Abstract
The sacroiliac joints are a source of low back pain (1) and sacroiliac joint disorders are a common occurrence in clinical practice (2). Sacroiliac dysfunction is considered to be the most common cause of sacroiliac joint pain and subsequent lower back pain (3). However, the anatomical location of these joints and the lack of a satisfactory criterion standard (the “gold standard”) make the diagnosis of sacroiliac joint dysfunction difficult (4). Nevertheless, many different sacroiliac joint tests have been described to detect the sacroiliac dysfunction however none have been validated against any independent criterion standard (5). Furthermore, numerous invalidated tests attempt to diagnose the type of sacroiliac joint dysfunction although they also lack that satisfactory criterion standard (4, 5). The Sacral Base Pressure Test has been shown in a previous study to have good validity as an indicator of sacroiliac dysfunction (6).
This study aimed to reconfirm the validity of the Sacral Base Pressure Test in diagnosing sacroiliac joint dysfunction. It also determined the predictive powers of the test in determining which type of sacroiliac joint dysfunction was present.
Sixty-two participants underwent a double-blind experimental study where the results from the Sacral Base Pressure Test were compared against a cluster of previously validated tests of sacroiliac joint dysfunction. The cluster of tests gave the diagnosis against which the Sacral Base Pressure Test’s validity and predictive powers were determined. The cluster of tests included Standing Flexion Test, the Iliac Springing Test, Spine Test and Supine Long-Sitting Test. The former two tests only determined the presence of the sacroiliac joint dysfunction, whilst the latter tests also determined the type of dysfunction present. The results occurring in the Sacral Base Pressure Test, namely the external rotation of the feet, were measured using a digital inclinometer.
There was no statistically significant difference in the results of the Sacral Base Pressure Test between the types of sacroiliac joint dysfunction. Only when the Sacral Base Pressure Test was performed on the right of the patient and when it analysed right-sided dysfunction types, was there a slight statistically significant difference (P = 0.0529) evident in the results. In terms of the results of validity, the Sacral Base Pressure Test was useful in identifying positive values of sacroiliac joint dysfunction but was not useful in identifying the negative values. The Sacral Base Pressure Test did not accurately diagnose patients with positive test results, however it was fairly helpful in correctly diagnosing patients with negative test results. The Sacral Base Pressure Test had only a “slight” agreement with the diagnosis according to the Landis and Koch Guidelines for Kappa interpretation.
At this stage of research into the Sacral Base Pressure Test, the results are varied. In this study, the test was not a clinically useful test for determining the presence of sacroiliac joint dysfunction or the type of dysfunction present. Further research comparing the agreement of the Sacral Base Pressure Test or other sacroiliac joint dysfunction tests with a gold standard of diagnosis is necessary.
Dr. E.K. Urli
Dr. J. Breitenbach
Dr. C. Yelverton