Comparative analysis of measurement methods for forefoot varus reliability: A systematic review and meta-analysis

Abstract

Background: 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. Methods: 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. Results: 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). Conclusion: 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.