Why do lesser toes deviate laterally in hallux valgus? A radiographic study

Area of Science:

• Orthopedic Surgery
• Radiology
• Podiatry

Background:

• Hallux valgus often presents with laterally deviated lesser toes, complicating treatment and potentially leading to recurrence.
• Ignoring lesser toe deviation in hallux valgus can result in suboptimal foot aesthetics and increased risk of surgical failure.

Purpose of the Study:

• To identify specific radiographic indicators associated with hallux valgus when lesser toes deviate laterally.
• To understand the relationship between lesser toe deviation and metatarsal alignment in hallux valgus patients.

Main Methods:

• Comparative analysis of weight-bearing anteroposterior foot radiographs from three groups: hallux valgus with lateral lesser toe deviation (L), hallux valgus with normal lesser toes (H), and normal feet (N).
• Utilized a 2D coordinate system to quantify foot shape and angular measurements, including hallux valgus angle, intermetatarsal angles, and metatarsus adductus.
• Calculated various angles and lengths from digitized radiographic points.

Main Results:

• Group L exhibited significantly wider 2-3 and 3-4 intermetatarsal angles compared to groups H and N.
• Patients with lateral lesser toe deviation showed larger hallux valgus angles, a more adducted first metatarsal, and divergent lateral splaying of the lesser metatarsals.
• The bases of the second, third, and fourth toes in group L were found to have shifted laterally from their respective metatarsal heads.

Conclusions:

• Increased 2-3 and 3-4 intermetatarsal angles are associated with lateral lesser toe deviation in hallux valgus.
• A larger hallux valgus angle, more adducted first metatarsal, and lateral splaying of lesser metatarsals are radiographic hallmarks of this complex foot deformity.