The effect of a patellar bandage on the postural control of individuals with patellofemoral pain syndrome.

A patellar bandage is often used by individuals with patellofemoral pain syndrome (PPS) to reduce pain and the additional sensorial input improves proprioception of the knee joint. The aim of this work was to assess the effect of a patellar bandage on the postural control of individuals with and without PPS. [Subjects and Methods] An analysis was performed of variables of center of pressure (CoP) as recorded by a force plate. Information about the forces and moments in three directions was used to obtain the CoP. Thirty women participated in this study: 15 with PPS and 15 without PPS. All subjects performed 3 trials in a unipodal stance with and without a patellar bandage. The force plate data were used to calculate the following variables: CoP sway area, CoP displacement frequency, and CoP mean velocity for the anteroposterior (AP) and mediolateral (ML) directions. A the linear mixed effects model was used for statistical analysis. [Results] Postural sway was significantly reduced in individuals with PPS when a patellar bandage was applied. [Conclusion] Additional sensory input from a patellar bandage increase proprioceptive feedback and this could be related to the improvement in postural control of PPS subjects.

Analysis of the center of pressure displacement, ground reaction force and muscular activity during step exercises.

Anterior Knee Pain (AKP) is considered as one of the most common, yet misunderstood, knee pathologies. The aim of this study was to evaluate the displacement area of the center of pressure, Ground Reaction Force (GRF), and the electromyography activity of the hip and the quadriceps muscles in healthy and AKP individuals during the step-up and step-down exercises. Both groups (Control group and AKP group) were composed of 15 volunteers submitted to the exercises on a force plate. The AKP group presented greater displacement area of the center of pressure for all the situations evaluated than the Control group (p<0.05), as well as a lesser magnitude of the GRF during the step-down exercise. The AKP group presented lower electromyography activity than the Control group in all situations evaluated. AKP individuals do not have muscle imbalances; they present a lower electromyography activity of the stabilizing muscles of the patella and hip and show greater instability in activities such as step up and down compared to normal subjects.

Controle postural em pacientes com lesão do ligamento cruzado anterior / Postural control in patients with anterior cruciate ligament injury

A lesão do ligamento cruzado anterior (LCA) do joelho acarreta alterações somatosensoriais em função da perda de informações provenientes dos mecanorreceptores presentes no LCA. Esses receptores constituem importante fonte de informação sensorial, afetando o desempenho de vários atos motores, dentre os quais o controle postural. O estudo objetivou analisar o controle postural de indivíduos com joelhos normais e com lesão unilateral do LCA. Participaram 15 voluntários com lesão do LCA (grupo lesado) e 15 voluntários com joelhos normais (grupo controle). O controle postural foi analisado por plataforma de força, sendo o voluntário instruído a assumir a situação experimental em apoio unipodal direito e esquerdo, posicionado no centro da plataforma de modo estático e com os olhos fechados. A plataforma de força forneceu informações de forças e momentos no eixo vertical e horizontal, a partir das quais foi obtida a área de deslocamento do centro de pressão nas direções ântero-posterior e médio-lateral. Os resultados mostram que indivíduos com lesão do LCA apresentaram maior amplitude média de oscilação comparados aos do grupo controle, sugerindo que o deficit no controle postural seja devido à perda de informações proprioceptivas nos indivíduos com LCA. Esses resultados têm implicações para a abordagem clínica de indivíduos com lesão do LCA.

Anterior cruciate ligament (ACL) injury leads to sensorimotor changes due to lack of information from mechanoreceptors at the ACL. These receptors are an important source of sensory information, affecting the performance of various motor responses, among which postural control. The purpose of this study was to assess postural control in individuals with normal knees and with unilateral ACL injury. Fifteen subjects with ACL injury and 15 healthy young subjects (control group) were submitted to postural control assessment by standing in single-leg stance (both right and left) on a force platform; they stood at the centre of the platform, with eyes closed, remaining in the position for 30 seconds. The force platform provided information on forces and moments along both vertical and horizontal axes, from which was obtained the centre of pressure displacement in anterior-posterior and medial-lateral directions. Individuals with ACL injury showed greater mean sway amplitude than healthy control ones, suggesting that their deficit in postural control might be due to lack of proprioceptive information. These results have implications for the clinical approach of individuals with ACL injury.