Introduction: Non-specific chronic low back pain (NSCLBP) is a leading cause of disability and reduced quality of life, with multiple biomechanical factors contributing to its pathophysiology. Flatfoot (Pes Planus), as a structural abnormality, may play a role in the onset or exacerbation of this condition by altering the distribution of mechanical forces, increasing spinal stress, and inducing movement instability. This systematic review evaluates the existing evidence regarding the relationship between flatfoot and NSCLBP.

Methods: This study was conducted following the PRISMA guidelines. Articles published between 2004 and 2025 were searched in PubMed, Scopus, Medline, Embase, and Google Scholar using MeSH Terms. Studies were selected based on predefined inclusion and exclusion criteria, and their methodological quality was assessed using the Newcastle-Ottawa Scale (NOS) for cohort and case-control studies and the PEDro scale for randomized controlled trials (RCTs). A total of 11 eligible studies were analyzed.

Results: Findings indicated that flatfoot may contribute to increased severity and persistence of chronic low back pain by inducing kinematic alterations in the lower limb, increasing internal rotation of the knee and hip, and affecting spinal biomechanics. However, some studies did not confirm this association definitively, possibly due to methodological differences and confounding factors.

Conclusion: Flatfoot may be considered a potential risk factor for NSCLBP. Altered mechanical force distribution and movement patterns could lead to functional spinal instability and increased lumbar stress. Further studies employing advanced biomechanical assessment methods are required to better understand this relationship and develop targeted interventions.