What is Hallux Valgus?
Hallux valgus, commonly known as a bunion, is a three-dimensional forefoot deformity characterized by lateral (fibular) deviation of the great toe combined with medial (varus) deviation of the first metatarsal bone (metatarsus primus varus), often accompanied by pronation of the hallux and medial soft-tissue enlargement over the first metatarsal head. 1, 2
Epidemiology and Risk Factors
Hallux valgus is the most common pathologic condition affecting the great toe and one of the most frequent forefoot deformities, with a prevalence of 23% in adults aged 18-65 years and 36% in those over 65 years. 1, 3
Women are disproportionately affected with a female-to-male ratio of 9:1, likely due to both biomechanical factors (joint laxity/instability) and restrictive footwear. 2, 4
The deformity typically begins between ages 30-60 years. 1
Risk factors include female gender, age, restrictive footwear, and hereditary predisposition. 4
Clinical Presentation and Associated Deformities
The deformity creates a medial prominence (bunion) at the first metatarsal head that can cause pain from shoe pressure and restrict mobility. 1
Hallux valgus frequently coexists with other foot deformities including splay foot, metatarsal adductus, equinus contracture, hammertoe deformity, and pes planus (flatfoot). 5, 4
When the hallux crosses over the second toe, it is termed hallux valgus superductus; when it moves under the second toe, it is termed hallux valgus subductus. 5
Mechanical pressure on the pseudoexostosis can result in bunion formation and possibly fistulization. 5
Overloading of the second through fourth metatarsal heads may cause midfoot pain, and increased load can deform the second through fifth toes into hammer or claw toes. 5
Differential Diagnosis
Hallux rigidus (degenerative arthritis of the first metatarsophalangeal joint) is the second most common cause of pain in this joint and must be differentiated from hallux valgus. 1
A combination of hallux valgus and hallux rigidus is not uncommon. 1
Diagnostic Approach
Hallux valgus is typically identifiable by physical examination alone. 1
Weight-bearing radiographs of the entire foot are essential for assessing deformity severity and treatment planning, including anteroposterior, lateral, and oblique views. 5, 3
The anteroposterior view allows measurement of the hallux valgus angle and the intermetatarsal angle (between rays 1 and 2). 5
Lateral films assess the longitudinal arch and stability of the first tarsometatarsal articulation. 5
Oblique views permit evaluation of metatarsophalangeal joint arthritis extent. 5
Clinical Context for PAD Patients
Hallux valgus (bunions) is specifically identified as a foot deformity that places patients with peripheral artery disease at moderate to high risk for foot ulcer development. 6
Patients with PAD and foot deformities including hallux valgus should be referred to a podiatrist for further evaluation and care. 6
Therapeutic footwear recommended by a specialist can prevent many complications in at-risk patients by reducing plantar pressure and ensuring proper fit. 6