Supervisors: Enas Fawzy Youssef, Mohammed Shawki Abdelsalam, Ahmad Hamdi Azzam.

Thesis (M.Sc.)-Cairo university, Faculty of Physical Therapy, 2021.

Includes bibliographical references.

Background: Balance is an essential indicator of physical function, and impaired balance control in cases suffering from knee osteoarthritis is well reported in the literature. The SWAY smartphone application is a recent mobile application used in balance assessment in patients.
Purpose: This study aimed to determine the concurrent validity of SWAY in comparison to the Balance Error Scoring System (BESS) in the assessment of balance in patients with bilateral knee osteoarthritis. Furthermore, it aimed to evaluate the test–retest reliability of SWAY in the same patient sample.
Methods: Forty patients diagnosed with bilateral knee osteoarthritis from both genders, aged 50–70 years, with Kellgren–Lawrence grades 2–3, participated in this study. Patients attended two visits separated by one week. During the first visit, they performed the SWAY Balance and BESS tests in a randomized order with a two-minute interval between assessments. During the second visit, patients repeated the SWAY Balance test only.
Results: For concurrent validity, moderate negative significant correlations were found between BESS foam tandem stance and the SWAY total score (r = −0.349, p = 0.02), semi-tandem (r = −0.317, p = 0.04), and tandem stance (r = −0.406, p = 0.009). The remaining associations were weak and not statistically significant (p > 0.05). Test–retest reliability demonstrated a moderate reliability for the SWAY total score (ICC = 0.667; 95% CI: 0.376–0.823).
Conclusions: Based on the assessment protocol used in this study, researchers could not confirm the validity of the SWAY Mobile Application for balance assessment in patients with knee osteoarthritis. However, SWAY demonstrated moderate reliability for the total balance score.