- Bunion Basics
- For Doctors
Every day, we subject our feet to more physical stress than probably we realize. From daily walking to extreme sports, our feet are expected to last a lifetime of repeated pounding against the ground and complex movements over all terrains. The foot is another engineering wonder of our body.
A normal foot is made up of 26 specifically shaped bones, vs. only four for the entire leg. Every foot bone has good reasons for its being and they are connected and moved by more than 100 ligaments, muscles and tendons. Any slight deviation from normal at birth or by trauma can result in suboptimal function and possible problems afterwards.
Similarly, reshaping foot for esthetic purpose by break-n-shift normal bones unnecessarily may have functional implications. This basic but essential understanding is especially true for bunion surgeries.
Bunion is the protrusion on the side of big toe. This is just one of the many problems that can happen to the forefoot of what is medically called the "hallux valgus deformity complex" (Fig. 1).
Hallux valgus means outward tilting of the big toe. Other associated forefoot problems can be widening of the forefoot, clawing of the lesser toes, collapse of the longitudinal and transverse arches of the foot, painful metatarsal calluses under the forefoot (Fig. 2) and even a bunionette (baby/tailor’s bunion) on the side of the little toe.
Fig.1 Hallux Valgus deformity complex
Fig 2. Calluses
Bunion is mostly made up of the normal distal end of first metatarsal bone that has leaned away from its neighboring second metatarsal bone due to loosening of its supporting ligaments. Hence, contrary to popular belief, the main underlying reason for the development of the bunion deformity is not in the bone but ligaments. Since bunion is the result of destabilized bones, they may still be further displaced by stresses in future daily walking activities. Hence, bunion is a well-known progressive condition that can become worse, although its speed and final severity is individual.
Also contrary to popular belief, high-heel shoes are actually not the main cause for bunion deformity, rather female hormone estrogen and heredity are much more important links. Our own survey with HK Baptist University in 2008 of more than 1,000 adult Chinese women in Hong Kong showed that almost a third had some degree of bunion deformity. Of these sufferers, about 80% had rarely worn high-heel shoes at all, but more than 80% had a family history of bunions. Only a small number (<5%) of feet with bunions was found to be possibly mainly caused by high-heel shoes.
We see bunion deformity is mostly a female condition relating to their sexA hormones and also mostly a hereditary condition. Shoes do play a role but not as much as having been speculated among Chinese population.
|Total 1056 surveyed||395 (36.5%) had bunions||High heels (+)||High heels (-)|
|395 (36.5%) had bunions||100%||17%||83%|
|Family History (+)||88%||14%||74%|
|Family History (-)||12%||3%||9%|
|Survey study -conducted by the Center for Special Bunion Surgery and the Hong Kong Baptist University, as published in Foot and Ankle online journal 2010.|
The bunion condition can cause two distinct problems depending on its severity. The first and most common problem is the increasingly more painful bunion and bunionette bumps in wearing close-toe shoes. These pains are related to gradual widening of the forefoot that is caused by splaying / displacement of the loosened first metatarsal bone. The second commonest problem is related to deteriorating function of the big toe side of foot which happens to be the most important part of forefoot for propelling body forward in walking. When the normal function of big toe diminishes, the foot has to compensate somehow and the altered gait can gradually lead to many secondary problems such as clawing deformity of the lesser toes, painful calluses, collapse of foot arches and straining of leg and low back.
For women who would like to wear high-fashion and high-heel shoes can check if they have any family history of bunion deformity. With negative history, then frequent and long term high heels wearing may pose a small risk of bunion development. If there is a family history, then bunion gene(s) may have been passed on but not always, then high-heel, pointed and tight shoes may precipitate an earlier onset and accelerate the deterioration of a bunion deformity.