Data extraction of the included studies.

Low back pain (LBP) is a prevalent and costly condition globally, prompting the need to identify risk factors for effective management. Lower extremity misalignment plays a crucial role in the incidence of LBP. Therefore, we aimed to investigate the current evidence on a link between lower limb alignment and LBP, enhancing the understanding of this relationship. We searched four databases, including PubMed, Embase, Web of Science, and Scopus, up to September 2024. Inclusion criteria encompassed studies related to LBP and lower limb alignment, with eligible study types including case-control, cohort, and cross-sectional studies, all written in English. Two authors independently screened and assessed the methodological quality of the retrieved papers using the Downs and Black quality assessment checklist. Data of interest including study design, age, sample size, cases, association, and P-value were extracted from the included studies. Mean differences and 95% confidence intervals (CI) were calculated with random effects model in RevMan version 5.4. Thirteen articles evaluating lower limb alignment in individuals with LBP were included (102,359 participants in total). The meta-analysis results demonstrated that increased pronation with strong evidence(p = 0.02), increased hip internal rotation with moderate evidence, and increased knee internal rotation with limited evidence are associated with an increased risk of LBP. Overall, while some studies supported a relationship between lower limb alignment and LBP, the heterogeneity of study designs and methodological limitations hindered drawing a definitive conclusion. Future research should emphasize prospective cohort studies, incorporating objective measures of lower extremity alignment and standardized outcome measures.

下腰痛（Low back pain, LBP）是全球范围内高发且造成沉重经济负担的病症，亟需明确其危险因素以实现有效临床管理。下肢力线异常在下腰痛的发病机制中发挥关键作用。因此，本研究旨在梳理当前关于下肢力线与下腰痛关联的研究证据，以深化对二者关系的认知。本研究检索了截至2024年9月的PubMed、Embase、Web of Science及Scopus四大数据库。纳入标准为涉及下腰痛与下肢力线的研究，符合要求的研究类型包括病例对照研究（case-control study）、队列研究（cohort study）及横断面研究（cross-sectional study），且所有研究均以英文发表。由两名研究者独立对检索获得的文献进行筛选，并采用Downs和Black质量评价量表评估其方法学质量。从纳入的研究中提取核心研究数据，包括研究设计、受试者年龄、样本量、病例数、关联效应及P值。采用RevMan 5.4版本软件中的随机效应模型（random effects model）计算均数差（mean difference, MD）及95%置信区间（confidence interval, CI）。最终纳入13篇评估下腰痛患者下肢力线的文献，累计纳入受试者102359名。本荟萃分析（meta-analysis）结果显示，足旋前程度增加（证据等级为强，p=0.02）、髋关节内旋角度增加（证据等级为中等）以及膝关节内旋角度增加（证据等级为有限）均与下腰痛发病风险升高存在关联。综合来看，尽管部分研究证实了下肢力线与下腰痛之间存在关联，但研究设计的异质性及方法学局限性使得目前无法得出确定性结论。未来研究应优先开展前瞻性队列研究，采用客观的下肢力线测量手段及标准化结局评价指标。