Acute systematic and variable postural adaptations induced by an orthopaedic shoe lift in control subjects

Abstract

A small leg length inequality, either true or functional, can be implicated in the pathogenesis of numerous spinal disorders. The correction of a leg length inequality with the goal of treating a spinal pathology is often achieved with the use of a shoe lift. Little research has focused on the impact of this correction on the three-dimensional (3D) postural organisation. The goal of this study is to quantify in control subjects the 3D postural changes to the pelvis, trunk, scapular belt and head, induced by a shoe lift. The postural geometry of 20 female subjects (X = 22, sigma = 1.2) was evaluated using a motion analysis system for three randomised conditions: control, and right and left shoe lift. Acute postural adaptations were noted for all subjects, principally manifested through the tilt of the pelvis, asymmetric version of the left and right iliac bones, and a lateral shift of the pelvis and scapular belt. The difference in the version of the right and left iliac bones was positively associated with the pelvic tilt. Postural adaptations were noted to vary between subjects for rotation and postero-anterior shift of the pelvis and scapular belt. No notable differences between conditions were noted in the estimation of kyphosis and lordosis. The observed systematic and variable postural adaptations noted in the presence of a shoe lift reflects the unique constraints of the musculoskeletal system. This suggests that the global impact of a shoe lift on a patient's posture should also be considered during treatment. This study provides a basis for comparison of future research involving pathological populations.

Effect of simulating leg length inequality on pelvic torsion and trunk mobility

“…3). This finding agrees with the results of other studies [19][20][21]. Pitkin and Pheasant [19] used a large lift (38 mm) and thereby induced relative anterior rotation of the innominate on the side opposite the lift as well as other effects on the pelvis and lumbar spine that they observed to be similar to a typical functional scoliosis.…”

“…Cummings et al [20] examined the effects of lifts ranging in height from 6 to 22 mm in subjects with leg length inequalities less than 4 mm and found relative anterior rotation of the contralateral innominate, to a degree proportional to the height of the lift. Beaudoin et al [21] used a 15-mm lift and likewise found relative anterior rotation of the contralateral innominate. The lifts in the present study ranged in height from 15 to 24 mm.…”

“…1), does not necessarily reflect lateral sacral tilt [17], in part because of accompanying pelvic torsion (Fig. 3) [19][20][21]. A clinician would thus be naïve to believe that a given difference in height between the iliac crests directly reflects a leg length inequality of the same magnitude.…”

Emerging Technology and Analytical Techniques for the Clinical Assessment of Scoliosis

“…The terms and measures that have been adopted to describe the position and orientation of the pelvis are quite extensive, and specific to the sacrum, iliac bones and pelvis [34,36,38,[42][43][44][45]. The anatomical landmarks that provide the point of reference to describe the pelvis include: Anterior-Superior Iliac Spines (ASIS), Posterior-Superior Iliac Spines (PSIS), Superior Lateral Border of the Iliac Crests, and the Sacral Plateau [34,36,38,[42][43][44][45].…”

The relationship between pelvic torsion and anatomical leg length inequality: a review of the literature

“…In 1999, Beaudoin et al 22 used video cameras and reflective markings to determine various postural responses to the placement of a 15-mm heel lift, under each leg sequentially, in 20 asymptomatic females, scoliotics excluded. In this carefully executed study, there was a very tight correlation between leg elevation and innominate rotation.…”