A bunion, technically termed Hallux Abducto Valgus, is a structural foot deformity involving the bones of the big toe (Hallux) and the 1st metatarsal and the joint involving these two bones.
The deformity is progressive and goes through 4 main stages. The first stage is hardly noticeable except for subtle changes on x-ray, through to the 4th stage where the big toe deviates right over pushing into and sometimes over or under-riding the second toe. There is also an associated bump at the side of the joint. There are a number of proposed risk factors or causes including foot posture, footwear, hereditary factors and associated disorders such as rheumatoid arthritis.
Pain associated with the bunion may be due to the joint degeneration and arthritic changes, inflammation and irritation of the surrounding soft tissue structures such as ligaments and tendons and Bursitis over the bony prominence on the side of the joint.
Bunion treatment by a podiatrist is generally aimed at reducing the speed at which the deformity progresses as the only option for complete repair and normalisation of the joint is surgery which is not always warranted or wanted.