Plantar Pressure Changes and Their Relationships with Low Back Pain during Pregnancy Using Instrumented Insoles

Abstract

Low back pain affects around 50% of pregnant women and presents significant morbidity and persistence for years in 20% of postpartum women who report that pain. Numerous studies have documented gait alterations during pregnancy and postpartum. Therefore, an analysis of the relationship between certain gait parameters and low back pain was attempted using low-cost validated instrumented insoles. This work presents a longitudinal cohort study carried out during routine gynecological follow-up visits in the first, second, and third trimesters of pregnancy at an Obstetrics and Gynecology Service. Sample size was 62. Plantar pressure data were collected with specially designed instrumented insoles containing four force sensors to measure peak pressure, center of pressure, and stance phase time in each foot and in each pregnancy trimester. The analysis was carried out on a two-dimensional level, simultaneously considering the data from both feet using Hotelling’s T2 test. This longitudinal study detected relationships between certain gait parameter changes and low back pain during pregnancy. It revealed a cyclic tendency of low back pain prevalence with a maximum in the second trimester and a decrease in the third trimester, which was correlated with alterations of the pregnant gait: excessive foot pronation and rearfoot pressure increase.

Assessment of COP characteristics and force-time changes during walking in the third trimester of pregnancy

“…This finding is valid for both groups, but it is statistically significant for the experimental group in comparison of the pre/post measurements. Generally, many published studies indicate that medially shifted COP, thus pronating tendency is observed during pregnancy (Martínez-Martí et al, 2019;Mitternacht, Klement & Lampe, 2013;Vico Pardo et al, 2018). Also, similar studies show that foot pronation is a kinematic effect of gestation.…”

“…So, it could be that wearing these orthopaedic shoes causes changes in COP trajectory so that feet are more in supination during walking. This could bring positive health aspects for legs, because increased pronation of the foot results in internal rotation of the tibia caused by the increased calcaneal eversion angle, which can lead to discomfort, back pain or pain in other parts of the lower extremities during pregnancy (Martínez-Martí et al, 2019;Anselmo, Love, Tango & Robinson, 2017). The length of COP is changed during the third trimester of pregnancy (Bertuit, Leyh, Rooze & Feipel, 2017), but we can register little difference between groups, where unlike the control group, women wearing orthopaedic shoes showed a tiny extension of COP trajectory, statistically significant only for the left foot (p=0.04).…”

Sensor Technologies to Manage the Physiological Traits of Chronic Pain: A Review

“…The analysis of gait has also been related to pain [270]. A study during pregnancy and postpartum with pressure sensors located in instrumented foot insoles correlated the prevalence of low back pain with alterations in the gait: increased pressure in the hindfoot and excessive pronation [270].…”

“…More studies are needed to analyze the characteristics of movements during gait or posture and their correlation with pain. These studies can be used to design exercise programs for preventive treatment and pain rehabilitation [270].…”