Stabilometric objectification of pelvic instabilities discriminated against by the Unipodal Pelvic Stability Test (UPST)

Abstract

Introduction The purpose of this study was to determine whether the UPST was objectived by stabilometric parameters in both bipodal and unipodal stations. Method Twenty-six women, 15 men, average age 34 ± 6.9 years, are divided into 2 groups by an expert practitioner according to the results of the UPST. They were then evaluated in bipodal stance on force platform (Medicapteurs©, Fusyo®, France) for 31.6 sec at 40 Hz, under 4 conditions: – open eyes; – closed eyes; – open eyes with foam and; – closed eyes with foam (Capitoner® 8sh 2 mm). Subjects were recorded in unipodal situation for 5 sec at 40 Hz on the left and right feet, eyes open and eyes closed. All registrations were randomized and volunteers with a dominant left foot (2) or a UPST dysfunction on the left were excluded (4). Data analysis was performed by two MANOVA for each experimental time. Results Subjects with bilateral instability to the UPST showed a significantly larger surface area of the Centre of Pressure in the bipodal situation with eyes closed (F (2.32) = 4.48; P = 0.02 (η2 = 0.22)) and in unipedal situation with eyes open, only on the left foot (F (2.32) = 5.7; P = 0.008 (η2 = 0.26)) compared to volunteers without pelvic instabilities. The subjects with right dysfunctions to the UPST showed no significant difference in stabilometric parameters compared to the control population. Conclusion Subjects with bilateral pelvic instability have poorer postural stability in both bipodal and unipedal stance while isolated right pelvic instability cannot be characterized by force platform exams.