Causes of hallux valgus

Several reasons ? 

While congenital deformity is the first culprit, it cannot be blamed for all the damage. 

Traumatic injuries (crushing, fractures), rheumatic diseases (rheumatoid polyarthritis, ankylosing spondylitis) deform the joints in a general way and the big toe is no exception. 

Does the position of the foot when walking have an influence? The mechanical cause is indeed a very favourable factor and all the more so if the shoe is very narrow since it grips the whole forefoot.

Let's look at this last point in more detail. The joint of the big toe is where the foot is strongly supported when walking, which is why it is bigger than the others. The extra bones (sesamoid bones) located just underneath strengthen the support point. As a result, the foot has a high degree of stability and mobility. When walking, movement of the back of the foot will have a direct influence on the forefoot. The movement needs to be precisely aligned to respect the physiology of the musculoskeletal system. A foot which sags too much inwards (also called valgus) will overload the internal area, i.e. the first metatarsal, and the joint will suffer. When it no longer functions properly, it is the other toes which will be stressed. These are smaller with joints that are more interlocked, which makes them less mobile and have less ability to function. Skin suffering (calluses, corns...) but also internal inflammation of the foot develops and this contributes to a poor walking position.