Obesity is often thought to be a major risk factor in common childhood diseases such as Blount’s Disease and Slipped Upper Femoral Epiphysis (also known as a (SUFE). The Nationwide Children’s Hospital in Ohio recently published about the impact of obesity in children with the association between high BMI and malalignment of the knee1. The lead author, Sharon Bout-Tabku stated that “obese children begin with slightly higher varus [than non-obese children] that moves to greater valgus alignment in late puberty” in an interview with Lower Extremity Review Magazine, May 2015. There has also been an association suggested between low Vitamin D levels and a high BMI where tibial bowing is observed or in more serious conditions such as Blount’s disease2.

Physiotherapy (physical therapy) or podiatry students aspiring to work with children are often advised to follow evidence based practice, and shy away from over treatment. This is especially important when assessing developmental biomechanics and orthopaedic lower limb postures. Common referrals from the local medical practitioner may state “bowed legs” in a one year old or “knock knees” in a 4 year old. This is commonly a typical presentation for age osseous development. What may be missed though, is when those postural measurements are at the extreme ends of the normative bell curve and BMI is factored in, we could be dealing with the development of serious pathology. Could we be overlooking some cases?

Recently an 18-month-old active toddler stormed into my clinical room. His parents were concerned regarding the intoeing (with associated tibial bowing) and tripping. This was a very active but tall and heavy set boy with a Sudanese heritage. The family migrated to Australia 10 years ago and commented that it was much cooler and had far less sunshine than they had expected. The child started walking at 10 months of age and his mother reported her Vitamin D levels were low during pregnancy. The child now weighed 14.6kgs (>3SD of weight for age WHO) with a BMI of 22 (>3SD – WHO chart). The child’s Intercondylar distance (Figure 1) was about 4cm (>2SD) and his thigh foot angle -14 (left) and -16 degrees (right) as measured (Figure 2).

Figure 1: Intercondylar distance courtesy of Toes2Hip iPhone App

Figure 2: Thigh foot angle courtesy of Toes2Hip iPhone App

This child strutted out of my office with a referral back to his general practitioner for their opinion regarding an orthopaedic, endocrinology sand dietetics referrals. I kept up with the latest research and hopefully this has made a difference in this toddlers developmental pathway.

The role of Vitamin D, hypertension and obesity in pathology such as Blount’s Disease, tibial bowing in the younger children and SUFE’s is still being explored3. What I take away from this is that different size cohorts and population groups means there is more to learn and understand.

Take home points

  • Know your red flags and normal range of motion for different ages – The Toes2Hip iPhone app can assist you.
  • If your assessment has raised red flags, please refer to a medical practitioner
  • Articles are for reference in the members section.


  1. Bout-Tabaku S, Shults J, Zemel BS, et al. Obesity is associated with greater valgus knee alignment in pubertal children, and higher body mass index is associated with greater variability in knee alignment in girls. J Rheumatol 2015;42(1):126-133.
  2. Montgomery CO, Young KL, Austen M, Jo CH, Blasier RD, Ilyas M. . Increased risk of Blount disease in obese children and adolescents with vitamin D deficiency. J Pediatr Orthop. 2010 Dec;30(8):879-82
  3. Taussig MD. (2015) Prevalence of Hypertension in Pediatric Tibia Vara and Slipped Capital Femoral Epiphysis. J Pediatr Orthop