Construct validity and reliability of tests for sacroiliac dysfunction: standing flexion test (STFT) and sitting flexion test (SIFT)

Abstract

Context Sacroiliac dysfunction is characterized by a hypomobility of the range of motion of the joint, followed by a positional change regarding the relationship between the sacrum and the iliac. In general, the clinical tests that evaluate the sacroiliac joint (SIJ) and its dysfunctions lack validity and reliability values. Objectives This article aims to evaluate the construct validity and intra- and inter-rater reliability of the standing flexion test (STFT) and sitting flexion test (SIFT). Methods In this prospective study, the sample consisted of 30 individuals of both sexes, and the evaluation team was composed of five researchers. The evaluations took place on two different days: first day, inter-rater reliability and construct validity; and second day, intra-rater reliability. The reference standard for the construct validity was 3-dimensional measurements obtained utilizing the BTS SMART-DX system. For statistical analysis, the percentage (%) agreement and the kappa statistic (K) were utilized. Results The construct validity was determined for STFT (70% agreement; K=0.49; p<0.01) and SIFT (56.7% agreement; K=0.29; p<0.05). The intra-rater reliability was determined for STFT (66.3% agreement; K=0.43; p<0.01) and SIFT (56.7% agreement; K=0.38; p<0.01). The inter-rater reliability was determined for STFT (10% agreement; K=−0.02; p=0.825) and SIFT (13.3% agreement; K=0.01; p=0.836). Conclusions The STFT confirmed the construct validity and was reliable when applied by the same rater to healthy people, even if the rater had no experience. It was not possible to achieve minimum scores using the SIFT either for construct validity or reliability. We suggest that further studies be conducted to investigate the measurement properties of palpatory clinical tests for SIJ mobility, especially in symptomatic patients.

Investigation of The Pain and Muscle Strength of Individuals with Sacroiliac Joint Dysfunction and Its Effect on Postural Stability

“…The participants were then asked to slowly perform maximum back flexion while keeping their knees extended and beginning the movement in the neck area. The test was ruled negative if the PSISs moved symmetrically, or positive if one side moved more than the other in the cranial direction [10,11,12,13] The SIFT test is similar to the STFT, but the individuals start from a sitting position. The participants were told to sit upright in a height-adjustable seat with their feet flat on the floor in parallel with no angle of rotation, their knees and hips at shoulder width, and their knees and hips flexed to about 90 degrees.…”

“…During palpating the PSISs, the assessor was in the same position as when doing the STFT. The next step was to have the participants put their hands behind their heads, stretch their backs as much as possible, starting in the cervical region, and slowly do so [10,11,13].…”

Standing Flexion Test: A Manual Diagnostic Test as First Indication of Sacroiliac Dysfunction – Study from Practice

“…The conclusion of a reliable test for healthy persons, as long as the SFT is performed by the same rater, was currently reached by another team of authors 3 . Furthermore, they confirmed the construct validity of the flexion test in standing, but not in sitting.…”

“…A literature search using the keyword "standing flexion test" yielded eight hits between 1987 and 2021, reflecting the paucity of scientific investigation of this test. Among the hits is a meta-analysis including Systematic Review [3] and a randomized controlled trial [4].…”