Forefoot Varus is characterized by inversion of the metatarsal heads relative to the calcaneal bisector. It is present in 83.67 % of cases and contributes to overpronation and related foot/knee/hip pathologies. Despite multiple assessment methods, their reliability remains unclear. This systematic review evaluates the most reliable measurement technique. This systematic review and meta-analysis selected studies from several databases: PubMed, Scopus, Cochrane Library, Web of Science, and PEDro. The search strategies included keywords such as "forefoot", "varus forefoot", "supinatus forefoot", "varus alignment of the foot-ankle complex" or "shank-forefoot" and their combinations were used. Studies published in the English, French, and Spanish language were included until July 4th, 2024. After identifying the articles, the methodological quality was assessed using the GRRAS checklist. The reported results were intra-class correlation coefficient, influence on gait, biomechanical factors, and pathologies. This meta-analysis of 13 studies (n = 1238) found excellent intra-observer reliability for forefoot varus measurements (pooled ICC = 0.92, 95 %CI 0.89-0.94), with significant inter-observer differences (Q = 38.7, p < 0.001): goniometry showed ICCs of 0.56-0.68 (isolated forefoot or JIG shank-forefoot alignment goniometer) versus 0.81-0.91 (shank-forefoot alignment), while photogrammetry maintained consistently higher reliability (ICCs 0.90-0.93). Photogrammetry and goniometry demonstrated moderate correlation between methods (r = 0.71, 95 %CI 0.63-0.78) across predominantly healthy populations studies (76.9 %, mean age 31.5 ± 15.2 years). Photogrammetric and shank-forefoot alignment methods demonstrate excellent reliability (ICC >0.90) for forefoot varus assessment, while traditional goniometry shows inconsistent results. Standardized protocols are recommended to ensure cross-study comparability.

Introduction: Forefoot varus prevalence varies widely (8.6–83.67%) and may be attributable to the lack of a gold standard. Clinical methods are limited by subjective positioning and landmark variability. This study established a reliable radiographic reference using a dual-method approach. Methods: Following GRRAS guidelines, 70 lower limbs (35 participants) were evaluated using consecutive sampling. Three blinded investigators performed the measurements. Reliability was assessed throughout inter-rater (30-min interval) and intra-rater (≥30-day washout) sessions. Dual radiographic methods (metallic nail vs. radiopaque markers) were compared against standardized goniometry. The analysis included ICC(2,1) and ICC(3,1), SEM, MDC₉₅, and Bland–Altman plots, with a significance threshold of p < 0.005. A sensitivity analysis using one randomly selected limb per participant (n = 35) confirmed the robustness of the findings. Results: Participants (mean age 32.77 ± 10.8 years, 54% female) had a mean forefoot varus of 15.53 ± 7.35°, with a prevalence of 97.1% (≥0°). Goniometric inter-rater reliability was excellent (ICC = 0.987, MDC₉₅ = 1.382°). The marker-based radiographic method demonstrated excellent intra-rater reliability (ICC = 0.906, MDC₉₅ = 1.129°). The agreement between goniometry and marker-based radiography was strong (ICC = 0.898). All analyses surpassed the p < 0.005 threshold. No significant differences were found for sex or laterality (p > 0.005). Conclusions: Marker-based radiography provides a validated reference standard with excellent reliability. Standardized clinical goniometry demonstrated excellent reliability and strong radiographic agreement, making it appropriate for routine assessment (changes > 1.4° represent true structural change). Radiography should be reserved for research or definitive structural confirmation. Limitations include the lack of inter-reader radiographic reproducibility assessment and limited generalizability to young adults (mean age 33 years) with predominantly forefoot varus alignment.