Hallux valgus: Advances in weightbearing CT imaging and three-dimensional assessment of first ray deformity.

Abstract

Hallux valgus (HV) is a complex triplanar deformity of the first ray that has traditionally been evaluated using weightbearing radiographs. However, these two-dimensional techniques are limited in their ability to assess the rotational and multiplanar components of the deformity. Weightbearing computed tomography (WBCT) now enables a three-dimensional assessment of the foot under physiological load, providing new insights into first ray pathology. Recent WBCT-based studies have shown that HV is part of a global malalignment of the first ray, characterized by first metatarsal pronation, medial column instability, and progressive sesamoid subluxation. These findings have refined the understanding of pathomechanical mechanisms and have influenced surgical decision-making, particularly regarding the correction of rotational deformities and instability of the tarsometatarsal joint. Emerging semi-automated tools and artificial intelligence-based methods further improve the reproducibility and efficiency of WBCT analysis. New quantitative techniques such as distance mapping and coverage mapping allow detailed assessment of articular relationships. Overall, WBCT represents a paradigm shift toward a more accurate, standardized, and comprehensive evaluation of HV.