review paper: evaluation of balance in patients with knee osteoarthritis compared to healthy controls

purpose: over the past 20 years, the center of pressure (cop) has been commonly used as an index of postural stability in standing. while many studies investigated cop excursions in patients with knee osteoarthritis and healthy individuals, no comprehensive analysis of the differences in their postural sway pattern exists. the present study aimed to review the previously published studies concerning differences in cop pattern performance in patients with knee osteoarthritis compared to healthy controls. methods: a literature search was performed on articles published from 1995 to 2014 using elsevier, science direct, proquest, google scholar, pubmed, and medline databases. the search keywords were “knee osteoarthritis”, “healthy people”, “postural stability”, “balance”, and “force plate”. results: five articles were selected according to the inclusion criteria of the study. there was a wide variation among studies in terms of methodology, sample size, and procedure. all available studies investigated postural control in patients with knee osteoarthritis. according to the results, 3 study showed that patients group reported more postural sway and less stability compared to healthy group with both eyes open and closed, especially with eyes closed. however, in 2 other studies, no difference was observed in the parameters of the balance between patients and healthy people. so that cop displacement was similar in patients compared to healthy people. conclusion: the results demonstrate that patients with knee osteoarthritis compared to healthy people show more postural instability. this difference was more pronounced under eyes closed condition. the possible mechanism in association with balance alteration can be pain inhibition, loss of proprioception, and muscle weakness.