Responsiveness of Static and Dynamic Postural Balance Measures in Patients with Anterior Cruciate Ligament Reconstruction Following Physiotherapy Intervention

Background:The main goal of physiotherapy for patients with anterior cruciate ligament reconstruction (ACL-R) is to improve postural control and retain knee function. Therefore, clinicians need to use evaluative tools that assess postural changes during physiotherapy. To maximize the clinical utility of the results of these tools, the extracted measures should have appropriate psychometric properties of reliability, validity and responsiveness. No study has yet addressed responsiveness of postural measures in these patients. This study was designed to investigate the responsiveness and determine the minimal clinically important changes (MCIC) of static and dynamic postural measures in patients with (ACL-R) following physiotherapy. Methods: Static and dynamic postural measures were evaluated at first occasion and again after four weeks physiotherapy. The static measures consisted of center of pressure (COP) parameters while dynamic measures included the stability indices. Correlation analysis and ROC curve were applied for assessing the responsiveness. Results:The meanand SD velocity of COP had acceptable responsiveness in both conditions of standing on injured leg with open-eyes and on uninjured leg with closed-eyes, both with nocognitive task. For dynamic measures, stability indices in double-leg standing with closed-eyes with cognitive task condition attained acceptable responsiveness. MCICs for mean and SD velocity in anteroposterior and mediolateral directions were 0.28cm/s, 0.008cm/s, 0.02cm/s, respectively in standing on injured leg with open-eyes; and 0.14cm/s, 0.07cm/s, 0.06cm/s, respectively in uninjured leg with closed-eyes condition. Also, MCICs for anteroposterior, mediolateral and total stability indices were 0.51◦, 0.37◦, 0.34◦, respectively in DCT condition. Conclusion:Our findings provide evidence for selection of appropriate static and dynamic postural measures for assessment of changes in these patients. MCICs for these measures were determined, which provide practical information for clinicians to make decision on clinical significance of changes in patients’ status.