Análise do ligamento redondo na instabilidade não traumática do quadril: estudo experimental em coelhos
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2018-02-22
Autores
Zuccon, Alexandre
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Universidade Estadual Paulista (Unesp)
Resumo
Introdução: A luxação do quadril em uma criança pode interferir com a função dessa articulação, causando dor, limitação de movimento, entre outras consequências. Na redução aberta da articulação, diversas estruturas anatômicas são abordadas como o ligamento redondo (LR) que, tradicionalmente, é ressecado. Porém, existe controvérsia a respeito de sua importância funcional. Objetivo: Comparar através de análise biomecânica, bioquímica e histológica o LR de quadris instáveis (luxados e subluxados) com o ligamento de quadris normais. Métodos: Estudo experimental com coelhos esqueleticamente imaturos, utilizando um modelo para luxação do quadril. Oitenta e oito coelhos foram submetidos à fixação do joelho de uma das patas traseiras em extensão, o que leva à instabilidade do quadril ipsilateral, devido ao desequilíbrio muscular e à alteração em posicionamento no membro. Dezenove coelhos morreram, 28 foram excluídos por não evoluírem com a luxação e 5 foram excluídos pela impossibilidade de identificação do LR. Dos 36 coelhos que compuseram a amostra, estratificamos as análises em quantitativas: biomecânica (12 coelhos), zimografia (8 coelhos), histologia (14 coelhos) e qualitativa: imuno-histoquímica (2 coelhos). Realizamos análise estatística para comparação entre o lado luxado e o controle de cada coelho quanto às análises quantitativas. Resultados: No ensaio biomecânico, a média da força máxima do ligamento redondo no lado luxado foi de 43,25 ± 16,25N e 46,62 ± 15,56N para o lado normal (p=0,594) e a média da deformação máxima foi de 3,94 ± 1,88mm para o lado luxado e 4,55 ± 1,19mm para o normal (p = 0,328). Histologicamente foi quantificada a celularidade, mostrando em média, para o ligamento do lado luxado, 6,83 ± 3,47 células por campo e 3,87 ± 2,13 para o lado normal (p<0,001), além de 74,3 ± 10,5% de ocupação por colágeno no lado luxado e 84,5 ± 9,5% no lado normal (p<0,001). Na zimografia, a quantidade de metaloproteinase 2 (MMP2) em forma ativa foi 481,8 ± 228UA, em média, para o lado luxado e de 294,4 ± 78UA para o lado normal (p=0,068). Conclusão: Embora tenham ocorrido alterações significativas no LR dos quadris instáveis do ponto de vista histológico e com diferença importante na zimografia, esta sem significância estatística, isso não foi observado no ensaio biomecânico, no qual não houve diferença estatística entre os lados.
In the open reduction, used in the treatment of the hip dislocation in children, several structures are approached, such as the round ligament (RL) that has traditionally been resected. However, there is controversy regarding its possible maintenance as well as its functional importance. The aim of this study was to compare the RL properties of stable and unstable hips. Methods: Experimental study with young rabbits using a model for congenital hip dislocation. Eighty-eight rabbits underwent fixation of the knee of one hind leg in extension, which leads to ipsilateral hip instability. Nineteen rabbits died and 28 were excluded because they did not develop dislocation. Five additional rabbits also excluded because they did not present the RL. Thirty-six rabbits composed the sample that was stratified for quantitative analysis: biomechanical (12 rabbits), zymography (8 rabbits), histology (14 rabbits) and qualitative: immunohistochemistry (2 rabbits). We performed statistical analysis for comparison between the unstable side and the control of each rabbit. Results: Biomechanical assay showed the mean maximal strength of the RL on the unstable side was 43.25 ± 16,25N and 46.62 ± 15,56N for the control side (p = 0.594) and the mean maximum deformation was 3.94 ± 1,88mm for the unstable side and 4.55 ± 1,19mm for the control (p = 0.328). Histologically, there was an increase in cellularity on the unstable side showing, on average, 6.83 ± 3,47 cells per field and 3.87 ± 2,13 for the control side (p <0.001), in addition to 74.3 ± 10,5% of collagen occupancy on the unstable side and 84, 5 ± 9,5% on the control side (p <0.001). In zymography, the amount of metalloproteinase 2 (MMP-2) was 481.8 ± 228UA, on average, for the unstable side and 294.4 ± 78UA for the control side (p = 0.068). Conclusions: Although there were significant changes in the RL of the unstable hips from the histological analysis and there were an important diference in zymography without statistical significance, that was not observed in the biomechanical test.
In the open reduction, used in the treatment of the hip dislocation in children, several structures are approached, such as the round ligament (RL) that has traditionally been resected. However, there is controversy regarding its possible maintenance as well as its functional importance. The aim of this study was to compare the RL properties of stable and unstable hips. Methods: Experimental study with young rabbits using a model for congenital hip dislocation. Eighty-eight rabbits underwent fixation of the knee of one hind leg in extension, which leads to ipsilateral hip instability. Nineteen rabbits died and 28 were excluded because they did not develop dislocation. Five additional rabbits also excluded because they did not present the RL. Thirty-six rabbits composed the sample that was stratified for quantitative analysis: biomechanical (12 rabbits), zymography (8 rabbits), histology (14 rabbits) and qualitative: immunohistochemistry (2 rabbits). We performed statistical analysis for comparison between the unstable side and the control of each rabbit. Results: Biomechanical assay showed the mean maximal strength of the RL on the unstable side was 43.25 ± 16,25N and 46.62 ± 15,56N for the control side (p = 0.594) and the mean maximum deformation was 3.94 ± 1,88mm for the unstable side and 4.55 ± 1,19mm for the control (p = 0.328). Histologically, there was an increase in cellularity on the unstable side showing, on average, 6.83 ± 3,47 cells per field and 3.87 ± 2,13 for the control side (p <0.001), in addition to 74.3 ± 10,5% of collagen occupancy on the unstable side and 84, 5 ± 9,5% on the control side (p <0.001). In zymography, the amount of metalloproteinase 2 (MMP-2) was 481.8 ± 228UA, on average, for the unstable side and 294.4 ± 78UA for the control side (p = 0.068). Conclusions: Although there were significant changes in the RL of the unstable hips from the histological analysis and there were an important diference in zymography without statistical significance, that was not observed in the biomechanical test.
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colágeno, luxação do quadril, ligamentos redondos, modelos animais, coelhos, collage, hip dislocation, round ligaments, models, animal, rabbits