Knock‐knees: Identifying genu valgum and understanding its relationship to vitamin D deficiency in 18th to 19th century northern England

Abstract Genu valgum is a condition in which a person's knees angle inwards and touch one another creating a “knock‐kneed” appearance during life and potentially causing pain and walking difficulties. The most common cause of genu valgum is medial torsion of the proximal tibia, such that the lateral side becomes more weight bearing. It is considered a feature of vitamin D deficiency and many other pathological conditions. Currently, bioarchaeologists lack clear diagnostic criteria to identify genu valgum in skeletal remains, and it is therefore likely to be underreported. The aim of this study was to develop a method for diagnosing genu valgum and apply it to the analysis of adult skeletons from two 18th to 19th century skeletal collections from the North of England. Six individuals from Coach Lane and three from Fewston showed evidence of genu valgum. All of these individuals had other skeletal indicators of vitamin D deficiency. We discuss the relationship between vitamin D deficiency and genu valgum alongside other possible etiologies identified in the clinical literature. The individuals who presented with vitamin D deficiency related genu valgum in this study were diagnosed with adolescent rickets. Individuals who were vitamin D deficient in early childhood were more likely to be vitamin D deficient later in life and exhibit more advanced genu valgum. Genu valgum is often overlooked in the palaeopathological literature but its presence may be an important indicator of broader health problems.