (Oreochromis niloticus) como curativo biológico oclusivo em feridas de equinos: nota prévia

Tilapia skin is being already use in humans and wild animals present burning wounds and showed a great result. The objective is to evaluate if tilapia skin used as an occlusive curative improves equine wound healing in two horses present chronic wound. Both animals are males, adults, both of breed Mangalarga Marchador South America. Every seven days wound we measured, photographed, biopsied for histopathological analysis, cleaned and tilapia curative was changed. Image J software was used to measure wound area. Tilapia skin as an occlusive biological factor seemed to improve healing process, wounds present an area reduction and clinical improvement during 35 days treatment, even though is still waiting for complete wound healing. In equine tilapia skin curative seemed to speed up healing process and allowed reduced curative change from every two days to once a week. This implies in decrease animal ́s stress, less pain and treatment cost reduction since we used less bandage amount. Beside that tilapia skin industrial waste. Furthermore, it allowed avoid using antibiotics, which reduces environment pollution and there ́s no antibiotic resistance issues.(AU)

A pele de tilápia está sendo utilizada em humanos e animais silvestres com feridas por queimadura demonstrando um excelente resultado. O objetivo do estudo é avaliar se a pele de tilápia utilizada como curativo oclusivo melhora o processo de cicatrização em dois equinos machos adultos da raça Mangalarga Machador, os quais apresentam feridas crônicas. A cada 7 dias as feridas eram medidas, fotografadas, biopsiadas para a análise histopatológica, limpas e o curativo de pele de tilápia trocado. O programa Image J foi utilizado para calcular a área da ferida. A pele de tilápia utilizada como curativo oclusivo parece ter um efeito positivo na cicatrização das feridas, a área diminuiu e a o aspecto clínico melhorou nos 35 dias avaliados, no entanto é necessário esperar pela cicatrização completa das feridas. Em equinos, a utilização de curativo de pele de tilápia parece diminuir o tempo de cicatrização e permite a redução do número de trocas de curativos de a cada dois dias para uma vez por semana. Isso implica em menos estresse e dor para o animal devido à menor manipulação e menor custo de tratamento, pois há menor quantidade de material de curativo sendo utilizado. Além disso, permite evitar a utilização de antibióticos, o que diminui o impacto ambiental e não gera resistência.(AU)

Histological and Radiographic Evaluation of Equine Bone Structure after Implantation of Castor Oil Polymer.

OBJECTIVE: The main purpose of this study was to evaluate the characteristics of a vegetal polymeric biomaterial intended for bone substitution in horses and to investigate the responses of the equine third metacarpal bone to biomaterial implantation. MATERIALS AND METHODS: Six horses were submitted to osteotomy on the dorsal aspect of the left and right third metacarpal bones; one bone defect was randomly selected for treatment with biopolymer, while the other was left untreated and served as a control. Bone density was monitored radiographically after surgery and bone biopsy fragments were collected at the end of the 120-day follow-up period. Biopsy fragments were analysed using light and scanning electron microscopy. RESULTS: Mean bone density values (mmAL) were greater in control defects (16.33 ± 1.6) than in polymer-treated defects (14.17 ± 1.7) at 120 days (p = 0.027). Light microscopy revealed greater percentages of new bone formation in control defects (50.15 ± 14.8) than in polymer treated defects (26.94 ± 12.1) at 120 days (p < 0.0001). Scanning electron microscopy analysis suggested a similar quality of pre-existing bone and new bone formed in the presence of biomaterial. CLINICAL SIGNIFICANCE: The absence of adverse reactions supports biomaterial biocompatibility and osteoconducting capacity and suggests the castor oil polymer is a suitable bone substitute for the treatment of bone defects in horses.

Physics behind the implants used for high strain fractures: literature review / A física por trás dos implantes utilizados para fraturas de alto strain: revisão de literatura

Whenever bone fractures occur, external forces produce continuous interfragmentary motion and a stabilization method is necessary. It is known that the mechanical conditions at the fracture site influence bone callus formation during healing process. To achieve primary (direct) bone healing, absolute stability at the fracture site is necessary. Perren's concept of strain determines that relative deformation at the fracture gap depends on the original gap's conformation. Simple fractures (without comminution) are considered high strain fractures since a small force applied to the fracture site results in great movement with deleterious effects on the healing process. The purpose of this study is to review the available literature regarding factors that influence the mechanics of high strain fractures in veterinary medicine, its treatment methods and implants available. Each fracture configuration requires special attention and critical care in choosing the osteosynthesis method and the type of stability required for consolidation to occur within the expected time. One must know the strain theory to become an orthopedic surgeon.(AU)

Quando fraturas ósseas ocorrem, forças externas produzem movimentação interfragmentária continuamente e um método de estabilização se faz necessário. É sabido que as condições mecânicas no local de fratura influenciam a formação de calo durante o processo de cicatrização óssea e para que cicatrização óssea primária seja obtida é necessária estabilidade absoluta no foco de fratura. O conceito de strain de Perren determina que a deformação relativa no foco de fratura estabilizado depende do tamanho da lacuna de fratura original. Fraturas redutíveis (sem cominuição) são consideradas de alto strain, pois uma pequena força aplicada a linha de fratura resulta em grande movimentação com efeito deletério ao processo de consolidação. O presente trabalho revisa a literatura disponível a respeito de fatores que influenciam a mecânica de fraturas de alto strain em medicina veterinária, seus métodos de tratamento e a física por trás dos implantes disponíveis. Cada configuração de fratura requer atenção especial e cuidado crítico na escolha do método de osteossíntese e no tipo de estabilidade necessária para que a consolidação ocorra no tempo esperado. Conhecimento da teoria do strain é mandatório para a formação de cirurgiões ortopédicos.(AU)

Power Doppler sonography in the assessment of neovascularization following surgical fracture repair in sheep: case report / Utilização da ultrassonografia Power Doppler no acompanhamento de neovascularização no pós-operatório de ovino submetido a osteossíntese: relato de caso

Sonography is a safe and non-invasive imaging modality, with the added benefit of providing dynamic images. Power Doppler sonography allows blood vessel identification regardless of flow intensity or direction. A one-year-old Ile de France ewe was admitted to the FMVZ-USP Veterinary Hospital with a complete tibial fracture. The animal was submitted to general inhalation anesthesia and fracture repair using a 3.5 mm locking compression plate. Power Doppler sonography was used to assess neovascularization over the course of the bone healing process. Formation of new vessels was noted between postoperative days 14 and 21; new vessels regressed progressively on subsequent assessments (postoperative days 28 and 35). Power Doppler sonography enabled early detection of newly formed blood vessels at the fracture site. The non-invasive nature of this imaging modality prevented patient stress and provided useful information on the progression of bone healing. Early neovascularization was thought to reflect successful postoperative healing of the tibial fracture described.(AU)

A ultrassonografia é técnica de imagem segura e não invasiva que fornece imagens dinâmicas. O Power Doppler é modalidade ultrassonográfica que permite a visualização de vasos sanguíneos sem depender de intensidade e direção de fluxo. Admitiu-se no Hospital Veterinário da FMVZ-USP um ovino fêmea, de raça Ile de France, com um ano de idade e apresentando fratura completa de tíbia em bisel. O animal foi submetido à anestesia inalatória para a realização de osteossíntese com placa bloqueada de 3,5 mm. Durante o período pós-operatório foram realizadas imagens de ultrassonografia Power Doppler para a avaliação da neovascularização ao longo do processo de regeneração óssea. Entre o 14º e o 21º dia do período pós-operatório, identificou-se a presença de vasos sanguíneos neoformados, que apresentaram sinais de regressão nas avaliações subsequentes (realizadas no 28º e no 35º dia pós-operatório). A ultrassonografia Power Doppler mostrou-se eficiente na detecção precoce de vasos sanguíneos neoformados na região da fratura no período pós-operatório, sendo um exame não invasivo, que não gerou estresse para o animal e que pode estar relacionado ao sucesso no reparo ósseo da tíbia do animal submetido à osteossíntese.(AU)

Mechanical evaluation of bone gap filled with rigid formulations castor oil polyurethane and chitosan in horses / Avaliação mecânica do preenchimento de falhas ósseas de equinos com formulações sólidas de poliuretana de mamona e quitosana

ABSTRACT: Often fractures of long bones in horses are comminuted and form bone gaps, which represent a major challenge for the fixation of these fractures by loss of contact between the fragments. Bone grafts help in treating this kind of fracture and synthetic materials have been gaining ground because of the limitations of autologous and heterologous grafts. In this study were performed compressive non destructive test in 10 bones with complete cross-bone gap in mid-diaphyseal of the third metacarpal bone of horses. Using a mechanism of "crossing" the 10 bones were used in the three groups (control, castor oil poliuretane and chitosan) according to the filling material. After the test with maximum load of 1000N bone had a gap filled by another material and the test was repeated. Deformations caused on the whole bone, plate and bone tissue near and distant of gap were evaluated, using strain gauges adhered to the surface at these locations. There was a reduction in bone deformation from 14% (control) to 3,5% and 4,8% by filling the gap with Chitosan and castor oil respectively, and a reduction of strain on the plate of 96% and 85% by filling gap with chitosan and castor respectively. An increase in intensity and direction of deformations occurred in bone near to gap after its filling; however, there was no difference in bone deformations occurring far the gap.

RESUMO: Frequentemente, as fraturas de ossos longos nos equinos são cominutivas, formando falhas ósseas, que representam um grande desafio no momento de sua fixação, devido à perda de contato entre os fragmentos. Os substitutos ósseos sintéticos auxiliam no tratamento desse tipo de fratura. Neste estudo, foram realizados ensaios compressivos não destrutivos em 10 ossos com falha óssea transversal completa em diáfise do terceiro metacarpiano de equinos. Utilizando um mecanismo de "crossing", os 10 ossos foram utilizados nos três grupos (controle, mamona e quitosana) de acordo com o material de preenchimento da falha. Para cada peça, realizaram-se ensaios referentes aos três grupos, com carga máxima de 1000N, por não se tratarem de ensaios destrutivos. Foram avaliadas as deformações causadas no osso, na placa e no tecido ósseo próximo e distante da falha, por meio de extensômetros. Observou-se que houve redução da deformação do osso de 14% (controle) para 3,5% e 4,8%, com o preenchimento da falha com quitosana e mamona, respectivamente. Houve redução da deformação na placa de 96% e 85% com o preenchimento da falha com quitosana e mamona, respectivamente. Houve aumento em intensidade e direção das deformações ocorridas no osso próximas à falha após seu preenchimento, contudo não se observaram diferenças nas deformações ocorridas no osso distantes a falha. Dessa forma, conclui-se que o preenchimento das falhas com quitosana e poliuretana de mamona trouxe benefícios quanto à redução das deformações no foco da fratura, alívio das cargas na placa, contudo elevou as cargas no tecido ósseo próximo à falha.

Morphological and mechanical characterization of chitosan-calcium phosphate composites for potential application as bone-graft substitutes

Introduction: Bone diseases, aging and traumas can cause bone loss and lead to bone defects. Treatment of bone defects is challenging, requiring chirurgical procedures. Bone grafts are widely used for bone replacement, but they are limited and expensive. Due to bone graft limitations, natural, semi-synthetic, synthetic and composite materials have been studied as potential bone-graft substitutes. Desirable characteristics of bone-graft substitutes are high osteoinductive and angiogenic potentials, biological safety, biodegradability, bone-like mechanical properties, and reasonable cost. Herein, we prepared and characterized potential bone-graft substitutes composed of calcium phosphate (CP) - a component of natural bone, and chitosan (CS) - a biocompatible biopolymer. Methods CP-CS composites were synthetized, molded, dried and characterized. The effect of drying temperatures (38 and 60 °C) on the morphology, porosity and chemical composition of the composites was evaluated. As well, the effects of drying temperature and period of drying (3, 24, 48 and 72 hours) on the mechanical properties - compressive strength, modulus of elasticity and relative deformation-of the demolded samples were investigated. Results Scanning electron microscopy and gas adsorption-desorption analyses of the CS-CP composites showed interconnected pores, indicating that the drying temperature played an important role on pores size and distribution. In addition, drying temperature have altered the color (brownish at 60 °C due to Maillard reaction) and the chemical composition of the samples, confirmed by FTIR. Conclusion Particularly, prolonged period of drying have improved mechanical properties of the CS-CP composites dried at 38 °C, which can be designed according to the mechanical needs of the replaceable bone.

Avaliação cirúrgica e laboratorial da utilização de pericárdio homólogo em lesões por abrasão em serosa de cólon maior (flexura pélvica) de equinos / Surgical evaluation and laboratory use of homologous pericardium in serous injuryby abrasion of large colon (pelvic flexure) of horses

Aderências intra-abdominais são complicações de cirurgias de equinos que podem resultar em processos obstrutivos e comprometer a sobrevida dos animais. O presente estudo utilizou dez equinos hígidos, machos, sem raça definida (SRD), com quatro a 15 anos de idade e peso vivo situado entre 300 e 400 quilogramas (kg). Os animais foram submetidos à laparotomia esquerda em estação com o objetivo de serem induzidas aderências, testar a utilização intestinal de membrana biológica de pericárdio como prevenção e avaliar as diferentes alterações sistêmicas e do líquido abdominal. Após sedação e analgesia local, foi utilizado o acesso cirúrgico em grade, na flexura pélvica foi criada uma área de abrasão que, no Grupo 1, foi coberta por pericárdio homólogo e no Grupo 2, lavada com solução fisiológica. Após reposicionamento foi realizada a sutura muscular, de subcutâneo e pele. O pós-operatório constou de avaliações clínicas, citologia do líquido abdominal, hematologia e bioquímica sérica nos momentos M0- pré-operatório e M7, M14, M21 e M28 dias de pós-operatório. Nova laparotomia foi realizada aos 30 dias para verificar aderências, aspecto e biópsia intestinal. A técnica cirúrgica possibilitou menor trauma e campo operatório restrito. A evolução clínica foi satisfatória e cicatriz fibrosa foi identificada entre os planos musculares. Aderências não foram observadas. As avaliações laboratoriais demonstraram aumento de bilirrubinas, hematócrito, monócito, ureia sanguíneos e de proteína, densidade e leucócitos segmentados no líquido peritoneal. Conclui-se que a abrasão foi insuficiente para promover aderências fibrosas. O implante, sem comprovada eficácia, é viável e possível, por não resultar em diferenças laboratoriais significativas ou alterações deletérias.

Intra-abdominal adhesions are equine surgery complications, which can result in obstructive processes and jeopardize the survival of these animals. The present study used 10 healthy, male mongrel horses (SRD), with four and 15 years of age and weighing between 300 and 400 kilograms (kg), who underwent laparotomy left station with the aim of inducing adhesions, test intestinal membrane using pericardium as prevention and evaluating the different systemic changes and the abdominal fluid. After sedation and local anesthesia, the surgical approach was used in grade; pelvic flexure was created in an area of abrasion that in Group 1 was covered by homologous pericardium and in Group 2, washed with saline. After repositioning muscle, the skin and subcutaneous tissue were sutured. Postoperative care consisted of clinical evaluation, abdominal fluid cytology, hematology and serum biochemistry in moments M0- preoperative, and M7, M14, M21 and M28 days postoperatively. New laparotomy was performed at 30 days from the surgery to verify adhesion, appearance and intestinal biopsy. The surgical technique allowed less trauma and restricted operative field. The clinical course was satisfactory, and fibrous scar was identified between the muscle planes. Adhesions were not observed. Laboratory evaluations showed increased bilirubin, hematocrit, monocyte, blood urea and protein density and segmented leukocyte peritoneal fluid. The present study concluded that the abrasion was insufficient to promote fibrous adhesions. The implant without proven efficacy is feasible and possible, and does not result in significant differences laboratory or deleterious changes.