What actually drives bunions, and why the toe box matters as much as the heel

A systematic review and meta-analysis pooled 23 observational studies to work out what is actually associated with hallux valgus, rather than what we assume. It followed PRISMA, searched five databases through November 2025, and reported each factor as an odds ratio where two or more studies measured it.

Eleven factors came out independently associated with bunions. In order of strength: female sex (OR 2.57), foot pain (OR 2.36), narrow-toed shoes (OR 2.25), knee pain (OR 2.04), scoliosis (OR 1.84), high-heeled shoes (OR 1.65), osteoporosis (OR 1.50), knee osteoarthritis (OR 1.47), history of stroke (OR 1.26), flatfoot (OR 1.19) and age (OR 1.11). BMI and heart problems showed no significant association.

Look at where the two footwear factors landed: narrow-toed shoes ranked above high heels on risk. Two caveats keep that honest. The confidence intervals overlap (1.64 to 3.07 for narrow toes, 1.27 to 2.15 for heels), so the two are not cleanly separated, and in practice they travel together anyway, since most heeled shoes also taper to a narrow front. The fair reading is that footwear shape matters and toe-box width is at least as important as heel height, not that one clearly beats the other.

This gives you a better bunion conversation than the usual one. Patients arrive believing heels caused it, or that it is purely genetic. The honest answer is that it is multifactorial, and that the single most modifiable mechanical factor is shoe shape at the forefoot, not heel height. A wide, deep toe box is the advice that actually maps to the evidence.

It also reframes who you watch. Female sex, age and a history of foot pain raise the odds, and so do knee pain and knee osteoarthritis, which is a neat reminder that the foot and the knee travel together. Flatfoot is in the list too, modestly. None of these are things a single insole fixes, but together they tell you which patients to counsel early on footwear and load, before the deformity is fixed and painful.

The clinical line that lands: we cannot change your sex or your age, but we can change what your forefoot is squeezed into every day, and that is one of the biggest levers we have.

Bunions are multifactorial, but footwear still matters, and toe-box width is at least as important as heel height. Counsel on width first, heel second.

https://pubmed.ncbi.nlm.nih.gov/42265673/