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.

Avaliação da composição macroelementar do osso terceiro metacarpiano de equinos / Evaluation of the macro elemental composition of the equine third metacarpal bone

O terceiro osso metacarpiano equino é uma região de particular interesse devido ao grande número de lesões a que está sujeito. Assim, justifica-se o estudo detalhado da sua estrutura anatômica, dimensões e composição elementar para o aprimoramento de técnicas de diagnóstico, tratamento e prevenção de lesões. Neste trabalho,foi estudada a composição macroelementar óssea de 30 pares de osso terceiro metacarpiano equino e sua relação com a idade, sexo, peso, raça, alimentação e atividade dos animais. As concentrações médias de cálcio e fósforo das amostras foram 205 ± 62 mg/g e 97 ± 32 mg/g, respectivamente. A relação [Ca]/[P] encontrada foi de 2,12 ± 0,13, indicando que a proporção entre o cálcio e fósforo no tecido ósseo é constante e aproximadamente igual à razão 2:1. A análise estatística dos dados mostrou normalidade para todo o conjunto de medidas. A avaliação entre os animais com atividade física intensa e os animais com atividade física leve, em que a quantidade de material mineralizado para o primeiro e segundo conjuntos são, respectivamente, [Ca] = 222 ± 57 mg/g e [Ca] = 179 ± 47 mg/g, evidenciou a existência de correlação estatística entre o depósito de material mineral e a função exercida pelos animais. Para as demais características, não foram verificadas evidências estatísticas de inter-relações. Tais achados serão subsídios para estudos posteriores acerca de possíveis correlações com enfermidades de origem fisiológica ou nutricional frente à casuística de fraturas e outras afecções comuns ao aparelho locomotor equino.

The equine third metacarpal bone has been seen as a region of particular interest due to the large number of injuries to which it is subject. Thus, the detailed study of its anatomical structure, size and elemental composition is justified for the improvement of diagnostic techniques, treatment and prevention of injuries. In this work it has been studied the macro elemental composition of 30 pairs of equine third metacarpal bone and its relation with age, sex, weight, breed, nutrition and activity of animals. The average concentrations of calcium and phosphorus of the samples were 205 ± 62 mg/g and 97 ± 32 mg/g, respectively. The ratio [Ca] / [P] was found to be 2.12 ± 0.13, indicating that the ratio of calcium and phosphorus in bone tissue is constant and approximately equal to the ratio 2:1. The statistical analysis showed normal values for the entire set of measurements. In the evaluation of the animals with intense physical activity, and animals with light physical activity, it was found that the amount of mineralized material for the first and second sets respectively ([Ca] = 222 ± 57 mg/g [Ca] = 179 ± 47 mg/g), showing the existence of statistical correlation between the deposit of mineral material and the function performed by the animals. For the other characteristics were not found statistical evidence of correlations. These findings will be input for further studies of possible correlations with diseases of nutritional origin or physiological outside the series of fractures and other disease common to the equine locomotor system.