Relationship between bilateral symmetry of foot posture and lower limb musculoskeletal injuries among workers engaged in physically demanding occupations: A cross-sectional investigation

Even though the link between foot posture and lower-extremity injuries remains controversial, there has been little research focus on bilateral foot symmetry. This study evaluated the correlation between bilateral symmetry in foot posture and lower extremity musculoskeletal injuries among workers in physically intensive occupations. A total of 248 participants with physically demanding roles were enrolled. Historical data on lower-limb musculoskeletal injuries were obtained through a review of medical records, supplemented by results from on-site consultations. The foot arch index (AI) was quantitatively measured using a 3D laser foot scanner, and foot posture was evaluated using the foot posture index-6 (FPI-6). The participants were categorized into subgroups based on bilateral symmetry assessments of their feet. Logistic regression analyses were performed for statistical comparisons after adjusting for potential confounding factors. The results indicate that abnormalities in foot posture and arch, assessed using the FPI-6 and AI, were identified in 42.3 ​% and 47.2 ​% of participants, respectively, with 20.9 ​% and 16.5 ​% demonstrating bilateral asymmetry in these parameters. When comparing bilateral and unilateral foot protonation with bilaterally normal feet, the risk adjustments revealed differences of 2.274 (95 ​% CI: 1.094-4.729, <i>P</i> ​= ​0.028) and 2.751 (95 ​% CI: 1.222-6.191, <i>P</i> ​= ​0.015), respectively. Furthermore, the risk adjustment for age, BMI, smoking status, physical training years, training time, training frequency, warm-up before training, relaxation after training, MIS prevention, and treatment learning for unilateral flatfoot relative to bilateral normal feet was 3.197 (95 ​% CI:1.235-8.279, <i>P</i> ​= ​0.017). This study demonstrates that workers in physically demanding occupations who exhibit unilateral foot protonation or unilateral flatfoot are at an increased risk of lower-extremity musculoskeletal injuries.