Physiological in vitro sacroiliac joint motion: a study on three‐dimensional posterior pelvic ring kinematics

Abstract

The sacroiliac joint (SIJ) is a well-known source of low back and pelvic pain, of increasing interest for both conservative and surgical treatment. Alterations in the kinematics of the pelvis have been hypothesized as a major cause of SIJ-related pain. However, definitions of both the range and the extent of physiological movement are controversial, and there are no clear baseline data for pathological alterations. The present study combined a novel biomechanical setup allowing for physiological motion of the lumbosacral transition and pelvis without restricting the SIJ movement in vitro, combined with optical image correlation. Six fresh human pelvises (81 AE 10 years, three females, three males) were tested, with bodyweight-adapted loading applied to the fifth lumbar vertebra and both acetabula. Deformation at the lumbopelvises was determined computationally from three-dimensional image correlation data. Sacroiliac joint motion under the loading of 100% bodyweight primarily consisted of a z-axis rotation (0.16°) and an inferior translation of the sacrum relative to the ilium (0.32 mm). Sacroiliac joint flexion-extension rotations were minute (< 0.02°). Corresponding movements of the SIJ were found at the lumbosacral transition, with an anterior translation of L5 relative to the sacrum of À0.97 mm and an inferior translation of 0.11 mm, respectively. Moreover, a flexion of 1.82°was observed at the lumbosacral transition. Within the innominate bone and at the pubic symphysis, small complementary rotations were seen around a vertical axis, accounting for À0.10°and 0.11°, respectively. Other motions were minute and accompanied by large interindividual variation. The present study provides evidence of different SIJ motions than reported previously when exerted by physiological loading. Sacroiliac joint kinematics were in the sub-degree and sub-millimeter range, in line with previous in vivo and in vitro findings, largely limited to the sagittal rotation and an inferior translation of the sacrum relative to the ilium. This given physiological loading scenario underlines the relevance of the lumbosacral transition when considering the overall motion of the lumbopelvis, and how relatively little the other segments contribute to overall motion.

Finite element analysis of load transition on sacroiliac joint during bipedal walking

“…Iliac rotation relative to the sacrum was later named nutation and counter-nutation 19 , thought ambiguity exists as nutation was also named the combined rotation and translation movement of the sacrum relative to both innominate bones 27 . The above studies 4 , 11 , 28 – 30 have reported that the sacrum rotates approximately 2° on the sagittal plane, which seems to indicate such movement. Bruna-Rosso et al have shown the rotation of the sacrum with vector diagrams in FEM 24 .…”

“…In addition, the SIJ had small motion of less than 1 mm, and moved separately on the left and right SIJ. The range of the SIJ movements has been investigated with various methods; on patients with SIJ disorders 0.7 mm by Sturesson et al 4 , 0.7 mm by Jacob and Kissling 28 , and 0.3 mm by Sturesson et al 29 , on healthy individuals 0.47 mm by Kibsgård et al 30 , on cadavers 0.8 mm by Miller et al 31 , less than 1 mm by Takayama 5 and 0.3 mm by Hammer et al 11 , and on FEM 0.3 mm by Bruna-Rosso et al 24 . Our study showed that displacement of SIJ cartilage was ranged from 0.3 to 0.6 mm, which was similar to previous studies.…”

“…In this study, computer simulations were performed using finite element analysis during normal walking, resembling the five walking phases of a living body. The finite element model of the pelvis used in this experiment has reproduced the SIJ and the surrounding ligaments by previous anatomical studies [9][10][11][12][13] . In addition, this finite element model included both femora, and simulations can be performed with walking data.…”

Kinematics of the Lumbo–Pelvic Complex under Different Loading Conditions

“…In most cases, loads are applied in only one direction of motion [4,5]. These movements are often measured on the surface of the specimen using only few tactile displacement meters [4] or glued-on markers [2]. The underlying soft tissue can induce inaccuracies of measurement.…”

“…Further improvement of implant fixation requires knowledge about the load transfer from the spine to the hip region, which is, therefore, a major field of biomechanical investigation. However, studies in the literature usually investigated only single directional loadcases [2,4]. To deepen our understanding how these components interact during load transfer, the current study aims for identification the kinematics of the interacting bone segments under different loading conditions.…”