Eliane Celina Guadagnin

Purpose: The spine and hips are biomechanically interconnected, and disorders affecting both are often categorized under hip-spine syndrome. This study explores the link between pelvic motion impairments and hip functional characteristics, specifically hip strength and flexibility, in low back pain patients with increased contralateral pelvic drop and anterior tilt during gait. The hypothesis was that hip strength and flexibility would correlate with pelvic gait kinematics. Methods: This cross-sectional retrospective study analyzed previously collected data from a clinical motion analysis laboratory biomechanical database. Participants aged 18–65 years with acute or chronic low back pain and the ability to ambulate independently were included. Participants had been previously categorized into distinct gait profiles (P1: Flexed trunk; P2: Lumbar rectification; P3: Pelvic impairment; P4: Trunk extension and rotation; P5: Tight axial control) based on three-dimensional gait kinematics using machine learning algorithms. The current analysis examined intra-profile correlations between pelvic motion during gait (pelvic drop and anteversion) and clinical measures of hip function (hip abductor strength and hip flexor/extensor flexibility). Spearman’s rho was used to assess linear correlations and normalized mutual information was computed to explore non-linear associations. Statistical significance was set at p < 0.05. Results: No statistically significant correlations were found for profiles 3, 4, and 5 ( p > 0.05). Although significant correlations emerged within profiles 1 and 2, as well as when considering profiles 1–5 as a single group ( p < 0.05), these lacked clinical relevance due to low biomechanical plausibility. Conclusion: This study builds on previous literature on biokinetic profiles in low back pain and provides new insights into the associations related to hip–spine kinematics. There was no association between hip strength or flexibility and altered pelvic kinematics during gait in the Pelvic Impairment profile. These findings raise the possibility that the observed pelvic motion impairments may reflect associations other than primary deficits in the hip musculature, such as compensatory or neuromotor strategies, which warrant investigation in longitudinal studies.

Purpose The following study aimed to investigate the existence of different gait profiles in patients with low back pain (LBP) and assess their clinical characteristics. Methods This is a cross-sectional retrospective study that included individuals with chronic or acute LBP. Three-dimensional gait kinematics were assessed, including mean angles, range of motion (ROM), and coordination of the trunk and pelvis across three planes. An artificial intelligence algorithm was leveraged to identify distinct gait profiles using principal component analysis, self-organizing maps, and K-means clustering techniques. Clinical characteristics, such as demographics, hip and trunk passive ROM, and hip strength, were compared across profiles using the Kruskal-Wallis test with Bonferroni adjustment at a 5% significance level. Results 111 patients were analyzed (mean age 44.6; 56% females). Five distinct gait profiles were identified. Profile 1 (Flexed Trunk) was mainly characterized by an increased lateral trunk ROM and flexed trunk (4.1^o; 5.2^o; p < 0.05). Profile 2 (Lumbar Rectification), by trunk flexion and posterior pelvic tilt (3.4^o; 7.2^o; p < 0.05). Profile 3 (Pelvic Impairment Profile), by excessive pelvic ROM and maximum angle in the coronal plane (2.9^o and 11.1^o; p < 0.05) and pelvic anterior tilt (12.2^o; p < 0.05). Profile 4 (Trunk Extension and Excessive Rotation), by trunk extension, and excessive trunk axial ROM (-3.0^o; 7.1^o; p < 0.05). Profile 5 (Tight Axial Control), by a prominent pelvis-trunk in-phase component in the coronal and axial planes with pelvic predominance (20.2%; 45.6%; p < 0.001). Profiles 1 and 2 predominantly consisted of males with higher body mass (> 77.3%; >76.8 kg; p < 0.001), while profiles 3 and 4, females with lower body mass (> 86.2%; p < 0.001). Profile 4 displayed increased hip passive ROM, and profiles 1 and 5 decreased (p < 0.05). No significant differences were found in age, hip strength, and passive trunk ROM between profiles (p > 0.05). Conclusion Each of the five profiles identified reveals distinct kinematic and physical characteristics, providing meaningful insights into clinical implications, associated pathologies, anatomical structures at risk, and management.