Gamma loop dysfunction in the quadriceps femoris of patients who underwent anterior cruciate ligament reconstruction remains bilaterally

Abstract

Purpose of this study was to investigate the effects of anterior cruciate ligament (ACL) repair on the gamma loop of the bilateral quadriceps femoris (QF). Maximal voluntary contraction (MVC) of knee extension and integrated electromyogram (I-EMG) of vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) were examined in uninjured and injured limbs of 18 patients and 10 normal subjects, before and after 20-min vibration applied to the QF. Mean percentage changes were calculated as: (pre-vibration value-post-vibration value)/pre-vibration value x 100. Patients were divided into two groups: short-term-group (tested </=12 months after ACL repair, n=8), long-term-group (tested >/=18 months after ACL repair, n=10). Mean percentage changes of the four groups were compared with those of controls. Results indicated that changes of MVC and I-EMG on the uninjured and injured sides in short-term-group in response to vibration were significantly different from those of controls. There were no significant differences between uninjured sides in long-term and control groups. MVC and I-EMG of VM and RF of injured side in patients in the long-term-group in response to vibration were not different from those of controls. From these results, we concluded that this abnormality of the gamma loop in both injured and uninjured sides did not recover despite ACL reconstruction. However, the abnormality in uninjured side might recover >/=18 months after repair.

Desempenho do membro não-acometido em pacientes com reconstrução do ligamento cruzado anterior

“…Esses dados contradizem a idéia de alguns estudos 7,10,11,15,22,23 segundo os quais o MNA não poderia ser utilizado como referência nas avaliações do membro acometido após reconstrução do LCA. Alguns autores 10,23 sugerem que a diminuição das informações sensoriais após a lesão do LCA não teria um impacto direto sobre a função dos motoneurônios alfa, mas sobre a função dos motoneurônios gama.…”

“…Essa condição pode levar a alterações como fraqueza do músculo quadríceps 4,5 , comprometimento do equilíbrio em apoio unipodal e no desempenho funcional 6 . Diversos estudos discutem se tais alterações também estão presentes no membro inferior não-acometido após a lesão e a cirurgia de reconstrução desse ligamento 7,8,9 .…”

“…Estudos encontraram esse deficit no membro não-acometido de indivíduos com ruptura e submetidos à reconstrução de LCA 7,11 . A similaridade entre diferentes estudos aponta para um mecanismo neurofisiológico comum.…”

“…A similaridade entre diferentes estudos aponta para um mecanismo neurofisiológico comum. Porém, pesquisas que avaliaram força 7,12,13 , equilíbrio [12][13][14] O tamanho da amostra foi calculado com o auxílio do programa EpiInfo 3.5.1. O intervalo de confiança foi de 95%, o poder do teste de 80%, o tamanho da amostra de 1:1 (controle/caso) e a freqüência esperada da exposição nos controles foi 30/100000.…”

Functional Outcomes After Surgical Management of Articular Cartilage Lesions in the Knee: A Systematic Literature Review to Guide Postoperative Rehabilitation

“…Many studies reported deficits in voluntary activation of the QF muscles early after acute knee injury and after knee surgical procedures, 62,63,67,77 as well as in chronic conditions such as knee osteoarthritis. 32,45,54 Though arthrogenic QF muscle inhibition has not been reported in individuals following articular cartilage surgical procedures, the factors common in this population, knee joint pain and effusion, are the main contributors to arthrogenic muscle inhibition, 21,38,53 suggesting that activation deficits, particularly early after injury or surgery, are likely. While decreased QF muscle crosssectional area has not been reported in individuals following articular cartilage surgical procedures, it may be a contributor to the early and persistent deficits in QF muscle strength identified in this literature review.…”