The psychometric properties of the Dubousset Functional Test in patients with thoracic hyperkyphosis

The Dubousset Functional Test (DFT) has precise metrics that evaluate the functionality of the spinopelvic muscle groups maintaining the spinal alignment. This study investigates concurrent validity, interrater reliability, responsivity, and feasibility of the DFT in patients with thoracic hyperkyphosis.

Thirty patients with thoracic hyperkyphosis performed the DFT twice, the Five-Repetition Sit-To-Stand test (5R-STS), and the Scoliosis Research Society-22 questionnaire (SRS-22) once on the same day. Patients sat between the two DFT administrations for an hour to avoid fatigue. Pain was assessed with the Visual Analogue Scale before and after the tests. The intraclass correlation coefficient (ICC), internal consistency, standard error of measurement (SEM), and minimal detectable change (MDC) were calculated.

The inter-rater reliability of the DFT and its subcomponents was excellent-good (ICC ≥ 0.76). The DFT had excellent internal consistency (Cronbach ɑ = 915). The DFT was well correlated to 5R-STS (r:0.75) and moderately correlated to SRS-22 (r:0.62) (p < 0.05). The SEM and MDC of the DFT were 0.86 and 2.37, respectively. The pain levels did not increase after performing the test, and no problems or adverse events occurred due to the tests.

The DFT can be used reliably even when different evaluators perform examinations. DFT's strong correlation against reference values supports deploying a comprehensive and multifactorial test in clinical settings and trials to measure functional capacity, mobility, and balance simultaneously. This easy-to-use, easy-to-understand, quick, and objective tool may be useful in assessing thoracic hyperkyphosis's impact and can supplement clinical decision-making.