Examining the diagnostic accuracy of static postural stability measures in differentiating among knee osteoarthritis patients with mild and moderate to severe radiographic signs

Abstract

BackgroundClinicians need a reliable and accurate tools that can best identify and classify balance impairments between mild and moderate to severe grades of knee osteoarthritis (OA). Research questionThis study was designed to investigate the accuracy of postural measurements to discriminate between these two groups of knee OA. MethodsA total of 130 patients with knee OA based on the Kellgren-Lawrence (KL) grading scale were categorized into 65 patients with mild (a KL grade≤ 2) and 65 patient with moderate to severe (a KL grade≥3) radiographic sign. Static postural control was assessed on the force plate in three conditions of double leg stance with open (DO) and closed eyes (DC) and single leg stance with open eyes (SO). The accuracy for static postural control parameters was determined by calculation of sensitivity, specificity, area under the Receiver Operating Characteristic (ROC) curve (AUC) and likelihood ratios (LRs). ResultsOur results showed that standard deviation (SD) of velocity in anterior-posterior (AP) direction had the highest sensitivity and specificity in conditions of DO and DC, respectively. ROC curve analysis indicated that measures of mean and SD velocity in medio-lateral (ML) direction in conditions of DO and DC had acceptable levels of accuracy (AUC > 0.70) in discriminating between the two groups of knee OA patients. Also, based on LR results, SD of velocity in AP direction had the best ability for ruling in and ruling out moderate to severe grade of knee OA patients in conditions of DC and DO, respectively. SignificanceOur findings provide evidence for selection of mean velocity and SD of velocity in identifying and discriminating static postural performance in patients with mild and moderate to severe grades of knee OA.