Exploring Femoral Neck-Shaft Angle Alterations in Post-Medieval Children with Vitamin D Deficiency Rickets.

The femoral neck-shaft angle (NSA) can adapt to the early onset of habitual but changeable loading behaviors, such as sitting, crawling, standing, and cruising behaviors, and the adoption of immature through to mature walking patterns. However, normal patterns of skeletal growth can be modified by underlying pathological conditions. Femoral head depression and neck angulation can occur during vitamin D deficiency rickets, but the pattern of NSA deformation occurring during the period of locomotor development in children with rickets has not been widely studied. This study aimed to broaden understanding of rickets beyond historical and bioarchaeological prevalence rates to explore the functional impacts of the condition on femoral development. Radiographs of 200 children from eighteenth-to nineteenth-century London (76 rickets, 124 non-rickets) were measured for femoral NSA. The results demonstrate notable differences in NSA in children with and without rickets, which vary depending on disease status, severity, and age at onset. Children under 2 years with severe and marked cases of active rickets typically presented a higher femoral NSA, which may be attributed to delayed development during this disease phase and/or limited or delayed activity, potentially exacerbated by pain, muscle weakness, and childcare practices. In contrast, children over the age of 1 year with healed rickets frequently displayed femoral neck deformation and reduced NSA likely linked to mechanical loading experienced during the deficiency. Importantly, defects in the proximal femur can develop during recovery from poor mineralization and endochondral defects and may exaggerate the appearance of femoral neck deformation during continued growth. [ABSTRACT FROM AUTHOR]