The Star Excursion Balance Test: Criterion and divergent validity on patients with femoral acetabular impingement.

BACKGROUND: A valid functional test, evaluating dynamic balance control, might be valuable clinic tool for evaluation of treatment outcome on patients with femoral acetabular impingement (FAI).

OBJECTIVES: The aim of this study was to evaluate criterion and divergent validity of the Star Excursion Balance Test (SEBT) on patients with bilateral FAI- changes, with unilateral clinical symptoms.

METHOD: In this cross sectional correlational and comparative study fifteen patients with bilateral FAI with unilateral symptoms and 15 controls participated. Criterion validity was determined by analysing agreement between SEBT and The Copenhagen Hip and Groin Outcome Score (HAGOS), The Hip Sports Activity Scale (HSAS), pain and leg strength on FAI patients. Divergent validity was determined by comparing SEBT on FAI patients with controls and by comparing SEBT on patient's symptomatic and asymptomatic hips.

RESULTS/FINDINGS: SEBT posterolateral and posteromedial direction had high criterion validity in relation to HAGOS subscale pain intensity and symptoms (rs  = 0.75, p = 0.001, respectively rs  = 0.70, p = 0.004). Criterion validity was low in relation to HAGOS subscales sports, recreation, participation in physical activity and quality of life. SEBT in the posterolateral and posteromedial direction had good divergent validity (p = 0.006, respectively p = 0.001) and in the posterolateral direction SEBT could differentiate between patient's symptomatic and asymptomatic hip (p = 0.005).

CONCLUSIONS: SEBT in posterolateral and posteromedial direction has good criterion validity in relation to pain and other symptoms. In the posterolateral and posteromedial direction SEBT also had divergent validity. Clinically it is recommended to combine SEBT in the posterolateral and posteromedial direction with other measurements on patients with FAI.