22 Sep Compromised feet: nature or nurture?
„When one’s feet hurt, one hurts all over.“ – Socrates
Structural disorders of the foot cause pain, mobility problems and decreased quality of life affecting over 60% of older adults (Dunn et al., 2004). Deformity of the great toe, specifically squashed in towards and even over the top of the lesser toes, is the most common disorder. Termed hallux valgus, it affects around 23% or 18-65 year-olds and over 36% of those over 65 years old (Nix et al., 2010). A correctly positioned great toe provides stability for the transfer of bodyweight in movement. A compromised toe position leads to excess foot roll, inward collapse at the knee, pain, injury and ultimately bunions.
Despite undisputed mechanical principles, and accepted laws of skeletal adaptation to imposed forces explaining the cause of deformity, and studies showing the link to years of wearing narrow shoes (Shine, 1965), recent papers still claim a genetic origin (Hannan et al., 2013). It is easy to criticise the conclusions of both studies based on their design, and the debate has continued. However, a new study with a powerful design has finally answered the nature-nurture dilemma (Munteanu et al., 2017).
Using a prospective study design (measures decided in advance), 74 pairs of identical twins (same genes) and 56 pairs of non-identical twins (different genes) were followed over time with hallux valgus and footwear use recorded over their lifespan. 27% of participants developed the great-toe deformity, but there was no evidence of a shared genetic factor. Instead, regularly wearing shoes with a restrictive toe box predicted development of the condition, with regular use increasing risk by almost three fold.
In summary, and in agreement with mechanical and biological laws, wearing narrow shoe-shaped shoes leads to great-toe deformity and shoe-shaped feet. Footwear habits can be passed down the generations, but not a predisposition for great-toe deformity. The solution to avoid or undo the problem, logically, is the use of anatomically-shaped shoes. Being nimble, begins with functional feet and functional feet begin with functional footwear.
Dr. Mick Wilkinson, PhD, MSc, BA (Hons)
Northumbria University, Newcastle, England
Senior Lecturer in Sport and Exercise Science & Department Ethics Lead
Dunn, J.E., Link, C.L., Felson, D.T., Crincoli, M.G., Keysor, J.J., McKinlay, J.B. (2004). Prevalence of foot and ankle conditions in a multi-ethnic community sample of older adults. American Journal of Epidemiology, 159, 491-498.
Hannan, M.T., Menz, H.B., Jordan, J.M., Cupples, A., Cheng, C-H., Hsu, Y-H. (2013). High heritability of hallux valgus and lesser toe deformities in adult men and women. Arthritis Care & Research, 65, 1515-1521.
Munteanu, S.E., Menz, H.B., Wark, J.D., Christie, J.J., Scurrah, K.J., Bui, M., Erbas., B., Hopper, J.L., Wluka, A.E. (2017). Hallux valgus, by nature or nurture? A twin study. Arthritis Care & Research. doi 10.1002/acr.23154.
Nix, S., Smith, M., Vicenzino, B. Prevalence of hallux valgus in the general population: a systematic review and meta-analysis. Journal of Foot and Ankle Research, 3, 21.
Shine, I.B. (1965). Incidence of hallux valgus in a partially shoe-wearing community. British Medical Journal, 1, 1648-1650.