Hallux valgus is a gradual deformity of the foot. The main cause is a complex mechanical deformity including rotation and medial displacement of the 1st metatarsal bone. The first metatarsiophalangeal joint is thus sublaxated and the first toe diverges outwards. The pressure created on the medial surface of the head of the 1st metatarsal, leads to inflammation of the soft tissues around (bursa) and bone hypertrophy, which forms into the bunion, one can see on the medial side of the foot. Gradually, arthritis is developed on the 1st metatarsiophalangeal joint, that presents with local pain, stiffness and skin erosions. The big toe moves further lateral, usually under or more rarely over the 2nd toe. For the 2nd toe to fit inside the shoe, it deforms into permanent flexion (hammer toe). The 2nd and 3rd metatarsals are overloaded and pain in the sole begins. It is therefore a complex deformity, that requires a combination of interventions.
Epidemiology: It is a common disease that is present – even in its milder forms – in 23-30% of adults between the ages 18 and 65, and in 36-38% of adults older than 65. It is more common in women.
Etiology: It is usually a hereditary deformity. Pes planovalgus (flat foot), tight Achilles tendon, hypermobility of the joints or the presence of systematic diseases (e.g. rheumatoid arthritis) have been linked with the disease. Tight shoes and high heels are also involved in the progression of the deformity.
Symptoms: Apart from the obvious deformity of the foot, patients also present with pain on the 1st metatarsal (bunion), on the 2nd toe – as it is in fixed flexion touching the roof of the shoes – and in the head of the 2nd and 3rd metatarsals. The 1st metatarsiophalangeal joint is dysfunctional, while weight bearing and wearing shoes is problematic.
Diagnosis: Plain radiographs are usually adequate for diagnosis and treatment planning.
Treatment: The use of braces has not been proven to prevent the deformity from occurring. They are only recommended if they relieve the symptoms or for hygiene reasons (to widen the interdigital space). The use of wide shoes decreases the pain, but incommodes proper walking. Custom made soles improve weight bearing but do not correct the deformity. Achille tendon stretching, and physiotherapy improve the mobility of the foot in a degree.
Surgical treatment: Various surgical methods can be used, depending on the degree of deformity.
In minor deformities, where bunion of the 1st metatarsal is the only deformity, surgical removal of the bunion with minor soft tissue intervention is adequate. The procedure can be performed with minimal invasive method, and the patient can go home within hours.
In more severe deformities, treatment includes more extensive intervention (mainly corrective osteotomies of the 1st metatarsal). Clinical examination and study of the radiographs with measurement of the angles between the bones of the foot, will decide the appropriate method to be used. A number of osteotomies (McBride, Chevron, Wilson, Scarf, Reverdin etc) can be used to correct the main deformity, which is the medial displacement of the 1st metatarsal.
When arthritis of the 1st metatarsiophalangeal joint co-exists arthrodesis of the joint or resection arthroplasty (Keller) is required. Additional interventions, such as partial resection of the Achilles tendon, hammer toe correction, tendon elongation, osteotomy of other metatarsals, may be needed.
The patient can stand up immediately post-operatively with the use of a special shoe.