ROLE OF JOINT AFFERENTS IN KNEE MEDIO-LATERAL STABILITY

我们建议研究关节传入神经在促进人膝关节内外侧稳定性中的作用。保持关节稳定性是防止软骨损伤和骨关节炎的必要条件。关节稳定性归因于五个因素：骨和软骨接触力、韧带和关节囊刚度、固有刚度、固有刚度和活动肌肉以及反射介导的肌肉刚度。反射作用可以反过来由肌肉牵张感受器或关节周围组织传入（韧带和关节囊）介导。后一类反射在关节的异常内翻/外翻负荷的情况下通过肌肉激活潜在地保护关节。我们假设，有针对性的肌肉收缩可以引起的应用程序的机械内翻/外翻刺激的人膝关节，这些反应显着增加关节的刚度内翻/外翻平面。将在35名受试者中确定个体膝关节肌肉活动的定量测量。我们将使用肌内电极来选择性地刺激穿过膝盖的肌肉，并且一个6自由度的测力传感器将测量产生的运动。对于相同的受试者人群，将通过膝关节镜对受试者膝关节施加快速内翻/外翻位置扰动。在机械扰动期间，将记录肌肉活动，并记录所有受试者的主要膝关节肌肉的反射反应。基于试验数据，我们认为，导致关节韧带拉伸的机械扰动将在穿过膝关节的肌肉中产生反射反应，并且这些反射可以被组织以选择性地补偿内翻或外翻载荷，并且这些反射可以被组织以选择性地补偿内翻和外翻载荷。为了保证反射介导的肌肉收缩所产生的僵硬度，在神经阻滞前后，对所有35名受试者的膝关节进行伪随机内翻/外翻微扰。关节刚度和阻尼系数将使用线性模型进行估计。将计算关节周围传入神经介导的反射僵硬度，即计算的关节僵硬度在有和没有神经阻滞的情况下的差异。我们相信膝关节周围组织中的牵张感受器在促进关节内外侧稳定性方面发挥着重要作用，我们进一步期望有关神经和机械组件之间相互作用的信息将对训练如何改善整体关节稳定性产生重大影响。通过物理治疗重新编程关节的神经成分可能有助于替代关节松弛引起的韧带功能丧失，从而限制OA进展的速度。

We propose to study the role of joint afferents in promoting medio- lateral stability of the human knee joint Preservation of joint stability is necessary to prevent cartilage damage and osteoarthritis. Joint stability has been attributed to five factors: bone and cartilage contact forces, ligament and capsule stiffness, intrinsic stiffness, intrinsic stiffness and active muscles, and reflexively mediated muscle stiffness.. Reflex action may, in turn, be mediated either by muscle stretch receptors or by periarticular tissue afferents (ligaments and capsule). The latter class of reflexes potentially protects the joint through muscle activation in situations of abnormal varus/valgus loading of the joint. We hypothesize that targeted muscle contractions can be elicited by the application of a mechanical varus/valgus stimulus to the human knee, and that these responses significantly increase the joint's stiffness in the varus/valgus plane. Quantitative measures of individual knee muscle action will be determined in 35 subjects. We will use intramuscular electrodes to selectivity stimulate muscles traversing the knee, and a 6-degree of freedom load cell will measure the movements produced. For the same subject population, a rapid varus/valgus positional perturbation will be applied at the subject knee via a servomotor. During the mechanical perturbation, muscle activity will be recorded and the reflex responses in major knee muscles recorded in all subjects. Based on pilot data, we believe that mechanical perturbations resulting in the stretching of joint ligaments will produce a reflex response in muscle traversing the knee joint, and that these reflexes may be organized so as to compensate selectively for varus or valgus loading, and that these reflexes may be organized so as to compensate selectively for varus and valgus loading. To quality the stiffness contributed by reflexively mediated muscle contractions, a pseudo-random varus/valgus perturbation will be applied to the knees of all 35 subjects before and after nerve blockade. Joint stiffness and damping coefficients will be estimated using linear models. The reflex stiffness mediated by periarticular afferents will be calculated to be the difference in the computed joint stiffness with and without the neural blockade. We believe that stretch receptors in periarticular tissues of the knee joint play a major role in promoting joint media-lateral stability, and we further expect that information about the interaction between neurological and mechanical components will have a major impact on how training may improve overall joint stability. Reprogramming the neural component of the joint by physiotherapy may help substitute the loss of function of ligaments induced by joint laxity and thus limit the rate of OA progression.