| Objective: The sacroiliac joint (SIJ) and its biomechanics have been the subject of much discussion in recent years, as this joint has been identified as a possible source of low back and pelvic girdle pain. It is thought that when the forces of vertical loading are increased during weight transfer on lifting one leg (as in gait), nutation (anterior rotation of the sacral base) together with posterior rotation of the innominate (os coxa or pelvic bone) should occur. This places the joint in a locked or ‘self braced’ position, which is better able to withstand those forces. The stork test on the weight bearing leg is a palpation test used to detect movement at the SIJ. The aim of the present study was to examine whether changing the stance of the starting position for the stork test on the weight-bearing leg altered the test outcome. Design: A within subjects experimental design. Independent variable – three different stances for the commencement of the test. Dependent variable – stork test outcome. All 222 tests were videoed and reviewed on a computer screen using horizontal lines to identify the vertical direction and relative distance of thumb movement. Setting: Videoing was carried out in an appropriately equipped studio in southern NSW. Participants: Seventy-four adult volunteers. Inclusion criteria – able to flex the hip to 90º. Exclusion criteria – stroke, spinal fusion, a scoliosis noted on x-ray or obvious to the eye, antalgic gait, hip or knee replacement, a leg length difference noted by a therapist. Outcome Measure: Change in distance between thumb locations on the posterior superior iliac spine of the side of the weight bearing leg and second sacral spinous process on the side of the lifting leg. Negative result – no change or decrease in distance between the thumbs. Positive result – increase in distance between the thumbs. Results: Stork test outcome was influenced by starting stance, with over 70% of subjects having inconsistent results across stances. Kappa values were poor to fair and ranged from 0.14 to 0.26 between stance pairs. Conclusion: When stork tests are used to assess the ‘self bracing’ mechanism of the SIJ pre, during and post treatment, the same starting stance should be used. This abstract is reproduced with the permission of the publisher; full text by subscription.
|
