Does the Gillet Test Assess Sacroiliac Motion or Asymmetric One-legged Stance Strategies?

Editorial Review

Does the Gillet Test Assess Sacroiliac Motion or Asymmetric One-legged Stance Strategies?

Robert Cooperstein, MA, DC and Felisha Truong, BSc

J Can Chiropr Assoc. 2018 Aug; 62(2): 85–97

Copyright 2018 Journal of the Canadian Chiropractic Association

JACO Editorial Reviewer: John S. Stites DC, DACBR, DACO

Published: March 2019
Journal of the Academy of Chiropractic Orthopedists
March 2019, Volume 16, Issue 1

The original article copyright belongs to the original publisher. This review is available from: https://ianmmedicine.org ©2019 Stites and the Academy of Chiropractic Orthopedists. This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Authors’ Abstract:

Objective

The purpose of this study was to quantify the extent to which apparent movements of the posterior superior iliac spine and sacral base areas Gillet sacroiliac motion testing were related to (a) degree of hip flexion and (b) the examiner’s palpatory pressure.

Methods

A preliminary exploratory study quantified relative PSIS/S2 displacements in 10 sacroiliac joints among 5 asymptomatic subjects at 10° increments of hip flexion from 0–90°. A comprehensive follow-up asymptomatic study quantified PSIS/S2 displacements at 0° vs. 30° vs. 90° hip flexion, and for light vs. firm pressure at 30° hip flexion. Displacements measured in pixels on digital photographs were transformed to mm. Mean differences for the various test conditions were evaluated for statistical significance using paired t-testing and Wilcoxon signed rank test.

Results

With light pressure, the left PSIS moved caudal for hip flexion ≤30° during right-legged stance, whereas the right PSIS moved cephalad relative to the sacral base. For hip flexion =90°, both PSISs moved cephalad. The use of firm palpatory pressure abolished the initial caudal movement of the left PSIS, as well as differences in the amount of cephalad PSIS movement at 30° vs. 90° hip flexion.

Conclusions

The results are consistent with there being left-right differences in gluteus medius and biceps femoris activation among asymptomatic individuals that result in different balancing strategies during one-legged stance. This may create the appearance of relative PSIS/SB displacement, even though the results of Gillet testing can be wholly or partially explained by pelvic obliquity owing to muscle function asymmetry. This study questions the validity of the upright Gillet test for sacroiliac motion.

JACO Editorial Summary:

  • Gillet test is purported to assess sacroiliac motion. The test is preformed by the examiner placing a digit on the inferior aspect of the PSIS and the S2 tubercle and having the participant raise their knee to 90 decrees or more hip flexion.
  • This study examined the extent of motion relative to the degree of hip flexion and the examiner’s palpatory pressure.
  • This study was informed by an earlier study that assessed the apparent motion between the PSIS and the sacral base at different degrees while performing the Gillet test. After measuring at increments of 10 degrees it was found that 30 degrees was associated with the greatest caudal motion of the PSIS. There were 5 subjects in that study.
  • The current study looked at movement of the PSIS at 30 degrees and 90 degrees hip flexion with lighter vs. firmer palpation.
  • Subject were described as a convenience sample of asymptomatic subjects. No demographic information was provided such as age, gender or handedness. 32 subjects were assessed from 0 degrees to 30 degrees, 25 subjects 30 vs. 90 degrees and 27 light vs. heavy pressure 3o degrees flexion.
  • Effort was made to reduce bias by using pixelated photos to measure the change in distance with the examiner asked to look away during testing.
  • Intra and inter examiner reliability was assessed for evaluating the photos using interclass correlation and showed high reliability.
  • When lifting the leg from 0 to 30 degrees the left PSIS moved caudally and the right apparently moved cephalad.
  • When lifting the leg to 90 degrees both the left and right PSIS moved cephalad.
  • As a side note, a number of p-values are reported as 0.00. Statistical software packages such as SPSS have a rounding algorithm where the output may be p=0.00 but this is inaccurate and implies that there is no possibility of chance being a factor. A better way to report this would be p<0.01.
  • When considering their findings, the authors surmised that if the Gillet test was purely an evaluation of SI motion then the left SIs with movable and the right hypomobile. This they deemed implausible.
  • The authors postulated 4 hypotheses to explain their findings:
    • Asymmetric balancing strategies in left and right one-legged stance
    • Asymmetric hamstring tone
    • A pelvic compression effect
    • A clamping effect

Summary:

The findings of this study suggest that there may be other factors contributing to the findings of a Gillet test other than sacroiliac motion. This brings in to question the validity of the test.