Quantificação da coativação muscular na extensão do joelho em pacientes com lesão do ligamento cruzado anterior

Abstract

Objetivo: A coativacao muscular e a ativacao simultanea de musculos agonistas e antagonistas. Em pacientes com lesao do ligamento cruzado anterior (LCA), o aumento da coativacao muscular na extensao ativa do joelho e considerada uma adaptacao neuromuscular compensatoria a instabilidade anterior, ajudando a estabilizar e proteger o joelho. O objetivo desse estudo foi avaliar a coativacao muscular da articulacao do joelho durante os movimentos ativos de extensao e de flexao em pacientes com lesao do LCA e comparar com o joelho contralateral sadio. Foram avaliados 32 pacientes com lesao do LCA, entre 18 e 40 anos de idade, e que apresentavam joelho contralateral sadio. A avaliação funcional dos pacientes foi realizada atraves do escore de Lysholm e através de 3 testes de salto ou hop tests (salto simples, salto triplo e salto triplo alternado). Foi utilizado dinamometro isocinetico (CSMIR, Humac NormR) para determinar a forca isocinetica maxima. Durante a avaliacao isocinetica, foi realizada aquisicao da eletromiografia de superficie (EMG) atraves de eletrodos descartaveis nos musculos vasto lateral, reto femoral, vasto medial, bíceps femoral e semitendineo. Foram identificados os valores de pico de torque (PT) dos membros lesionado e normal, representados pelo maior valor instantâneo observado pelo dinamometro durante os movimentos executados. O valor encontrado para a escala de funcionalidade de Lysholm foi de 66,4 } 17,11 pontos. De acordo com a categorizacao da escala, 50% dos pacientes foram classificados como Ruim, 26,7% como Regular e os demais como Bom. O membro lesionado obteve desempenho inferior em todas as condicoes dos testes de salto. O membro lesionado demonstrou valores de PT significativamente inferiores quando comparados ao membro contralateral tanto para extensao quanto para flexao (p < 0,001). Contudo, nao foram observadas diferencas significativas relacionadas o angulo de ocorrencia do PT. Foi observada maior coativacao dos musculos biceps e semitendineo no membro lesionado, entretanto apenas o bíceps apresentou significancia estatistica. O joelho com lesao do LCA apresenta um aumento da coativacao dos isquiotibiais, quando comparado ao membro contralateral sem lesao. Dessa forma, interpreta-se que que ocorre um mecanismo de adaptacao contra a instabilidade anterior do joelho.

Objective: Muscle coactivation is the simultaneous activation of agonist and antagonist muscles. In patients with anterior cruciate ligament (ACL) injury, increased muscle coactivation on active knee extension is considered a compensatory neuromuscular adaptation to anterior instability, helping to stabilize and protect the knee. The aim of this study was to evaluate the muscular coactivation of the knee joint during active extension and flexion movements in patients with ACL injury and to compare it with the contralateral knee. Thirty-two patients with ACL lesion, aged between 18 and 40 years, who had healthy contralateral knee were evaluated. The functional evaluation of the patients was performed through the Lysholm score and through 3 hop tests (single jump, triple jump and alternating triple jump). Isokinetic dynamometer (CSMIR, Humac NormR) was used to determine maximum isokinetic strength. During the isokinetic evaluation, surface electromyography (EMG) was acquired through disposable electrodes in the vastus lateralis, rectus femoris, vastus medialis, bíceps femoris, and semitendinosus muscles. The peak torque values (PT) of the injured and normal limbs, represented by the highest instantaneous value observed by the dynamometer during the movements performed, were identified. The value found for the Lysholm functionality scale was 66.4 } 17.11 points. According to the categorization of the scale, 50% of the patients were classified as Bad, 26.7% as Regular and the others as Good. The injured member obtained inferior performance in all conditions of the jump tests. The injured limb showed significantly lower PT values when compared to the contralateral limb for both extension and flexion (p <0.001). However, no significant differences were observed regarding the angle of PT occurrence. Muscle coactivation was greater in biceps and semitendinous muscles of the injured limb, however, only the biceps presented statistical significance. The knee with ACL lesion presents an increased hamstring coactivation, when compared to the contralateral limb without injury. In this way, it is interpreted that an adaptation mechanism occurs against the anterior knee instability. Muscle coactivation is the simultaneous activation of agonist and antagonist muscles. In patients with anterior cruciate ligament (ACL) injury, increased muscle coactivation on active knee extension is considered a compensatory neuromuscular adaptation to anterior instability, helping to stabilize and protect the knee. The aim of this study was to evaluate the muscular coactivation of the knee joint during active extension and flexion movements in patients with ACL injury and to compare it with the contralateral knee. Thirty-two patients with ACL lesion, aged between 18 and 40 years, who had healthy contralateral knee were evaluated. The functional evaluation of the patients was performed through the Lysholm score and through 3 hop tests (single jump, triple jump and alternating triple jump). Isokinetic dynamometer (CSMIR, Humac NormR) was used to determine maximum isokinetic strength. During the isokinetic evaluation, surface electromyography (EMG) was acquired through disposable electrodes in the vastus lateralis, rectus femoris, vastus medialis, biceps femoris, and semitendinosus muscles. The peak torque values (PT) of the injured and normal limbs, represented by the highest instantaneous value observed by the dynamometer during the movements performed, were identified. The value found for the Lysholm functionality scale was 66.4 } 17.11 points. According to the categorization of the scale, 50% of the patients were classified as Bad, 26.7% as Regular and the others as Good. The injured member obtained inferior performance in all conditions of the jump tests. The injured limb showed significantly lower PT values when compared to the contralateral limb for both extension and flexion (p <0.001). However, no significant differences were observed regarding the angle of PT occurrence. Muscle coactivation was greater in biceps and semitendinous muscles of the injured limb, however, only the biceps presented statistical significance. The knee with ACL lesion presents an increased hamstring coactivation, when compared to the contralateral limb without injury. In this way, it is interpreted that an adaptation mechanism occurs against the anterior knee instability.