A Bunion is a first ray deformity where the 1st metatarsal shaft adducts medically. The result is a medial protrusion of the 1st metatarsal head. The primary cause is hypermobility of the 1st ray or a short 1st metatarsal which during propulsion of feet during gait results in excess pronation and the hallux then abducts at toe off phase of gait.
The condition has numerous causes, including hereditary factors, trauma, inappropriate footwear, joint diseases and arthropathies, short 1st metatarsal and structural leg length discrepancy where the longer leg over pronates to compensate for the discrepancy.
Hallux Abducto Valgus (Bunions) can progress to three stages, primary, secondary and Tertiary stages. The primary stage begins between 18-25 years and presents as a slight bump on the medial 'inner' aspect of the 1st MTPJ 'big toe joint'. The secondary stage occurs between 25-55 years of age. The 1st metatarsal head adducts 'turns inwards' and the hallux abducts 'turns outwards' causing pressure on the second digit. At this stage clawing the 2nd and 3rd digits occur which increase plantar underneath pressure of the transverse arch causing pain and callus formation. The tertiary stage is characterised by the complete overlapping of the hallux either over or under the 2nd and 3rd digits. As this takes place shoe fitting can be a problem and cause extreme pain. By the time the bunion has progressed to a tertiary level, conservative therapy might not help and often referral to a foot surgeon is recommended.
Treatment of a bunion depends on its progression and what stage it is at. Primary and secondary stages can be treated with custom made orthotics which basically increase arch support to reduce pressure on the big toe joint therefore slowing progression of deformity. Extra forefoot additions can also be used on the orthotics to reduce forefoot pressure and hence reduce pain. The tertiary stage requires surgical intervention. Additional modalities such as dry needling and joint manipulations can be used to reduce strain, eliminate scar tissue and provide pain relief.